Inadequate pain relief with labor epidurals: a multivariate analysis of associated factors

Background: Labor epidural analgesia providing inadequate pain relief may cause maternal dissatisfaction and may fail to produce effective anesthesia when topped up for operative delivery. This study looked at factors a sociated with inadequate labor epidural analgesia. Methods: Data were prospectively collected from 275 parturients, receiving labor epidural analgesia. Pain was assessed 30 min after epidural insertion using a verbal pain scale of 0 to 100. A score of 10 or more wits considered to represent inadequate pain relief. Sixteen factors chosen by experienced obstetric anesthesiologists for their association with inadequate labor epidural analgesia were studied. Results: Fifteen parturients were excluded. Forty-four of the remainder (16.9%) experienced inadequate pain relief. Multiparity, history of a previous failure of epidural analgesia, the use of air for loss of resistance, cervical dilatation >7 cm at insertion all had a statistically significant association with inadequate epidural analgesia (P < 0.05). Logistic regression showed that cervical dilatation >7 cm, a history of opioid tolerance, a previous failed epidural and insertion of the epidural by a trainee anesthesiologist increased the odds ratio for inadequate pain relief. Conclusions: The final model correctly classified 93% of the epidurals that provided effective analgesia but classified only 9.3% of those providing inadequate pain relief. This information can be used to develop a predictive score and change practice resulting in fewer inadequate epidurals. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.