Endotracheal intubation - Mechanical Ventilation & weaning: Endotracheal intubation - Mechanical Ventilation & weaning Prepared by dr.Mustafa Khreshy Under supervision of Dr. kathem Abu Zant Slide 2: Endotracheal intubation Routes of Endotracheal Intubation: Routes of Endotracheal Intubation Nasotracheal Orotracheal Pericutaneous Cricothyroidotomy Tracheotomy OBJECTIVE MEASURES INDICATING THE NEED FOR INTUBATION: OBJECTIVE MEASURES INDICATING THE NEED FOR INTUBATION RR >35 VC <15 ml/kg PaO2 <60 on >40% PaCO2 >50 (except in chronic retainers) A-a gradient > 300 on 100% oxygen INDICATION FOR ENDOTRACHEAL INTUBATION: INDICATION FOR ENDOTRACHEAL INTUBATION 1) For supporting ventilation in patient with some pathologic disease U pper airway obstruction R espiratory failure L oss of conciousness INDICATION FOR ENDOTRACHEAL INTUBATION (CON’T): INDICATION FOR ENDOTRACHEAL INTUBATION (CON’T ) 2 ) For supporting ventilation during general anesthesia Type of surgery Operative site near the airway Abdominal or thoracic surgery INDICATION FOR ENDOTRACHEAL INTUBATION (CON’T) : INDICATION FOR ENDOTRACHEAL INTUBATION (CON’T) Prone or lateral position Long period of surgery Patient has risk of pulmonary aspiration Difficult mask ventilation Complication of endotracheal intubation: Complication of endotracheal intubation 1 ) During intubation Trauma to lip, tongue or teeth Hypertension and tachycardia or arrhythmia Pulmonary aspiration Laryngospasm Bronchospasm Complication of endotracheal intubation (Con’t): Complication of endotracheal intubation (Con’t ) 1) During intubation Laryngeal edema A rytenoid dislocation -> hoarseness Increased intracranial pressure Spinal cord trauma in cervical spine injury Esophageal intubation Complication of endotracheal intubation(Con’t): Complication of endotracheal intubation(Con’t ) Obstruction from kinking , secretion or overinflation of cuff Accidental extubation or endobronchial intubation Disconnection from breathing circuit 2) During remained intubation Complication of endotracheal intubation(Con’t): Complication of endotracheal intubation(Con’t ) 2) During remained intubation Pulmonary aspiration Lib or nasal ulcer in case with prolong period of intubation Sinusitis or otitis in case with prolong nasoendotracheal intubation Complication of endotracheal intubation(Con’t): 3) During extubation Laryngospasm Pulmonary aspiration Edema of upper airway Complication of endotracheal intubation(Con’t ) Complication of endotracheal intubation(Con’t): Complication of endotracheal intubation(Con’t ) 4) After extubation Sore throat Hoarseness Tracheal stenosis (Prolong intubation ) Laryngeal granuloma Care of ETT: Care of ETT The distance from the tip of the ETT to the lips should be ~22-24 cm The tube can move by as much as 4 cm with changes in neck position (flexion vs extension) High cuff inflation pressure (>20 cm H2O), oversized ETT, head movement, and prolonged intubation cause pressure-induced ulcers, granulation tissue, and eventually tracheal stenosis Slide 15: Mechanical ventilation Mechanical Ventilation: Mechanical Ventilation Definition: Positive pressure ventilation provides pressure and flow to the airway in order to effect Oxygen and CO 2 transport between the environment & pulmonary capillary bed. Indications for Mechanical Ventilation: Indications for Mechanical Ventilation Acute Respiratory Failure (66%) Acute Respiratory Distress Syndrome Heart Failure (through pulmonary edema/hypertension) Pneumonia Sepsis Complications of Surgery Trauma Head injury Coma (15%) Acute Exacerbation of Chronic Obstructive Pulmonary Dz (13%) Neuromuscular Disease (5%) Abnormalities suggestive of the need for mechanical ventilation : Abnormalities suggestive of the need for mechanical ventilation Parameter Value Loss of ventilatory reserve Respiratory rate >35 breaths/min Tidal volume <5 mL/kg Vital capacity <10 mL/kg Negative inspiratory force Weaker than -25 cmH20 Minute ventilation <10 L/min Rise in PCO2 >10 mmHg Refractory hypoxemia Alveolar-arterial gradient (FiO2 = 1.0) >450 PaO2/PAO2 <0.15 PaO2 with supplemental O2 <55 mmHg Discontinuing Mechanical Ventilation: Discontinuing Mechanical Ventilation Death Weaning Up to 25% of patients have