Objective

.

To Show that postoperative complications are more frequent in patients who remain longer with BIS low (< 40) during the transanestesic period, than in those where it has less depth.

Material and methods.

A prior approval through informed consent for anesthetic procedure was preanesthetic assessment including test mental confusion and minimental prior to the surgical event and 24 hours later to the same. Patients ASA II and III were included.

The subjects were divided into two groups according to the duration of the anesthetic depth (BIS low for less than 30 minutes and BIS low for 30 minutes or more). An observation and a report of the levels of anesthetic depth measurement with BIS without maneuvers which alter the same. Was made in 41 patients were included. During the procedure a monitoring of the brain activity with BIS from the entry of the patient and every 5 minutes taking record of those values, was made.

Results.

The Group of subjects with BIS low for more than 30 minutes presented a higher incidence of complications that subjects with BIS low for less than 30 minutes, (77.8% vs. 21.7%, respectively).

Conclusions.

Undoubtedly the cumulative deep anesthesia affects negatively patients who have risk factors, being clear that the longer and the deeper, the risk of complications increase.