Magnetic Resonance Imaging in Neurocritically Ill Patients: Who Fails and How?

OBJECTIVES

Performing magnetic resonance imaging (MRI) in neurocritically ill patients is challenging because it often requires sedation and withholding care in the neurological intensive care unit. This study investigated the incidence of and reasons for failed or complicated MRI (MRI-FC) in such patients.

METHODS

A consecutive series of 218 neurocritically ill patients who underwent brain MRI were retrospectively evaluated. Failed or complicated MRI included failure to obtain all ordered sequences, unscheduled sedative administration, decrease in oxygen saturation to less than 90%, hypotension (≥40-mm Hg decrease and/or use of inotropic agents), and cardiac or respiratory arrest.

RESULTS

Failed or complicated MRI occurred in 66 patients (30.3%) and included failure to obtain MRI sequences (n = 13), unscheduled use of sedatives (n = 62), oxygen desaturation (n = 9), and hypotension (n = 6). Cardiac or respiratory arrest did not occur. Use of sedative agents while in intensive care (P < 0.01), high Acute Physiology and Chronic Health Evaluation II score (P = 0.031), and low Glasgow Coma Scale score on admission (P = 0.047) were associated with MRI-FC. Scan times were longer (P = 0.004) and Glasgow Coma Scale (P < 0.001) and Richmond Agitation Sedation Scale (P = 0.003) scores were lower (P = 0.004) after imaging in patients with MRI-FC. Previous use of sedative agents was independently associated with MRI-FC (adjusted odds ratio = 3.57, 95% confidence interval = 1.78 to 7.24, P < 0.001).

CONCLUSIONS

Failed or complicated MRI was common and was associated with the use of sedative agents, severity of illness, and lower level of consciousness. Studies to ensure effective and safe performance of MRI in neurocritically ill patients are needed.