Regional Anaesthesia for Children Indispensable! but also safe? PD Dr. med. Jacqueline Mauch
Outline Significance of regional anaesthesia in paediatric surgery Risks and complications of regional anaesthesia Local anaesthetics systemic toxicity (LAST) Prevention Early detection Therapy Take home messages
Significance of RA Cornerstone of current paediatric anaesthesia practice Inherent part of the multimodal concept of pain treatment Non-Opioid- Analgetics Regional anaesthesia Caudal block Epidural catheter Peripheral nerve block Wound infiltration Paracetamol Ibuprofen Diclofenac Metamizol Co- Analgetics Dexamethasone Ketamine Clonidine Lidocaine Opioids Morphine Nalbuphine Pethidine Fentanyl
Significance of RA Intraoperative and initial postoperative benefits Effective pain relief Opioids Stress response Hypnotics Stable anaesthesia course Smooth awakening Emergence delirium PONV Respiratory depression Apoptosis?
Techniques Caudal block Epidural block (catheter technique) Brachial plexus block axillary approach Peripheral nerve blocks lower extremity
Local anaesthetics (LA) Bupivacaine and ropivacaine (long duration of action) Adverse events: Allergic reaction: Ester > amide Systemic toxicity: Central nervous system Cardiovascular system Adult - conscious Circumoral numbness, paraesthesia, tinnitus, slurred speach, restlessness Seizures, coma, apnea Hypotention, bradykardia, slowed conduction of cardiac impulses Circulatory arrest Child - anaesthetised None None Hypotention, bradykardia, slowed conduction of cardiac impulses Circulatory arrest
Risks and complications of RA 3 large prospective studies of complication rates in paediatric regional anaesthesia Giaufré E Anesth Analg 1996 n=24 409 Ecoffey C Paediatr Anaesth 2010 n=31 132 Polaner DM Anesth Analg 2012 n=14 917 No deaths, no complications with permanent sequelae in >70 000 regional blocks Transient complications Technical problems (anatomy, material) Dural penetration, excessive spread of LA, total spinal Short duration paresthesias Intravascular injection of LA, overdose, systemic intoxication (LAST)
Recommendation for preventing LAST There is no single measure that can prevent LAST in clinical practice. Aspriate needle / catheter Lowest effective dose of LA Slow injection rate Incremental injection of LA, pausing 15-30 s between injections Intravascular marker test dose Ultrasound guidance may reduce the frequency of intravascular injection Neal JM Reg Anesth Pain Med 2010
Intravascular marker: Test dose Goal: Timely detection of inadvertent intravascular LA administration Desired effect: transient changes in haemodynamics Elektrocardiogram (ECG), heart rate, blood pressure Preferred marker: Epinephrine T-waves controversial in the literature Caused by LA or by epinephrine? Sensitivity / reliability?
Test dose bupivacaine + epinephrine Injection Injection + 30 sec Bupivacaine Group 1 Group 2 Bupivacaine + epinephrine Epinephrine Group 3 Pre-injection 30 s after injection of TD Mauch J Br J Anaesth 2010
T-wave elevation caused by bupivacaine A: before bupivacaine infusion B: after 1.25 mg/kg BW C: after 2.5 mg/kg BW D: after 5 mg/kg BW Mauch J Br J Anaesth 2010
Test dose ropivacaine + epinephrine Pre-injection After injection of test solution RA Delta heart rate (min -1 ) Delta mean arterial pressure (mmhg) 150 100 100 80 60 50 40 0 20 0-50 Group R Group RA -20 Group R Group RA Mauch J Paediatr Anaesth 2013
Test dose in children 105 children, aged 0.2-16 yr Test solution 0.2 ml/kg injected intravenously Bupivacaine 0.125% Bupivacaine 0.125% + epinephrine 5 μg/ml Epinephrine 5 μg/ml
Positive results (%n) Test dose in children Positive intravascular test dose criteria in children: T-wave: 25% HR: 10 bpm BP syst.: 15 mmhg T-wave delta HR delta BPs 1 delta BPs 2 Tobias JD. Anesth Analg 2001 100 80 60 40 20 0 Group B Group BE Group E Mauch J Br J Anaesth 2012
Test dose in children Mauch J Br J Anaesth 2012
Test dose in children The inclusion of T-wave and HR allows detection of an epinephrine-containing test dose with a reliability of 100%. Mauch J Br J Anaesth 2012
Injection dose rate Influence of intravascular injection dose rate of bupivacaine on bupivacaine plasma concentrations and timing of LAinduced cardiovascular compromise. Continuous bupivacaine infusion until MAP was reduced by 50% of baseline values. Group A: 1 mg/kg/min Group B: 4 mg/kg/min Group C: 16 mg/kg/min
Injection dose rate Ratio plasma-bupivacaine to bupivacaine infused Group A: 11.2 (2.9-22.2) Group B: 18.8 (12.3-60.9) Group C: 25.9 (16.2-41.2) Overproportionally high bupivacaine plasma concentrations with higher dose rates 5 of 15 piglets in group A spontaneously recovered Mauch J J Anaesth 2011
Conclusion injection dose rate With a slow LA injection technique earlier recognition of cardiac toxicity with lower doses of administered LA lower LA plasma concentrations higher chance of succesful outcome Mauch J J Anaesth 2011
Treatment of local anaesthetic systemic toxicity (LAST) Lipid Rescue TM Intravenous infusion of lipid emulsion Mechanism of action Lipid sink Improved oxidation of fatty acids Literature: Several case reports with encouraging results Risks Fat embolism? Pancreatitis? Overestimation as magic bullet Losing sight of standard resuscitation therapy
Intralipid for treatment of severe cardiovascular compromise Starting condition: Bupivacaine-induced depression of MAP to 50% of baseline values Treatment: Group 1: Epinephrine 3 μg/kg Group 2: Intralipid 20% 2 ml/kg Group 3: Intralipid 20% 4 ml/kg Mauch J Paediatr Anaesth 2011
Intralipid in resuscitation of bupivacaine-induced cardiac arrest E L E+L V+L A (n=7) B (n=7) C (n=7) D (n=7) Survival 5 2 6 4 ROSC due to study medication 5 0 6 0 ROSC due to epinephrine rescue 10 µg/kg 0 2 0 4 Epinephrine support required: A (n=5) B (n=2) C (n=6) D (n=4) Epinephrine 3 µg/kg 0x 2 1 6 3 1x 2 - - - 2x 1 1-1 Mauch J Paediatr Anaesth 2012
Take home messages Paediatric regional anaesthesia: Inherent part of the multimodal concept of pain treatment Excellent safety profile, low incidence of complications, no permanent sequelae after single injection Prevention and timely diagnosis of LAST Aspirate needle Slow injection dose rate Intravascular marker: Epinephrine Treatment priorities for LAST Primary: Resuscitation according guidelines, epinephrine Secondary: Lipid solution