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Premium member Presentation Transcript Paediatric anaesthesia: Paediatric anaesthesia Moderator: DR ARATHI Presentor : DR KHUSHBU GOELchildren are not small adults: children are not small adults special anatomy adaptive physiology developmental pharmocology Congenital or acquired pathologyterminology: terminology Newborn: first 24 hours Neonates – a baby within 44 weeks of age from the date of conception/ 28 days postnatal Infants – a child of up to 12 months of age Toddler-1-3yr Small children:4-12yr Child – 1 to 12 yrs Adolescent – 13 to 16 yrs The differences between paediatric and adult anaesthetic practice are reduced as the patients become oldercns: cns Soft & pliable cranium Non fused sutures 2 open fontannelle : ant font close by 18 months Post fontanelle close by 6-9 month at brain/ tbw Birth 10% 6mth 20% 1 yr 30% Poorly developed cerebral cortex, incomplete myelination till 2yr age cerebral vessels in the preterm infant are fragile . prone to IVH (concern during awake laryngoscopy & intubation of neonates)Cns ctd: Cns ctd Predominant constituent in neonatal brain is water- decreses with age decreased partition coffiecient & decreased solubility of inhalational agent in neonates--- -more rapid washin washout of Inh agent -altered requirement for inh agents BBB is poorly formed. Drugs such as barbiturates, opioids, antibiotics and bilirubin cross the BBB easily causing a prolonged and variable duration of action .PowerPoint Presentation: Perception of noxious stimuli present as early as 6 wk of gestation Rxn to pain is generalised & localisation starts at 3-10 mths Response to o2 co2 is attenuatedRs-transition: Rs -transition System develops rapidly during last trimester During fetal life it is filled with ultrafiltrate of plasma Gas exchange taken care by placenta By 24wks- surfactant precursor by 28wks-surfactant Within a minute of clamping umblical cord-neonate take first breath with resp pressure of -70cmh2o-recruiting alveoli Within 10-20mins neonatal frc n pulm b flow establishesRs cntd: Rs cntd Absence of adequate surfactant leads to Collapse of alveoli Maldistribution of ventilation Impaired gas exchange Decrease compliance Increase work of breathing respiratory distress syndrome ( RDS)Factors prevent hypoxia perintaly: Factors prevent hypoxia perintaly Fetal hb At 36wk gestation-90-95% Birth-75-80% 6mths-negligible High hb & hct At birth-18-19g/dl By 2-3mths of age—9-11g/dl(physiological anaemia Greater bv-80ml/kg at birthRespiratory & airway: Respiratory & airway Large head/ prominent occiput Small neck / poor muscle control Retrognathic chin/ obtuse angle of jaw Narrow nares(50 % of airway resistance is from the nasal passages .) obligatory nasal breathers( can b converted to oral breathing in c/o nasal obstruction after 5 mths Relatively large tongue nOn ossified palate Epiglottis- omega shaped, stubby base, project posteriorly at 45* to base of tongue (adult-15-20*) thus it should be lifted during laryngoscopyPowerPoint Presentation: Glottis:more anterior & more cephalad full term-c4 preterm infant-c3 3yrs- c4-c5 adult- c6 V cords are anterior slanting Subglottis - funnel shaped/narrowest part- cricoid ring/ achilles heel Uncffed tube in less than 6yr childPowerPoint Presentation: Tracheal length 2-5cm, supportedd by non calcified tracheal rings(compliant) Horizontally place pliable ribs Immature n weak intercostal muscles Sternum n thoracic cage is soft n more compliant-low frc Diaphragm placed high up premature neonate mature Diaphragm type1 10% 25-30% 55%PowerPoint Presentation: Airway diameter small & compliant Alveoli 20-50million (adult-300) Alveoli increases in size n no upto 8 yr of age Atelectasis common-underdeveloped alveoli -less surfactant -compliant chest wall Minute ventilation is rate dependant as there is little means to increase tidal volumePowerPoint Presentation: closing volume is larger than the FRC until 6-8 years of age-causes an increased tendency for airway closure at end expiration. Thus would benefit from a higher RR and the use of PEEP. CPAP during spontaneous ventilation improves oxygenation and decreases the work of breathing . NEONATE ADULT MV:FRC 5:1 2:1 Less oxygen reservePowerPoint Presentation: Apnoeas are common in premature infant n significant if they last longer than 15 seconds and are associated with desaturation or bradycardia . Caffeine 10-20 mg/kg oral or IV given peri -operatively may be useful Control of ventilation; Immature (Respond less to hypercapnia ) During first 3 weeks- vent response to hypoxia depends on temp Normothermic - biphasic response Hypothermic-hypoventilationthermoregulation: thermoregulation Babies and infants have a large surface area to weight ratio with minimal subcutaneous fat. They have poorly developed shivering, sweating and vasoconstriction mechanisms. Brown fat (located in small amounts around the scapulae, the mediastinum, the kidneys and adrenal glands) metabolism is required for non-shivering thermogenesis. It comprises 2-6% of neonatal body weight. More oxygen is required for the metabolism of these brown fat stores.n b fat response lost under anaesthesiaPowerPoint Presentation: Heat lost during anaesthesia is mostly via radiation but may also be lost by conduction, convection and evaporation. The optimal ambient temperature to prevent heat loss is 34ºC for the premature infant, 32ºC for neonates and 28ºC in adolescents and adults. Low body temperature causes respiratory depression, acidosis, decreased cardiac output, increases the duration of action of drugs, decreases platelet function and increases the risk of infection.Fetal circulation: Fetal circulationFetal circulation: Fetal circulation Oxygenated blood leaves the placenta in the umbilical vein Umbilical vein blood joins blood from the viscera in the inferior vena cava. Approximately half of the inferior vena cava flow passes through the foramen ovale to the left atrium, where it mixes with a small amount of pulmonary venous blood, and this relatively well-oxygenated blood supplies the heart and brain by way of the ascending aorta. The other half of the inferior vena cava stream mixes with superior vena cava blood and enters the right ventricle . Because the pulmonary arterioles are constricted, most of the blood in the main pulmonary artery flows through the ductus arteriosus (DA) so the descending aorta's blood has less oxygen than does blood in the ascending aorta.High PVR IN PULM ARTERIES: High PVR IN PULM ARTERIES Lung is filled with 20-30ml/kg of isotonic fluid(amniotic fluid) Alveoli are collapsed,bv are compressed Relatively low pao2&ph of blood in vessels—leads to vasoconstrictionChanges at birth: Changes at birth Placenta removed from circulation Portal bp falls– svr increases– systemic bp increases– LAP>RAP( foramen ovale closes) With first breath:--air enters alveoli- luid shift into pulmonary interstitial space & thence into intravascular space O2 tension increses,co2 decreses —PVR decreases(takes3-4 days to come to n)– increase PBF—increase pao2-wn it reaches 50mmhg-physiological closure of DA3 shunts: 3 shunts Foramen ovale - functional closure at birth Anatomical closure-6wks Ductus venosus - Func clos-1 st week Anatomical-2-3mths Remnant- ligamentum venosum Ductus arteriosus Fibrous closur-10-15hrs May remain open upto 4wksPowerPoint Presentation: May remain open due to(PDA) increase pge2, decrease calcium, decrese glucose, increased pulm artery pressureFlip flop circulation: Flip flop circulation Neonates a re vulnerable to flip flop circulation in first few wks of life i.e going from adult type to feta type circulation Factors– hypoxia/ acidosis/hypothermia/ hypocalcemia / overhydrationResponse of neonates to hypoxia: Response of neonates to hypoxia Pulmonary vasoconstriction(can result to opening of FO,DA) Systemic vasoconstriction( UNLIKE ADULTS) Bradycardia Decrease Cadiac outputAt birth: At birth RV muscular mass>LV muscular mass(RAD) 30% less contractile tissue in neonate’s myocardium compared to adults Myofibril element are less fewer & less organised Less mature sarcoplasmic reticulum—less ca -ATP activity- less contractility(more ependant on exogenous calcium) More connective tissue thus less compiant ventricles- ability to increase SV is less C.o - is mainly HR dependantCvs ctd: Cvs ctd First 3 months- parasympathetic dominance- low afterload Resting CO/KGWT is much higher than adult to meet high metabolic demand Co-at birth-350-400ml/kg/min at 1wk- 150-200ml/kg/min adult- 70ml/kg/minrenal: renal In utero- fetal waste material removed by placenta& fetal kidneys are passive- less RBF, less GFR Kidneys receive only 3% co (25% adult) cz Low systemic art pressure High renal vascular resistance Low permiabilty of glomerular cappilaries Small size/ no of g cappilaries GFR at birth-20ml/min/1.73cm2 2wks- doubles 2yrs- adult levelPowerPoint Presentation: Tubular reabsorption is pooor- inability to concen urine Inability to conserve water-tolerate fluid restriction poorly Inabilty to excrete large amt of h2o-tolerate overload of fluid poorly Neonate is vol dependant & vol intolerantHepatic & metabolic physiology: Hepatic & metabolic physiology Most enzymes system are present but not induced at birth Different hepatic metabolic pathways mature at different pathways Phase1 rxns at birth50%-equals adult level by 6 mths Phase2- matures by 1 yr of life Decrease level of albumin- mot drug remain in free form Vit k dependant clotting factors is20-60% in neonate- exogenous vit k requiredHepatic & metabolic physio: Hepatic & metabolic physio Glucose metabolism : Facilitated diffusion across placenta maintains the fetal blood glucose value at about two-thirds the maternal value. In the later stages of fetal development there is a build-up of glycogen stores in the liver, skeletal and cardiac muscles . Following delivery the neonate mainly depends on glycolysis until exogenous glucose is supplied. As the ability of the neonate to use fat and protein, as substrate for gluconeogenesis is limited, hepatic glycogen stores are very rapidly depleted- risk of hypoglycemiahypoglycemia: hypoglycemia neonatal blood glucose level below 40mg/dl. non-specific signs include a weak or high pitched cry, cyanosis, apnea, jitteriness, apathy, seizures, abnormal eye movements, temperature instability, hypotonia and weak suck. Some of the infants may also be totally asymptomatic. As most neonates requiring surgical intervention are at risk of developing hypoglycemia, they should be on intravenous fluids containing 10% dextrose.hyperglycemia: hyperglycemia blood glucose level higher than 125 mg/dl and is particularly common in premature infants on TPN but may be seen in other sick neonates also . It is mainly a manifestation of inadequate insulin response to glucose . The major clinical problems associated with hyperglycemia are hyperosmolarity , osmotic diuresis