Bronchoscopic therapy with neodymium-yttrium-aluminum-garnet laser during intravenous anesthesia. Effect on arterial blood gas levels, pH, hemoglobin saturation, and production of abnormal hemoglobin

Photoresection with the neodymium-yttrium-aluminum-garnet (Nd-YAG) laser has been shown to be an effective bronchoscopic treatment for patients with obstructive lesions of the airway. We monitored levels of arterial blood gases, carbon monoxide, methemoglobin, and sulfmethemoglobin, and the hemoglobin oxygen saturation by ear oximeter in patients during intravenous anesthesia. The measurements were made after induction but before treatment with the Nd-YAG laser, during treatment, and immediately after treatment. Thirteen patients were entered into the study, ten of whom were used for statistical analysis. Partial arterial oxygen pressure decreased significantly during treatment (p<0.001). The alveolar-arterial oxygen pressure difference increased significantly during treatment (p<0.0025). The partial arterial carbon dioxide pressure increased significantly (p<0.005). The pH decreased significantly (p<0.02). No statistically significant change was found in the levels of carbon monoxide, methemoglobin, or sulfmethemoglobin. Comparison of arterial hemoglobin oxygen saturation and hemoglobin oxygen saturation by ear oximeter revealed no statistically significant difference in the two methods. During the procedure, careful attention must be given to the patient's oxygenation and ventilation. These variables can be monitored satisfactorily during general anesthesia by the use of an ear oximeter and endtidal carbon dioxide analyzer.