After laparotomy in postoperative period, there are restrictive type of ventilatory changes. All these postoperative PFT decrease are more in male patients, in patients undergoing upper abdominal surgeries and in obese patients. All these changes are favorable for producing postoperative pulmonary complications. These changes are mainly due to altered pattern of ventilation in postoperative period. Since these postoperative pulmonary changes can be easily diagnosed by spirometer, all patients undergoing laparotomy should undergo preoperative and postoperative spirometry....