Unusual Response to Muscle Relaxants in the Pregnant Woman Undergoing Cesarean Section.

Because the parturient should be always considered as a patient with a full stomach and a possible difficult airway, succinylcholine is considered the muscle relaxant of choice for rapid sequence induction of general anesthesia. During pregnancy, the level of plasma cholinesterase which hydrolyses succinylcholine is moderately decreased, and hence hydrolysis of succinylcholine remains within the normal range. Also, the duration of action of succinylcholine will be only moderately prolonged in the heterozygote atypical parturient. However, in the parturient inheriting homozygote atypical esterase, hydrolysis of the injected succinylcholine is negligible with a consequent very prolonged neuromuscular block, which allows the transmission of the unhydrolysed succinylcholine across the placenta to the fetal circulation. This can be complicated by neuromuscular block in the fetus who may have inherited a homozygote atypical plasma cholinesterase if the father is homozygote or heterozygote carrier of the enzyme.