Research article

Head CT is of limited diagnostic value in critically ill patients who remain unresponsive after discontinuation of sedation

Jay S Balachandran¹ , Mairaj Jaleel² , Manu Jain¹ , Niraj Mahajan³ , Ravi Kalhan⁴ , Rajesh Balagani⁴ , Helen K Donnelly⁴ , Eugene Greenstein⁵ and Gökhan M Mutlu⁴

¹Division of Pulmonary and Critical Care Medicine, Harvard Medical School, Boston, MA, USA

²Division of Pulmonary and Critical Care Medicine, University of Wisconsin, Madison, WI, USA

³Pulmonary and Critical Care Medicine, Rush University Medical Center, Chicago, IL, USA

⁴Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA

⁵Division of Cardiology Northwestern University Feinberg School of Medicine, Chicago, IL, USA

author email corresponding author email

BMC Anesthesiology 2009, 9:3doi:10.1186/1471-2253-9-3

Published:	7 May 2009

Abstract

Background

Prolonged sedation is common in mechanically ventilated patients and is associated with increased morbidity and mortality. We sought to determine the diagnostic value of head computed tomography (CT) in mechanically ventilated patients who remain unresponsive after discontinuation of sedation.

Methods

A retrospective review of adult (age >18 years of age) patients consecutively admitted to the medical intensive care unit of a tertiary care medical center. Patients requiring mechanical ventilation for management of respiratory failure for longer than 72 hours were included in the study group. A group that did not have difficulty with awakening was included as a control.

Results

The median time after sedation was discontinued until a head CT was performed was 2 days (interquartile range 1.375–2 days). Majority (80%) of patients underwent head CT evaluation within the first 48 hours after discontinuation of sedation. Head CT was non-diagnostic in all but one patient who had a small subarachnoid hemorrhage. Twenty-five patients (60%) had a normal head CT. Head CT findings did not alter the management of any of the patients. The control group was similar to the experimental group with respect to demographics, etiology of respiratory failure and type of sedation used. However, while 37% of subjects in the control group had daily interruption of sedation, only 19% in the patient group had daily interruption of sedation (p < 0.05).

Conclusion

In patients on mechanical ventilation for at least 72 hours and who remain unresponsive after sedative discontinuation and with a non-focal neurologic examination, head CT is performed early and is of very limited diagnostic utility. Routine use of daily interruption of sedation is used in a minority of patients outside of a clinical trial setting though it may decrease the frequency of unresponsiveness from prolonged sedation and the need for head CT in patients mechanically ventilated for a prolonged period.