Non-invasive cerebral perfusion monitoring in cardiac arrest patients: a prospective cohort study.

OBJECTIVES: To determine if non-invasive cerebral perfusion estimation provided by a new acousto-optic technology can be used as a reliable predictor of neurological outcome.

PATIENTS AND METHODS: We performed a prospective, observational cohort study of consecutive comatose patients successfully resuscitated from out-of-hospital cardiac arrest. Patients were monitored using c-FLOW (Ornim Medical) from critical care unit admission up to 72 h, full awakening, or death. Primary outcome was favourable neurological outcome at hospital discharge, defined as a Cerebral Performance Category score of 1 or 2.

RESULTS: A total of 21 patients were enrolled, without any loss to follow-up. Mean perfusion index over the monitoring period was not associated with functional outcome at hospital discharge (OR 1.03 [0.93, 1.17]). Adjustment for initial rhythm, time to return of spontaneous circulation and Glasgow coma scale motor score did not significantly alter the results (OR 1.06 [0.99, 1.12]). Mean perfusion index showed a poor discriminative value with an area under the curve of 0.60 for functional outcome (0.64 for survival). Correlation between the probes was weak (Pearson coefficient 0.35).

CONCLUSION: Cerebral perfusion monitoring using a c-FLOW device in survivors of cardiac arrest is feasible, but reliability of the information provided has yet to be demonstrated. In our cohort, we were unable to identify any association between the perfusion index and clinical outcomes at discharge. As such, clinical management of cardiac arrest patients based on non-invasive perfusion index is not supported and should be limited to research protocols. The trial was registered with ClinicalTrials.gov, number NCT02575196.