///2017 Abstract Details
2017 Abstract Details2019-08-02T15:54:53-06:00

Prospective Observational Study of the Relationship Between Labor Epidural Analgesia Onset Time and Subsequent Analgesic Requirements in Laboring Women

Abstract Number: T-16
Abstract Type: Original Research

Andrey Nevo MD1 ; Idit Matot MD2; Or Goren MD3; Carolyn F Weiniger MB ChB4

Background: The relationship between labor epidural analgesia (LEA) onset time and subsequent pain intensity during labor has not been reported. We aimed to investigate the relationship between LEA onset time and subsequent pain intensity and analgesic requirements in nulliparas.

Methods: Observational prospective cohort, term nulliparas in a large tertiary center, who had signed IRB on admission, and had cervical dilatation ≤5cm at request for LEA. After LEA was performed, initial bolus was 5cc bupivacaine 0.1%+fentanyl 1.67mcg/cc, followed by 10cc. Patient controlled epidural analgesia (PCEA): bupivacaine 0.083%+fentanyl 1.67mcg/cc, bolus 5cc, infusion 6cc/hr, lock-out time 10min. Our primary measured variable was LEA onset time, defined as time to numerical pain rating score (NPRS=0-10) ≤3, asked after each contraction, and measured from the time of initial 5cc bolus. We report NPRS at 60 and 120min and at pushing in the second stage, and analgesic requirements (PCEA attempts and bupivacaine consumption) during 1st stage using Spearman's rank correlation.

Results: We completed assessments for 105 nulliparas; age31±4yrs; BMI 22±3kg/m2. Half the nulliparas achieved NPRS≤3 by 14mins (IQR)[total range](10-19)[4-55]. There was a significant correlation between LEA onset time and NPRS at 60min, R2=0.286, p=0.003; and between NPRS at 60 and 120min, R2=0.469, p<0.0001, Table 1. The strongest correlations were between number of PCEA attempts at 120min and: LEA onset time, R2=0.321, p=0.001; NPRS at 60min, R2=0.588, p<0.001; and NPRS at 120min, R2=0.539, p<0.001. Weaker but signifcant correlations existed between number of PCEA attempts at 60min and: LEA onset time; NPRS at 60min; and NPRS at 120min. Total bupivacaine consumption/hour was significantly correlated with NPRS at 60min, R2=0.403, p<0.0001 and NPRS at 120min, R2=0.433, p<0.0001. There were significant correlations between cervical dilatation at 60min and NPRS at both 60min and at 120min. There were signifcant correlations between cervical dilatation at 120min and LEA onset time; NPRS at 60; and NPRS at 120min.

Conclusion: Our data suggest a relationship between analgesic requirements and LEA onset time and subsequent pain intensity in nulliparous laboring women. This may be explained by faster labor progression. Evaluation of NPRS at 60 and 120min may faciliate active management of LEA,(1) by identifying nulliparas who have greater analgesic requirements.

Reference: 1. Bauer.etal.A&A2016;123:1074

SOAP 2017