respiratory distress severe enough to require reinstitution of ventilator. Extubation 10 - 20 % of extubated patients who were successfully weaned require reintubation . Modes Of Ventilation: Modes Of Ventilation Mechanical ventilation is sometimes classified according to the mechanism used to terminate inspiration. Specifically , mechanical ventilation can be volume-, pressure-, flow-, or time-limited Slide 21: MODE INDICATION ADVANTAGE/ DISADVANTAGE SPECIAL MONITORING A/C Used as initial mode of ventilation Ad: ensures vent. Support during every breath Each breath same Vt Dis : hyperventilation , air trapping Work of breathing may be increased if sensitivity or flow rate is too low SIMV Used as initial mode of ventilation or weaning Ad : allows spontaneous breath Weaning is accomplished by gradually lowering the set rate and allowing the Pt to assume more work Dis : Pt-ventilator asynchrony possible PSV Intact Respiratory drive in Pt necessary Used as weaning mode , and in some cases of dyssynchrony Ad : decreases work of breathing, increases Pt comfort Dis : should not be used in Pt with bronchospasm Adjust PSV level to maintain desired RR and Vt , monitor for changes in compliance, which can cause Vt to change, monitor RR and Vt at least hourly PCV Used to limit plateau pressure that can cause barotrauma Severe ARDS DIS : Pt-ventilator asynchrony possible , necessitating sedation/paralysis Monitor Vt at least hourly , monitor for barotrauma , hemodynamic instability IRV Usually used in conjunction with PCV, increases ratio I:E to allow for recruitment of alveoli and improve oxygenation Dis: almost requires paralysis Monitor for auto-PEEP ,barotrauma , hemodynamic instability Slide 22: Mode Indication Advantage/ Disadvantage Special Monitoring CPAP Constant positive airway pressure for Pts who breathe spontaneously Ad : used in intubated or nonintubated Pts Dis: on some systems, no alarm if respiratory rate fails work of Monitor for increased breathing Non invasive (Bi-Pap) Nocturnal hypoventilation in Pts with neuromuscular disease , chest wall deformity, obstructive sleep apnea, COPD, to prevent intubation , to prevent reintubation initially after extubation Ad : decreases cost when Pts can be cared for at home ; no need for artificial airway Dis : Pt discomfort or claustrophobia Monitor for gastric distension , air leaks from the mouth VGPO combines advantages of pressure ventilation with guaranteed Vt Ad : ensures a delivered Vt Dis : requires sophisticated knowledge of the mode and waveform analysis Modes Of Mechanical Ventilation: Modes Of Mechanical Ventilation Controlled Mechanical Ventilation Assist-Control Ventilation Synchronized Intermittent Mandatory Ventilation (SIMV) Pressure-Support Ventilation (PSV) Pressure-Controlled Ventilation Continuous Positive Airway Pressure (CPAP) Controlled Mechanical Ventilation: Controlled Mechanical Ventilation Preset rate and tidal volume No patient interaction with ventilator Advantages: rests muscles of respiration Disadvantages: requires sedation/neuro-muscular blockade, potential adverse hemodynamic effects Assist-Control Ventilation: Assist-Control Ventilation Preset tidal volume and minimal ventilator rate Additional patient-initiated breaths receive preset tidal volume Advantages: reduced work of breathing; allows patient to modify minute ventilation Disadvantages: potential adverse hemodynamic effects or inappropriate hyperventilation Synchronized Intermittent Mandatory Ventilation (SIMV): Synchronized Intermittent Mandatory Ventilation (SIMV) Preset tidal volume at a preset rate Additional spontaneous breaths at tidal volume and rate determined by patient Often used with pressure support SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV): SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV) Potential advantages Better patient-ventilator interaction Less hemodynamic effects Potential disadvantages Higher work of breathing than CMV, AC Pressure-Support Ventilation (PSV): Pressure-Support Ventilation (PSV) Pressure assist during spontaneous inspiration Pressure assist continues until inspiratory effort decreases Delivered tidal volume dependent on inspiratory effort and resistance/compliance