What is the recommended respiratory assessment and management for patients post cardiac surgery?

Respiratory Assessment and Management Post Cardiac Surgery

Comprehensive respiratory assessment and management post cardiac surgery should include preoperative respiratory optimization, protective intraoperative ventilation strategies, and structured postoperative respiratory care to reduce pulmonary complications and improve outcomes.

Preoperative Respiratory Optimization

• A cardiorespiratory and muscular prehabilitation program of at least 4 weeks before surgery is recommended to reduce postoperative pulmonary complications and hospital length of stay 1
• Inspiratory muscle training using a device with an adjustable inspiratory pressure valve is most effective, requiring at least 5 days (preferably 2 weeks) of preparation with twice-daily practice 1
• Preoperative respiratory training decreases risk of postoperative pneumonia (RR 0.44-0.45) and atelectasis (RR 0.53-0.59) 1
• Cardiorespiratory prehabilitation improves preoperative physical condition as measured by 6-minute walking tests and reduces hospital length of stay by 1-3.2 days 1, 2
• For patients with limited time before surgery, high-intensity interval training can improve fitness in just 2 weeks 2

Intraoperative Respiratory Management

• Protective lung ventilation strategy during pre- and post-cardiopulmonary bypass (CPB) periods is recommended, especially for patients with acute respiratory failure 1
• Use low tidal volumes (6-8 mL/kg ideal body weight), positive end-expiratory pressure (PEEP), and recruitment maneuvers 1
• Ventilation during CPB is not recommended as it does not reduce the incidence of postoperative pulmonary complications 1
• Consider volatile anesthetics for potential organ protection, though evidence is mixed regarding their superiority over intravenous agents 1, 3

Immediate Postoperative Assessment and Management

• Systematic respiratory assessment should include monitoring of oxygen saturation, respiratory rate, work of breathing, and breath sounds 1, 4
• For patients with FVC <50% of predicted (especially <30%), consider extubation directly to non-invasive positive pressure ventilation (NPPV) 1
• Delay extubation until respiratory secretions are well controlled and SpO2 is normal or at baseline in room air 1
• Use supplemental oxygen cautiously and monitor SpO2 continuously; whenever possible, monitor blood or end-tidal carbon dioxide levels 1
• Assess if hypoxemia is due to hypoventilation, atelectasis, or airway secretions, and treat appropriately 1, 5

Ongoing Postoperative Respiratory Care

• Use manually assisted cough and mechanical insufflation-exsufflation techniques for patients with impaired cough (peak cough flow <270 L/min or MEP <60 cm H2O) 1
• Optimize pain control to facilitate deep breathing and effective coughing; if sedation/hypoventilation occurs, delay extubation or use NPPV 1, 6
• Monitor for common respiratory complications including atelectasis, pneumonia, pulmonary edema, and pleural effusions 4, 5
• Implement early mobilization and respiratory physiotherapy to prevent atelectasis and promote lung expansion 1, 6
• Continue respiratory exercises and incentive spirometry in the postoperative period 2, 6

Special Considerations

• For post-cardiac surgery cardiac arrest with respiratory etiology, consider potential causes such as tension pneumothorax, severe obstruction leading to air trapping, or breath stacking 1
• In patients with air trapping, use lower tidal volumes, lower respiratory rates, and increased expiratory time to minimize auto-PEEP and barotrauma 1
• For respiratory deterioration, assess for potential surgical complications such as bleeding, tamponade, or pneumothorax 1, 4
• Monitor for respiratory failure (requiring intubation ≥72 hours), which occurs in approximately 9% of cardiac surgery patients and is associated with increased mortality 4
• Higher risk for respiratory complications exists in patients undergoing combined valve/CABG procedures (14.8%) and aortic procedures (13.5%) 4

Long-term Respiratory Follow-up

• Pulmonary function typically remains slightly decreased (4-5% reduction in FVC and FEV1) one year after cardiac surgery 6
• Patients with more pronounced decreases in pulmonary function may experience dyspnea limitations and impaired subjective breathing 6
• Continue to monitor respiratory function, especially in patients with pre-existing pulmonary disease 2, 6