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

Jay S Balachandran,Niraj Mahajan,Ravi Kalhan,Mairaj Jaleel,Eugene Greenstein,Manu Jain,Helen K Donnelly,Rajesh Balagani,Gökhan M Mutlu

doi:10.1186/1471-2253-9-3

Abstract

BackgroundProlonged 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.MethodsA 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.ResultsThe 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).ConclusionIn 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.

Highlights

Prolonged sedation is common in mechanically ventilated patients and is associated with increased morbidity and mortality
Sedation is frequently required for comfort in patients who require mechanical ventilation for management of respiratory failure, but it is associated with the common complication of delayed awakening
Three hundred and eight patients were admitted to medical intensive care unit (ICU) with respiratory failure requiring mechanical ventilation for longer than 72 hours

Summary

Introduction

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. Delayed awakening holds up the discontinuation of mechanical ventilation and increases length of stay in the ICU but may prompt physicians to embark on a medical work-up to evaluate the cause of continued unresponsiveness after discontinuation of sedatives. Head computed tomography (CT) scans and other neurologic work-up are often obtained to further evaluate these patients. Obtaining a head CT requires transportation of critically ill patients out of ICU, which can be challenging due to increased morbidity and mortality related to the transport itself. The benefits of diagnostic testing should be weighed against the risks of transport before the decision for transport is made [2]

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