Residual curarization in the neonate after caesarean section.
The transplacental transfer and the neonatal effects of atracurium 0.3 mg.kg-1 (ED95) were compared with those of d-tubocurarine at the usual clinical dose of 0.3 mg.kg-1 (ED90) in 46 patients undergoing elective Caesarean section. The atracurium group (25 patients) was similar to the d-tubocurarine group (21 patients) as far as age, parity and time intervals between precurarization, induction, skin incision, muscle relaxant administration, hysterotomy and birth. The transplacental transfer of atracurium was lower than that of d-tubocurarine, with a feto-maternal ratio of 9 +/- 3% for atracurium and 12 +/- 5% for d-tubocurarine (P less than 0.05). The transplacental transfer of laudanosine was low at 14 +/- 5%, with blood levels of 0.101 +/- 0.032 microM.L-1 in the umbilical vein. Newborns in the two groups were comparable in terms of Apgar scores at one, five and ten minutes, as well as for NACS scores (neurological and adaptive capacity scoring test) at two and 24 hours after birth. However, at 15 min after birth, only 55% of newborns in whom the mothers received atracurium had a normal NACS score (greater than or equal to 35/40) compared with 83% of newborns in whom the mothers received d-tubocurarine (P less than 0.05). Further analysis of the five variables related to active muscle tone revealed that the modal score for active extension of the neck of newborns from the atracurium group was lower than for newborns from the d-tubocurarine group (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Anesthesia, University of Montreal.
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Perreault
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Guay
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Gaudreault
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Cyrenne
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Varin
D000771:Anesthesia, Intravenous; D000773:Anesthesia, Obstetrical; D001034:Apgar Score; D001279:Atracurium / Q000097:blood / Q000494:pharmacology*; D002585:Cesarean Section; D004311:Double-Blind Method; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005333:Fetus / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D007546:Isoquinolines / Q000097:blood / Q000494:pharmacology*; D008431:Maternal-Fetal Exchange; D009129:Muscle Tonus / Q000187:drug effects; D009132:Muscles / Q000187:drug effects; D009892:Opium / Q000097:blood / Q000494:pharmacology*; D011247:Pregnancy; D013997:Time Factors; D014403:Tubocurarine / Q000097:blood / Q000494:pharmacology*
D007546:Isoquinolines; D001279:Atracurium; D009892:Opium; C001522:laudanosine; D014403:Tubocurarine