Prediction of Postoperative Pulmonary Complications in Patients Undergoing Functional Endoscopic Sinus Surgery: A Cohort Study

Introduction: Considering the pathophysiology of nasal obstruction, changes in certain parameters such as Peripheral Blood Eosinophil Count (PBEC), bedside pulmonary function test, Peak Expiratory Flow Rate (PEFR), and Electrocardiography (ECG) may have some correlation with postoperative pulmonary complications such as upper airway obstruction, loss of pharyngeal muscle tone, and postobstructive pulmonary oedema. Aim: To observe and analyse the changes in PBEC, bedside pulmonary function test, PEFR, and ECG in patients undergoing Functional Endoscopic Sinus Surgery (FESS). Materials and Methods: A prospective cohort study was conducted at Bharati Hospital, Pune, Maharashtra, India over a two-year duration from December 2020 to October 2022. A total of 50 patients aged above 18 years undergoing FESS surgery were included in the study. The statistical analysis was performed using the Chi-square test and student’s t-test. After thorough preoperative evaluation, the aforementioned predictors were recorded. General anaesthesia management for FESS surgery was done according to the standard protocol. Vigilant intraoperative monitoring of vital parameters including peak airway pressure and plateau pressure was performed. After shifting the patients to the recovery room, they were observed for: 1) Hypoxia; 2) Hypercarbia; 3) Laryngospasm; 4) Bronchospasm; and 5) Pulmonary oedema. Results: A total of 50 patients aged between 18 years and 65 years with the mean age was 41.7±15.4 years were included in the study, with 32 males and 18 females. Only 24% of the study population showed postoperative hypoxia, while the rest of the complications were not observed in any patient. Changes in eosinophil count, PEFR, and ECG did not have any correlation with postoperative hypoxia and were statistically insignificant. Bedside pulmonary function tests, including the Sabrasez breath-holding test and the Sabrasez single breath count test, showed changes in 30% and 76% of patients, respectively. Forced Expiratory test change was seen in 72% of patients. Among these, 19.4% showed hypoxia. Out of the 12 cases showing postoperative hypoxia, seven had a disease duration of less than six months. Conclusion: The Sabrasez breath-holding test and Sabrasez single breath count are good predictors for postoperative hypoxia in patients undergoing FESS surgery. Shorter duration of nasal obstruction also showed postoperative hypoxia.