Pain upon local anesthesia infiltration before spinal anesthesia is associated with acute post-cesarean pain

Abstract Number: S-46
Abstract Type: Original Research

Introduction:

Prediction of acute post-cesarean pain is an important clinical question. To date, most studies have mostly used experimental models to assess pain (1,2) or preoperative questionnaires (3) to categorize women into different risk groups for post-operative pain. Pain upon IV placement was not found to predict labor pain intensity (4). The goal of this study was to evaluate whether pain upon injection of local anesthesia (ILA) before spinal anesthesia predicts acute post-cesarean pain.

Methods:

103 women scheduled for an elective cesarean delivery were enrolled to receive a standardized ILA (lidocaine 1% 3-5ml via 25G needle) before spinal anesthesia (bupivacaine 12mg, fentanyl 20mcg, morphine 100mcg). The anesthesiologist performing the procedure used a standardized script to inform that ILA was about to occur (‘I am giving you now the numbing dose, please rate your pain on a scale between 0-100’). Outcome measures included: demographics, ILA pain (verbal numeric pain scale; 0-100), average and peak pain (at rest, with movement and uterine cramping at 24 & 48h). Statistical analysis included t-test for equality of means (p<0.05).

Results:

Women were categorized into one of 3 groups based on ILA pain score [mild (0-30), moderate (31-69) or severe (70-100)] with no difference in demographic data (Table). Acute post-cesarean pain at 24h was significantly different based on ILA pain scores (Table), but not at 48h (data not shown).

Conclusion:

This is the 1st study evaluating a clinical test to predict post-cesarean pain. Our main findings were that up to 12% of women experience severe pain upon local anesthesia infiltration, which was associated with significantly increased pain (at rest, upon mobilisation and uterine cramping) during the first 24h. Further studies are needed to evaluate whether these women may benefit from higher spinal morphine dosing to improve post-operative pain.

1. Anesthesiology 2003;98:1422-6

2. Eur J Pain 2013;17:111-23

3. Anesthesiology 2013;118:1170-9

4. Br J Anaesth 2013;110:600-6

SOAP 2014