Introduction

Cranial computer tomography (CCT) scans are often required in patients after successful resuscitation therapy either in an in- or out-of-hospital setting, in order to identify the underlying cause for cardiac arrest or altered mental state (AMS). Performing CT scans in these critically ill and often unstable patients is therefore sometimes challenging and furthermore numbers of negative CCT scans remain high. Relevant clinical risk factors that potentially increase the diagnostic yield for a clinically relevant pathologic CCT scans are still unknown, but urgently needed.

Objective

The aim of this study was to identify potential clinical risk factors for a pathologic CCT scan in patients after in-hospital (IHCA) or out-of-hospital (OHCA) cardiac arrest.

Methods

We therefore retrospectively analysed the data of 202 patients with IHCA (n=38; 19%) or OHCA (n=164; 81%). All patients were successfully resuscitated and treated on the intensive care unit (ICU) and received an urgent CCT scan between 2012 and 2016. CCT scan results were classified as “positive” if a new pathology, either bleeding, stroke or hypoxia was found.  

Results

Urgently performed CCT scans in 202 patients with a mean age of 61 years (±15 years) and 73% being male (n=147) were positive in a total of 66 patients (33%). Thereof, 38 patients (19%) were newly diagnosed with hypoxia, 18 patients (9%) had intracranial bleeding and a stroke was suspected in 10 patients (5%). Anisocoria was an independent risk factor for a positive CCT scan (HR=3.29; 95% C. I. 1.51-7.18; p=0.003) (figure). Younger age, male sex, normal coagulation factors and therapeutic hypothermia predicted a negative CCT scan result (all p<0.04). Patients undergoing CCT for new-onset anisocoria receiving negative results were more often septic, had liver failure and/or a haemato-oncologic disease (p=0.05). Patients with and without new-onset anisocoria had a comparable risk for mortality (p(log rank)=0.79), but AMS and a positive CCT scan emerged as independent predictors for death (all p=0.02).

Conclusions

This data shows, for the first time, that anisocoria can be used as an independent predictor for a pathologic CCT scan in successfully resuscitated patients after IHCA or OHCA.