Placental transfer and neonatal effects of dexmedetomidine during cesarean section under general anesthesia

Abstract

Objective To investigate the placental transfer and neonatal effects of dexmedetomidine during the cesarean section under general anesthesia. Methods Thirty-eight nulliparous parturients, of American Society of Anesthesiologists physical statusⅠ or Ⅱ, aged 22-37 yr, weighing 56-82 kg, who were at full term with a singleton fetus, scheduled for elective caesarean section under general anesthesia, were randomly divided into 2 groups (n=19 each) using a random number table: dexmedetomidine group (group D) and normal saline group (group N). In group D, dexmedetomidine was infused in a loading dose of 0.6 μg/kg starting from 10 min before induction of anesthesia, followed by an infusion of 0.4 μg·kg-1·h-1 until peritoneal closure.Group N received the equal volume of normal saline.Blood samples were collected from the maternal artery (MA), umbilical vein (UV), and umbilical artery (UA) for blood gas analysis and for determination of plasma dexmedetomidine concentrations (CMA, CUV and CUA) by high-performance liquid chromatography-mass spectrometry, and CUV/CMA and CUA/CUV were calculated.Apgar scores were recorded at 1 and 5 min after delivery, and the occurrence of respiratory depression was also recorded.The I-D interval (the time from administration of anesthetics to delivery) and U-D interval (the time from incision of the uterus to delivery) were recorded. Results There were no significant differences in the blood gas analysis parameters in blood samples collected from the MA, UV and UA, I-D interval, U-D interval, and Apgar scores between the two groups (P>0.05). No neonatal respiratory depression was found in both groups.In group D, CMA, CUV and CUA were 471±119, 359±88 and (321±78) ng/ml, respectively, CUV/CMA was 0.76±0.06, and CUA/CUV was 0.89±0.03. Conclusion Although the metabolism of dexmedetomidine is little after easy placental transfer, dexmedetomidine has no adverse effects on the newborn during the cesarean section under general anesthesia. Key words: Dexmedetomidine; Cesarean section; Infant, newborn; Placenta