Bispectral Index Monitoring in a Severe Comatose Patient During Surgery

Abstract

Abstract:A comatose patient required a tracheostomy. His Glasgow Coma Score was 4 and he was intubated with mydriatic and isochoric pupils, without corneal and light reflexes. Two previous EEGs showed signs of severe and diffuse encephalopathy (arreactive delta and theta rhythms) and there were no somatosensory evoked potentials recordable at the scalp. When the tracheostomy procedure was carried out, the Bispectral Index (BIS) helped to titrate the hypnotic and analgesic requirements keeping the haemodynamic parameters stable. IMPLICATIONS STATEMENTA comatose patient had to undergo surgery. We guided the hypnotic and analgesic requirements by the bispectral index.The bispectral index (BIS) has been used in severely comatose patients as an assessment of the onset of brain death [1]. Moreover, in patients in a persistent vegetative state, BIS has helped to guide anaesthetic depth during surgery [2]. We show the clinical state, electrophysiological tests and the anaesthetic management of a patient in coma after cardiac arrest due to near drowning, who needed to undergo a tracheostomy. CASE REPORTA 72 yr old 80 kg male, was resuscitated (advanced CPR lasting 40 minutes). He was endotracheal intubated with a Glasgow Coma Score (GCS) of 3, his pupils were mydriatic and isochoric, without corneal or light reflexes. At the intensive care unit (ICU) and for two weeks, he went on ventilated using pressure support mode, because he had spontaneous breathing. The neurological condition evolved to a GCS equal to 4 + tube, with a rigid posture, sporadic passive eye opening and weak withdrawal responses to the nociceptive stimulus. Two EEG were carried out, the first, 24 h after admission to ICU and the second a week later, both showed signs of severe and diffuse encephalopathy (arreactive delta and theta rhythms). The somatosensory evoked potentials recorded at the scalp, were absent when the posterior tibial nerves were stimulated.After two weeks, it was decided to perform a tracheostomy. At the operating theatre, the conventional monitoring went on while the BIS was measured with an Aspect A-2000 monitor / BIS TM quatro sensor (Aspect Medical Systems Inc., Newton MA). We guided the hypnotic and analgesic requirements by BIS, observing the haemodynamic parame-*Address correspondence to this author at the Department of Anaesthesiology, Hospital Universitario del Mar, UAB, Paseo Marítimo 25-29 08003 Barcelona, Spain; Tel: 34932483350; Fax: 34932483617; E-mail: 18569@imas.imim.es ters, too. At the beginning, the systolic blood pressure (SBP) was higher than 200 mmHg while BIS values ranged from 90 to 100, so we used intravenous labetalol (5 mg) and administered cis atracurium (4 mg), to adapt the mechanical ventilation and to attenuate the rigidity (EMG activity 50). Thus, the SBP decreased to150 mmHg while the BIS and EMG values fell to almost 50 and 30 respectively. As BIS and EMG values were restored, we began to administer sevoflurane at 1,5 % end -tidal concentration, a dose that allowed him to reach an anaesthesia depth r...