Diagnostic yield and safety of CT scans in ICU

Critically ill patients often require CT scans. Adverse events (AE) can occur during intra-hospital transport (IHT). The aim of this prospective study was to determine the diagnostic and therapeutic yield and the safety of CT scans in ICU patients.

All ICU patients having a CT scan for diagnostic purposes were eligible. Diagnostic yield was evaluated by the agreement (full, partial or disagreement) between the physician main diagnostic hypothesis before the CT scan and the diagnosis established after the CT scan. Therapeutic yield was assessed by therapeutic changes after the CT scan. The safety was determined by the AE rate during IHT.

A total of 533 CT scans were performed on 359 patients in three teaching hospital ICUs. The diagnostic yield of CT scan showed 40.7 % of full agreement, 5.6 % of partial agreement and 53.7 % of disagreement with the main diagnostic hypothesis formulated before the CT scan. The CT-scan brought new elements to the diagnosis in 22.9 % of the cases. There was 54.4 % of therapeutic change after CT scan, while 22.3 % of AE occurred during IHT, including 6.7 % of life-threatening events. AE occurred more frequently in the first 48 h after ICU admission, in the most severely ill patients (higher SAPS II at admission), and when there was a large amount of equipment required for transport.

The CT scan as a diagnostic procedure invalidated a diagnostic hypothesis and led to a therapeutic change in more than half of the cases.