and subsequent dehydration . Further, hyperosmolar status causes water to move from intracellular to extracellular compartment, resulting in contraction of intracellular volume of the brain and can lead to intra-ventricular haemorrhage .calcium: calcium Placental transfer of calcium to the fetus is an active process and 75% of this transfer occurs after 28 week of gestation . This explains the high incidence of hypocalcemia in premature infants, but all neonates have a tendency for hypocalcemia due to limited calcium stores, renal immaturity, and relative hypoparathyroidism .git: git At birth- gastric ph - alkaline 2 nd day- reaches n level Coordination of swallowing with respiration do not mature up to 4-5 mths - incresed incidence of refluxpsychology: psychology Infants less than 6 months of age are not usually upset by separation from their parents and will more readily accept a stranger. Children up to 4 years of age are upset by the separation from their parents and stranger anxiety present School age children are more upset by the surgical procedure, its mutilating effects and the possibility of pain. Adolescents fear the loss of control, asthetics and the possibility of not being able to cope with the illness. This is worsened by long periods of hospitalisation . Parental anxiety is readily perceived and reacted on by the child.Developmental pharmacology: Developmental pharmacologyFACTORS AFFECTING pkS OF DRUG in neonates: : FACTORS AFFECTING pkS OF DRUG in neonates: Body composition/ vol of distribution : ECF& TBW is more in proportion of body wt in infants- need for higher initial dose of drug which is water soluble eg . Sch /antibiotics Protein binding :Decreased total protein, less albumin,(reaches adult level by 5 mnths ) & lower binding affinity– leads to increase free drug level- increase toxicity & pharmac effects Fat content- less fat & muscle in neonates lead to greater level of drugs in plasma that r primarily redistributed to muscl n at eg . Thio , fentanyl(muscle)Pharmac ctd: Pharmac ctd Poorly developed BBB:greater fraction of dru lik barbiturate n morphine in cns - more adv effects Poor hepatic metabolism& delayed renal elimnationInduction agents: Induction agents Propofol : alkyl phenol that is formulated in 10% soybean oil, 2.25% glycerol, and 12% purified egg phosphatide-ALLERGIES Rapid distribution/ hepatic glucorinidation /renal clearance--result in a short duration of action - drug can limit its own clearance volume of the central compartment IS LARGE IN CHILDREN-THUS infants-2.9mg/kg 6-12yr-2.2mg/kgPropofol drawback: Propofol drawback Pain on administration- 0.2mg/kg lidocaine mixed lidocaine 15-20secs prior to administration of propofol with prior application of tourniquet( mini bier block tech) Propofol infusion syndrome allergiesMethohexital 1%: Methohexital 1% 1-2mg/kg iv (1% soltn ) 10mg/kg im 25-30mg/kg rectally(10% soltn ) CI- epileptic pts Adv effec - burning, hiccups, apne , extrapyramidal movtsthiopentone: thiopentone 2.5%-5-6mg/kg iv bolus in n built 1-4yr child Termination of efect through redistribution in muscle n at which is less in children thus reduced doses(2-4mgkg) in malnourished child/ neonates 30mg/kg-rectally Avoided in neonates with chd - hypotensionketamine: ketamine Iv 1-2mg/kg( sedation/ analgsia ) 2-4mg/kg ( induction) Im 4-5mg/kg(sedation) 10mg/kg (induction) Rectal 6-10mg/kg Intranasal 3-6mg/kgKet ctd: Ket ctd Useful in hypovolemic child/ chd Spontaneous respiration Adv efec Secretions- atropine0.02mg/kg im Post op hallucination/delirium-midaz0.5mg/kg im Laryngospsm /apnea CI - active URTI, increase ict,open globe injury, psychiatric/ seizure disorder, full stomach/ hiatal herniaSedatives & anxiolytic: Sedatives & anxiolytic Diazepam Painful on iv administration Hepatic metabolism Not used in infants <6mnths Neonates extremely long HL-80hrs Oral-0.1-0.3mg/kg-peak sedation in 1hr,,EHL-18 HRSMidajolam : Midajolam Water soluble Approved by FDA for use in neonates(hl-6-12hrs) cz decreased clearance Im-0.1-0.15mg/kg max 7.5kg Oral 0.25-1mg/kg max 20mg Rectal 0.75mg/kg max 20mg Nasal 0.2mg/kg Sublingual 0.2mg/ kgore chances of resp depression wn used with narcoticsmorphine: morphine infants,<10days--use controversial- cz low clearance, permeableBBB Term infants>10d- can b used Metabolite can cause resp depressionfentanyl: fentanyl Mc narcotic used in infants& children Rapid onset brief DOA Lipophilic Very stable cv response Abdominal sx-prolon DOA- 12.5ug/kg Cardiac sx-30-100ug/kg- bradycardia Chest wall rigidty / glottic rigidity( with as low as 1-2ug/kg)Inhalational agent: Inhalational agent Uptake n distribution of inh anes in neonates is more rapid cz Alv vent: FRC 5:1 Greater fraction of co is distributed to brain-18%in neonate/ 6% in adult Lower protein n lipid concen & more water in tissues reduces solubility- rapid wash in outNitrous oxide: Nitrous oxide Infequently used in neonates Used mainly in premature infants with at risk of high o2 toxicity Avoided in bowel obst , gas filled closed spaces N2 better than N2O – 34 times less soluble in bloodhalothane: halothane MAC of halothane increased as age decreases Have weak MR action facilitating induc & intub Potent bronchodilator May decrease airway reflex assoc with intubation Myocardium dpressant - caution in CHD pts Prone to hypotension Decreases BP no change in HR Sensitises myocardium to cardiac dysarrythmiashalothane: halothane Less excitement during induction& emergence comparedto sevolurane Halothane hepatitis( more in older children/ adults) Decreases TV increases RRSevoflurane : Sevoflurane Less pungent than isolurane MAC increase in stepwise manner as age decrease1-6mnth- 3.2% >6mnt- 2.5% f ewer hemodynamic changes compred to halothane bt greater effect on resp depression( deceases both TV, RR) Less laryngospasm/ b holding/coughingSevoflurane concerns: Sevoflurane concerns Risk of exothermic reaction- resulted in fire/ explosion Production of compound A-NEPHROTOXIC Emergence agitation Seizure like activity during inductionisoflurane: isoflurane Pungent odour MAC decreses stedily as age decreases Incr HR hence predispose to dysarrythmias Greater incidence of airway related eventsdesflurane: desflurane High incidence of laryngospasm Highest rate of emergence reaction Rapid wake up No hepatic metabolismsucchinylcoline: succhinylcoline Ultra short acting depolarising MR Highly water soluble-large vol of distribution 2.0 mg/kg IV; 4.0 mg/kg IM Consider Atropine 10-15 mcg/kg given prior SUX Potential side effects: Rhabdomyolysis Hyperkalemia Masseter spasm MHNDMR: NDMR Infants generally more sensitive Vec - DOA twice that of adults Pancuronium - vagolytic , causes tachy Rocuronium - Dose related DOA 0.3mg/kg-SA 0.6MG/KG-INTERMEDIATE ACTING 1.2MG/KG- 45-75MINS Can b given im-onset:3-4mins, DOA-1hrPaediatric equipments: Paediatric equipments paed equipent : paed equipent Should have: Minimal resistance Minimal dead space Light wt Easy to use able to conserve heat n moistureFace mask: Face mask Good fit-most appropriate anesthesia facemask for a child spans vertically from the bridge of the nose to just below the lower lip, without compressing the nasal passages Minimal dead space Transparent- allows recognition of cyanosis, the condensation of exhaled gas, and the presence of excess secretions or vomitus Non latex containing- allergyCommonly used paed mask: Commonly used paed maskCommonly used paed mask: Commonly used paed mask Plastic disposable mask with inflatable pad Rendell baker & soucek mask(RBS) - for age<10yrs dead space 0-preterm 3cm3 1-infants 4cm3 2 smal children 8cm3 3 for4-10yr 12cm3 Patil syracuse endoscopic maskairways: airways to improve patency of the upper airway and to facilitate delivery of oxygen or anesthetic gases to the lungs . Other uses: suctioning bite blockOropharyngeal airway: Oropharyngeal airwayPowerPoint Presentation: Ideal length: from angle of mouth to angle of mandible Too small airway pushes the posterior portin of tongue against post pharyngeal wall Too large airway itself causes airway obstruction t laryngeal inlet by compressing epiglottis Complic ; lip/tooth damage inserted in its normal orientation position with the aid of a tongue depressor . In older children, insertion may be accomplished with the distal tip oriented cephalad , and then turned 180 degrees when the tip has reached the posterior aspect of the palateCuffed oropharyngeal airway(COPA): Cuffed oropharyngeal airway(COPA)Nasopharyngeal airway: Nasopharyngeal airway Ideal- soft, round tip, fange to prevent slipping Size;12-16F(OD) Distance from tip of nose to tragus Complications- trauma to the nasal or pharyngeal mucosa that results in minor bleeding. Adenoidal tissue may be disrupted and may bleed into the oropharynx.LMA: LMAlMA: lMA rigid tube with a standard 15-mm connector at the most proximal end and a fenestrated, elliptical cuff cavity at the distal end distal cuff overlies the laryngeal inlet, and the fenestrations prevent the epiglottis from obstructing the lumen. Once inflated through a pilot tube, the cuff creates a seal in the pharynx that permits both spontaneous and controlled ventilation without a large gas leak when the peak pressure is below 15 cm H2O.lma: lma Adv : In pt with anatomical abnormalities Fibreoptic intubation through LMA For bronchoscopy Diadv : Laryngospasm, ischeic injury,aspiration Epiglottis can get folded under lmalaryngoscope: laryngoscope Generally, the straight Miller blade is used in children This allows the cephalad aspect of the larynx to be exposed more easily, because the base of the tongue can be lifted out of the line of sight, and the protruding epiglottis can be retracted with the tip . Wide blades and large-flange blades, like the Robertshaw , the Flagg, and the Wis-Hipple , allow the wide tongue of the small child to be flattened during laryngoscopyEndotracheal tube: Endotracheal tube Should be: Non inflammatory Not easily kinkable Easily sterlisable Shud seal trache against aspiration Too large tube-ischemia to tracheal mucosaSelecting the size: Selecting the size Measuring diameter of distal jt of index finger of child or lumen of external nares Penlington’s formula <6yrs- age( yrs )/3 +3.5 >6yrs-age( yrs )/4+ 4.5Breathing systems: Breathing systems Ayre’s t piece( up to 20 kg) Circle system Bain’s crcuitBreathing circuit: Breathing circuitPowerPoint Presentation: Advantages of T-piece systems Compact Inexpensive No valves Minimal dead space Minimal resistance to breathing Economical for controlled ventilation Disadvantages The bag may get twisted and impede breathing High gas flow requirement Uses Children under 20 kg weightMapleson F The most commonly used T-piece system is the Jackson-Rees' modification of the Ayre's T-piece (sometimes known as the Mapleson F system). This system connects a two-ended bag to the expiratory limb of the circuit; gas escapes via the `tail' of the bag. : Mapleson