Success going from failure to failure without loss of enthusiasm

Success going from failure to failure without loss of enthusiasm

Failure of neuraxial analgesia: factors within & beyond our control tips, trick & solutions science, evidence & guidance Dr Matt Wilson

Failed epidural Definition? Frequency? Outcome measure? Spectrum Insufficient analgesia Ineffective anaesthesia Discontinuation Dislodgement

Commoner than we care to admit Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries P.H. Pan, T.D. Bogard, M.D. Owen International Journal of Obstetric Anesthesia Volume 13, Issue 4, Pages 227-233, October 2004 12% inadequate or no sensory block 6.8% failure after initial effective analgesia

Other estimates.. Eapen & colleagues 550/4240 (13.1%) Parturients Catheter replacement (any) Kinsella 302/1286 (23.5%) Anaesthesia Caesarean Section Ready Thoracic 32% All surgical patients Lumbar 27%

Technical factors Anatomical dislocation Primary misplacement Paravertebral Intra-spinous Subdural Intravascular Intra-thecal Dislodgement Migration

Epidural catheter exiting through the transforaminal passage Hermanides J et al. Br. J. Anaesth. 2012;bja.aes214 The Author [2012]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Asymmetric block Unilateral/Missed segment/dermatomal sparing Epidural anatomical studies Resin injection Epiduroscopy CT Dorsal Median Connective Tissue Band Rare Incomplete

Radiographic Findings of Unilateral Epidural Block Asato, Fumio; Goto, Fumio Anesthesia & Analgesia. 83(3):519-522, September 1996.

Catheter migration Maternal movement Posture at placement CSF dynamics Tunnelling Fixation devices Hamilton CL et al. Anesthesiology 1997; 86: 778-84

Changes in Position of Epidural Catheters Associated with Patient Movement Hamilton, Catherine L.; Riley, Edward T.; Cohen, Sheila E. Anesthesiology. 86(4):778-784, April 1997. Copyright 2013 Anesthesiology. Published by Lippincott Williams & Wilkins. 12

Catheter insertion 4cm in space >5cm? Coiling?

The effect of the Lockit epidural catheter clamp on epidural migration: a controlled trial Anaesthesia Volume 56, Issue 9, pages 865-870

Equipment Multi vs. Single orifice Manufacturing error Air-lock Bacterial filter 0.3-0.7 ml

Maternal position at insertion Sitting insertion time 1 st success Vagal reflexes? Venous distension Lateral LOR Skin distance technical difficulty

Puncture site Estimation inaccuracy Cranial Creep USS?

Accuracy in estimating the correct intervertebral space level during lumbar, thoracic and cervical epidural anaesthesia Acta Anaesthesiologica Scandinavica Volume 48, Issue 3, pages 347 349, March 2004

Localisation (LORS/A) WETS DRYS

Drys vs. Wets

It is rather like sending your opening batsmen to the crease only for them to find, the moment the first balls are bowled, that their bats have been broken before the game by the team captain. Rt. Hon. G. Howe. 1990 Like being savaged by a dead sheep

Epidural Space Identification: A Meta-Analysis of Complications After Air Versus Liquid as the Medium for Loss of Resistance Schier et al. Anesthesia & Analgesia. 109(6):2012-2021, December 2009. 5 RCTs (4 Obstetric) 4422 subjects No differences: Difficult catheter insertion Paresthesia i.v. catheter ADP PDPH Partial block

Grondin, Lydia S.; Nelson, Kenneth; Ross, Vernon; Aponte, Orlando; Lee, Sherman; Pan, Peter H.Anesthesiology. 111(1):165-172, July 2009. Copyright 2013 Anesthesiology. Published by Lippincott Williams & Wilkins. 23

A Retrospective Effectiveness Study of Loss of Resistance to Air or Saline for Identification of the Epidural Space Segal, Scott; Arendt, Katherine W. Anesthesia & Analgesia. 110(2):558-563, February 2010. Preferred technique associated with Fewer attempts (median [interquartile range], 1 [1 1] vs 1 [1 2], P < 0.001). Fewer paresthesias (8.7% vs 18.5%, OR = 0.42, P= 0.007). Fewer unintentional dural punctures (1.0% vs 4.4%, OR = 0.23, P = 0.03). Copyright 2013 International Anesthesia Research Society. Published by Lippincott Williams & Wilkins. 24

Ultrasound localisation

USS guidance Pre-puncture localisation Midline c/f Obesity & Scoliosis Skin-to-space distance Angle of insertion Real-time? Paramedian insonnation Teaching tool

Pharmacological optimisation Dose vs. Volume Local anaesthetic Bupivacaine Ropivacaine Levo-bupivacaine Opioids Bolus vs. continuous PCEA +/- background +/- IMB

PCEA Satisfaction Workload LA consumption Motor-block

Number of women requiring No unscheduled intervention

Local anaesthetic dose

Outcomes

Proportion of PCEA+AMB and PCEA+BCI parturients who did not self-bolus after induction of CSE. Sia A T et al. Anesth Analg 2007;104:673-678 2007 by Lippincott Williams & Wilkins

Automated Mandatory Bolus Same volume/hr, superior analgesia Infusion/PCEA vs. PCEA & AMB LA consumption Breakthrough/Intervention Driving pressure Uniformity LA spread Multiorifice catheters Spinal translocation

Immovable obstacles:

Weight watchers Obesity a risk factor for adverse pregnancy outcomes. UK parturient population: 33% BMI>25 23% BMI>30

Linear association between maternal BMI and risk of caesarean section in term deliveries BJOG: An International Journal of Obstetrics & Gynaecology Volume 113, Issue 10, pages 1173-1177, 13 SEP 2006

Irresistible forces: pharmacogenetics 118 OPRM1 Gene (Opioid μ receptor) Response to neuraxial opioids ED50 spinal fentanyl Hz 304A:6.8 μg vs. Htz 304G:17.7 μg Modulation of pain perception ADRβ2 Labour progress Clinical implications?

Minimising failure Find the epidural space! Use saline or air Leave a catheter in 4-5cm Fix it Dilute LA + Opioid PCEA (+ INF/AMB) Be realistic! Recognise & replace!

Learning from our mistakes Experience is simply the name we give our mistakes. Oscar Wilde