Glasgow Coma Scale for outcome prediction after cardiac surgery: is it applicable?

Objectives: The Glasgow Coma Scale (GCS) is used commonly for assessing patients' neurologic condition and outcome in intensive care units (ICUs); however, its reliability in cardiac surgical patients has been questioned. It has been claimed that active sedation is the cause of its unsuitability for these patients. This study aimed to compare the accuracy of GCS in cardiac surgical patients with and without active sedation to find out if the inapplicability of GCS in surgical patients is related to active sedation.

Design: This was an observational cohort study.

Setting: The study was conducted in a cardiac surgical intensive care unit between January 1, 2007 and December 31, 2009.

Participants: All consecutive adult cardiac surgical patients were included in this study.

Interventions: All types of cardiac surgical procedures performed during the study period were included without any exceptions. The study population was divided into 2 groups: sedated and non-sedated.

Measurements And Main Results: GCS was calculated daily for the first 7 postoperative days. The authors developed a new 4-point neurologic descriptor (ND): (1) neurologically free, (2) ICU psychosis, (3) actively sedated, and (4) documented focal neurologic deficits. The accuracy of both scales (GCS and ND) at predicting ICU mortality was compared by replacing the GCS in the Sequential Organ Failure Assessment (SOFA) score with the new ND, producing a modified SOFA. GCS was not an accurate outcome predictor in non-sedated or sedated patients. The ND was superior to GCS. Correspondingly, the modified SOFA showed a significantly higher accuracy of ICU-mortality prediction than the original SOFA.

Conclusions: Regardless of active sedation, GCS is not accurate at outcome prediction for cardiac surgical patients. The suggested ND is a simple and more accurate risk stratification variable in cardiac surgical ICUs.