The incidence of flushing on induction of anaesthesia in patients who blush easily

Summary Flushing (reddening and blotching of the skin) is seen frequently at induction of anaesthesia, is associated with anaesthetic agents such as thiopental and muscle relaxants, and is attributed to histamine release. The changes are generally confined to the neck and upper chest (the blush area). In conscious subjects, the mechanisms responsible for blushing in the same skin distribution are well defined and neurally mediated. We investigated the relationship between a history of blushing easily and flushing after intravenous induction of anaesthesia. We interviewed 898 patients about to undergo general anaesthesia and asked them if they blushed easily. Anaesthesia was induced with thiopental followed by suxamethonium and/or alcuronium. We noted skin colour and the presence of a flush every 5 min for 20 min. Women reported blushing more than men (47% of women, compared with 33% of men, p < 0.001), and blushing was more common in young people (p < 0.001). In those women with a history of blushing, 32% flushed on induction of anaesthesia, compared with 6% of those who did not blush. In men, a flush was seen in 22% of those who blushed, and in 0.2% of those who did not. These differences in the frequency of flushing were significant (p < 0.001). In conclusion, flushing after induction of anaesthesia appears to be related to individual predisposition and may be neurally mediated.