Decreased thiopental requirements in early pregnancy
Language: 
English
Abstract: 

BACKGROUND: Anesthetic requirements for inhalational agents are decreased during pregnancy, but there are no data regarding requirements for intravenous agents. The quantal dose-response curves for thiopental were calculated for 70 nonpregnant women having gynecologic surgery and for 70 pregnant women of 7-13 weeks' gestation having elective abortions. METHODS: Groups of 10 patients were given 2, 2.4, 2.8, 3.3, 3.8, 4.5, or 5.3 mg/kg thiopental as a bolus dose during a period of 10 s. 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-s, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve as a test for anesthesia. Purposeful movement indicated that there was no anesthesia. Log dose-response curves for hypnosis and anesthesia were calculated after logit transformation. RESULTS: In the nonpregnant women, the median effective doses (ED50s) (95% confidence interval) for hypnosis and anesthesia were 3.1 (2.8-3.4) mg/kg and 4.9 (4.5-5.4) mg/kg, whereas in the pregnant women the corresponding ED50s were 2.6 (2.3-2.8) mg/kg and 4 (3.7-4.4) mg/kg. In the non-pregnant women, the ED95s (95% CI) for hypnosis and anesthesia were 4.4 (3.9-5.4) mg/kg and 6.4 (5.7-7.9) mg/kg, whereas in the pregnant women the corresponding ED95s were 3.7 (3.3-4.5) mg/kg and 5.2 (4.7-6.3) mg/kg. The pregnant to nonpregnant relative median potency (95% CI) ratio for hypnosis was 0.83 (0.67-0.96) and for anesthesia it was 0.82 (0.62-0.94). CONCLUSIONS: The dose of thiopental for hypnosis was 17% less and that for anesthesia was 18% less in pregnant women of 7-13 weeks' gestation compared with that in nonpregnant women.

Author(s): 
Gin, T.
Mainland, P.
Chan, M. T.
Short, T. G.
Item Type: 
Journal Article
Publication Title: 
Anesthesiology
Journal Abbreviation: 
Anesthesiology
Publication Date: 
Jan-97
Publication Year: 
1997
Pages: 
73-78
Volume: 
86
Issue: 
1
ISSN: 
0003-3022
Library Catalog: 
PubMed
Extra: 
PMID: 9009942

Turabian/Chicago Citation

T. Gin, P. Mainland, M. T. Chan and T. G. Short. Jan-97. "Decreased thiopental requirements in early pregnancy." Anesthesiology 86: 1: 73-78.

Wikipedia Citation

<ref> {{Cite journal | doi = | issn = 0003-3022 | volume = 86 | pages = 73-78 | last = Gin | first = T. | coauthors = Mainland, P., Chan, M. T., Short, T. G. | title = Decreased thiopental requirements in early pregnancy | journal = Anesthesiology | date = Jan-97 | pmid = | pmc = }} </ref>