Vascular Occlusion Test to Dynamically Assess Microcirculation During Normothermic Pulsatile Cardiopulmonary Bypass
Nousjka P A Vranken1, Yuri M Ganushchak1, Henriëtte M Willigers2
1Department of Cardiothoracic Surgery, Maastricht University Medical Center and Cardiovascular Research Institute, Maastricht, The Netherlands.
Objective:
To evaluate parameters of the vascular occlusion test (VOT) before, during, and after pulsatile cardiopulmonary bypass (CPB).
Design:
Prospective, observational study.
Setting:
Single-center university hospital.
Participants:
Adult patients undergoing elective cardiac surgery with pulsatile CPB.
Interventions:
An oximeter sensor and adult-sized pneumatic tourniquet were positioned at the right forearm. A VOT with a predefined ischemic time of 3 minutes was performed before, during, and after CPB. Changes in tissue oxygen saturation were recorded.
Measurements And Main Results:
Thirty-four patients who underwent cardiac surgery were enrolled in the study. The lowest tissue oxygen saturation measured during the ischemic challenge differed among all 3 stages of surgery, with median values of 62.9% before, 57.5% during, and 59.3% after perfusion (p<0.05). Both occlusion (p<0.001) and reperfusion (p<0.05) slopes were steeper after bypass compared with before initiating bypass, whereas the reperfusion time remained constant among the different time points.
Conclusions:
The microcirculatory function as demonstrated by changes in VOT parameters was enhanced during and after normothermic pulsatile CPB. Clinical relevance, however, needs to be further explored.
