Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting

Background. In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypas s grafting. Studies on the effects of unilateral CO2 insufflation on hemody namics produced controversial results, and bilateral insufflation has not b een studied to our knowledge. The present study sought to investigate hemod ynamics and gas exchange during unilateral and bilateral CO2 insufflation i n patients who underwent totally endoscopic coronary artery bypass grafting . Methods. Eleven hemodynamic and gas exchange variables were monitored durin g 22 totally endoscopic coronary artery bypass grafting procedures with uni lateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, a fter institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation. Results. Arterial oxygen tension decreased significantly during SLV, wherea s the peak inspiratory pressure increased. In addition, central venous pres sure and heart rate increased significantly during insufflation, but mean a rterial pressure remained unchanged. Although the end-tidal CO2 pressure di d not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and betw een groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unalt ered. No patient required inotropic or vasopressor support. Conclusions. Carbon dioxide insufflation for totally endoscopic coronary ar tery bypass grafting with SLV had no adverse effects on hemodynamics. In co ntrast to a moderate increase of arterial carbon dioxide tension during uni lateral insufflation, markedly elevated arterial carbon dioxide tension lev els remain a cause of concern during bilateral insufflation. (Ann Thorac Su rg 2001;71:1496-502) (C) 2001 by The Society of Thoracic Surgeons.