Abstract # 19: Risk Factors for Inadequate Pain Relief with Labor Epidurals ›ÛÒ Multivariate Analysis, a Prospective Observational Study

19 Risk Factors for Inadequate Pain Relief with Labor Epidurals – Multivariate Analysis, a Prospective Observational Study Abstract Type: Original Research Rudram Naidu Muppuri, M.D.1; Shvetank Agarwal, M.D.1; Daisy Sangroula, M.D.2; Vitaly Soskin, M.D.1 Detroit Medical Center / Vanguard Health SystemsWayne State University1; University of Louisville2Type: Original Research Rudram Naidu Muppuri, M.D.1; Shvetank Agarwal, M.D.1; Daisy Sangroula, M.D.2; Vitaly Soskin, M.D.1 Detroit Medical Center / Vanguard Health SystemsWayne State University1; University of Louisville2 Introduction: The reported percentage of failed or inadequate labor epidurals range from 0.9% to 24%. Inadequate relieve of labor pain may cause maternal dissatisfaction and inability to provide surgical anesthesia in cases of C-section. The aim of our study was to examine the affect of several factors on the incidence of inadequate pain relief with labor epidurals. Methods: After institutional HIC approval and written informed consent was obtained, data was collected from 400 parturients. In all cases epidural catheters were inserted in a sitting position, using LOR technique with air or saline, at L2-L3, L4-L5 interspace with 17G Tuohy needle. The standard bolus of 0.125% bupivacaine with 10mcg/ml Fentanyl was given, followed by the infusion of 0.125% bupivacaine with 2.5mcg/ml Fentanyl solution at 8-10 ml/h. Pain was assessed 30 minutes after epidural insertion using a verbal pain scale (VPS) of 0 to 100. A score of 10 or more was considered as an inadequate analgesia. 20 independent factors were collected from each parturient. Data were analyzed using χ2 test, and multivariate analysis. Results: 84 parturients (21%) had inadequate pain relief. Univariate analysis using χ2 test showed that previous failure of epidural analgesia, multiparity, oxytocin, cervical dilatation>7cm at insertion and paresthesia had statistically significant association with inadequate analgesia. (Table 1) A forward stepwise logistic regression model showed cervical dilatation > 7, previous failed epidurals and paresthesia were found to be the best predictors of inadequate epidural analgesia. (Table2)A classification table was constructed and showed that overall 80.8% of the epidurals were classified as successful by the model(Table 3). Discussion: Our incidence of failed epidurals was 21% compared to reported range of 0.9% to 24%, and the odds ratio of inadequate pain relief was not increased with a less experienced operator as compared to Agaram study. The final model correctly classified 98% of the epidurals that provided effective analgesia; but classified only 14.3 % of that providing inadequate pain relief. The overall predictive rate with our model was 80% and a predictive score include three factors (previous failed epidural, cervical dilatation > 7 cm and paresthesia) with the greatest impact on the occurrence of inadequate epidurals. This information can be used to develop a predictive score and change practice Resulting in fewer inadequate labor epidurals. Table 1: Factors associated with inadequate epidural analgesia Univariate analysis Variable P value ( Pearson’s) obesity 0.17 previous failed epidural 0.001 multiparity Vs primiparity 0.002 air vs saline for loss of resistance 0.66 single vs multiple pregnancies 0.956 midline Vs paramedian approach 0.006 cervical dilation >7 cm 0.001 oxytocin usage 0.017 induction of labor 0.087 opioid tolerance 0.079 illicit drug use 0.246 difficult insertion 0.11 back abnormality 0.394 paresthesia 0.02 anesthesiologist 0.147 no of epidural attempts 0.153 time of epidural insertion 0.191 malpresentation 0.176 Table 2: Logistic regression : factors and odds ratios – multivariate analysis Variable P odds ratio 95%confidence interval history of previous failed epidural 0.001 2.51 0.95 4.35 cervical dilation >7 cm 0.001 8.14 1.37 8.6 paresthesia 0.02 3.31 1.28 7.59 Table 3: Classification table Predicted