DOES INTRATHECAL ANALGESIC EFFICACY OF FENTANYL DIFFER BETWEEN SPONTANEOUSLY LABORING AND INDUCED LABORING PATIENTS?

Abstract

S383 Introduction: Previous reports have shown that the intrathecal analgesic duration (IAD) of fentanyl during combined spinal-epidural (CSE) anesthetic varies with parity and stage of labor. It has not been shown whether the efficacy of intrathecal narcotic differs between spontaneously laboring parturients (SLP) and parturients (ILP) with labor induced by pitocin. Method: After IRB approval and written informed consent, 19 spontaneously laboring nulliparous parturients (SLP) and 13 nulliparous parturients with labor induced by pitocin (ILP) were enrolled. All subjects were in active labor with cervical dilation between 2-5 cm and requesting regional labor analgesia. With a needle through needle technique, CSE anesthetic was performed with patients in sitting position after preloaded with 1 L of lactated ringers. After return of clear cerebral spinal fluid in the spinal needle, each patient received fentanyl 35 micrograms intrathecally. Patients remained at bed rest in an upright 45 degree position and were evaluated every 5 minutes for the first 15 minutes, then every 15 minutes until they requested more analgesia. Investigators evaluating the patients were blinded to the use of pitocin. Parameters assessed were: IAD - time from intrathecal injection to patient requested additional analgesia, visual and verbal analog pain scale (VAPS), sensory/motor block, vital signs, fetal heart rate, side effects and patients' satisfaction. Chi-square, ANOVA & unpaired t-test were used for analysis. Result: 2 patients, in whom we were unable to obtain cerebral spinal fluid through the spinal needle, were excluded. Of the remaining, 19 were SLP and 11 were ILP. The demographics (weight, height, age, childbirth education, fetal weight, cervical dilation before CSE. VAPS before CSE) were similar between groups. The results are summarized in Table 1 below. The IAD of fentanyl was significantly longer for SLP than for ILP. All patients rated the quality of analgesia from intrathecal fentanyl as excellent or good.Table 1Discussion: Our data shows that intrathecal fentanyl alone is more efficacious in spontaneously laboring nulliparous parturients than in nulliparous parturients with labor induced by pitocin. The quality of analgesia are similar between the 2 groups, but the duration of analgesia is significantly shorter in the nulliparous ILP than the nulliparous SLP. Parturients with induced labor are thought to have more frequent and intense contraction; and may experience more severe pain than the spontaneously laboring parturients. Data are mean_SD except for patient with excellent or good satisfaction rating in percent.