What is the management approach for patients with abnormal lung sounds after heart surgery?

Management of Abnormal Lung Sounds After Heart Surgery

The management of patients with abnormal lung sounds after cardiac surgery should follow a systematic approach including respiratory assessment, non-invasive ventilation as first-line treatment for respiratory failure, and implementation of protective lung ventilation strategies to reduce morbidity and mortality. 1, 2

Initial Assessment and Diagnosis

• Systematic respiratory assessment should include monitoring of oxygen saturation, respiratory rate, work of breathing, and auscultation of breath sounds to identify the specific abnormality 1, 2
• Common abnormal lung sounds post-cardiac surgery include:
  • Crackles: Often indicating atelectasis, pulmonary edema, or pneumonia 3
  • Wheezes: May suggest bronchospasm or airway obstruction 3
  • Decreased or absent breath sounds: Potentially indicating pleural effusion, pneumothorax, or significant atelectasis 4
• Consider lung ultrasound for rapid bedside assessment, which can accurately diagnose pleural effusions and atelectasis that may be missed on chest X-rays 4

Management Algorithm

Step 1: Immediate Interventions

• Ensure adequate oxygenation with appropriate oxygen therapy targeting SpO2 ≥92% (or patient's baseline) 1
• Position patient with head of bed elevated 30-45 degrees to optimize lung expansion 2
• Implement early mobilization as soon as hemodynamically stable to prevent atelectasis 3
• Initiate respiratory physiotherapy including deep breathing exercises (30 deep breaths per hour while awake) 3

Step 2: Non-Pharmacological Interventions

• Implement multimodal pulmonary hygiene:
  • Incentive spirometry hourly while awake for patients at high risk for pneumonia 3
  • Supported coughing techniques with splinting of incision site 3
  • Early progressive mobilization (bed mobility → sitting → standing → walking) 2, 3
• For patients with impaired cough (peak cough flow <270 L/min), use manually assisted cough and mechanical insufflation-exsufflation techniques 2

Step 3: Management of Respiratory Failure

• For post-operative acute respiratory failure, non-invasive ventilation (NIV) should be the first-line treatment 1, 5
  • NIV reduces risk of tracheal re-intubation within 7 days (33% vs 46% with standard oxygen therapy) 1
  • NIV decreases incidence of healthcare-associated infections (31% vs 49% with standard oxygen therapy) 1
• Consider extubation directly to NIV for patients with FVC <50% of predicted (especially <30%) 2
• Be cautious with NIV initiated within 24 hours after extubation, as early respiratory failure is associated with higher NIV failure rates 5

Step 4: Ventilation Strategies (If Mechanical Ventilation Required)

• Implement protective lung ventilation strategy:
  • Use low tidal volumes (6-8 mL/kg of ideal body weight) 1, 2
  • Apply moderate positive end-expiratory pressure (PEEP) 1, 2
  • Perform recruitment maneuvers as needed 1, 2
• Consider Airway Pressure Release Ventilation (APRV) as it has shown improved oxygenation (PaO2/FiO2 ratio) and lung compliance in post-cardiac surgery patients 6

Special Considerations

• For patients with air trapping, use lower tidal volumes, lower respiratory rates, and increased expiratory time to minimize auto-PEEP and barotrauma 2
• For respiratory deterioration, promptly assess for potential surgical complications such as bleeding, cardiac tamponade, or pneumothorax 2
• Ensure adequate pain management to facilitate effective deep breathing and coughing 3
• Consider chlorhexidine oral rinse (0.12%) during the perioperative period to reduce risk of respiratory infections 3

Prevention of Complications

• High-dose dexamethasone (1 mg/kg) may be considered for lung protection in selected patients, reducing the incidence of prolonged ventilation (>24h) from 4.9% to 3.4% and postoperative pneumonia from 10.6% to 6% 1
• Avoid hyperoxia during cardiopulmonary bypass as it is not recommended for lung protection 1
• For future cardiac surgeries, consider preoperative respiratory optimization:
  • Implement cardiorespiratory prehabilitation program of at least 4 weeks before surgery 2
  • Use inspiratory muscle training with an adjustable inspiratory pressure valve for at least 5 days (preferably 2 weeks) with twice-daily practice 2

Monitoring and Follow-up

• Monitor for improvement in respiratory status through:
  • Regular assessment of respiratory rate, work of breathing, and oxygen requirements 2
  • Auscultation to detect changes in abnormal lung sounds 7
  • Arterial blood gas analysis as indicated to assess oxygenation and ventilation 6
• Delay extubation until respiratory secretions are well controlled and SpO2 is normal or at baseline in room air 2