Context: Incidence of postoperative pulmonary complications is between 30­50% in patients undergoing abdominal surgery. Addressing pain at surgical site and improving respiratory mechanics , to reduce postoperative hypoxia have a key role in mitigating hospital stay and costs. Aims: To observe the changes in lung function tests and effect of different postures on postoperative oxygen saturations in patients undergoing upper abdominal surgery on the first, fourth and seventh postoperative days and to compare the respective pain scores. Settings and Design: Prospective observational study. Methods and Material: The study was done on 40 patients undergoing upper abdominal surgeries under general anaesthesia. Peripheral oxygen saturations (SpO2) was measured using pulse oximeter and lung function tests using Medispiror preoperatively and on postoperative day 1, 4 and 7. The SpO2 was measured in supine, sitting and standing positions. The FVC, FEV1 and PEFR was measured in the sitting position on all 4 days. Pain was recorded using Numeric Rating Scales. Statistical analysis used: The Statistical software
namely SPSS 18.0, and R environment ver. 3.2.2 were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables. Results: The improvement in oxygen saturation from supine (mean 95.95±1.77) to sitting (97.98±1.37) on the first postoperative was statistically significant with a p value of <0.001. Reductions in FVC from the preoperative (mean 2.35+0.48) value to the first post operative day (mean 1.29+0.39) was statistically significant with a p value of < 0.001. The FVC , PEFR and FEV1 were not at preoperative values even on the 7th postoperative day with a significant p value < 0.001 Conclusions: Postoperative oxygen saturations improve statistically in the sitting and standing position after upper abdominal surgery as compared to supine position. Simple maneuvers like change in position from supine to sitting and mobilization in the early postoperative period can improve the oxygen saturation and lung functions significantly and help in reducing lung atelectasis and resulting postoperative pulmonary complications.