Paediatric regional anaesthesia: caudal block dosing and safety

Meet the patient

A 10 kg infant for bilateral orchidopexy. The registrar proposes 1.25 mL/kg of 0.25% bupivacaine for a good high block. Do the maths before you draw up: 12.5 mL at 2.5 mg/mL equals 31.25 mg equals 3.125 mg/kg — over the taught 2.5 mg/kg ceiling (confirm local formulary). That plan will poison the child.^[3]

The fellowship answer is always the same: calculate milligrams first, then see if Armitage volume fits at a dilute concentration. If it does not, redesign — dilute, reduce volume, lower the target, or choose another technique. This single algorithm prevents almost every caudal toxicity disaster.^[7]

References19ShowHide

1. [1]Davidson AJ, Disma N, de Graaff JC, et al. Neurodevelopmental outcome at 2 years of age after general anaesthesia and awake-regional anaesthesia in infancy (GAS): an international multicentre, randomised controlled trial Lancet, 2016.PMID 26507180
2. [2]McCann ME et al. Neurodevelopmental outcome at 5 years of age after general anaesthesia or awake-regional anaesthesia in infancy (GAS): an international, multicentre, randomised, controlled equivalence trial. Lancet, 2019.PMID 30782342
3. [3]Koo BN, Hong JY, Kil HK Spread of ropivacaine by a weight-based formula in a pediatric caudal block: a fluoroscopic examination. Acta Anaesthesiol Scand, 2010.PMID 20236099
4. [4]Sikich N, Lerman J Development and psychometric evaluation of the pediatric anesthesia emergence delirium scale. Anesthesiology, 2004.PMID 15114210
5. [5]Flick RP, Wilder RT, Pieper SF, et al. Risk factors for laryngospasm in children during general anesthesia. Paediatric Anaesthesia, 2008.PMID 18315633
6. [6]Wiegele M, Marhofer P, Lönnqvist PA Caudal epidural blocks in paediatric patients: a review and practical considerations. Br J Anaesth, 2019.PMID 30857607
7. [7]Sinha C, Kumar A, Sharma S, et al. Ultrasound assessment of cranial spread during caudal blockade in children: Effect of different volumes of local anesthetic. Saudi J Anaesth, 2017.PMID 29033727
8. [8]Ponde V, Shah D, Nagdev T, et al. Ultrasound determination of the dural sac to sacrococcygeal membrane distance in premature neonates. Reg Anesth Pain Med, 2022.PMID 35115413
9. [9]Burstal R, Hollard J, McFadyen B Simulated epidural test doses using adrenaline and adrenaline/clonidine in sevoflurane-anaesthetized children. Anaesth Intensive Care, 2003.PMID 12973958
10. [10]Lee SH, Sohn JT Mechanisms underlying lipid emulsion resuscitation for drug toxicity: a narrative review. Korean J Anesthesiol, 2023.PMID 36704816
11. [11]Frawley G, Cortinez LI, Anderson BJ, Bjorksten A, King S Levobupivacaine plasma concentrations following repeat caudal anesthetics. Paediatr Anaesth, 2022.PMID 36106368
12. [12]Lauder G, Emmott A Confronting the challenges of effective pain management in children following tonsillectomy. Int J Pediatr Otorhinolaryngol, 2014.PMID 25241379
13. [13]Hansen TG, Ilett KF, Reid C, et al. Caudal ropivacaine in infants: population pharmacokinetics and plasma concentrations. Anesthesiology, 2001.PMID 11379676
14. [14]Chalkiadis GA, Anderson BJ, Tay M, et al. Pharmacokinetics of levobupivacaine after caudal epidural administration in infants less than 3 months of age. Br J Anaesth, 2005.PMID 16100236
15. [15]Aggarwal A, Sahni D, Kaur H, et al. The caudal space in fetuses: an anatomical study. J Anesth, 2012.PMID 22076688
16. [16]Sepulveda EA, Pak A Lipid Emulsion Therapy. StatPearls, 2024.PMID 31751087
17. [17]Kohler JE, Cartmill RS, Kalbfell E, et al. Continued Prescribing of Periprocedural Codeine and Tramadol to Children after a Black Box Warning J Surg Res, 2020.PMID 32693330
18. [18]Neal JM et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017. Reg Anesth Pain Med, 2018.PMID 29356773
19. [19]Dadure C et al. [Interest of ultrasonographic guidance in paediatric regional anaesthesia]. Ann Fr Anesth Reanim, 2009.PMID 19819099