of lung/thorax Pressure-Support Ventilation: Pressure-Support Ventilation Potential advantages Patient comfort Less WOB than spontaneous breathing May enhance patient-ventilator synchrony Used with SIMV to support spontaneous breaths Pressure-Support Ventilation: Pressure-Support Ventilation Potential disadvantages Variable tidal volume if pulmonary resistance/compliance changes rapidly If sole mode of ventilation, apnea alarm is only backup Gas leak from circuit may interfere with cycling Pressure-Controlled Ventilation: Pressure-Controlled Ventilation Used to limit inflationary pressures Allows setting of inspiratory time Complexity of interacting ventilatory variables necessitates critical care consultation Continuous Positive Airway Pressure (CPAP): Continuous Positive Airway Pressure (CPAP) No machine breaths delivered Allows spontaneous breathing at elevated baseline pressure Patient controls rate and tidal volume Slide 33: Ventilator management algorithim Initial intubation FiO 2 = 50% PEEP = 5 RR = 12 – 15 V T = 8 – 10 ml/kg S a O 2 < 90% S a O 2 > 90% S a O 2 > 90% Adjust RR to maintain PaCO 2 = 40 Reduce FiO 2 < 50% as tolerated Reduce PEEP < 8 as tolerated Assess criteria for SBT daily S a O 2 < 90% Increase FiO 2 (keep S a O 2 >90%) Increase PEEP to max 20 Identify possible acute lung injury Identify respiratory failure causes Acute lung injury No injury Fail SBT Acute lung injury Low T V (lung-protective) settings Reduce T V to 6 ml/kg Increase RR up to 35 to keep pH > 7.2, P a CO 2 < 50 Adjust PEEP to keep FiO 2 < 60% S a O 2 < 90% S a O 2 > 90% S a O 2 < 90% Dx/Tx associated conditions (PTX, hemothorax, hydrothorax) Consider adjunct measures (prone positioning, HFOV, IRV) S a O 2 > 90% Continue lung-protective ventilation until: PaO 2 /FiO 2 > 300 Criteria met for SBT Persistently fail SBT Consider tracheostomy Resume daily SBTs with CPAP or tracheostomy collar Pass SBT Airway stable Extubate Intubated > 2 wks Consider PSV wean (gradual reduction of pressure support) Consider gradual increases in SBT duration until endurance improves Prolonged ventilator dependence Pass SBT Pass SBT Airway stable Modified from Sena et al, ACS Surgery: Principles and Practice (2005). Complication of Mechanical Ventilation: Complication of Mechanical Ventilation Pulmonary effects of positive pressure ventilation include pulmonary barotrauma, ventilator-associated lung injury, intrinsic positive end expiratory pressure (auto-PEEP), heterogeneous ventilation, increased physiologic dead space, decreased physiologic shunting, diaphragmatic muscle atrophy, respiratory muscle weakness, and diminished mucociliary motility. Auto-PEEP exists when there is positive airway pressure at the end of expiration due to incomplete exhalation. It exacerbates the hemodynamic effects of positive pressure ventilation, increases the risk of pulmonary barotrauma, and makes it more difficult for the patient to trigger a ventilator-assisted breath. Detection of auto-PEEP should prompt immediate ventilator setting changes, efforts to reduce ventilatory demand, and efforts to reduce expiratory flow resistance. Positive pressure ventilation may reduce cardiac output and impair hemodynamic monitoring. In addition, it is associated with gastrointestinal stress ulceration, decreased splanchnic perfusion, gastrointestinal hypomotility, fluid retention acute renal failure, increased intracranial pressure, weakness, inflammation , and disordered sleep Slide 35: WEANING Definition of Weaning: Definition of Weaning The transition process from total ventilatory support to spontaneous breathing. This period may take many forms ranging from abrupt withdrawal to gradual withdrawal from ventilatory support. Weaning: Criteria: Weaning : Criteria Adequate oxygenation Hemodynamically stable Correction of underlying lung disease Correction of acid-base/electrolyte disorders Adequate nutrition Mentally alert Avoidance of sedation Oxygenation Status : Oxygenation Status Pa O2 ≥ 60 mm Hg Fi O2 ≤ 0.40 PEEP ≤ 5 cm H 2 O Ventilation Status: Ventilation Status Intact ventilatory drive: ability to control their own level of ventilation Respiratory rate < 30 Minute ventilation of < 12 L to maintain Pa CO2 