AWARENESS UNDER GENERAL ANAESTHESIA: INCIDENCE, RISK FACTORS AND CAUSES IN NIGERIAN PATIENTS

Abstract

BACKGROUND: Awareness under general anaesthesia is an anaesthetic
complication that receives little or no attention from surgical care providers in the
West African sub-region. This is evidenced by the few literature reports on the
subject. This study sought to establish the occurrence of awareness, its incidence,
causes and risk factors as well as recall of intraoperative events in our surgical
patient population.
METHOD: Patients who had elective and emergency surgical procedures done
under general anaesthesia and were capable of responding intelligently to
questions were interviewed after full recovery from anaesthesia, 6-72 hours
postoperatively. Anaesthetists were unaware of the purpose of the study, thus
their normal anaesthetic techniques appropriate for the surgery were not altered.
Data on patient demographics, premedication, anaesthetic technique, surgical risk
classification and intra-operative complications were collected from the
anaesthetic chart. Postoperatively, eligible patients were interviewed to determine
the occurrence of awareness with recall.
RESULTS: Analysis of data collected showed that 1.07% of the patients
experienced awareness under general anaesthesia as they recalled statements
made by staff during surgery. Awareness was significantly associated with
intraoperative complications such as hypotension, difficult intubation resulting in
hypoxia, severe haemorrhage and hypoxia from any cause. (P <0.0001). Other
risk factors were nonuse of anxiolytics/ amnestic agents as premedication, use of
relaxant technique, Obstetric emergencies done under general anaesthesia, and
emergency surgery performed after normal working hours. Surprisingly, 96.7%
of the respondents were satisfied with the anaesthesia received, including some
of those who probably had some awareness.
CONCLUSIONS: Awareness does occur among our surgical patients. The
incidence of 1.07% in this study is higher than that reported in studies in the
developed world. Inappropriately light anaesthesia, late presentations of patients
with complications, emergency nature of surgery may account for this difference.

AWARENESS UNDER GENERAL ANAESTHESIA: INCIDENCE, RISK FACTORS AND CAUSES IN NIGERIAN PATIENTS