Journal of Anesthesia

, Volume 22, Issue 2, pp 105–111

The effects of remifentanil or acetaminophen with epidural ropivacaine on body temperature during labor

Authors

  • Shmuel Evron
    • Department of Anesthesia, Obstetric Anesthesia UnitEdith Wolfson Medical Center
    • Outcomes Research Group
  • Tiberiu Ezri
    • Department of Anesthesia, Obstetric Anesthesia UnitEdith Wolfson Medical Center
    • Outcomes Research Group
  • Michael Protianov
    • Department of Anesthesia, Obstetric Anesthesia UnitEdith Wolfson Medical Center
  • Gleb Muzikant
    • Department of Anesthesia, Obstetric Anesthesia UnitEdith Wolfson Medical Center
  • Oscar Sadan
    • Department of Obstetrics and Gynecology, Obstetric Anesthesia Unit, Edith Wolfson Medical Center, Affiliated with the Sackler School of MedicineTel Aviv University
  • Amir Herman
    • Department of Anesthesia, Obstetric Anesthesia UnitEdith Wolfson Medical Center
  • Peter Szmuk
    • University of Texas Medical School and Children’s Medical Center at Dallas, Department of AnesthesiologyUniversity of Texas
    • Outcomes Research Group
Original Article

DOI: 10.1007/s00540-007-0589-8

Cite this article as:
Evron, S., Ezri, T., Protianov, M. et al. J Anesth (2008) 22: 105. doi:10.1007/s00540-007-0589-8

Abstract

Purpose

Epidural analgesia is associated with hyperthermia during labor and presumably causes it, although no convincing mechanism has been postulated. It seems likely that fever associated with pyrogenic factors related to labor is suppressed by opioids, whereas it is expressed normally in patients given epidural analgesia. We examined this hypothesis and the possible etiology of temperature elevation in labor.

Methods

In this prospective, randomized, controlled study, we assessed 201 parturients during spontaneous labor. Analgesia was randomly provided with one of four treatment groups: (1) epidural ropivacaine alone, (2) IV remifentanil alone, (3) epidural ropivacaine plus IV remifentanil, and (4) epidural ropivacaine plus IV acetaminophen. At randomization, patients were normothermic. Intrapartum hyperthermia (≥38°C) was correlated to the analgesic technique.

Results

The maximum increase in oral temperature was greatest in the ropivacaine group (0.7 ± 0.6°C) and least in the remifentanil group (0.3 ± 0.4°C; P = 0.013). The percentage of patients who became hyperthermic (≥38°C) during the first 6 h of labor was greatest in the ropivacaine group (14%) and least in the remifentanil-alone group (2%), but the difference was not statistically significant. The maximum forearm-finger gradients were lower (less vasoconstriction) in the remifentanil group when compared to the gradients in patients with epidural analgesia (1.4 ± 1.8 vs 3.0 ± 1.7, respectively; P < 0.001).

Conclusion

Our results are consistent with the theory that low-dose opioids inhibit fever in patients not given epidural analgesia. However, in view of the negative results, the hypothesis of epidural-induced hyperthermia may be questionable.

Key words

HyperthermiaLaborEpiduralAcetaminophenRemifentanil

Copyright information

© Japanese Society of Anesthesiologists 2008