SPINAL AND EPIDURAL

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SPINAL AND EPIDURAL

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SPINAL AND EPIDURAL ANAESTHESIA: 

SPINAL AND EPIDURAL ANAESTHESIA PRESENTED BY ---- Dr. KHAWER MUNEER MODERATOR ---- Dr. JAVED IQBAL

Objectives : 

Objectives 2 HAVE A BASIC UNDERSTANDING OF Anatomic structure of spine and vertebra Anatomic structure of spinal cord Blood supply of spinal cord Features of neuraxial blockade Indications/ contraindications Patient evaluation and preparation Techniques Local anesthetics and factors effecting spread complications

BRIEF HISTORY OF SPINAL ANAESTHESIA : 

BRIEF HISTORY OF SPINAL ANAESTHESIA CSF DISCOVERED ---- by Domenico Catugno 1764 CSF CIRCULATION---- by F . Magendie 1825 FIRST SPINAL ANALGESIA--- by J Leonard Corning 1885 FIRST PLANNED SPINAL ANAESTHESIA--- by August Bier in 1891 The epidural space was first described by Corning in 1901, and Fidel Pages first used epidural anaesthesia in humans in 1921.

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ANATOMY cervical vertebrae (7) thoracic vertebrae (12) lumbar vertebrae (5) sacral vertebrae (5) coccygeal vertebrae (4 )

LUMBAR VERTEBRA: 

LUMBAR VERTEBRA

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SPINAL CORD ADULTS– approx L1 CHILDREN--approx L3

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ARTERIAL SUPPLY OF SPINAL CORD

DERMATOMES: 

DERMATOMES A dermatome is an area of skin innervated by sensory fibers from a single spinal nerve

Dermatomal Levels of Spinal Anesthesia for Common Surgical Procedures: 

Dermatomal Levels of Spinal Anesthesia for Common Surgical Procedures Procedure Dermatomal Level Upper abdominal surgery T4 Intestinal, gynecologic , and urologic surgery Transurethral resection of the prostate T6 Vaginal delivery of a fetus , and hip surgery T10 Thigh surgery and lower leg amputations L1 Foot and ankle surgery L2 Perineal and anal surgery S2 to S5 (saddle block)

PHYSIOLOGICAL EFFECTS OF NEURAXIAL BLOCKADE : 

PHYSIOLOGICAL EFFECTS OF NEURAXIAL BLOCKADE Vasomotor tone determined by sympathetic fibers arising from T5 to L1 innervating arterial & venous smooth muscle. A ↓ in blood pressure that may be accompanied by ↓ in heart rate. With high sympathetic block, sympathetic cardiac accelerator fibers arising at T1-T4 are blocked, leading to ↓ cardiac contractility. Bezold-Jarisch reflex has been implicated as a cause of bradycardia , hypotension and cardiovascular collapse after central neuraxial anaesthesia , in particular spinal anaesthesia . CARDIOVASCULAR EFFECTS:

Pulmonary effects:: 

Pulmonary effects: Even with high thoracic levels, tidal volume is unchanged. A small decrease in vital capacity due to paralysis of abdominal muscles necessary for forced exhalation & not due to decrease in phrenic nerve or diaphragmatic function. Effective coughing & clearing of secretions may get affected with higher levels of block. Rare respiratory arrest associated with spinal anaesthesia due to hypoperfusion of respiratory centers in brain stem.

Gastrointestinal function:: 

Gastrointestinal function: Nausea and vomiting in upto 20% patients due to gastrointestinal hyperperistalsis caused by unopposed parasympathetic( vagal ) activity. Vagal tone dominance results in small contracted gut with active peristalsis & can provide excellent operative conditions for some laproscopic procedures when used as an adjunct to GA. Hepatic blood flow will ↓ with reductions in mean arterial pressure.

Renal function:: 

Renal function: Renal function has a wide physiological reserve. ↓ in renal blood flow is of little physiological importance. Neuraxial blocks are a frequent cause of urinary retention which delays discharge of outpatients & necessitates bladder catheterization in inpatients.

COMMON INDICATIONS OF NEURAXIAL ANAESTHESIA: 

COMMON INDICATIONS OF NEURAXIAL ANAESTHESIA SPINAL 1. lower extremities 2. pelvic /lower abdomen 3. pain mgmt intra/post operative (narcotics) EPIDURAL 1. similar surgeries as spinal 2. labour and delivery 3. post op pain mgmt 4. chronic pain mgmt 5. in combination with GA for abdominal & thoracic procedures.