F The most commonly used T-piece system is the Jackson-Rees' modification of the Ayre's T-piece (sometimes known as the Mapleson F system). This system connects a two-ended bag to the expiratory limb of the circuit; gas escapes via the `tail' of the bag. This allows respiratory movements to be more easily seen and permits intermittent positive ventilation if necessary. The bag is, however, not essential to the functioning of the circuit. Intermittent positive pressure ventilation (IPPV) may be performed by occluding the tail of the bag between a finger and thumb and squeezing the bag. Alternatively, a `bag-tail valve', which employs an adjustable resistance to gas flow, may be attached to the bag tail. This causes the bag to remain partially inflated and so facilitates one-handed performance of IPPV.How much FGF needed?: How much FGF needed? Mapleson Systems Uses FGF SV FGF IPPV A Magill Lack Spontaneous Gen Anaesthesia 70-100 ml/kg/min Min 3 x MV B Very uncommon, not in use today C Resuscitation Bagging Min 15 lpm D Bain Spontaneous IPPV, Gen. Anaes 150-200 ml/kg/min 70-100 ml/kg/min E Ayres T Piece Very uncommon, not in use today F Jackson Rees Paediatric <25 Kg 2.5 – 3 x MV Min 4 lpmPAE: PAE PAE is unique and different in neonates N young children cz ,:- Informant will be parent / relative There is a need to elicit :- Maternal and ante-natal history Birth history and immediate post natal history H/O consanguineous marriage & similar complaint in siblings Present illness, associated medical problems, surgical problems and other congenital anomalies.Maternal illness n its implications: Maternal illness n its implications MATERNAL HEALTH IMPLICATIONS Diabetes mellitus Neonatal hypoglycemia, macrosomia , birth injuries, RDS, cardiac & vertebral anomalies Pre- eclampsia, H.T. IUGR, Pre-term delivery, meconium aspiration Alcohol abuse Mental retardation, CHD, cleft palate & skeletal anomaliesAntenatal history n its implications: Antenatal history n its implications Maternal infections: ( TORCH ) Rubella IUGR, Ocular lesions, congenital deafness, & CHD Toxoplasmosis IUGR, Hydrocephalus & microcephaly Polyhydromnios Malformations of GI tract- TEF, Atresias Oligohydromnios Genito urinary abnormalities, pulmonary HypoplasiaBirth history and immediate post- natal history : Birth history and immediate post- natal history Gestational age at birth – Pre-term , full-term, post-term Normal delivery / caesarean delivery ( Indication) Home / Hospital delivery APGAR score at birthProblems of Pre-term neonate:- : Problems of Pre-term neonate:- Neurological problems:- Apnea of prematurity Hypoxic ischemic encephalopathy Intra ventricular haemorrhage Retinopathy of prematurity Cardiovascular system:- Patent ductus arteiosus Respiratory system:- Respiratory distress syndrome Chronic lung disease GIT and metabolic system:- Inguinal hernias Necrotizing enterocolitis Hypoglycemia Hypocalcaemia Haematologic system:- Anemia Thrombocytopenia Hyperbilirubinemia Kernicterus Others:- Hypothermia Neonatal sepsis Pneumonia & Urinary tract infection-Problems of Post-term neonate:- : Problems of Post-term neonate:- Sudden infant death syndrome Macrosomia & birth injuries Asphyxia Meconium aspiration syndrome Hypocalcaemia, seizuresGeneral Physical Examination:-: General Physical Examination:- Look for Activity of the baby •Cry -- Vigorous = Healthy Weak cry = Sick Hoarseness = Hypocalcaemia /Airway injury High pitch = CNS causes-Kernicterus ●Color—Pink Pallor Cyanosis Jaundice ● Hydration status- Fontenella Eyes & lips Skin turgour Pulse & UOPEXAMINATION: EXAMINATION Between the ages of 4 and 8 years, children must be examined for loose primary teeth . Enlarged cervical nodes and otitis media occur frequently with respiratory tract infections. Unilateral nasal discharge is unusual and suggests a foreign body (or, rarely, choanal atresia ). Vitals Systemic examination Weight(kg)= (age+3)*5 2 Look for iv lines Spine examinationExamination of the Airway:-: Examination of the Airway:- Inspect the general appearance of the head and face including the neck. Following factors are the indicators of difficult airway:- Abnormal shape of the head- Microcephaly / Hydrocephalus Dysmorphic facial appearance Presence of cleft lip / palate Receding mandible / Retrognathia Web neck Presence of neck swellings- Cystic hygroma / Cevical encephalocele / Sternocledomastoid tumorLab testing: Lab testing Elective minor sx ; CBC, S glucose For neonates with / ch illness- CBC, electrolytes,albumin , coagultion profile Pt with midline lesions- ECG,echoPsychological preparation: Psychological preparation Issues such as anaesthetic risk, plan, recovery, postop analgesia n discharge criteria have to b discussed with parents in detailPowerPoint Presentation: Risk Factors for Preoperative Anxiety Child Related Young age (1 to 5 years) Poor previous experience with medical procedures and illness Children with shy and inhibited temperament Lack of developmental maturity and social adaptability High cognitive levels Parent Related High trait and state anxiety Divorced parents Parents who had multiple surgical proceduresTo relieve child’s anxiety : To relieve child’s anxiety Behavioural intervention: Tour of operating room Written or audiovisual material Presence of parents during induction Music/ acupuncture/hypnosis Describe to the child-procedure Pharmacological ; midajolamCoexisting health condition: Coexisting health condition URTI; irritable airway, increase risk of laryngospasm, bronchospasm, o2 debt, post extubation croup, post op atelectasis More significant in child with asthama /SCD/ infants/children for bronchoscopy Bronchial hyperreactivity may persist for upto 6 weeks so decision to delay sx - risk to benefit ratioPowerPoint Presentation: OSA - adenotonsillar hypertrophy with OSA is frequent At risk of airway obstruction wth use of preop sedation/ intubation Post op pt with severe OSA may exhibit worsening of obscure symptomsPreop Fasting : Preop Fasting Purpose; to decrease risk of severe aspiration pneumonitis should regurgitation occur It is possible if gastric fluid pH <2.4 & vol >0.8ml/kg is aspirated into lungs Gastric Ph At birth:6-8 8hrs: 4 24hrs: 1-2PowerPoint Presentation: Emptying time: Formula feeds 20%>breast milk 20%>clear fluids Pt taken as full stomach if any gastric outlet obstruction, ileus, vomiting, electrolyte disorderFasting guidelines: Fasting guidelines Fasting Time ( hr ) * Age Milk and Solids Clear Liquids <6 months 4 2 6-36 months 6 3 >36 months 8 3PowerPoint Presentation: a “2-4-6-8 rule” represents the majority of institutions providing pediatric care This rule restricts clear fluids for 2 hours . Infants less than 6 months of age on breast milk require 4 hours of fasting . Older infants over 6 months of age on milk or infant formula should be fasted for 6 hours Children on solid food, including toast, cereal, and juice with pulp, such as orange juice, are usually fasted for 8 hours (or NPO after midnight)t formula should be fasted for 6 hours ;premedication: premedication Not neessary usually for <6mnths Midajolam - fruit flavored syrup to mask its bitter taste (0.3 to 0.5 mg/kg given orally) nasal (0.2 to 0.3 mg/kg) or rectal (0.3 mg/kg) routes but with their own disadvantages Ketamine Ketamine solution (6 mg/kg) diluted with fruit-flavored syrup and given orally produced effective sedation in 12 minutes Im ketamine (2.4-10mg/kg) Atropine (0.02mg/kg)orally/ im less than 45 mins before induction OTFC ( 15-20ug/kg)_- pruritis , vomiting, hypoxemia Oral clonidine (4 mcg/kg) provides satisfactory anxiolysis and sedation DEXMED 3-4ug/kg orallyOperating Room Preparation : Operating Room Preparation Warm operating room Turn on warming devices (e.g., warming blanket, intravenous line warmer, radiant light heat source ) Anesthesia Equipment DrugsPrevention of hypothermia: Prevention of hypothermia evaporative heat losses from the respiratory tract account for only about 5% to 10% of total heat loss during anesthesia , it is obvious that keeping the operating room temperature at an optimal level is crucial in the prevention of hypothermia. The major source of heat loss in the anesthetized patient is radiationHypothermia ctd: Hypothermia ctd In adults, 21°C is reported as the critical ambient temperature for maintaining normal (36° to 37.5°C) nasopharyngeal or esophageal temperatures Operating room temperatures of 27° and 29°C are recommended for full-term and premature newborns, respectively It is essential that every operating room be equipped with an individual thermistor control unitHypothermia ctd: Hypothermia ctd Radiant heaters are used during induction of anesthesia and insertion of catheters, until the patient is prepared and draped. Prolonged use of radiant heaters may result in increased insensible water losses. Also, if radiant heaters are too close to the patient, they can cause skin burns wrapping infants in reflective blankets to cover 60% of the body surface area may be cumbersome or impossible, we recommend that uninvolved skin areas be covered. Of particular concern in this regard is the head, which comprises up to 20% of the total skin surface area in a neonate and shows the highest regional heat flux abilityHypothermia ctd: Hypothermia ctd The practice of covering the head with a plastic bag easily and significantly reduces radiant, convective, and evaporative heat loss. Passive insulators are commonly used to prevent cutaneous heat loss . passive and active skin surface warmers are available, including circulating hot water blankets infrared radiant heater and convective forced-air heaters, which blow warm air through a disposable blanketHypothermia ctd: Hypothermia ctd use of warming mattresses reduces conductive heat loss. Warming mattresses set at 40°C and covered with two layers of cotton blankets have been demonstrated to effectively conserve heat It is important to warm fluids in instances of rapid or massive fluid administration solutions for intraoperative lavage should always be warmed to body temperature . Although desirable from a thermoregulatory point of view, preparation solutions should not be warmed, because heat can cause a chemical breakdown of the iodine solution and thereby inactivate its antimicrobic propertiesHypothermia ctd: Hypothermia ctd Heat and humidity can be added actively to inspired gases by evaporative or ultrasonic heated humidifiers or passively by heat and moisture exchanging filters (“artificial noses”)transportation: transportationMonitoring during induction: Monitoring during induction basic montoring : Pulse ox, ECG, BP, temp, precordial steth , ETCO2. Invasive; arterial n CV cathetersPulse oximeter: Pulse oximeter Flexible probes; can b placed Across web space b/w thumb n first finger Lat /medial aspect of hand Foot,ear,nose,tongue Esp in first 2wks of life(HBF) pulse ox do not compensate for lt shift of HB desaturation