The Study of Intraoperative Consciousness after Tracheal Intubation

Awareness following noxious stimuli like intubation could be as high as 25% compared to postoperative recall. The isolated forearm technique (IFT) allows us to assess consciousness by verbal command to move isolated hand. Hence we conducted study to establish IFT responses following intubation under standard general anaesthesia.

We enrolled 132 adult patients undergoing general anaesthesia. A tourniquet was applied on other arm. Following intravenous induction of anaesthesia, torniquet was inflated 100mmhg above systolic BP. After giving muscle relaxant, three minutes patients were ventilated with oxygen and inhalational agent. Before laryngoscopy first verbal command (Squeeze my hand) was given to the patient. Once intubation and tube confirmation done, second verbal command was given. Lack of paralysis in isolated hand was confirmed with TOF stimuli and tourniquet was deflated. Surgery was carried in routine manner. Postoperatively all patients were evaluated for any explicit recall using Modified Brice questionnaire. The primary outcome is number of patients who responded to verbal command postintubation. Secondary outcome is number of patients responded prelaryngoscopy and number of patients reporting explicit recall in the Modified Brice interview.

None of the patients had positive IFT response. On postoperative interview none reported awareness. 10.7% of patients had dreams which were pleasant. Worst thing about surgery was pain.(43%).

Our study suggests that intraoperative consciousness after intubation and postoperative recall is an uncommon occurrence.