CONTRAINDICATIONS: 

CONTRAINDICATIONS ABSOLUTE 1. patients refusal 2.coagulopathy 3. infection at local site 4. severe hypovolemia 5. increased ICT 6. allergy to drugs 7. shock 8. sever AS or MS RELATIVE 1. uncoperative pt 2. preexisting neurological deficits 3. demyelinating lesions 4. severe spinal deformity 5. infection at site remote from infection 6. sepsis

SEQUENCE OF ONSET: 

SEQUENCE OF ONSET Principal site of action is the nerve root. Sequence of onset depends on conc. of LA achieved, duration of contact, size & myelination of nerve fibers. CLINICALLY OBSERVED SEQUENCE Sympathetic nervous system fibers (B fibers: vasodilation , skin temp ↑) Temperature & pain conduction (A & C fibers) Proprioception & touch (A γ & A β fibers) Motor function (A fibers)

Summary: 

Summary Medication Preparation Dose Lower Limbs Dose Lower Abdomen Dose Upper Abdomen Procaine 10% Solution 75 mg 125 mg 200 mg Lidocaine 5% Solution in 7.5% dextrose 25-50 mg 50-75 mg 75-100 mg Tetracaine 1% Solution in 10% glucose or as niphanoid crystals 4-8 mg 10-12 mg 10-16 mg Bupivacaine 0.5-0.75% Isobaric Solution 0.5-0.75% Hyperbaric Solution in 8.25% Dextrose Hypobaric Solution 4-10 mg 12-14 mg 12-18 mg Ropivacaine 0.2—1% solution 8-12mg 12-16 16-18 DOSAGE AND ACTIONS OF COMMONLY USED SPINAL ANESTHETIC DRUGS

Factors Affecting the Level of Spinal Anesthesia : 

Factors Affecting the Level of Spinal Anesthesia MOST IMPORTANT FACTORS Baricity of the drug Position of the patient Drug dosage Site of injection OTHER FACTORS Age Csf Curvature of Spine Intraabdominal Pressure Needle direction Patient Height Pregnancy Weight of pt

PROCEDURE PREPERATION: 

PROCEDURE PREPERATION Remove your jewellery /watches Wash your hands I.V access/fluids bolus if needed Emergency drugs /equipment Position Sedation if needed Monitoring NIBP/SPO2/ECG Verbal contact with pt

POSITIONING 1. Sitting 2. Lateral 3. Prone TECHNIQUES FOR SPINAL 1. Midline 2. Paramedian 3. Taylor approach The structures that will be passed in spinal : Skin , subcutaneous tissue, supraspinous ligament , interspinous ligament , lagementum flavum , dura mater , subdural space , arachnoid matter,subarachnoid space in midline approach

SPECIFIC TECHNIQUES FOR EPIDURAL : 

SPECIFIC TECHNIQUES FOR EPIDURAL LOSS OF RESISTANCE HANGING DROP AGENTS FOR EPIDURAL ANAESTHESIA AGENT CONCENTRATION ONSET SENSORY BLOCK MOTOR BLOCK CHLOROPROCAINE 2% 3% Fast Fast Analgesic Dense Mild to mod dense LIDOCAINE <1% 1.5% 2% Intermediate Intermediate Intermediate Analgesic Dense Dense Minimal Mild to mod dense BUPIVICAINE <0.25% 0.5% 0.75% Slow Slow Slow Analgesic Dense Dense Minimal Mild to mod Mod to dense ROPIVICAINE 0.2% 0.5% 0.75%--1.0% Slow Slow Slow Analgesic Dense Dense Minimal Mild to mod Mod to dense

EPIDURAL NEEDLES : 

EPIDURAL NEEDLES

SPINAL NEEDLES : 

SPINAL NEEDLES

COMPLICATIONS/SIDE EFFECTS OF NEURAXIAL ANESTHESIA: 

COMPLICATIONS/SIDE EFFECTS OF NEURAXIAL ANESTHESIA Systemic toxicity Hypotension Postdural Puncture Headache High Spinal Anesthesia Total spinal anaesthesia Neurological complications Arachnoiditis / Meningitis Spinal / Epidural Hematoma Formation Epidural Abscess Backache Urinary retension Pruritus

POSTDURAL PUNCTURE HEADACHE: 

POSTDURAL PUNCTURE HEADACHE ONSET= 12—72 hrs it is postural and it is often fronto --occipital associated with stiff neck , nausea, vomiting , dizziness and photophobia. CAUSE---loss of CSF at a faster rate than it can be produced causing traction on the structures supporting brain, particularly dura and tentorium . INCIDENCE---25% FACTORS---that increase the risk are young age,female,pregnancy,large gauge needle, multiple punctures It is aggravated by sitting or standing and decreased or relieved by lying down flat. TREATMENT----- conservative t/t involves recumbent position, analgesics, i.v or oral fluids and caffeine. 29

Epidural Blood Patch: 

Epidural Blood Patch The epidural blood patch consists of injecting 5-20 mLs of autologous blood into the epidural space, in the region of the suspected dural 'hole.' Autologous blood is typically drawn in a sterile fashion, and then injected as a bolus into the epidural space. In 90% of cases, the response is positive and immediate. Subsequently, long-term relief of PDPH occurs in the majority of cases

