Reversal of the No-Reflow Phenomenon after Prolonged Cardiac Arrest by Controlled Automated Reperfusion of the Whole Body: Preliminary Results of an Ongoing [15O] Water Pet Study

Objectives: Survival after cardiac arrest (CA) remains low despite multiple advances in the field of cardiopulmonary resuscitation (CPR). After 20 minutes of CA, a neurologically unimpaired survival is rare. A major reason appears to be the cerebral no-reflow phenomenon which has been reported even hours after return of spontaneous circulation (ROSC). Aim of this study was to investigate cerebral blood flow (CBF) during reperfusion by controlled automated reperfusion of the whole body (CARL) after prolonged CA.

Methods: At date of submission N = 3 pigs (German landrace) underwent 20 minutes of normothermic CA induced by ventricular fibrillation and were treated with CARL for up to two hours. CARL represents a therapy bundle based on high-flow, pulsatile extracorporeal circulation and includes hypothermia of up to 32°C, head elevation of 30 degrees and a hyperosmolar priming solution. CBF was measured quantitatively at baseline and at multiple times during reperfusion by positron emission tomography (PET) with 15O-labeled water and arterial blood sampling.

Result: In all three pigs, global CBF (mean = 24.3 mL/min/100 g) was reduced in the first minutes after reperfusion (mean decrease = −34%, range: −6 to −69%) compared with baseline (mean CBF = 36.9 mL/min/100 g). Regional analyses showed virtually absent cortical CBF (no-reflow) with regionally unchanged to elevated CBF in brainstem and cerebellum. Subsequently, CBF continuously increased within the first hour of reperfusion to CBF levels above baseline in all regions. At 1 hour after start of reperfusion global CBF (mean = 63.8 mL/min/100 g) was increased (mean = +73%, range: +3 to +143%) compared with baseline. The latter values exceeded values reported in the literature for one hour after ROSC following conventional CPR (possible differences in anesthesia and physiological parameters have to be considered).

Conclusion: For the first time, we report the successful measurement of CBF by PET during extracorporeal CPR. CARL showed the potential to overcome the cerebral no-reflow phenomenon after prolonged CA. This treatment may therefore contribute to an improved neurological survival after CA, which is up to date very dismal. Further research is needed to evaluate and define specific therapy targets after ROSC.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
19 February 2021