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

Effect of bupivacaine dose in combined spinal epidurals in laboring parturients: A randomized double-blinded prospective study -- Preliminary results

Abstract Number: SAT-25
Abstract Type: Original Research

Jason J White MD1 ; Jonathan Epstein MD2; Barbara Orlando MD3; Migdalia Saloum MD4; Julio Marenco MD5; Deborah Stein MD6

Effect of bupivacaine dose in combined spinal epidurals in laboring parturients: A randomized prospective double-blinded study— Preliminary results

Background: Combined spinal epidural anesthesia (CSE) is a safe and simple procedure which provides adequate analgesia in laboring patients. Two possible complications of this technique are maternal hypotension and fetal bradycardia, which have been demonstrated to result from both rapid pain relief and sympathetic blockade (1). Previous studies have shown the ED95 of bupivacaine to be 1.66mg (less than the standard 2.5mg being used) (2). It is not well-studied whether the smaller dose of local anesthetic will result in a lower complication rate.

Material and Methods: Two hundred patients (ASA 1-2) between 37-42 weeks gestational age were sought from Labor and Delivery patients who had expressed interest in neuraxial anesthesia for labor. Excluded patients were parturients with pre-eclampsia, gestational hypertension, and parturients in whom spinal anesthetics are contraindicated or cannot be performed. Patients were administered a spinal dose that was removed from the pyxis machine, loaded daily by pharmacy, labeled only with a numerical code. The syringe contained 20mcg of fentanyl with 2.5mg, 1.66mg, or 1.25 mg of bupivacaine. VAS pain score, fetal heart rate, and maternal blood pressure were recorded prior to administration and regularly for the first hour afterwards.

Results: Although currently 84 patients have been enrolled, some results are salient enough to report without unblinding of the dosing syringes. Of the 84 patients, only one had fetal bradycardia requiring treatment with nitroglycerin. Additionally, in 80 of the 84 patients, the VAS pain score at 8 minutes was less than 3.

Preliminary Conclusions: CSE with fentanyl 20mcg and varying doses of bupivicaine (1.25mg to 2.5mg) does not cause significant fetal bradycardia. Additionally, superior analgesia (VAS less than 3 at eight minutes) was achieved by all three doses of bupivacaine in the CSE. Unblinding the study after full enrollment will demonstrate the effect of the bupivicaine doses on maternal hypotension.

1) Clarke VT, Smiley RM, Finster M. Uterine hyperactivity after intrathecal injection of fentanyl for analgesia during labor: a cause of fetal bradycardia? Anesthesiology. 1994;81(4):1083

2) Whitty, R., et al. "Determination of the ED95 for intrathecal plain bupivacaine combined with fentanyl in active labor." International journal of obstetric anesthesia 16.4 (2007): 341-345.

SOAP 2017