IRCT201011012560N5 IRCT 2010-12-02 Qom University of Medical Sciences and Health Services Effect of deep breathing exercises on oxygenation of patients undergoing major abdominal surgery Effect of deep breathing exercises on oxygenation of patients undergoing major abdominal surgery 2010-11-22 anticipated 40 Complete https://irct.ir/trial/2309 interventional Randomization: Randomized, Blinding: Not blinded, Placebo: Not used, Assignment: Parallel, Purpose: Supportive. N/A Acute pulmonary insufficiency following obdoman surgery. Intervention 1: Experimental group: The patients in the experimental group will be informed and practiced the breathing technique preoperatively. Deep breathing exercise (DBE) will be initiated approximately 2 hours after surgery when patients awake (in daytime). While resting in a semi-recumbent position, the patients will be instructed to inhale as slowly and deeply as possible, hold their breath for 3 seconds, and then exhale in a relaxed manner while coughing during it. With the help of a researcher nurse using proprioceptive input, the patients will be encouraged to make each subsequent breath deeper than the previous breath for 10 breaths. After 10 breaths, the patients will perform incentive spirometry by latex glove for 2 minute. These periods will be followed by a rest period (ie, normal breathing), and the cycle will be repeated four times per hour for 2 consecutive hours. Intervention 2: Control group: Patients in the control group receive routine care by the nurses. They don't receive any deep breathing exercise (DBE).