Hemodynamic effects of intrathecal fentanyl in nonlaboring term parturients

Abstract

Study objective: To determine the effect of intrathecal fentanyl on maternal hemodynamics.

Design: Prospective.

Setting: Labor and delivery suite of a university medical center.

Patients: 23 ASA status I nonlaboring term parturients presenting for elective cesarean section.

Interventions: Patients were given either 1,200 ml lactated Ringer's Solution (Group 1, n = 12) or no intravenous (i.v.) fluid (Group 2, n = 11). A combined spinal-epidural technique was then performed. Fentanyl 25 micrograms was administered intrathecally through a 24-gauge Sprotte or 25-gauge Whitacre spinal needle. After completion of the hemodynamic study, a catheter was threaded into the epidural space for local anesthetic administration.

Measurements and main results: Baseline hemodynamic data [systolic (SBP), diastolic, and mean arterial pressure, heart rate, stroke volume, cardiac output, end-diastolic volume, and ejection fraction] were obtained in triplicate using noninvasive blood pressure monitoring and impedance cardiography. After administration of intrathecal fentanyl, hemodynamic measurements were recorded at 3-minute intervals for 30 minutes. These values were compared with baseline for both groups. Ten patients in each group completed the study. Intrathecal fentanyl administration did not result in any maternal hemodynamic changes in Group 1, and a few small statistically significant changes in Group 2. Measured SBP was always greater than 100 mmHg in all patients during the study.

Conclusion: Intrathecal administration of fentanyl 25 micrograms in nonlaboring term parturients does not produce clinically important maternal hemodynamic changes.