This study is the first clinical trial study in Indonesia to assess the benefits of using incentive spirometry in the incidence of pulmonary complications after major abdominal surgery.

This study was a randomized clinical trial in three tertiary-level referral hospitals in Indonesia (Cipto Mangunkusumo Hospital, Fatmawati Hospital, and Persahabatan Hospital). The investigators randomly assigned adult patients who underwent major abdominal elective surgery in July-August 2015 to two groups.

All study subjects were simple randomly allocated to the intervention and control groups according to the randomization table.

The hypothesis of the study team was that preoperative incentive spirometry can improve the incidence of postoperative pulmonary complications in major abdominal surgery

This study was a randomized clinical trial in three tertiary-level referral hospitals in Indonesia (Cipto Mangunkusumo Hospital, Fatmawati Hospital, and Persahabatan Hospital). The researchers randomly assigned adult patients who underwent major abdominal elective surgery in July-August 2015 to two groups.

The researchers included patients aged between 18 and 65 years old who underwent elective major abdominal surgery into random allocation. Patients were excluded if had a history of pulmonary disease and were unwilling or unable to take a deep breath effectively due to pain, diaphragmatic dysfunction, or opiate analgesia.

All study subjects were simple randomly allocated into the intervention and control groups according to the randomization table. The intervention group (23 subjects) received respiratory exercise with incentive spirometry before surgery, and the control group (23 subjects) were given standard preoperative care.

Subjects in the intervention group were trained to perform 15 minutes of respiratory exercise with incentive spirometry four times a day for two days before surgery by trained medical personnel. First, subjects were instructed to make a good seal over the incentive spirometry mouthpiece with their lips. Afterward, The subjects were asked to inhale deeply and slowly, and were also directed to hold their breath at the end of inspiration.

With alpha of 5%, beta of 10%, 39% postoperative pulmonary complication rate, as mentioned in the previous study,13 and assumption of that incentive spirometry can reduce the PPC to 30%, this study required at least 23 subjects in each group to see the effectiveness of using incentive spirometry before surgery in preventing PPC.

Measures In the intervention group, pulmonary function (vital capacity [VC], vital functional capacity [VFC], and Forced expiratory volume in the first second [FEV1]) were measured three times: two times before surgery (first day before undergoing the incentive spirometry procedure and second day after using the incentive spirometry) and one time after surgery. The control group measured pulmonary function three times: two times before surgery (on the first day of admission, on the day before surgery) and one time after surgery. In addition, postoperative pulmonary function was measured up to seven days following abdominal surgery, depending on the patient's ability.

On the first day after surgery, all subjects were examined by a pulmonologist, supplemented with a chest x-ray and blood gas analysis to assess the occurrence of postoperative pulmonary complications. PPC in this study included atelectasis (lung volume diminishing, caused by inadequate expansion of air cavity within lung parenchyma), pneumonia (all kinds of lung infection), and hypoxemia (ratio of PaO2: FiO2 less than 300).

The researchers used means (standard deviation, SD) and numbers (percentage,%) to describe the baseline subjects demographic and clinical characteristics. Henceforth, The researchers compared the change in lung function before and after surgery between intervention and control groups. An unpaired T-test was conducted to determine if the data were normally distributed. Alternatively, the Mann-Whitney test was done for abnormally distributed data. The researchers analyzed the comparison of lung complication incidence between experimental and control groups using chi-square or Fisher's exact test method. In this study, The researchers investigated the lung function of the experimental group before and after the incentive spirometry procedure.

Inclusion Criteria:

• Patients undergoing major abdominal surgery
• aged between 18 and 65 years old
• Sign research informed consent

Exclusion Criteria:

• Emergency surgery
• Have a history of lung disorders
• Refusing to continue incentive spirometry
• Patients who cannot follow instructions in using the device incentive spirometry.

The data in this study cannot be shared because the research database is no longer available due to damage to the hard disk where the data is stored.