Head computed tomography in medical intensive care unit patients: Clinicalindications

Objective: To assess whether clinical variables might be useful in selectin g patients who will have an acute intracranial abnormality seen in head com puted tomographic scans (HCT). Design: Retrospective study. Setting: Medical intensive care unit (MICU) in a tertiary teaching hospital . Measurements: Medical records of patients admitted to the MICU who underwen t HCT between January 1, 1994, and December 31, 195, were reviewed. Patient s with acute intracranial abnormalities (HCT-positive) and those without ne w acute findings (HCT-negative) were compared on various clinical variables , including demographics, indications for obtaining the HCT (mental status change, neurologic deficit, fever, seizures), coagulation profiles, when th e HCT was performed (at admission or after admission), and ordering physici an. Main Results: Of 297 HCTs obtained in 230 patients, 37% (109/297) were posi tive. When the clinical variables were examined univariately, only the pres ence of a neurologic deficit (70% vs. 37%; difference, 33%; p < .001) diffe red significantly between positive and negative HCTs. Multivariate analysis confirmed that only the frequency of a new neurologic deficit differed sig nificantly in the two groups (p < .001; odds ratio, 3.9; 95% confidence int erval, 2.3-6.4). In patients without neurologic deficits, only the presence of seizures was associated with a positive HCT (p < .01: logistic regressi on). The presence of either neurologic deficit or seizures best predicted a positive HCT: sensitivity 0.81, specificity 0.53, positive predictive valu e 0.50, and negative predictive value 0.83. Conclusion: Among MICU patients, the presence of either neurologic deficit or seizures is associated with the presence of an acute intracranial abnorm ality seen in HCT, but the association is not powerful enough to reliably d epend on these clinical variables to select patients for HCTs in the MICU.