Endovascular Vein Harvest: Systemic Carbon Dioxide Absorption

Objective: Endovascular vein harvest (EDVH) requires CO2 insufflation to expand the subcutaneous space, allowing visualization and dissection of the saphenous vein. The purpose of this study was to assess the extent of CO2 absorption during EDVH.Design: Prospective observational study.Setting: Single tertiary care hospitalPatients: Sixty patients (30 EDVH and 30 open-vein harvest) undergoing isolated coronary artery bypass graft surgery.Methods: Hemodynamic, procedural, and laboratory data were collected prior to (baseline), during, and at it the conclusion (final) of vein harvesting. Data were also collected during cardiopulmonary bypass (CPB). Data were compared by using t tests, analysis of variance, and correlation statistics when needed.Results: There were significant increases in arterial CO2 (PaCO2, 35%) and decreases in pH (1.35%) during EDVH. These were associated with increases in heart rate, mean blood pressure, and cardiac output. Within the EDVH group, greater elevations (>10 mmHg) in PaCO2 were more likely during difficult harvest procedures, and these patients exhibited greater increase in heart rate. Elevated CO2 persisted during CPB, requiring higher systemic gas flows and greater use of phenylephrine to maintain desired hemodynamics.Conclusion: EDVH was associated with systemic absorption of CO2. Greater absorption was more likely in difficult procedures and was associated with greater hemodynamic changes requiring medical therapy.