in normal range V D /V T < 60% Functional respiratory muscles Intact Airway Protective Mechanism: Intact Airway Protective Mechanism Appropriate level of consciousness Cooperation Intact cough reflex Intact gag reflex Functional respiratory muscles with ability to support a strong and effective cough Function of Other Organ Systems: Function of Other Organ Systems Optimized cardiovascular function Arrhythmias Fluid overload Myocardial contractility Body temperature 1 ◦ degree increases CO 2 production and O 2 consumption by 5% Normal electrolytes Potassium, magnesium, phosphate and calcium Adequate nutritional status Under- or over-feeding Optimized renal, Acid-base, liver and GI functions Weaning: Predictors (Parameters): Weaning: Predictors (Parameters ) Respiratory Rate < 30/min Spontaneous V t > 4 ml/kg Inspiratory Pressure > - 20 cm H 2 O Breathing Index (f/ V t ) < 105 PEEP < 8 cmH 2 O PaO 2 /FIO 2 > 200 FIO 2 < .50 Weaning: Weaning What methods of weaning are there? T-piece trial Spontaneous trial on ventilator (CPAP = 0) SIMV Pressure Support Ventilation (PSV) SIMV + PSV Extubation + noninvasive ventilation Spontaneous Breathing Trials: Spontaneous Breathing Trials SBT to assess extubation readiness T-piece or CPAP 5 cm H2O 30-120 minutes trials If tolerated, patient can be extubated SBT as a weaning method Increasing length of SBT trials Periods of rest between trials and at night Slide 45: Daily SBT <100 Mechanical Ventilation RR > 35/min Spo2 < 90% HR > 140/min Sustained 20% increase in HR SBP > 180 mm Hg, DBP > 90 mm Hg Anxiety Diaphoresis 30-120 min PaO2/FiO2 ≥ 200 mm Hg PEEP ≤ 5 cm H2O Intact airway reflexes No need for continuous infusions of vasopressors or inotrops RSBI Extubation No > 100 Rest 24 hrs Yes Stable Support Strategy Assisted/PSV 24 hours Low level CPAP (5 cm H2O), Low levels of pressure support (5 to 7 cm H2O) “T-piece” breathing Pressure Support: Pressure Support Gradual reduction in the level of PSV PSV that prevents activation of accessory muscles Gradula decrease on regular basis (hours or days) to minimum level of 5-8 cm H2O Once the patient is capable of maintaining the target ventilatory pattern and gas exchange at this level, MV is discontinued SIMV: SIMV Gradual decrease in mandatory breaths It may be applied with PSV Has the worst weaning outcomes in clinical trials Its use is not recommended Failure to Wean: Failure to Wean Weaning to exhaustion Auto-PEEP Excessive work of breathing Poor nutritional status Overfeeding Left heart failure Decreased magnesium and phosphate leves Infection/fever Major organ failure Technical limitation Weaning to Exhaustion: Weaning to Exhaustion RR > 35/min Spo2 < 90% HR > 140/min Sustained 20% increase in HR SBP > 180 mm Hg, DBP > 90 mm Hg Anxiety Diaphoresis Auto-PEEP: Auto-PEEP Increases the pressure gradient needed to inspire Use of CPAP is needed to balance alveolar pressure with the ventilator circuit pressure Start at 5 cm H2O, adjust to decrease patient stress Inspiratory changes in esophageal pressure can be used to titrate CPAP Work-of-Breathing: Work-of-Breathing Pressure= Volume/compliance+ flow X resistance High airway resistance Low compliance Aerosolized bronchodilators, bronchial hygiene and normalized fluid balance assist in normalizing compliance, resistance and work-of-breathing Left Heart Failure: Left Heart Failure Increased metabolic demands that are associated with the transition from mechanical ventilation to spontaneous breathing Increases in venous return as that is associated with the negative pressure ventilation and the contracting diaphragm which results into an increase in PCWP and pulmonary edema Appropriate management of cardiovascular status is necessary before weaning will be successful Nutritional/Electrolytes: Nutritional/Electrolytes Imbalance of electrolytes causes muscular weakness Nutritional support improves outcome Overfeeding elevates CO2 production due to excessive carbohydrate ingestion Infection/Fever/Organ Failure: Infection/Fever/Organ Failure Organ failure precipitate weaning failure Infection and fever increase O2 consumption and CO2 production resulting in an increase ventilatory drive The End: The End Are there any Questions?????