Objective: To determine the incidence of hypoxemia (peripheral oxygen saturation less than 95%) in patients receiving oxygen supplementation via oxygen cannula during the early postoperative period after lung resection.
Material and Method: This prospective cohort study in a post-anesthetic care unit (PACU) of a university hospital included 35 patients with ASA physical status I-III undergoing thoracotomy under general anesthesia and continuous epidural analgesia. Oxygen supplementation via oxygen cannula 5 L/min was given during transportation and in the PACU for two hours postoperatively. Peripheral oxygen saturation (SpO2 ) was continuously monitored using pulse oximeter and recorded at interval until 2 hours after surgery.
Results: Three patients (8.6%) experienced hypoxemia in PACU. The main causes were secretion obstruction, oxygen delivery system malfunction and pain medication with over sedation. The average SpO2 at 30 minutes after operation in 32 nonhypoxemic patients was 99.8+0.5%. Thirty percent of the patients had satisfaction score for having nasal cannula of 8. The average satisfaction score of nasal cannula was 6.7+2.0. Nearly 66% of the patients did not remove oxygen cannula during oxygen supplementation.
Conclusion: Though oxygen cannula can be used for prevention and treatment postoperative hypoxemia in most of the patients undergoing lung resection surgery with general anesthesia and postoperative epidural analgesia. But closed monitoring is still mandatory.

Keywords: Oxygen cannula, Lung surgery, Desaturation, PACU