Effect of maternal hypocapnia eucapnia on the foetus during caesarean section

Abstract

Summary: Studies were made to ascertain the influence of maternal ventilation on foetal oxygen tension and acid-base status during Caesarean section under general anaesthesia. The anaesthetic technique of nitrous oxide, muscle rclaxants and mechanical ventilation was used. In the first group of 15 cases using this technique, maternal respiratory alkalaemia as the result of hyperventilation was observed. In the second group of 23 cases using a similar technique, in which 2% carbon dioxide was added to the inspired gas mixture and the carbon dioxide absorber in the circle system bypassed, maternal Pco2 and pH were maintained within normal limits Maternal hypocapnia, when compared with maternal eucapnia, was associated with a significant decrease in foetal blood Po,, increases in base deficit, lower 1-minute Apgar scores, and a delay in the onset of rhythmic neonatal breathing. Using the carbon dioxide rebreathing method described, undesirable effects of maternal alkalaemia could be prevented. © 1972 John Sherratt & Son Ltd.