Differential Hypoxemia During Veno-Arterial Extracorporeal Organ Support: Its Impact on Mortality and Different Treatment Strategies
Abstract
Objectives
Extracorporeal Life Support (ECLS) has evolved into an established treatment for severe cardiogenic shock. As most patients have residual antegrade left ventricular output toward the descending aorta that meets the retrograde blood flow from the arterial ECLS cannula, they may develop differential hypoxemia. The location of the mixing cloud is critical for coronary and brain oxygenation. We analyzed the effects of the development of differential hypoxemia on morbidity and mortality of ECLS patients. Moreover, we analyzed the impact of two different treatment options for this phenomenon, including the administration of beta-blockers and the provision of a supplementary arterial cannula, on survival.
Methods
We performed a retrospective review of patient demographics, outcomes, laboratory, and respiratory parameters during and after ECLS support for 76 ECLS patients treated at our institution.
Results
Overall, 38 ECLS patients developed differential hypoxemia. Treatment of this phenomenon included either the administration of beta-blockers (n = 18) or the introduction of a second arterial ECLS cannula (n = 20). There were no significant differences in median SOFA-Scores (Sequential Organ Failure Assessment Scores) between groups (p = 0.072; ECLS vs. ECLS with differential hypoxemia patients). Under all respiratory and laboratory values analyzed, only bilirubin levels were significantly different (p = 0.020). Development of differential hypoxemia was associated with significantly decreased survival rates (p = 0.05). Moreover, insertion of a second arterial ECLS cannula was a risk factor for mortality (OR: 3.68, 95% CI 1.18–11.47, p = 0.025).
Conclusions
Development of differential hypoxemia is associated with significantly increased mortality rates among ECLS patients and should therefore be prevented as far as possible. Non-invasive administration of beta-blockers seems to be the more effective treatment option for differential hypoxemia, as the introduction of a second arterial ECLS cannula was a risk factor for mortality.