Coronary artery disease (CAD) is a heart disease caused by the buildup of plaque inside the coronary arteries that restricts blood flow to the heart which leads to heart attack. If it involve more than one artery it will be more critical so the preferred treatment will be coronary artery bypass graft. Respiratory failure after Coronary Artery Bypass Grafting (CABG) is a serious complication with multifactorial causes i.e. pneumonia and atelectasis in inpatients.

Postoperative pulmonary complications will be diagnosed using the Melbourne Group Scale (MGS), applied daily from postoperative day 1 to day 7. A score of ≥4 positive criteria will be used to identify PPCs. The scale's criteria will include chest radiograph findings, oxygen saturation, sputum characteristics, inflammatory markers, and ventilation data, physician diagnosis of pneumonia, readmission to ICU for respiratory reasons, prolong ventilation> 24 hours, unplanned use of non-invasive ventilation.

The study will be randomized clinical trial. It will be conducted at Gulab Devi Chest Hospital Lahore, Pakistan. Total sample size will be 42. Attrition rate is 10%. The data will be analyzed using SPSS v25. Sample size will be conducted via non probability consecutive sampling technique as per inclusion criteria participants will be randomly assigned into two groups. Group A will receive standard rehabilitation treatment for inpatients. This includes the physical reconditioning, promote patient independence, Provide education about lifestyle changes and respiratory muscle strength. For example Day 1-2(Sitting up in bed or in a chair, Breathing exercises (incentive spirometer) and Coughing with pillow support (to protect the sternum).Day 2-3(Standing and walking short distances with assistance and Gentle range-of- motion (ROM) exercises. Day 4-5 (Walk longer distances (50-100 meters) and Stair climbing (if appropriate). It's necessary to monitor the vital signs (HR, BP, O2 saturation), pain levels, wound inspection and signs of orthostatic intolerance or arrhythmias. Group B will receive E- CARE protocol with IMT threshold device to improve respiratory muscle strength. This study focuses on the LOHS and the incidence of respiratory failure.

Inclusion Criteria:

• Male and female of >45 years diagnosed with CAD and are undergone Coronary Artery Bypass Graft with stable circulation.
• Stable vitals.
• With normal cognition and being able to cooperate with the CR training.
• Agreed to participate in the trial and signed the consent for .

Exclusion Criteria:

• Pregnant
• Undergoing aortic surgery or equivalent surgery within 6 months
• History of cardiogenic shock or sudden cardiac arrest and severe hypertension
• Having complications with persistent ischemia, hemodynamic impairment, or at risk of arterial occlusion with massive myocardial infarction
• Having complications with unstable angina, malignant arrhythmia