Obstetric Anaesthesia Annual Scientific Meeting 2025

“The curious incident of the p-wave asystole at the crash section”

- a case report

Dr Ben Matthews, Dr Tori Millington & Dr Bruce Olojede

Background:

•25-year-old primiparous patient

•Fit and well. NKDA. Normal BMI

•Admitted to labour ward with reduced foetal movements at 37+2/40

•No concerns throughout pregnancy - low risk

The Case:

•“Maternal request” labour epidural inserted approx. 12:00

•Dural tap with 18G Tuohy needleat L3/4. Needle removed. Epidural successfully sited at L2/3

•Uneventful test dose of 5mls + 15mls loading dose given (0.1% Levobupivacaine + 2mcg/ml Fentanyl)

•Haemodynamically stable post-test and loading dose, epidural commenced

•Approximately 40 minutes post-loading dose, patient became unresponsive while repositioning on bed

- episode lasted approx.15 seconds, associated with hypotension

•Resolved with 100mcg Phenylephrine + 1000ml Hartmann’s solution

Transfer to theatre:

•Category 2 LSCS at 20:00 due to failure to progress

•Epidural top up: 7.5ml 2% Lignocaine + 7.5ml 0.5% Levobupivacaine - block to T4 after 10 minutes

•Patient repositioned prior to knife-to-skin – further unresponsive episode associated with airway obstruction and upper limb hyperextension

•Immediately transferred to left lateral position with jaw thrust to maintain airway

•3-lead ECG showed Asystole, SpO2 normal, NIBP cycling

•Carotid pulse not palpable so transferred to supine position in preparation for chest compressions

•3-lead ECG then showed normal sinus rhythm, GCS returned to 14/15 and pulses

•Cat 1 LSCS declared: further loss of consciousness, airway obstruction, abnormal posturing and asystole at knife to uterus

- resolved spontaneously after 15-20 seconds

•Arterial line placed. Uneventful rest of the surgery

•Multiple further asystolic episodes on transfer off surgical table and on removal of epidural catheter

Post-op:

•Diagnosis of P-wave asystole made by cardiology team

•Transferred to ICCU for further investigation and monitoring

•72-hour tape recording and ECHO performed - both NAD

•Patient made full, uneventful recovery and discharged home

Diagnosis:

•Seen in follow-up clinic by anaesthetist with cardiology interest

•No cardiac cause established

•Asystole attributed to inadvertent intrathecal local anaesthetic spread secondary to accidental dural puncture

Don’t get in a flap:

• “Flap-valve” between epidural and intrathecal spaces created by accidental dural puncture

•Resulted in intrathecal local anaesthetic boluses on movement, causing hypotension, arrhythmias and loss of consciousness

•P-wave asystole recognised as a severe manifestation of high spinal block due to sympathetic blockade

•↑intrathecal drug spread is a recognised complication of dural puncture

•However such distinct, pressure-related “boluses” causing transient high block are less well described

Key learning points:

·Consider the risks and benefits of inserting a (carefully-managed and well-labelled) intrathecal catheter in the event of accidental dural puncture

·Siting a successful, working epidural catheter following inadvertent dural puncture does not remove the risk of complications, particularly when using the epidural for surgical anaesthesia

Rapid multidisciplinary assessment is required for patients with arrhythmias compromising

Obstetric Anaesthesia Annual Scientific Meeting 2025

The curious incident of the p-wave asytole at the crash section

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