Are the Requirements of Propofol Decreased in Early Pregnancy during Anesthetic Induction? |
Myoung Hee Kim, Su Yeon Kim, Kyung Sook Cho, Eun Chi Bang, Yong In Kang, Hyun Sook Lee, Dae Hyun Jo |
1Department of Anesthesiology, College of Medicine, Pochon CHA University, Seoul. 2Inha University, Inha General Hospital, Sungnam, Korea. |
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Abstract |
BACKGROUND Minimum alveolar concentration (MAC) is decreased during pregnancy, but there are no data regarding the requirements for intravenous agents. Recently only one study showed that the requirement for thiopental in pregnant women of 7-13 weeks' gestation was less than the requirement obtained in nonpregnant women. Thus we wanted to determine whether pregnant patients needed less propofol for hypnosis and anesthesia than nonpregnant patients.
METHODS One hundred nonpregnant women having gynecologic surgery and 100 pregnant women of 5-13 weeks' gestation undergoing elective abortions were recruited. They were randomly allocated 10 groups according to the doses of propofol and each group had 10 patients. During a period of 30 seconds, one of the doses of propofol 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0 or 3.25 mg/kg was administered. Two minutes later, patients were asked to open their eyes as a test for hypnosis. Patients who did not open their eyes were given a 10 seconds, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve as a test for anesthesia. Estimates of ED50 and ED95 for hypnosis and anesthesia were obtained by logistic regression.
RESULTS In the pregnant women, the median effective doses (ED50) (95% confidence interval) for hypnosis and anesthesia were 1.25 (1.13-1.35) mg/kg and 2.71 (2.49-3.04) mg/kg, the ED95 (95% CI) were 1.51 (1.16-1.87) mg/kg and 3.04 (2.80-3.58) mg/kg respectively. Whereas in the nonpregnant women, the ED50 for hypnosis and anesthesia were 1.27 (1.39-1.90) mg/kg and 4.12 (3.50-6.01) mg/kg, the ED95 were 1.53 (1.41-1.93) mg/kg and 4.35 (3.66-7.26) mg/kg respectively.
CONCLUSIONS In early pregnant women, the doses of propofol for hypnosis and anesthesia were 1.6% and 34.2% less compared with those in nonpregnant women. |
Key Words:
Anesthetics, Intravenous, propofol, hypnosis, anesthesia; Induction, anesthesia.; Potency, Anesthetic, ED50, ED95; Pregnancy, abortion |
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