curve& pulse ox values rad about 2% higher than blood statusPrecordial steth: Precordial steth HR Heart rhythm Strength of heart sounds Breath soundscapnography: capnography Shape n magnitude of CO2 waveform ay indicate bronchospasm, endobronchial intubation, kinked ETT Drawback: inaccuracy of recording obtained with use of non rebreathing circuitInduction In infants <10-12mts : Induction In infants < 10-12mts Mask induction without premedication Allowing neonates & small infants to suck on a rubber nipple or on a gloved finger generally prevent crying during induction 70%N2O+30%O2+ 8% sevoflurane /incremental halothane It is critical to rapidly reduce the inspired concentration of halothane(1-1.5%) & sevo (2-4%) until iv line is placed Vapouriser shud b closed b4 laryngoscopy to avoid myocardial depression due to overdoseInduction in older paed pts: Induction in older paed pts Parents in OT depend on developmental level of child Vital to explain to them what they might see Inhalational / mask induction- using flavoured mask Play a game technique Single breath technique Rectal induction Methohexital / thipental /ketamine/ midajolamMAC Multiples for a Neonate Allowed by Current Vaporizer : MAC Multiples for a Neonate Allowed by Current Vaporizer Agent Maximum Vaporizer Output (%) MAC (%) Maximum Possible MAC Multiples Halothane 5 0.87 5.75 Isoflurane 5 1.20 4.2 Sevoflurane 8 3.3 2.42 Desflurane 18 9.16 1.96PowerPoint Presentation: Im Methohexital (10mg/kg ) Ketamine((2-10mg/kg ) Iv advantage in full stomach pts Disadv : securing an iv line EMLA amethocaine gelEmla cream: Emla cream (eutectic mixture of local anesthetics 2.5% lidocaine and 2.5% prilocaine EMLA cream must be applied at least 1 hour prior to iv cannulation to provide sufficient dermal analgesia The EMLA cream is placed on intact skin over a promising vein with an occlusive dressing applied over the cream. Two potential sites of venous cannulation should be prepared with EMLA cream, usually on opposite hands . EMLA sometimes causes vasoconstriction and makes the insertion of a cannula more difficult. Removing the EMLA patch 10 to 15 minutes before venipuncture and warming the site causes vasodilation and eases the cannulation . EMLA should not be used in infants under 12 months of age with glucose-6-phosphate deficiency or other children more susceptible to methemoglobinemiaMaintenance of upper airway during induction: Maintenance of upper airway during induction During induction of anesthesia, airway obstruction frequently occurs as the pharyngeal and laryngeal muscles are preferentially relax In order to maintain the airway patent, the neck must be extended, the jaw thrust forward in a sniffing position, and the mouth open in case of nasal obstruction (the triple airway maneuver), with a moderate continuous positive airway pressure (CPAP; 10 to 15 cm H2O).PowerPoint Presentation: A, Infant glottis. B, Adult glottis. Note the soft, edematous appearance of infant tissue and folded, omega (ω) or “U” shape of the infant glottisPowerPoint Presentation: Before intubation is attempted, the anesthesiologist is seated comfortably or standing at the proper height in relation to the OT table, with eye level about 1 foot above the patient's head The child's neck is moderately extended beyond a neutral position or “sniffing” position to align the oral, pharyngeal, and laryngeal axesPowerPoint Presentation: For laryngoscopy a straight blade is most commonly used. The mask is lifted and the oral airway, if used, is removed. The blade held by the left hand is moistened and inserted through the right corner of the mouth while the head is held in the extended position by the right handPowerPoint Presentation: The laryngoscope blade is now moved gently toward the midline to displace the tongue to the left . It is then advanced further toward the epiglottis, the laryngoscope handle is gently lifted forward and upward along its axis. The larynx is now exposed, and the posterior portion of the vocal cords should be visible below or behind the epiglottis The tip of the blade is advanced to lift the epiglottis directly instead of placing it in the valleculaPowerPoint Presentation: If the glottis is not easily seen, cricoid pressure can be applied with the little finger of the hand holding the handle or by an assistant, often improving the viewaIrway management In child with full stomach : aIrway management In child with full stomach In child with full stomach Most neonates who present with sx emergency are considered to be at risk of full stomach Awake intubation/ rapid sequence intubation Prep of intubating equipment & suction Preo2 of lungs Rapid induction(iv) Application of cricoid pressure Rapid onset of paralysis ( sch / rocuronium ) Intubation of trachea without ventilating lungsDifficult airway: Difficult airway Dificult airway cart Cant ventilate/ cant intubate Surgical airway Cricothyrotomy seldinger technique Armoured transtracheal catheter Iv catheterStandard Intraop monitoring: Standard Intraop monitoring Physiology Clinical observation by qualified anesthesiologist: Pt color, capillary refill, warmth of skin, muscle tone, fullness of fontanelle , chest expansion, heart n breath sounds, compliance during hand ventillation , appaearance of bleeding in surgical field Oxygenation: pulse oximeter Ventilation: stethoscope, capnograph , gas flow meter Circulation: stethoscope, blood pressure cuff Electrocardiograph Temperature probe: rectal, esophageal, or axillary Anesthetic depth: BIS monitorSupplemental intraop monitors: Supplemental intraop monitors Fluids given Urine output (catheterization and urinometer ) Blood loss Direct arterial pressure Central venous pressure Pulmonary arterial pressure and wedge pressure Cardiac output (noninvasive or invasive ) Electroencephalogram Somatosensory-evoked potentialsIntermittent intraop monitoring: Intermittent intraop monitoring Train-of-four twitch response on nerve stimulator Arterial blood gas tensions, pH hematocrit Serum levels of Na+, K+, Ca2+, glucose Colloid oncotic pressure Coagulation profileIv fluids: Iv fluids Howland measured energy consumption <1yr(3-10kg)-100kcal/kg/day Older children-75 kcal/kg/day Adults- 35 kcal/kg/day newborns Day1-70ml/kg Day 3- 80ml/kg Day 5- 90ml/kg Day 7- 120ml/kgCalculation of Maintenance Fluid Requirements for Pediatric Patients Holiday n segar : Calculation of Maintenance Fluid Requirements for Pediatric Patients Holiday n segar Weight (kg) Hourly Fluid Requirements (mL) <10 4 mL/kg 11-20 40 mL + 2 mL/kg for each kilogram above 10 >20 60 mL + 1 mL/kg for each kilogram above 20 In general deficits caused by fasting calculated by multiplying the hourly maintenance by no of hrs of fluid restrictionPowerPoint Presentation: half of the estimated fluid deficit, plus the hourly maintenance fluid requirement, should be given during the first hour of anesthesia, with a balanced salt solution such as lactated Ringer's solution ; one quarter of the fluid deficit plus the hourly maintenance fluid is infused during the second and third hours of anesthesia and surgery , and the replacement of any third-space fluid loss Third space loss 1ml/kg/ hr -for minor sx 15ml/kg/ hr for major abdominal sx Fever increases caloric requirement by 10-12% for every centigrade rise in temp above normalType of fluid: Type of fluid no longer recommend routine use of glucose-containing solutions, especially for brief operative procedures . a balanced salt solution (e.g., lactated Ringer's solution) should be used for all deficits and third-space losses . If a child is thought to be at risk for hypoglycemia, 5% dextrose in 0.45% normal saline should be administered by “piggyback” infusion at maintenance rates . This minimizes the chance of a bolus administration of glucose and satisfies the concern for unrecognized hypoglycemia or accidental hyperglycemia.PowerPoint Presentation: Children receiving intravenous alimentation present a special problem. Transition to 10% glucose is often recommended to avoid intraoperative hyperglycemia with continuation of the current alimentation fluid and to avoid hypoglycemia if it is stopped suddenly reduce the established intravenous alimentation fluid infusion rate by 33% to 40% (to account for the reduced metabolic rate under anesthesia) and periodically check blood glucose values.Transfusion therapy: Transfusion therapy Blood loss<10% BV-no replacement or crystalloid 10-20%- colloids or blood > 20%- blood Estimated Blood volume Preterm-100-120ml/kg Full term infant-90ml/kg 3-12mths-80ml/kg >1yr-70ml/kgPowerPoint Presentation: MABL= EBV*(starting hct -target hct ) hematocrit of PRBC’S MABL replaced with 3ml of RL/ml of blood loss The most common blood component used is packed red blood cells, which have a hematocrit value between 70% and 80%. An average of 1 m L/kg packed red blood cells raises the hematocrit value by 1.5 %. Vol of PRBC’s to b transfused= Desired HCT-present HCT*EBV HCT of PRBC’sFfp’s: Ffp’s to replenish clotting factors lost during massive blood transfusion (usually defined as blood loss exceeding one blood volume ), for disseminated intravascular coagulopathy, or for congenital clotting factor deficit . need FFP until blood loss exceeds 1 and probably 1.5 blood volumes . This generalization applies to children given PRBCs ; children given whole blood will not need FFP, even when blood loss exceeds several blood volumes.ffp: ffp Transfusion of FFP at rates exceeding 1.0 mL/kg/min is sometimes followed by severe ionized hypocalcemia because of their decreased ability to mobilize calcium and metabolize citrate; exogenous calcium chloride (2.5 to 5 mg/kg) or calcium gluconate (7.5 to 15 mg/kg) should be administered during rapid transfusion of FFPPostoperative Pain Control for Neonates and Infants: Postoperative Pain Control for Neonates and Infants Intravenous Opioids: morphine, fentanyl, methadone NSAIDs: ketorolac Oral Acetaminophen(20 mg/kg) Ibuprofen(5 mg/kg ) Hydrocodone(0.1 mg/kg). Codeine (0.5 mg/kg) Rectal Acetaminophen(20 to 30 mg/kg) Diclofenac Regional and local anesthesiaRegional Anesthesia Techniques Useful in Neonates: Regional Anesthesia Techniques Useful in Neonates Central neuraxial Caudal Epidural (lumbar, thoracic, caudal) Spinal Peripheral nerve blocks Infraorbital block Brachial plexus block (axillary, infraclavicular ) Lateral femoral cutaneous block Penile block Ilioinguinal block Scalp blocksCaudal block: Caudal block landmarks are the coccyx, the two sacral cornua , and the posterior superior iliac spines The sacral cornua are identified. A styletted needle is introduced into the caudal space through the sacral hiatus. A “pop” is felt as the sacrococcygeal ligament is accessed. After aspiration, 0.8 mL/kg of local anesthetic solution is injected. This provides analgesia for hernia repair, circumcisions, and lower abdominal surgeriesThank you: Thank you You do not have the permission to view this presentation. 