Objective: To study the influence of chronic smoking on explicit learning abilities, during propofol sedation.
Methods: For 24 smokers and 25 matching non-smokers, learning performance was evaluated during three increasing depths of propofol sedation. Twenty-four hours after anaesthesia, delayed performances (recall and recognition)
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Objective: To study the influence of chronic smoking on explicit learning abilities, during propofol sedation.
Methods: For 24 smokers and 25 matching non-smokers, learning performance was evaluated during three increasing depths of propofol sedation. Twenty-four hours after anaesthesia, delayed performances (recall and recognition) were assessed. Recognition scores were computed using both raw data and a validated recognition discriminability index (d’), which took false recognitions into account.
Results: Learning performances during propofol induction were equal in both groups: 21 words recalled from 24 presented words (range in smokers 14 to 24 words, in non-smokers 13 to 24 words [p = 0.58]). No differences were observed in recall, 24 h after anaesthesia: median recall of the 24 words was 7 words in smokers (range, 13 to 24), and 6 words in non-smokers (range, 3 to 10) (p = 0.58). Increasing depth of sedation decreased learning performances in both groups but did not reveal differences in learning or recall performances between smokers and non smokers. In the delayed recognition task, there was no difference in the number of correct recognitions in both groups (smokers, 16 ± 4.8 words from 24; non-smokers, 15.8 ± 4.5; p = 0.86), neither interaction between sedation stage, groups and performances. Only d’ was lower (1.9 ± 0.6) for smokers, than for nonsmokers (2.8 ± 1.5; p = 0.019). Post hoc analyses showed a higher number of false recognitions in smokers (4.7 ± 3.9) than in non-smokers (2.4 ± 2.9; p = 0.029).
Conclusions: Otherwise healthy, chronic smokers undergoing propofolbased general anaesthesia present no differences in explicit memory abilities compared with matched, non-smoking controls, except for a slight but significant increase in false recognition.
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