Monitoring Mitochondrial Partial Oxygen Pressure During Cardiac Arrest and Extracorporeal Cardiopulmonary Resuscitation. An Experimental Pilot Study in a Pig Model

Introduction: Ischemia and reperfusion are crucial in determining the outcome after cardiac arrest and can be influenced by extracorporeal cardiopulmonary resuscitation (ECPR). The effect of ECPR on the availability and level of oxygen in mitochondria remains unknown. The aim of this study was to find out if skin mitochondrial partial oxygen pressure (mitoPO(2)) measurements in cardiac arrest and ECPR are feasible and to investigate its course. Materials and Methods: We performed a feasibility test to determine if skin mitoPO(2) measurements in a pig are possible. Next, we aimed to measure skin mitoPO(2) in 10 experimental pigs. Measurements were performed using a cellular oxygen metabolism measurement monitor (COMET), at baseline, during cardiac arrest, and during ECPR using the controlled integrated resuscitation device (CIRD). Results: The feasibility test showed continuous mitoPO(2) values. Nine experimental pigs could be measured. Measurements in six experimental pigs succeeded. Our results showed a delay until the initial spike of mitoPO(2) after ECPR initiation in all six experimental tests. In two experiments (33%) mitoPO(2) remained present after the initial spike. A correlation of mitoPO(2) with mean arterial pressure (MAP) and arterial partial oxygen pressure measured by CIRD (CIRD-PaO(2)) seemed not present. One of the experimental pigs survived. Conclusions: This experimental pilot study shows that continuous measurements of skin mitoPO(2) in pigs treated with ECPR are feasible. The delay in initial mitoPO(2) and discrepancy of mitoPO(2) and MAP in our small sample study could point to the possible value of additional measurements besides MAP to monitor the quality of tissue perfusion during cardiac arrest and ECPR.