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Premium member Presentation Transcript Paediatric anaesthesia: Paediatric anaesthesia Moderator: DR ARATHI Presentor : DR KHUSHBU GOELchildren are not small adults: children are not small adults special anatomy adaptive physiology developmental pharmocology Congenital or acquired pathologyterminology: terminology Newborn: first 24 hours Neonates – a baby within 44 weeks of age from the date of conception/ 28 days postnatal Infants – a child of up to 12 months of age Toddler-1-3yr Small children:4-12yr Child – 1 to 12 yrs Adolescent – 13 to 16 yrs The differences between paediatric and adult anaesthetic practice are reduced as the patients become oldercns: cns Soft & pliable cranium Non fused sutures 2 open fontannelle : ant font close by 18 months Post fontanelle close by 6-9 month at brain/ tbw Birth 10% 6mth 20% 1 yr 30% Poorly developed cerebral cortex, incomplete myelination till 2yr age cerebral vessels in the preterm infant are fragile . prone to IVH (concern during awake laryngoscopy & intubation of neonates)Cns ctd: Cns ctd Predominant constituent in neonatal brain is water- decreses with age decreased partition coffiecient & decreased solubility of inhalational agent in neonates--- -more rapid washin washout of Inh agent -altered requirement for inh agents BBB is poorly formed. Drugs such as barbiturates, opioids, antibiotics and bilirubin cross the BBB easily causing a prolonged and variable duration of action .PowerPoint Presentation: Perception of noxious stimuli present as early as 6 wk of gestation Rxn to pain is generalised & localisation starts at 3-10 mths Response to o2 co2 is attenuatedRs-transition: Rs -transition System develops rapidly during last trimester During fetal life it is filled with ultrafiltrate of plasma Gas exchange taken care by placenta By 24wks- surfactant precursor by 28wks-surfactant Within a minute of clamping umblical cord-neonate take first breath with resp pressure of -70cmh2o-recruiting alveoli Within 10-20mins neonatal frc n pulm b flow establishesRs cntd: Rs cntd Absence of adequate surfactant leads to Collapse of alveoli Maldistribution of ventilation Impaired gas exchange Decrease compliance Increase work of breathing respiratory distress syndrome ( RDS)Factors prevent hypoxia perintaly: Factors prevent hypoxia perintaly Fetal hb At 36wk gestation-90-95% Birth-75-80% 6mths-negligible High hb & hct At birth-18-19g/dl By 2-3mths of age—9-11g/dl(physiological anaemia Greater bv-80ml/kg at birthRespiratory & airway: Respiratory & airway Large head/ prominent occiput Small neck / poor muscle control Retrognathic chin/ obtuse angle of jaw Narrow nares(50 % of airway resistance is from the nasal passages .) obligatory nasal breathers( can b converted to oral breathing in c/o nasal obstruction after 5 mths Relatively large tongue nOn ossified palate Epiglottis- omega shaped, stubby base, project posteriorly at 45* to base of tongue (adult-15-20*) thus it should be lifted during laryngoscopyPowerPoint Presentation: Glottis:more anterior & more cephalad full term-c4 preterm infant-c3 3yrs- c4-c5 adult- c6 V cords are anterior slanting Subglottis - funnel shaped/narrowest part- cricoid ring/ achilles heel Uncffed tube in less than 6yr childPowerPoint Presentation: Tracheal length 2-5cm, supportedd by non calcified tracheal rings(compliant) Horizontally place pliable ribs Immature n weak intercostal muscles Sternum n thoracic cage is soft n more compliant-low frc Diaphragm placed high up premature neonate mature Diaphragm type1 10% 25-30% 55%PowerPoint Presentation: Airway diameter small & compliant Alveoli 20-50million (adult-300) Alveoli increases in size n no upto 8 yr of age Atelectasis common-underdeveloped alveoli -less surfactant -compliant chest wall Minute ventilation is rate dependant as there is little means to increase tidal volumePowerPoint Presentation: closing volume is larger than the FRC until 6-8 years of age-causes an increased tendency for airway closure at end expiration. Thus would benefit from a higher RR and the use of PEEP. CPAP during spontaneous ventilation improves oxygenation and decreases the work of breathing . NEONATE ADULT MV:FRC 5:1 2:1 Less oxygen reservePowerPoint Presentation: Apnoeas are common in premature infant n significant if they last longer than 15 seconds and are associated with desaturation or bradycardia . Caffeine 10-20 mg/kg oral or IV given peri -operatively may be useful Control of ventilation; Immature (Respond less to hypercapnia ) During first 3 weeks- vent response to hypoxia depends on temp Normothermic - biphasic response Hypothermic-hypoventilationthermoregulation: thermoregulation Babies and infants have a large surface area to weight ratio with minimal subcutaneous fat. They have poorly developed shivering, sweating and vasoconstriction mechanisms. Brown fat (located in small amounts around the scapulae, the mediastinum, the kidneys and adrenal glands) metabolism is required for non-shivering thermogenesis. It comprises 2-6% of neonatal body weight. More oxygen is required for the metabolism of these brown fat stores.n b fat response lost under anaesthesiaPowerPoint Presentation: Heat lost during anaesthesia is mostly via radiation but may also be lost by conduction, convection and evaporation. The optimal ambient temperature to prevent heat loss is 34ºC for the premature infant, 32ºC for neonates and 28ºC in adolescents and adults. Low body temperature causes respiratory depression, acidosis, decreased cardiac output, increases the duration of action of drugs, decreases platelet function and increases the risk of infection.Fetal circulation: Fetal circulationFetal circulation: Fetal circulation Oxygenated blood leaves the placenta in the umbilical vein Umbilical vein blood joins blood from the viscera in the inferior vena cava. Approximately half of the inferior vena cava flow passes through the foramen ovale to the left atrium, where it mixes with a small amount of pulmonary venous blood, and this relatively well-oxygenated blood supplies the heart and brain by way of the ascending aorta. The other half of the inferior vena cava stream mixes with superior vena cava blood and enters the right ventricle . Because the pulmonary arterioles are constricted, most of the blood in the main pulmonary artery flows through the ductus arteriosus (DA) so the descending aorta's blood has less oxygen than does blood in the ascending aorta.High PVR IN PULM ARTERIES: High PVR IN PULM ARTERIES Lung is filled with 20-30ml/kg of isotonic fluid(amniotic fluid) Alveoli are collapsed,bv are compressed Relatively low pao2&ph of blood in vessels—leads to vasoconstrictionChanges at birth: Changes at birth Placenta removed from circulation Portal bp falls– svr increases– systemic bp increases– LAP>RAP( foramen ovale closes) With first breath:--air enters alveoli- luid shift into pulmonary interstitial space & thence into intravascular space O2 tension increses,co2 decreses —PVR decreases(takes3-4 days to come to n)– increase PBF—increase pao2-wn it reaches 50mmhg-physiological closure of DA3 shunts: 3 shunts Foramen ovale - functional closure at birth Anatomical closure-6wks Ductus venosus - Func clos-1 st week Anatomical-2-3mths Remnant- ligamentum venosum Ductus arteriosus Fibrous closur-10-15hrs May remain open upto 4wksPowerPoint Presentation: May remain open due to(PDA) increase pge2, decrease calcium, decrese glucose, increased pulm artery pressureFlip flop circulation: Flip flop circulation Neonates a re vulnerable to flip flop circulation in first few wks of life i.e going from adult type to feta type circulation Factors– hypoxia/ acidosis/hypothermia/ hypocalcemia / overhydrationResponse of neonates to hypoxia: Response of neonates to hypoxia Pulmonary vasoconstriction(can result to opening of FO,DA) Systemic vasoconstriction( UNLIKE ADULTS) Bradycardia Decrease Cadiac outputAt birth: At birth RV muscular mass>LV muscular mass(RAD) 30% less contractile tissue in neonate’s myocardium compared to adults Myofibril element are less fewer & less organised Less mature sarcoplasmic reticulum—less ca -ATP activity- less contractility(more ependant on exogenous calcium) More connective tissue thus less compiant ventricles- ability to increase SV is less C.o - is mainly HR dependantCvs ctd: Cvs ctd First 3 months- parasympathetic dominance- low afterload Resting CO/KGWT is much higher than adult to meet high metabolic demand Co-at birth-350-400ml/kg/min at 1wk- 150-200ml/kg/min adult- 70ml/kg/minrenal: renal In utero- fetal waste material removed by placenta& fetal kidneys are passive- less RBF, less GFR Kidneys receive only 3% co (25% adult) cz Low systemic art pressure High renal vascular resistance Low permiabilty of glomerular cappilaries Small size/ no of g cappilaries GFR at birth-20ml/min/1.73cm2 2wks- doubles 2yrs- adult levelPowerPoint Presentation: Tubular reabsorption is pooor- inability to concen urine Inability to conserve water-tolerate fluid restriction poorly Inabilty to excrete large amt of h2o-tolerate overload of fluid poorly Neonate is vol dependant & vol intolerantHepatic & metabolic physiology: Hepatic & metabolic physiology Most enzymes system are present but not induced at birth Different hepatic metabolic pathways mature at different pathways Phase1 rxns at birth50%-equals adult level by 6 mths Phase2- matures by 1 yr of life Decrease level of albumin- mot drug remain in free form Vit k dependant clotting factors is20-60% in neonate- exogenous vit k requiredHepatic & metabolic physio: Hepatic & metabolic physio Glucose metabolism : Facilitated diffusion across placenta maintains the fetal blood glucose value at about two-thirds the maternal value. In the later stages of fetal development there is a build-up of glycogen stores in the liver, skeletal and cardiac muscles . Following delivery the neonate mainly depends on glycolysis until exogenous glucose is supplied. As the ability of the neonate to use fat and protein, as substrate for gluconeogenesis is limited, hepatic glycogen stores are very rapidly depleted- risk of hypoglycemiahypoglycemia: hypoglycemia neonatal blood glucose level below 40mg/dl. non-specific signs include a weak or high pitched cry, cyanosis, apnea, jitteriness, apathy, seizures, abnormal eye movements, temperature instability, hypotonia and weak suck. Some of the infants may also be totally asymptomatic. As most neonates requiring surgical intervention are at risk of developing hypoglycemia, they should be on intravenous fluids containing 10% dextrose.hyperglycemia: hyperglycemia blood glucose level higher than 125 mg/dl and is particularly common in premature infants on TPN but may be seen in other sick neonates also . It is mainly a manifestation of inadequate insulin response to glucose . The major clinical problems associated with hyperglycemia are