Duration and clinical features of cardiac arrest predict early severe cerebral edema

Abstract

Background: Severe brain edema appears early after cardiopulmonary resuscitation (CPR) in a subset of patients and portends a poor prognosis. We tested whether clinical features of patients or resuscitation during out-of-hospital cardiac arrest (OHCA) are associated with early, severe cerebral edema.

Method/research design: We reviewed pre-hospital and hospital records for comatose patients surviving to hospital admission after OHCA who had computed tomography (CT) of brain at the time of hospital admission available for inspection. We measured the gray-white ratio (GWR) of X-ray attenuation between the caudate nucleus and posterior limb of the internal capsule, defining severe cerebral edema as GWR < 1.20. We calculated associations between severe cerebral edema and patient or resuscitation variables.

Results: Between 2010 and 2019, 1340 subjects were admitted of whom 296 (22%) showed severe cerebral edema on initial CT. Subjects with severe edema had lower survival (5/296, 2% vs. 377/1044, 36%). Severe edema was independently associated with total CPR duration, total dose of epinephrine, younger age, non-shockable arrest rhythms, fewer total number of rescue shocks, rearrest after initial return of pulses, and non-cardiac arrest etiology. Prevalence of severe cerebral edema increased from 2% among subjects with 0-10 min of CPR to 31% among subjects with >40 min of CPR.

Conclusion: CPR duration along with easily measurable clinical and resuscitation characteristics predict early severe cerebral edema after OHCA. Future interventional trials should consider targeting or preventing cerebral edema after prolonged hypoxic-ischemic brain injury especially in patients with high risk clinical features.

Keywords: Cerebral edema; Imaging; Prognostication.

Figure 1:

Association between time interval from cardiac arrest to CT scan and GWR. Each point represents a single subject, and the regression line is least-squares regression between the variables. GWR decreases with increasing delay until CT scan (slope (95%CI) =−0.005 (−0.008 to −0.002) /hour, r=0.10).

Figure 2:

(A) GWR decreases with increasing duration of CPR. Proportion of CT scans for subjects with each GWR is depicted for 10-minute bins of CPR duration. Number of subjects for each bin: 0–10 min: 186; 11–20 min: 220; 21–30 min: 181; 31–40 min: 106; >40 min: 119. (B) GWR decreases with increasing total number of epinephrine doses. Number of subjects for each dose: 0 mg: 136; 1 mg: 136, 2 mg: 216; 3 mg: 191; 4 mg: 146; 5 mg: 103; 6 mg: 77; 7 mg: 45; 8 mg: 32: 9mg: 22; 10mg: 8; >10 mg: 18.