Left, but not right, one-lung ventilation causes hypoxemia during endoscopic transthoracic sympathectomy

To describe the respiratory and cardiovascular effects of one-lung ventilation, using a double-lumen tube, during endoscopic transthoracic sympathectomy. A prospective clinical study. A university-affiliated medical center. Nineteen adult patients (10 men, 1 woman) between 16 and 35 years of age, ASA (American Society of Anesthesiologists) physical status I and II, participated in the study. Endoscopic transthoracic sympathectomy was performed under general anesthesia, using a double-lumen endobronchial tube, after induction of artificial pneumothorax plus insufflation of CO 2 into the operated chest. Via radial artery cannulae, one to three arterial blood gas samples were taken during two-lung ventilation before surgery, at each one-lung ventilation, in most cases during the period of two-lung ventilation when switching between the operated sides, and after surgery. Comparisons were performed using the Wilcoxon matched-pairs single-ranks test. Left-lung ventilation and right-chest operation caused profound decrease of arterial oxygen partial pressure (PaO 2), compared with two-lung ventilation before surgery (70.7%, P > 0.0003) and compared with PaO 2 at two-lung ventilation during and after surgery (decrease of 80.1% and 75.3%, respectively; P > 0.001 and < 0.005, respectively). Right-lung ventilation and left-chest operation did not cause hypoxemia. Arterial CO 2 partial pressure, pH, and bicarbonate, as well as hemodynamic parameters, did not change from baseline values throughout surgery. Pulse oximetry and repeated blood gas measurements are needed during endoscopic transthoracic sympathectomy in order to detect and treat hypoxemic events, which may jeopardize the patient's life.