hyperosmolarity , osmotic diuresis and subsequent dehydration . Further, hyperosmolar status causes water to move from intracellular to extracellular compartment, resulting in contraction of intracellular volume of the brain and can lead to intra-ventricular haemorrhage .calcium: calcium Placental transfer of calcium to the fetus is an active process and 75% of this transfer occurs after 28 week of gestation . This explains the high incidence of hypocalcemia in premature infants, but all neonates have a tendency for hypocalcemia due to limited calcium stores, renal immaturity, and relative hypoparathyroidism .git: git At birth- gastric ph - alkaline 2 nd day- reaches n level Coordination of swallowing with respiration do not mature up to 4-5 mths - incresed incidence of refluxpsychology: psychology Infants less than 6 months of age are not usually upset by separation from their parents and will more readily accept a stranger. Children up to 4 years of age are upset by the separation from their parents and stranger anxiety present School age children are more upset by the surgical procedure, its mutilating effects and the possibility of pain. Adolescents fear the loss of control, asthetics and the possibility of not being able to cope with the illness. This is worsened by long periods of hospitalisation . Parental anxiety is readily perceived and reacted on by the child.Developmental pharmacology: Developmental pharmacologyFACTORS AFFECTING pkS OF DRUG in neonates: : FACTORS AFFECTING pkS OF DRUG in neonates: Body composition/ vol of distribution : ECF& TBW is more in proportion of body wt in infants- need for higher initial dose of drug which is water soluble eg . Sch /antibiotics Protein binding :Decreased total protein, less albumin,(reaches adult level by 5 mnths ) & lower binding affinity– leads to increase free drug level- increase toxicity & pharmac effects Fat content- less fat & muscle in neonates lead to greater level of drugs in plasma that r primarily redistributed to muscl n at eg . Thio , fentanyl(muscle)Pharmac ctd: Pharmac ctd Poorly developed BBB:greater fraction of dru lik barbiturate n morphine in cns - more adv effects Poor hepatic metabolism& delayed renal elimnationInduction agents: Induction agents Propofol : alkyl phenol that is formulated in 10% soybean oil, 2.25% glycerol, and 12% purified egg phosphatide-ALLERGIES Rapid distribution/ hepatic glucorinidation /renal clearance--result in a short duration of action - drug can limit its own clearance volume of the central compartment IS LARGE IN CHILDREN-THUS infants-2.9mg/kg 6-12yr-2.2mg/kgPropofol drawback: Propofol drawback Pain on administration- 0.2mg/kg lidocaine mixed lidocaine 15-20secs prior to administration of propofol with prior application of tourniquet( mini bier block tech) Propofol infusion syndrome allergiesMethohexital 1%: Methohexital 1% 1-2mg/kg iv (1% soltn ) 10mg/kg im 25-30mg/kg rectally(10% soltn ) CI- epileptic pts Adv effec - burning, hiccups, apne , extrapyramidal movtsthiopentone: thiopentone 2.5%-5-6mg/kg iv bolus in n built 1-4yr child Termination of efect through redistribution in muscle n at which is less in children thus reduced doses(2-4mgkg) in malnourished child/ neonates 30mg/kg-rectally Avoided in neonates with chd - hypotensionketamine: ketamine Iv 1-2mg/kg( sedation/ analgsia ) 2-4mg/kg ( induction) Im 4-5mg/kg(sedation) 10mg/kg (induction) Rectal 6-10mg/kg Intranasal 3-6mg/kgKet ctd: Ket ctd Useful in hypovolemic child/ chd Spontaneous respiration Adv efec Secretions- atropine0.02mg/kg im Post op hallucination/delirium-midaz0.5mg/kg im Laryngospsm /apnea CI - active URTI, increase ict,open globe injury, psychiatric/ seizure disorder, full stomach/ hiatal herniaSedatives & anxiolytic: Sedatives & anxiolytic Diazepam Painful on iv administration Hepatic metabolism Not used in infants <6mnths Neonates extremely long HL-80hrs Oral-0.1-0.3mg/kg-peak sedation in 1hr,,EHL-18 HRSMidajolam : Midajolam Water soluble Approved by FDA for use in neonates(hl-6-12hrs) cz decreased clearance Im-0.1-0.15mg/kg max 7.5kg Oral 0.25-1mg/kg max 20mg Rectal 0.75mg/kg max 20mg Nasal 0.2mg/kg Sublingual 0.2mg/ kgore chances of resp depression wn used with narcoticsmorphine: morphine infants,<10days--use controversial- cz low clearance, permeableBBB Term infants>10d- can b used Metabolite can cause resp depressionfentanyl: fentanyl Mc narcotic used in infants& children Rapid onset brief DOA Lipophilic Very stable cv response Abdominal sx-prolon DOA- 12.5ug/kg Cardiac sx-30-100ug/kg- bradycardia Chest wall rigidty / glottic rigidity( with as low as 1-2ug/kg)Inhalational agent: Inhalational agent Uptake n distribution of inh anes in neonates is more rapid cz Alv vent: FRC 5:1 Greater fraction of co is distributed to brain-18%in neonate/ 6% in adult Lower protein n lipid concen & more water in tissues reduces solubility- rapid wash in outNitrous oxide: Nitrous oxide Infequently used in neonates Used mainly in premature infants with at risk of high o2 toxicity Avoided in bowel obst , gas filled closed spaces N2 better than N2O – 34 times less soluble in bloodhalothane: halothane MAC of halothane increased as age decreases Have weak MR action facilitating induc & intub Potent bronchodilator May decrease airway reflex assoc with intubation Myocardium dpressant - caution in CHD pts Prone to hypotension Decreases BP no change in HR Sensitises myocardium to cardiac dysarrythmiashalothane: halothane Less excitement during induction& emergence comparedto sevolurane Halothane hepatitis( more in older children/ adults) Decreases TV increases RRSevoflurane : Sevoflurane Less pungent than isolurane MAC increase in stepwise manner as age decrease1-6mnth- 3.2% >6mnt- 2.5% f ewer hemodynamic changes compred to halothane bt greater effect on resp depression( deceases both TV, RR) Less laryngospasm/ b holding/coughingSevoflurane concerns: Sevoflurane concerns Risk of exothermic reaction- resulted in fire/ explosion Production of compound A-NEPHROTOXIC Emergence agitation Seizure like activity during inductionisoflurane: isoflurane Pungent odour MAC decreses stedily as age decreases Incr HR hence predispose to dysarrythmias Greater incidence of airway related eventsdesflurane: desflurane High incidence of laryngospasm Highest rate of emergence reaction Rapid wake up No hepatic metabolismsucchinylcoline: succhinylcoline Ultra short acting depolarising MR Highly water soluble-large vol of distribution 2.0 mg/kg IV; 4.0 mg/kg IM Consider Atropine 10-15 mcg/kg given prior SUX Potential side effects: Rhabdomyolysis Hyperkalemia Masseter spasm MHNDMR: NDMR Infants generally more sensitive Vec - DOA twice that of adults Pancuronium - vagolytic , causes tachy Rocuronium - Dose related DOA 0.3mg/kg-SA 0.6MG/KG-INTERMEDIATE ACTING 1.2MG/KG- 45-75MINS Can b given im-onset:3-4mins, DOA-1hrPaediatric equipments: Paediatric equipments paed equipent : paed equipent Should have: Minimal resistance Minimal dead space Light wt Easy to use able to conserve heat n moistureFace mask: Face mask Good fit-most appropriate anesthesia facemask for a child spans vertically from the bridge of the nose to just below the lower lip, without compressing the nasal passages Minimal dead space Transparent- allows recognition of cyanosis, the condensation of exhaled gas, and the presence of excess secretions or vomitus Non latex containing- allergyCommonly used paed mask: Commonly used paed maskCommonly used paed mask: Commonly used paed mask Plastic disposable mask with inflatable pad Rendell baker & soucek mask(RBS) - for age<10yrs dead space 0-preterm 3cm3 1-infants 4cm3 2 smal children 8cm3 3 for4-10yr 12cm3 Patil syracuse endoscopic maskairways: airways to improve patency of the upper airway and to facilitate delivery of oxygen or anesthetic gases to the lungs . Other uses: suctioning bite blockOropharyngeal airway: Oropharyngeal airwayPowerPoint Presentation: Ideal length: from angle of mouth to angle of mandible Too small airway pushes the posterior portin of tongue against post pharyngeal wall Too large airway itself causes airway obstruction t laryngeal inlet by compressing epiglottis Complic ; lip/tooth damage inserted in its normal orientation position with the aid of a tongue depressor . In older children, insertion may be accomplished with the distal tip oriented cephalad , and then turned 180 degrees when the tip has reached the posterior aspect of the palateCuffed oropharyngeal airway(COPA): Cuffed oropharyngeal airway(COPA)Nasopharyngeal airway: Nasopharyngeal airway Ideal- soft, round tip, fange to prevent slipping Size;12-16F(OD) Distance from tip of nose to tragus Complications- trauma to the nasal or pharyngeal mucosa that results in minor bleeding. Adenoidal tissue may be disrupted and may bleed into the oropharynx.LMA: LMAlMA: lMA rigid tube with a standard 15-mm connector at the most proximal end and a fenestrated, elliptical cuff cavity at the distal end distal cuff overlies the laryngeal inlet, and the fenestrations prevent the epiglottis from obstructing the lumen. Once inflated through a pilot tube, the cuff creates a seal in the pharynx that permits both spontaneous and controlled ventilation without a large gas leak when the peak pressure is below 15 cm H2O.lma: lma Adv : In pt with anatomical abnormalities Fibreoptic intubation through LMA For bronchoscopy Diadv : Laryngospasm, ischeic injury,aspiration Epiglottis can get folded under lmalaryngoscope: laryngoscope Generally, the straight Miller blade is used in children This allows the cephalad aspect of the larynx to be exposed more easily, because the base of the tongue can be lifted out of the line of sight, and the protruding epiglottis can be retracted with the tip . Wide blades and large-flange blades, like the Robertshaw , the Flagg, and the Wis-Hipple , allow the wide tongue of the small child to be flattened during laryngoscopyEndotracheal tube: Endotracheal tube Should be: Non inflammatory Not easily kinkable Easily sterlisable Shud seal trache against aspiration Too large tube-ischemia to tracheal mucosaSelecting the size: Selecting the size Measuring diameter of distal jt of index finger of child or lumen of external nares Penlington’s formula <6yrs- age( yrs )/3 +3.5 >6yrs-age( yrs )/4+ 4.5Breathing systems: Breathing systems Ayre’s t piece( up to 20 kg) Circle system Bain’s crcuitBreathing circuit: Breathing circuitPowerPoint Presentation: Advantages of T-piece systems Compact Inexpensive No valves Minimal dead space Minimal resistance to breathing Economical for controlled ventilation Disadvantages The bag may get twisted and impede breathing High gas flow requirement Uses Children under 20 kg weightMapleson F The most commonly used T-piece system is the Jackson-Rees' modification of the Ayre's T-piece (sometimes known as the Mapleson F system). This system connects a two-ended bag to the expiratory limb of the circuit; gas escapes