Effectiveness of Oscillation on Postoperative Pulmonary Complications After Elective Postcardiac Surgery

Inclusion Criteria: * Adult patients (18 years or older) undergoing elective cardiac surgery will be included. Participants must provide informed consent upon ICU admission and have at least one risk factor for PPCs, including age ≥ 75 years, American Society of Anesthesiologists (ASA) score ≥ 2, history of chronic obstructive pulmonary disease (COPD) stage ≥ 2 or asthma (moderate to severe), current heavy smoking or heavy smoking history within the past 6 months, obstructive sleep apnea, frailty index \> 0.21 or body max index (BMI) ≥ 30 kg/m². Exclusion Criteria: * Patients will be excluded if they have contraindications for oscillation treatment (e.g., untreated tension pneumothorax); have pneumothorax or air leak syndrome at entry; require more than 2 μg/kg/min of norepinephrine; have been diagnosed with pneumonia within 2 weeks prior to surgery; have refractory arrhythmia at entry; have a left ventricular ejection fraction \< 35%; have mean pulmonary artery pressure (mPAP) \> 35 mmHg; are postoperative from spinal surgery within the past 2 weeks; require a ventricular assist device; have renal failure requiring continuous renal replacement therapy (CRRT) at entry; are planned for re-operation within 48 hours or have undergone organ transplantation.