Detecting awareness during general anaesthetic Caesarean section An evaluation of two methods

Authors

  • D. G. BOGOD,

    Corresponding author
    1. Chinese University of Hong Kong, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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  • J. K. ORTON,

    1. Chinese University of Hong Kong, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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  • H. M. YAU,

    1. Chinese University of Hong Kong, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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  • T. E. OH

    1. Chinese University of Hong Kong, Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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should be addressed to Dr D.G. Bogod, Department of Anaesthetics, City Hospital, Hucknall Road, Nottingham NG5 1PB.

Summary

Seventy-four patients received general anaesthesia for Caesarean section. Seven percent of the elective group and 28% of the emergency patients reported dreaming or recall of voices during the procedure (p < 0.05) at postoperative interview. One patient from each group reported feeling pain or suffocation. All patients were monitored for awareness using the isolated forearm technique and lower oesophageal contractility. Provoked lower oesophageal contractility was the most effective of the different indices. A value greater than 35 mmHg on at least one occasion had a false negative rate of 33%, a false positive rate of 28% and a predictive value of 25%. A value greater than 13 mmHg picked up all patients who dreamed, with a false positive rate of 68%. Both of the ‘aware’patients had provoked lower oesophageal contractility response of greater than 70 mmHg, an attribute shared by only 8% of the rest. The isolated forearm was particularly ineffective.

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