After obtaining approval from Postgraduate research monitoring committee (PGRMC), Institute ethics committee, and completing CTRI registration, patients satisfying eligibility criteria will be selected by consecutive sampling technique. Written informed consent explaining about the procedure, risks and any adverse events will be obtained before being enrolled into the study.

            The attending anesthesiologist will do a thorough preoperative assessment and history on duration of illness will be obtained. Patients will be shifted in to the OT table and all standard monitors will be attached and baseline parameters will be recorded.(PR, SBP, ECG). Pulmonary function test will be performed using a bedside spirometer and the parameters like Tidal volume(TV), Vital capacity(VC), forced vital capacity(FVC), forced expiratory volume (FEV1) and peak expiratory flow rate (PEFR) will be recorded in supine position. An experienced anaesthesiologist will visualize the diaphragm using a curvilinear probe of high resolution portable ultrasound machine. In 2- dimensional mode, the probe will be placed on the right anterior axillary lines at the level of 8^th to 10^th intercostal space to achieve the best view of the hemidiaphragm. Patient will be asked to take deep inspiration and the movement of the hemidiaphragm will be recorded on M-mode sonography at zone of opposition. During M-mode imaging, the normally functioning diaphragm is represented as an echogenic line that moves freely during inspiration and expiration. Inspiration is identified on the sonographic tracing as an upward flexion and expiration will be identified as downward flexion.

             Diaphragmatic excursion will be measured by the vertical distance between the upward flexion at the end of inspiration and downward flexion at the end of expiration ie, the vertical distance between the bottom and the peak of the tracing line; This vertical distance represents diaphragmatic excursion. Diaphragm thickness will be estimated as the vertical distance between the pleural and peritoneal layers at the end of expiration. Parameters like repiratory rate, arterial blood gas analysis(ABG) and abdominal girth will be measured before induction. General anaesthesia will be induced as per departmental protocol. At the end of the surgery, duration of surgery and whether patient was extubated or not will be noted. If not extubated, duration of mechanical ventilation will be noted.