via the `tail' of the bag. : Mapleson F The most commonly used T-piece system is the Jackson-Rees' modification of the Ayre's T-piece (sometimes known as the Mapleson F system). This system connects a two-ended bag to the expiratory limb of the circuit; gas escapes via the `tail' of the bag. This allows respiratory movements to be more easily seen and permits intermittent positive ventilation if necessary. The bag is, however, not essential to the functioning of the circuit. Intermittent positive pressure ventilation (IPPV) may be performed by occluding the tail of the bag between a finger and thumb and squeezing the bag. Alternatively, a `bag-tail valve', which employs an adjustable resistance to gas flow, may be attached to the bag tail. This causes the bag to remain partially inflated and so facilitates one-handed performance of IPPV.How much FGF needed?: How much FGF needed? Mapleson Systems Uses FGF SV FGF IPPV A Magill Lack Spontaneous Gen Anaesthesia 70-100 ml/kg/min Min 3 x MV B Very uncommon, not in use today C Resuscitation Bagging Min 15 lpm D Bain Spontaneous IPPV, Gen. Anaes 150-200 ml/kg/min 70-100 ml/kg/min E Ayres T Piece Very uncommon, not in use today F Jackson Rees Paediatric <25 Kg 2.5 – 3 x MV Min 4 lpmPAE: PAE PAE is unique and different in neonates N young children cz ,:- Informant will be parent / relative There is a need to elicit :- Maternal and ante-natal history Birth history and immediate post natal history H/O consanguineous marriage & similar complaint in siblings Present illness, associated medical problems, surgical problems and other congenital anomalies.Maternal illness n its implications: Maternal illness n its implications MATERNAL HEALTH IMPLICATIONS Diabetes mellitus Neonatal hypoglycemia, macrosomia , birth injuries, RDS, cardiac & vertebral anomalies Pre- eclampsia, H.T. IUGR, Pre-term delivery, meconium aspiration Alcohol abuse Mental retardation, CHD, cleft palate & skeletal anomaliesAntenatal history n its implications: Antenatal history n its implications Maternal infections: ( TORCH ) Rubella IUGR, Ocular lesions, congenital deafness, & CHD Toxoplasmosis IUGR, Hydrocephalus & microcephaly Polyhydromnios Malformations of GI tract- TEF, Atresias Oligohydromnios Genito urinary abnormalities, pulmonary HypoplasiaBirth history and immediate post- natal history : Birth history and immediate post- natal history Gestational age at birth – Pre-term , full-term, post-term Normal delivery / caesarean delivery ( Indication) Home / Hospital delivery APGAR score at birthProblems of Pre-term neonate:- : Problems of Pre-term neonate:- Neurological problems:- Apnea of prematurity Hypoxic ischemic encephalopathy Intra ventricular haemorrhage Retinopathy of prematurity Cardiovascular system:- Patent ductus arteiosus Respiratory system:- Respiratory distress syndrome Chronic lung disease GIT and metabolic system:- Inguinal hernias Necrotizing enterocolitis Hypoglycemia Hypocalcaemia Haematologic system:- Anemia Thrombocytopenia Hyperbilirubinemia Kernicterus Others:- Hypothermia Neonatal sepsis Pneumonia & Urinary tract infection-Problems of Post-term neonate:- : Problems of Post-term neonate:- Sudden infant death syndrome Macrosomia & birth injuries Asphyxia Meconium aspiration syndrome Hypocalcaemia, seizuresGeneral Physical Examination:-: General Physical Examination:- Look for Activity of the baby •Cry -- Vigorous = Healthy Weak cry = Sick Hoarseness = Hypocalcaemia /Airway injury High pitch = CNS causes-Kernicterus ●Color—Pink Pallor Cyanosis Jaundice ● Hydration status- Fontenella Eyes & lips Skin turgour Pulse & UOPEXAMINATION: EXAMINATION Between the ages of 4 and 8 years, children must be examined for loose primary teeth . Enlarged cervical nodes and otitis media occur frequently with respiratory tract infections. Unilateral nasal discharge is unusual and suggests a foreign body (or, rarely, choanal atresia ). Vitals Systemic examination Weight(kg)= (age+3)*5 2 Look for iv lines Spine examinationExamination of the Airway:-: Examination of the Airway:- Inspect the general appearance of the head and face including the neck. Following factors are the indicators of difficult airway:- Abnormal shape of the head- Microcephaly / Hydrocephalus Dysmorphic facial appearance Presence of cleft lip / palate Receding mandible / Retrognathia Web neck Presence of neck swellings- Cystic hygroma / Cevical encephalocele / Sternocledomastoid tumorLab testing: Lab testing Elective minor sx ; CBC, S glucose For neonates with / ch illness- CBC, electrolytes,albumin , coagultion profile Pt with midline lesions- ECG,echoPsychological preparation: Psychological preparation Issues such as anaesthetic risk, plan, recovery, postop analgesia n discharge criteria have to b discussed with parents in detailPowerPoint Presentation: Risk Factors for Preoperative Anxiety Child Related Young age (1 to 5 years) Poor previous experience with medical procedures and illness Children with shy and inhibited temperament Lack of developmental maturity and social adaptability High cognitive levels Parent Related High trait and state anxiety Divorced parents Parents who had multiple surgical proceduresTo relieve child’s anxiety : To relieve child’s anxiety Behavioural intervention: Tour of operating room Written or audiovisual material Presence of parents during induction Music/ acupuncture/hypnosis Describe to the child-procedure Pharmacological ; midajolamCoexisting health condition: Coexisting health condition URTI; irritable airway, increase risk of laryngospasm, bronchospasm, o2 debt, post extubation croup, post op atelectasis More significant in child with asthama /SCD/ infants/children for bronchoscopy Bronchial hyperreactivity may persist for upto 6 weeks so decision to delay sx - risk to benefit ratioPowerPoint Presentation: OSA - adenotonsillar hypertrophy with OSA is frequent At risk of airway obstruction wth use of preop sedation/ intubation Post op pt with severe OSA may exhibit worsening of obscure symptomsPreop Fasting : Preop Fasting Purpose; to decrease risk of severe aspiration pneumonitis should regurgitation occur It is possible if gastric fluid pH <2.4 & vol >0.8ml/kg is aspirated into lungs Gastric Ph At birth:6-8 8hrs: 4 24hrs: 1-2PowerPoint Presentation: Emptying time: Formula feeds 20%>breast milk 20%>clear fluids Pt taken as full stomach if any gastric outlet obstruction, ileus, vomiting, electrolyte disorderFasting guidelines: Fasting guidelines Fasting Time ( hr ) * Age Milk and Solids Clear Liquids <6 months 4 2 6-36 months 6 3 >36 months 8 3PowerPoint Presentation: a “2-4-6-8 rule” represents the majority of institutions providing pediatric care This rule restricts clear fluids for 2 hours . Infants less than 6 months of age on breast milk require 4 hours of fasting . Older infants over 6 months of age on milk or infant formula should be fasted for 6 hours Children on solid food, including toast, cereal, and juice with pulp, such as orange juice, are usually fasted for 8 hours (or NPO after midnight)t formula should be fasted for 6 hours ;premedication: premedication Not neessary usually for <6mnths Midajolam - fruit flavored syrup to mask its bitter taste (0.3 to 0.5 mg/kg given orally) nasal (0.2 to 0.3 mg/kg) or rectal (0.3 mg/kg) routes but with their own disadvantages Ketamine Ketamine solution (6 mg/kg) diluted with fruit-flavored syrup and given orally produced effective sedation in 12 minutes Im ketamine (2.4-10mg/kg) Atropine (0.02mg/kg)orally/ im less than 45 mins before induction OTFC ( 15-20ug/kg)_- pruritis , vomiting, hypoxemia Oral clonidine (4 mcg/kg) provides satisfactory anxiolysis and sedation DEXMED 3-4ug/kg orallyOperating Room Preparation : Operating Room Preparation Warm operating room Turn on warming devices (e.g., warming blanket, intravenous line warmer, radiant light heat source ) Anesthesia Equipment DrugsPrevention of hypothermia: Prevention of hypothermia evaporative heat losses from the respiratory tract account for only about 5% to 10% of total heat loss during anesthesia , it is obvious that keeping the operating room temperature at an optimal level is crucial in the prevention of hypothermia. The major source of heat loss in the anesthetized patient is radiationHypothermia ctd: Hypothermia ctd In adults, 21°C is reported as the critical ambient temperature for maintaining normal (36° to 37.5°C) nasopharyngeal or esophageal temperatures Operating room temperatures of 27° and 29°C are recommended for full-term and premature newborns, respectively It is essential that every operating room be equipped with an individual thermistor control unitHypothermia ctd: Hypothermia ctd Radiant heaters are used during induction of anesthesia and insertion of catheters, until the patient is prepared and draped. Prolonged use of radiant heaters may result in increased insensible water losses. Also, if radiant heaters are too close to the patient, they can cause skin burns wrapping infants in reflective blankets to cover 60% of the body surface area may be cumbersome or impossible, we recommend that uninvolved skin areas be covered. Of particular concern in this regard is the head, which comprises up to 20% of the total skin surface area in a neonate and shows the highest regional heat flux abilityHypothermia ctd: Hypothermia ctd The practice of covering the head with a plastic bag easily and significantly reduces radiant, convective, and evaporative heat loss. Passive insulators are commonly used to prevent cutaneous heat loss . passive and active skin surface warmers are available, including circulating hot water blankets infrared radiant heater and convective forced-air heaters, which blow warm air through a disposable blanketHypothermia ctd: Hypothermia ctd use of warming mattresses reduces conductive heat loss. Warming mattresses set at 40°C and covered with two layers of cotton blankets have been demonstrated to effectively conserve heat It is important to warm fluids in instances of rapid or massive fluid administration solutions for intraoperative lavage should always be warmed to body temperature . Although desirable from a thermoregulatory point of view, preparation solutions should not be warmed, because heat can cause a chemical breakdown of the iodine solution and thereby inactivate its antimicrobic propertiesHypothermia ctd: Hypothermia ctd Heat and humidity can be added actively to inspired gases by evaporative or ultrasonic heated humidifiers or passively by heat and moisture exchanging filters (“artificial noses”)transportation: transportationMonitoring during induction: Monitoring during induction basic montoring : Pulse ox, ECG, BP, temp, precordial steth , ETCO2. Invasive; arterial n CV cathetersPulse oximeter: Pulse oximeter Flexible probes; can b placed Across web space b/w thumb n first finger Lat /medial aspect of hand Foot,ear,nose,tongue Esp in first 2wks of life(HBF) pulse ox do not compensate for