HIGH NEURAL BLOCKADE ,HIGH SPINAL AND TOTAL SPINAL ANAESTHESIA: 

HIGH NEURAL BLOCKADE ,HIGH SPINAL AND TOTAL SPINAL ANAESTHESIA Can occur both with spinal and epidural Admins . Of an excessive dose,failure to reduce doses in selected pts ( elderly,pregnant,obese , very short) or unusual sensitivity or spread of LA maybe responsible SA ascending into cervical level causes severe hypotension,bradycardia and respiratory insufficiency and even apnea Total spinal can occur following attempted epidural/caudal anesthesia if there is inadvertent intrathecal injection TREATMENT--- vasopressors,atropine , fluids,oxygen ,assisted ventillation and even intubation and mechanical ventillation may be needed

TRANSIENT NEUROLOGICAL SYMPTOMS AND CAUDA EQUINA SYNDROME: 

TRANSIENT NEUROLOGICAL SYMPTOMS AND CAUDA EQUINA SYNDROME TNS or transient radicular irritation refers to pain , dysesthesia or both in the legs or buttocks after spinal anesthesia, resolving spontaneously within several days Most common with hyperbaric lidocaine and after surgery in lithotomy position CES characterized by bowel and bladder dysfunction together with evidence of multiple nerve root injury, assoc with use of continous spinal catheters and 5% lidocaine

NEURAXIAL BLOCKADE IN SETTING OF ANTICOAGULANTS AND ANTIPLATELET AGENTS---AMERICAN SOCIETY FOR REGIONAL ANESTHESIA RECOMMENDATIONS: 

NEURAXIAL BLOCKADE IN SETTING OF ANTICOAGULANTS AND ANTIPLATELET AGENTS---AMERICAN SOCIETY FOR REGIONAL ANESTHESIA RECOMMENDATIONS Pts taking NSAIDS or receiving subcutaneous unfractioned heparin for DVT prophylaxsis are not viewed as being at increased risk of spinal hematoma DISCONTINUE--- ticlopidine 2 weeks, clopidogrel for 1 week , abciximab 24 to 48 hrs, eptifibate and tirofiban 4 to 8 hrs before performing central neuraxial block. Pt who are fully anticoagulated or who are receiving thrombolytic or fibrinolytic theraphy should not receive central neuraxial block except in very unusual circumstances where other options are not viable. Delay atleast 10 -12 hrs after last dose of LMWH Post op t/t with LMWH delay 12hrs after compl of surgery Removal of epi , spi catheters should take place 10—12hrs after last dose with subs dosing delay for atleast 2hrs.

Advantages of spinal anesthesia (SPA): 

Advantages of spinal anesthesia (SPA) 1. Cost. The costs associated with SPA are minimal. 2. Patient satisfaction. the majority of patients are very happy with this technique. 3. Respiratory disease. SPA produces few adverse effects on the respiratory system as long as unduly high blocks are avoided. 4. Patent airway. As control of the airway is not compromised, there is a reduced risk of airway obstruction or the aspiration of gastric contents. 5. Diabetic patients. There is little risk of unrecognised hypoglycaemia in an awake patient.

Advantages of spa contd: 

Advantages of spa contd 6. Muscle relaxation. SPA provides excellent muscle relaxation for lower abdominal and lower limb surgery. 7. Bleeding. Blood loss during operation is less than when the same operation is done under general anaesthesia 8. Splanchnic blood flow. Because of its effect on increasing blood flow to the gut, spinal anaesthesia reduces the incidence of anastomotic dehiscence 9. Visceral tone. The bowel is contracted by SPA and sphincters relaxed although peristalsis continues. Normal gut function rapidly returns following surgery. 10. Coagulation. Post-operative deep vein thromboses and pulmonary emboli are less common following spinal anaesthesia.

Differences between Spinal and Epidural Anesthesia : 

Differences between Spinal and Epidural Anesthesia Spinal anaesthesia Epidural Anaesthesia Level: below L1/L2, where the spinal cord ends Level: at any level of the vertebral column. Injection: subarachnoid space i.e punture of the dura mater Injection: epidural space (between Ligamentum flavum and dura mater) i.e without punture of the dura mater Identification of the subarachnoid space: When CSF appears Identification of the Peridural space: Using the Loss of Resistance technique. Dosis : 2.5- 3.5 ml bupivacaine 0.5% heavy Doses : 15- 20 ml bupivacaine 0.5% Onset of action: rapid (2-5 min) Onset of action: slow (15-20 min) Density of block: more dense Density of block: less dense Hypotension: rapid Hypotension: slow Headache: is a probably complication Headache: is not a probable. 37

Regional vs general anaesthesia : 

Regional vs general anaesthesia

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THANK YOU