ORIGINAL ARTICLE Sevoflurane analgesia in obstetrics: a pilot study q A. Toscano, C. Pancaro, S. Giovannoni, G. Minelli, C. Baldi, G. Guerrieri, J. A. Crowhurst, a V. A. Peduto Department of Anesthesia and Intensive Care, University Hospital, Perugia, Italy and a Department of Anaesthesia and Intensive Care, Queen Charlotte’s Hospital, London, UK SUMMARY. Continuous and intermittent administration of inhalational anesthetics has been successfully employed for treating pain during labor. We conjectured that intermittent sevoflurane administration would be effective for pain relief during labor without side effects to the mother or fetus. Fifty parturients breathed a mixture of 2–3% sevo- flurane, oxygen and air before each uterine contraction began. The patients assessed the quality of analgesia by using a visual analogue scale (0–10) before the administration of sevoflurane and after each uterine contraction. All parturients but one were satisfied, demonstrating a mean visual analogue score before and after sevoflurane ad- ministration of 8:7 1:1 and 3:3 1:5, respectively. Apgar scores at 1 and 5 min were 9 (range 5–9) and 10 (range 8– 10), respectively. Our findings suggest that sevoflurane could be effective for the treatment of labor pain. Ó 2003 Elsevier Science Ltd. All rights reserved. INTRODUCTION Although epidural and combined spinal-epidural anal- gesia are commonly used techniques for pain relief during labor and delivery, inhalational analgesia may be useful in various circumstances, including urgent de- livery for obstetric complications, patient refusal of local or regional analgesia, 1 and inadequate facilities or skills to allow a safe neuraxial or perineal block. Moreover, when neuraxial block is contraindicated, a volatile an- esthetic can be an effective alternative if it provides rapid analgesia with minimal impairment of conscious- ness and upper airway reflexes. The rapid uptake and effect of sevoflurane, its not unpleasant odor and minimal airway irritation make it a popular choice for mask induction of anesthesia. 2 These qualities and its lack of toxic metabolites might make sevoflurane suitable for analgesia during labor, but there are no previous studies of sevoflurane for this purpose. Thus, the aim of this study was to test the hypothesis that sevoflurane in sub-anesthetic doses is effective for pain relief during the first and the second stages of labor in normal parturients. In addition, we sought to evaluate the effect of maternal sevoflurane on fetal heart rate and neonatal wellbeing. METHODS After approval by the local ethics committee and written informed consent, 50 healthy, singleton parturients in normal spontaneous labor at term were recruited for the study. Those with a history of significant gastrointesti- nal, hepatic, renal, endocrine or respiratory disease, seizures or other neurological disorders, fetal distress, alcohol or drug abuse were excluded. Parturients en- rolled in the study were fasted for at least 8 h and during the first and second stages of labor. Median initial cer- vical dilation was 5 cm (range 3–9). A Mapleson C circuit, including antibacterial filter and scavenging system, was connected to a small anesthesia system designed for magnetic resonance imaging (Titus, Dr€ager). Values of inspired (F I ) and end-tidal (F ET ) concentrations of sevoflurane, oxygen and carbon di- oxide were monitored continuously and recorded at 10-s intervals by a gas analyzer (Capnomac Ultima Datex, Helsinki, Finland) (Fig. 1). Oxyhemoglobin saturation International Journal of Obstetric Anesthesia (2003) 12, 79–82 Ó 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0959-289X(02)00195-4 Accepted October 2002 q Presented in part at the Italian National meeting of Anesthesia SIAARTI 2000, Napoli, Italy, October 2000. Adelchi Toscano MD, Carlo Pancaro MD, Simone Giovannoni MD, Giulio Minelli MD, Claudio Baldi MD, Giulia Guerrieri MD, Vito A. Peduto MD, Department of Anesthesia and Intensive Care, University Hospital, Perugia, 06125 Italy; John A. Crowhurst MBBS, FANZCA, FRCA, Department of Anaesthesia and Intensive Care, Queen CharlotteÕs Hospital, London, UK. Correspondence to: Adelchi Toscano MD, Department of Anesthesia, CTO hospital, Firenze, 50100, Italy; E-mail: adelchitoscano@hotmail.com 79