Emergency airway management in obstetric general anaesthesia

We read with great interest Lucas and Yentis's editorial about obstetric general anaesthesia and the changing consensus regarding thiopental 1. Of particular significance was their discussion of the role of ‘human factors’ and other aspects complicating general anaesthesia in the parturient. The editorial questioned whether it is justifiable to continue to use arguably dated techniques for obstetric general anaesthesia, and pointed to the need for up-to-date research in this area. In particular, we think there are key issues relating to emergency airway management that could improve safety. Reluctance to use manual ventilation during ‘traditional’ rapid sequence induction leaves the patient at the point of rapid desaturation during the first intubation attempt, compounding an already stressful situation. Anxiety about maternal or fetal hypoxia can tempt anaesthetists to intubate before optimal paralysis has been achieved, increasing the likelihood of intubation difficulties 2, 3. The use of apnoeic oxygenation (administering high-flow oxygen via nasal speculae before intubation to achieve passive oxygenation during apnoea) has been shown to prolong ‘time to desaturation’ safely in high-risk patient groups, for example those with anticipated airway difficulty, while definitive airway control is obtained 4, 5. Therefore, we would advocate administration of high-flow nasal oxygen before and during induction in all caesarean sections under general anaesthesia. This, combined with gentle manual ventilation of of the lungs for all patients soon after induction, would reduce the likelihood of early desaturation. The theoretical risk of stomach inflation caused by gentle manual ventilation is, in our opinion, outweighed by the certain benefit of maintaining adequate oxygenation 2. Furthermore, inadequate inflation of the chest whilst attempting gentle bag-mask ventilation could indicate airway maintenance problems at an early stage, and allow senior help to be sought more promptly. We believe that the addition of these simple modifications to rapid sequence induction for caesarean section under general anaesthesia (and arguably any other form of emergency surgery) could significantly improve patient safety, and welcome comments from other anaesthetists on these proposals.