EFFECTS OF INSUFFLATION ON HEMODYNAMICS DURING THORACOSCOPY

Thoracic procedures once requiring open thoracotomy are now being performed with video-assisted thoracoscopy. To visualize adequately the intrathoracic structures, creation of an artificial pneumothorax by carbon dioxide insufflation under positive pressures has been advocated. We hypothesized that positive-pressure insufflation during thoracoscopy would cause significant hemodynamic compromise. Eight healthy female pigs underwent general endotracheal anesthesia and placement of monitoring lines. After placement of a thoracoscope, baseline hemodynamic measurements were obtained at 0 mm Hg (atmospheric pressure). Measurements were taken randomly at 5, 10, and 15 mm Hg using carbon dioxide insufflation after stabilization at each pressure. Data were analyzed using Page's test for nonparametric variables. Insufflation pressures of 5 mm Hg or greater resulted in significant decreases in cardiac index, mean arterial pressure, stroke volume, and left ventricular stroke work index, whereas central venous pressure increased (p < 0.001). Changes in heart rate were not significant. We do not recommend routine positive-pressure insufflation during thoracoscopy because of the significant hemodynamic compromise in our experimental model.