PEDIATRIC REGIONAL ANESTHESIA

1. PEDIATRIC REGIONAL ANESTHESIA Jodie L. Johnson, M.D. Assistant Professor of Clinical Anesthesia Riley Hospital for Children

2. Introduction • Regional anesthesia being used more frequently in pediatric setting • Most blocks placed at beginning of case • “preemptive analgesia” • Some placed at end • Rarely used as sole anesthetic

3. General Principles • Must acquire experience/dexterity with RA in adults before employing techniques in kids • Be aware of anatomical differences between small child and adult • Be aware of pharmacokinetic differences

4. General Principles • Consider individual drug profiles • Skin infection in area of needle/catheter insertion is contraindication • Coagulation disorders are contraindication (unless corrected) • Chemotherapeutic agents cause vascular fragility and thus central blocks are contraindicated in pts on chemo

5. General Principles • Have clear strategy • Good organization of equipment, drugs and assistant helps avoid delays • Close monitoring just as important as with GA

6. General Principles • Significant development in regional anesthesia in peds due to: • Advances in safety information • Advances in pharmacology(Ropivicaine) • Improvements in equipment • Types of blocks limited only by skill and interest of individual anesthesiologist

7. Benefits • Analgesia provided by block reduces amount of GA • More rapid recovery • Decreased incidence of nausea & vomiting • Faster return of appetite • Earlier discharge • Decreased need for opioids

8. Benefits • Regional block eliminates undesirable autonomic reflexes • Laryngospasm decreased • Cardiac dysrhythmias decreased • Muscle relaxation can be obtained with suitable local anesthetic • Can avoid use of muscle relaxants, decrease risk of respiratory insufficiency

9. Benefits • Easier to obtain immobilization of limb after delicate surgery if child is pain-free and there is some residual motor block

10. Benefits • Hypotension and urinary retention rarely seen in children • Intra- and post-operative bleeding reduced under neural blockade • A technique of choice if history of MH • Can avoid interference with respiratory tract in premies with BPD

11. Benefits • Diminished stress response • Fewer episodes of hypoxia • Greater cardiovascular stability • Faster return of GI function • Reduced need for postop vent support • Shorter stay in ICU

12. Safety • Low complication rates • Lack of hypotensive response from sympathectomy produced by LA • Loose perineurovascular sheaths • Wider spead of LA from single injection site

13. Pharmacology and Physiology • Increased risk of toxicity with local anesthetics • Infants have immature hepatic metabolism • Increased total body water • Larger Volume of Distribution • Longer elimination half-life • Decreased plasma proteins ( more drug in free/active form) • Rapid increase in blood levels due to higher cardiac output/regional blood flow

14. Pharmacology • Long-acting local anesthetics provide for 6-12 hours of post-operative pain relief • Bupivicaine 0.2% to 0.5% • Ropivicaine 0.2%

15. Pharmacology • Strictly follow maximal dosing guidelines to prevent side effects

16. Physiology • Decreased minimum anesthetic concentration required to block impulse conduction • Nerves have thinner myelin sheaths • Nerves have smaller fiber diameter and a shorter internodal distance • Adequate surgical block with smaller concentrations of LA

17. Equipment • Appropriate equipment decreases risk of injury despite risks of increased toxicity • Use nerve stimulator in anesthetized kids to improve success rate of peripheral nerve blockade • 1- or 2-inch insulated needles used

18. Caudal Blockade • Most common regional block in children • Simple to perform • Easily adaptable to ambulatory anesthesia practice • Greatly decreases risk of reflex laryngospasm

19. Caudal - Anatomy • Sacral hiatus easy to identify • Palpable large bony processes on each side of hiatus called cornua • Hiatus covered by sacrococcygeal membrane • Dural sac may extend to S3 or S4 in infants (short distance between hiatus and dural sac)

21. Caudal- Technique • Lateral decubitus position • Palpate coccyx • Move finger gently from side to side and proceed in cephalad direction • First double bony protuberance encountered are sacral cornua which define the sacral hiatus

23. Caudal - Technique • Sterile prep/drape • 21 g butterfly needle usually used • Insert at 45-60 degree angle with bevel facing anteriorly • Distinct pop felt as sacrococcygeal membrane pierced • Lower angle of needle and advance 2-3 mm

25. Caudal Blockade • If outpatient, use just local anesthetic • 0.25% Bupiv or 0.2% Ropiv with epi • Test dose: 0.1 ml/kg with 5mcg/ml of epi (max 3ml) • Look for signs of intravascular injection • Increased heart rate > 10 bpm above baseline • Increased blood pressure • >25% change in T-wave amplitude • Doses: • 0.5cc/kg for LE/perineal surgery • 0.75cc/kg for T-10 level • 1cc/kg for lower thoracic level