lt shift of HB desaturation curve& pulse ox values rad about 2% higher than blood statusPrecordial steth: Precordial steth HR Heart rhythm Strength of heart sounds Breath soundscapnography: capnography Shape n magnitude of CO2 waveform ay indicate bronchospasm, endobronchial intubation, kinked ETT Drawback: inaccuracy of recording obtained with use of non rebreathing circuitInduction In infants <10-12mts : Induction In infants < 10-12mts Mask induction without premedication Allowing neonates & small infants to suck on a rubber nipple or on a gloved finger generally prevent crying during induction 70%N2O+30%O2+ 8% sevoflurane /incremental halothane It is critical to rapidly reduce the inspired concentration of halothane(1-1.5%) & sevo (2-4%) until iv line is placed Vapouriser shud b closed b4 laryngoscopy to avoid myocardial depression due to overdoseInduction in older paed pts: Induction in older paed pts Parents in OT depend on developmental level of child Vital to explain to them what they might see Inhalational / mask induction- using flavoured mask Play a game technique Single breath technique Rectal induction Methohexital / thipental /ketamine/ midajolamMAC Multiples for a Neonate Allowed by Current Vaporizer : MAC Multiples for a Neonate Allowed by Current Vaporizer Agent Maximum Vaporizer Output (%) MAC (%) Maximum Possible MAC Multiples Halothane 5 0.87 5.75 Isoflurane 5 1.20 4.2 Sevoflurane 8 3.3 2.42 Desflurane 18 9.16 1.96PowerPoint Presentation: Im Methohexital (10mg/kg ) Ketamine((2-10mg/kg ) Iv advantage in full stomach pts Disadv : securing an iv line EMLA amethocaine gelEmla cream: Emla cream (eutectic mixture of local anesthetics 2.5% lidocaine and 2.5% prilocaine EMLA cream must be applied at least 1 hour prior to iv cannulation to provide sufficient dermal analgesia The EMLA cream is placed on intact skin over a promising vein with an occlusive dressing applied over the cream. Two potential sites of venous cannulation should be prepared with EMLA cream, usually on opposite hands . EMLA sometimes causes vasoconstriction and makes the insertion of a cannula more difficult. Removing the EMLA patch 10 to 15 minutes before venipuncture and warming the site causes vasodilation and eases the cannulation . EMLA should not be used in infants under 12 months of age with glucose-6-phosphate deficiency or other children more susceptible to methemoglobinemiaMaintenance of upper airway during induction: Maintenance of upper airway during induction During induction of anesthesia, airway obstruction frequently occurs as the pharyngeal and laryngeal muscles are preferentially relax In order to maintain the airway patent, the neck must be extended, the jaw thrust forward in a sniffing position, and the mouth open in case of nasal obstruction (the triple airway maneuver), with a moderate continuous positive airway pressure (CPAP; 10 to 15 cm H2O).PowerPoint Presentation: A, Infant glottis. B, Adult glottis. Note the soft, edematous appearance of infant tissue and folded, omega (ω) or “U” shape of the infant glottisPowerPoint Presentation: Before intubation is attempted, the anesthesiologist is seated comfortably or standing at the proper height in relation to the OT table, with eye level about 1 foot above the patient's head The child's neck is moderately extended beyond a neutral position or “sniffing” position to align the oral, pharyngeal, and laryngeal axesPowerPoint Presentation: For laryngoscopy a straight blade is most commonly used. The mask is lifted and the oral airway, if used, is removed. The blade held by the left hand is moistened and inserted through the right corner of the mouth while the head is held in the extended position by the right handPowerPoint Presentation: The laryngoscope blade is now moved gently toward the midline to displace the tongue to the left . It is then advanced further toward the epiglottis, the laryngoscope handle is gently lifted forward and upward along its axis. The larynx is now exposed, and the posterior portion of the vocal cords should be visible below or behind the epiglottis The tip of the blade is advanced to lift the epiglottis directly instead of placing it in the valleculaPowerPoint Presentation: If the glottis is not easily seen, cricoid pressure can be applied with the little finger of the hand holding the handle or by an assistant, often improving the viewaIrway management In child with full stomach : aIrway management In child with full stomach In child with full stomach Most neonates who present with sx emergency are considered to be at risk of full stomach Awake intubation/ rapid sequence intubation Prep of intubating equipment & suction Preo2 of lungs Rapid induction(iv) Application of cricoid pressure Rapid onset of paralysis ( sch / rocuronium ) Intubation of trachea without ventilating lungsDifficult airway: Difficult airway Dificult airway cart Cant ventilate/ cant intubate Surgical airway Cricothyrotomy seldinger technique Armoured transtracheal catheter Iv catheterStandard Intraop monitoring: Standard Intraop monitoring Physiology Clinical observation by qualified anesthesiologist: Pt color, capillary refill, warmth of skin, muscle tone, fullness of fontanelle , chest expansion, heart n breath sounds, compliance during hand ventillation , appaearance of bleeding in surgical field Oxygenation: pulse oximeter Ventilation: stethoscope, capnograph , gas flow meter Circulation: stethoscope, blood pressure cuff Electrocardiograph Temperature probe: rectal, esophageal, or axillary Anesthetic depth: BIS monitorSupplemental intraop monitors: Supplemental intraop monitors Fluids given Urine output (catheterization and urinometer ) Blood loss Direct arterial pressure Central venous pressure Pulmonary arterial pressure and wedge pressure Cardiac output (noninvasive or invasive ) Electroencephalogram Somatosensory-evoked potentialsIntermittent intraop monitoring: Intermittent intraop monitoring Train-of-four twitch response on nerve stimulator Arterial blood gas tensions, pH hematocrit Serum levels of Na+, K+, Ca2+, glucose Colloid oncotic pressure Coagulation profileIv fluids: Iv fluids Howland measured energy consumption <1yr(3-10kg)-100kcal/kg/day Older children-75 kcal/kg/day Adults- 35 kcal/kg/day newborns Day1-70ml/kg Day 3- 80ml/kg Day 5- 90ml/kg Day 7- 120ml/kgCalculation of Maintenance Fluid Requirements for Pediatric Patients Holiday n segar : Calculation of Maintenance Fluid Requirements for Pediatric Patients Holiday n segar Weight (kg) Hourly Fluid Requirements (mL) <10 4 mL/kg 11-20 40 mL + 2 mL/kg for each kilogram above 10 >20 60 mL + 1 mL/kg for each kilogram above 20 In general deficits caused by fasting calculated by multiplying the hourly maintenance by no of hrs of fluid restrictionPowerPoint Presentation: half of the estimated fluid deficit, plus the hourly maintenance fluid requirement, should be given during the first hour of anesthesia, with a balanced salt solution such as lactated Ringer's solution ; one quarter of the fluid deficit plus the hourly maintenance fluid is infused during the second and third hours of anesthesia and surgery , and the replacement of any third-space fluid loss Third space loss 1ml/kg/ hr -for minor sx 15ml/kg/ hr for major abdominal sx Fever increases caloric requirement by 10-12% for every centigrade rise in temp above normalType of fluid: Type of fluid no longer recommend routine use of glucose-containing solutions, especially for brief operative procedures . a balanced salt solution (e.g., lactated Ringer's solution) should be used for all deficits and third-space losses . If a child is thought to be at risk for hypoglycemia, 5% dextrose in 0.45% normal saline should be administered by “piggyback” infusion at maintenance rates . This minimizes the chance of a bolus administration of glucose and satisfies the concern for unrecognized hypoglycemia or accidental hyperglycemia.PowerPoint Presentation: Children receiving intravenous alimentation present a special problem. Transition to 10% glucose is often recommended to avoid intraoperative hyperglycemia with continuation of the current alimentation fluid and to avoid hypoglycemia if it is stopped suddenly reduce the established intravenous alimentation fluid infusion rate by 33% to 40% (to account for the reduced metabolic rate under anesthesia) and periodically check blood glucose values.Transfusion therapy: Transfusion therapy Blood loss<10% BV-no replacement or crystalloid 10-20%- colloids or blood > 20%- blood Estimated Blood volume Preterm-100-120ml/kg Full term infant-90ml/kg 3-12mths-80ml/kg >1yr-70ml/kgPowerPoint Presentation: MABL= EBV*(starting hct -target hct ) hematocrit of PRBC’S MABL replaced with 3ml of RL/ml of blood loss The most common blood component used is packed red blood cells, which have a hematocrit value between 70% and 80%. An average of 1 m L/kg packed red blood cells raises the hematocrit value by 1.5 %. Vol of PRBC’s to b transfused= Desired HCT-present HCT*EBV HCT of PRBC’sFfp’s: Ffp’s to replenish clotting factors lost during massive blood transfusion (usually defined as blood loss exceeding one blood volume ), for disseminated intravascular coagulopathy, or for congenital clotting factor deficit . need FFP until blood loss exceeds 1 and probably 1.5 blood volumes . This generalization applies to children given PRBCs ; children given whole blood will not need FFP, even when blood loss exceeds several blood volumes.ffp: ffp Transfusion of FFP at rates exceeding 1.0 mL/kg/min is sometimes followed by severe ionized hypocalcemia because of their decreased ability to mobilize calcium and metabolize citrate; exogenous calcium chloride (2.5 to 5 mg/kg) or calcium gluconate (7.5 to 15 mg/kg) should be administered during rapid transfusion of FFPPostoperative Pain Control for Neonates and Infants: Postoperative Pain Control for Neonates and Infants Intravenous Opioids: morphine, fentanyl, methadone NSAIDs: ketorolac Oral Acetaminophen(20 mg/kg) Ibuprofen(5 mg/kg ) Hydrocodone(0.1 mg/kg). Codeine (0.5 mg/kg) Rectal Acetaminophen(20 to 30 mg/kg) Diclofenac Regional and local anesthesiaRegional Anesthesia Techniques Useful in Neonates: Regional Anesthesia Techniques Useful in Neonates Central neuraxial Caudal Epidural (lumbar, thoracic, caudal) Spinal Peripheral nerve blocks Infraorbital block Brachial plexus block (axillary, infraclavicular ) Lateral femoral cutaneous block Penile block Ilioinguinal block Scalp blocksCaudal block: Caudal block landmarks are the coccyx, the two sacral cornua , and the posterior superior iliac spines The sacral cornua are identified. A styletted needle is introduced into the caudal space through the sacral hiatus. A “pop” is felt as the sacrococcygeal ligament is accessed. After aspiration, 0.8 mL/kg of local anesthetic solution is injected. This provides analgesia for hernia repair, circumcisions, and lower abdominal surgeriesThank you: Thank you