Breakthrough Pain in Labour Analgesia: An Anaesthetist’s Dilemma

Hemalata K and Akshat D

Published on: 2022-12-03

Abstract

Keywords

Labour analgesia, epidural, epidural catheter

Introduction

Labour analgesia by placement of an epidural catheter in the epidural space is a safe modality and continuous epidural infusion of a dilute solution of local anaesthetic is a popular technique for maintenance of epidural analgesia. Epidural analgesia can be started at any time of labour when the parturient experiences painful contractions.  It provides stable level of analgesia and carries a diminished risk of maternal hypotension. [1] However breakthrough pain is a disadvantage of this method and sometimes throws unexpected challenges to the anaesthetist.

Case Report

A 37 year old primigravida presented with labour pains. Labour epidural analgesia was planned for her. She had no co-morbidities, height 153 cm, weight 63 kg and on per vaginal examination dilatation was 3-4 cm with 60-70% effacement. After starting an intravenous infusion of Ringers lactate through an 18 G cannula the vital parameters were recorded. Her blood pressure was 110/60 mm of Hg and pulse rate 74/minute. Under full aseptic precautions, in the left lateral decubitus position, using the loss of resistance to air technique, epidural needle was advanced in the lumbar3-4 interspace. The epidural space was identified at 4.5 cm and the epidural catheter was advanced cephalad. The epidural catheter was fixed at 10 cm mark. The placement of the catheter in the epidural space was confirmed by the meniscus sign. Aspiration did not yield cerebrospinal fluid or blood and a 3ml test dose of lignocaine hydrochloride 2% was given without any resistance. The presence of clinical signs of an intravascular injection was sought for the next 2-3 minutes by asking the patient whether she felt dizzy or had tinnitus. After another 2 minutes an additional dose of 2 ml of lignocaine hydrochloride 2% was given and the catheter was secured. The labour pain was considerably reduced in the next contraction. The patient was placed in the supine position and the epidural catheter was connected to an infusion of 0.1% bupivacaine and 2 microgram/ml fentanyl at the rate of 8 ml per hour. The patient was pain free and comfortable and fell asleep shortly. After 60 minutes the patient started complaining of severe pain during contractions. A 2 ml bolus of the infusion was given. The labour room nurse helped the patient to turn to her side and found the patients gown to be wet between the scapulae. On carefully removing the micropore in that area the epidural catheter was found to be broken. A fragment of catheter about 10 cm in length was attached to the filter and the infusion was leaking through it. After wiping the remaining catheter with spirit swab a one centimeter piece was further cut with a sterile no 15 blade and the tip was reinserted into the filter. A bolus of 8 ml of the infusion was given and after 5 minutes adequate pain relief was obtained. An additional dose of antibiotic was given. After the normal delivery the patient had retained placenta and anaesthesia was provided through the epidural catheter in the labour operation theatre for manual evacuation. Due to the shortened length of the catheter it was fixed diagonally so that the filter was in the mid axillary line. At the end of the procedure and after observing the patient for an hour the epidural catheter was removed.

Discussion

Although breakage of epidural catheter during insertion or removal is a rare complication, all anaesthetists are well versed with it. Literature shows some case reports regarding broken epidural catheters.[2,3,4] Various factors have been implicated like withdrawl of catheter through the needle, heavy contact of needle with bone with catheter protruding through the tip, manufacturing defect, entanglement of catheter due to excessive threading and kinking of catheter under the skin.[2] Various practice guidelines are instilled during anaesthesia training like removal of needle with the catheter in case the catheter cannot be threaded, use of gentle continuous force both during insertion and removal, avoiding excessive threading of epidural catheter, etc. Radio-opaque epidural catheters have been reported to have lower tensile strength than the non-radio opaque catheters.[3]

We reassessed the steps of the epidural catheter placement in our patient. The patient was placed in the left lateral decubitus position and the gown was folded upwards between the scapulae. The epidural space was located easily and the catheter was threaded smoothly. The needle was withdrawn over the catheter gently without kinking it at any point. The sterile dressing was placed at the site of entry under vision.  The catheter was placed cranially over the back and taken under the folded gown towards the right side of the neck. The micropore was stuck under vision. However some part of the micropore was placed blindly under the folded gown. Most likely the finger nail kinked and fractured the catheter at that point.  Usually the gloves are removed to stick the micropore to prevent it from sticking to the gloves. A manufacturing defect at that point on the catheter could be an additional factor. In the operation theatre when inserting an epidural catheter the patients shirt is often removed and patient covered with OT sheet. However our labour patients have a gown which is rolled up before giving a spinal or an epidural.

Recent innovations in delivery systems and advances in drug combinations have made labour analgesia the most effective form of analgesia. However a small mistake in the train of labour analgesia can derail the smooth flow of things and cause unnecessary discomfort to the parturient. The anaesthesia provider or the dedicated labour nurse should make it a habit to keep an eye on the workflow processes when labour analgesia is provided.

References