26. Caudal Blockade • For inpatients, can add PF MSO4 for 18 to 24 hours of postop analgesia • 50 mics/kg for perineal surgery • 60 mics/kg for mid abdominal incision • 70 mics/kg for sternotomy (open hearts)

27. Caudal Blockade • Recent interest in Clonidine • Less respiratory depression • Less nausea/vomiting • Less pruritis • Similar/prolonged analgesia VS. Morphine • ? Dose • 1, 2 or 3 mcgs/ kg… to be determined

28. Caudal Blockade • ? Use of Clonidine in outpatients • Some staff do not use at all • Some use if > 1 year of age • ? Use of hydromorphone • ? Use of ketamine

29. Caudal Blockade • Major complications rare • Intravascular injection with systemic toxicity • Dural puncture causing high spinal blockade • Infection (especially after interosseous puncture/penetration)

30. Continuous Caudal Catheter • Manufactured kits available • Styletted catheter increases passage to thoracic level • Care taken to prevent fecal contamination

31. Continuous Caudal Catheter • Caudal approach to thoracic epidural anesthesia used in children > 10 years of age • Success related to less densely packed epidural fat • Easy cephalad passage of catheter

32. Continuous Caudal Catheter • Correct placement confirmed by: • Ease of injection • Negative aspiration • Radiographic imaging • Nerve Stimulation through catheter

33. Epidural Block • Improved surgical outcomes: • Decreased stress response • Fewer episodes of hypoxia • Decreased cardiac morbidity • Decreased pulmonary infections • Decreased thromboembolic events • Decreased blood loss • Faster return of GI function

34. Epidural Block • Drugs Used: • Ropivacaine/Bupivacaine • 2 - Chloroprocaine • Morphine • Clonidine

35. Epidural Block • Line drawn between two iliac crests passes closer to L5 (vs. L3-4 interspace in adults) • Under 1 year of age: • Spinal cord ends at lower level (L3 vs. L1) • Dural sac ends at lower level (S4 vs. S2)

36. Epidural block • Lateral decub position • Surgical side down • Hips and knees flexed by 90 degrees • Sterile prep/drape • “Loss of Resistance” technique with saline

37. Epidural Block • Epidural space more superficial in children than adults • Guideline for determining epidural depth: • 1mm/kg of body weight • Depth (cm) = 1 + 0.15 X age (years) • Depth (cm) = 0.8 + 0.05 X weight (kg) • Use shorter needles and extreme care

38. Epidural Block • Dosing: • Depends on upper level of analgesia required • > 10 years of age: • Volume to block one spinal segment • V (in ml) = 1/10 X (age in years) • < 10 years old: • 0.04ml/kg/segment

39. Epidural Block • Dosing:

40. Epidural Block • Complications: • Intrathecal injection • High block • Postdural puncture headache • Intravascular injection/Local anesthetic toxicity • Sympathectomy • Hypotension • Bradycardia

41. Epidural Block • Complications: • Opioid –induced respiratory depression • Damage to neural structures • Infection • Epidural Hematoma  paraplegia • < 1 in 150,000 • Usually associated with anticoagulation

42. Epidural Block • Although potential complications, there are multiple benefits • Decreased stress response • Decreased thromboembolic complications • Decreased pulmonary problems • Improved patient/parent satisfaction

43. Ilioinguinal and Iliohypogastric Nerve Block • Simple Block • Good pain relief for hernia repair, hydrocelectomy and orchiopexy • Can be done at beginning of case for both intraop and postop analgesia • May be done intraop under direct visualization

44. Ilioinguinal Nerve Block • Anatomy • Nerves run between abdominal muscles • Close to ASIS • Both blocked by infiltration in area medial to ASIS

45. Ilioinguinal Nerve Block • 25-gauge needle • Puncture skin 1 cm medial and 1 cm inferior to ASIS • Three fan-shaped injections • Sub Q wheal as needle withdrawn • Bupiv 0.25% w/ epi up to 2mg/kg used

47. Penile Nerve Block • Provides analgesia after superficial surgery of penis • Circumcision • Meatotomy • Blocks both dorsal nerves at base of penis • Anesthesia to distal two-thirds of penis

48. Penile Nerve Block • Usually performed by surgeon • Avoid epinephrine • May lead to ischemia of tissue • Complications: • Intravascular injection • Hematoma formation

49. Brachial Plexus Block • Can be done at three levels: • Axillary • Interscalene • Supraclavicular • Excellent analgesia during/after surgery on the upper extremities

50. Brachial Plexus Block • Axillary approach used most • Major complications rare • Interscalene/ Supraclavicular approaches provide better analgesia of upper arm/shoulder • Higher complication rate : pneumothorax and subarachnoid blockade