Re-awakening the carotid bodies after anaesthesia: managing hypnotic and neuromuscular blocking agents

Neuromuscular blocking drugs (NMB) are used in just under half of all general anaesthetics in the UK [1]. However, they have their own unintended effects, especially during early recovery from surgery. Wenow know that one of these is the risk of accidental awareness during general anaesthesia, which occurs almost exclusively in patients who are paralysed with NMBs [2]. Accidental awareness during recovery arises from too early re-awakening from hypnotic effects of anaesthesia coupled with delayed reversal of paralysis [2]. Postoperative respiratory effects of residual neuromuscular blockade are another well-known sideeffects, self-evident if the diaphragm or intercostal muscles are weak or if there is a degree of upper airway collapse [3]. Such clinically detectable paralysis after surgery is at worst evidenced by dyspnoea, agitation, obvious weakness and, if the vocal cords are also partially paralysed, difficulty speaking or coughing (and this last can lead to atelectasis or aspiration). Together these can create a dangerous and frightening situation for patients. Indeed, personal histories from the UK’s 5th National Audit Project (NAP5) report suggest that these respiratory symptoms can be interpreted by patients as a perception of having been accidentally awake ‘during anaesthesia’ [2]