Post on 01-Mar-2021
“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 AnesthesiaVolume 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
Parturients
Catheter replacement (any)
Kinsella
Anaesthesia
Caesarean Section
Ready
All surgical patients
• 550/4240 (13.1%)
• 302/1286 (23.5%)
• Thoracic 32%
• 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
Copyright © 2013 Anesthesiology. Published by Lippincott Williams & Wilkins. 12
Hamilton, Catherine L.; Riley, Edward T.; Cohen, Sheila E.
Anesthesiology. 86(4):778-784, April 1997.
Changes in Position of Epidural Catheters Associated with Patient Movement
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
↑ 1st 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 ScandinavicaVolume 48, Issue 3, pages 347–349, March 2004
Localisation (LORS/A)
WETS DRYS
“Drys” vs. “Wets”
“Like being savaged by a dead sheep…”
“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
Epidural Space Identification: A Meta-Analysis of Complications After Air Versus Liquid as the Medium for Loss of ResistanceSchier 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
Copyright © 2013 Anesthesiology. Published by Lippincott Williams & Wilkins. 23
Grondin, Lydia S.; Nelson, Kenneth; Ross, Vernon; Aponte, Orlando; Lee, Sherman; Pan, Peter H.Anesthesiology. 111(1):165-172, July 2009.
“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
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.
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 & GynaecologyVolume 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