What are the recommended vent settings for patients in the Cardiovascular Intensive Care Unit (CVICU)?

Recommended Ventilator Settings for CVICU Patients

For patients in the Cardiovascular Intensive Care Unit (CVICU), lung-protective ventilation strategies should be implemented with tidal volumes of 4-8 mL/kg predicted body weight, plateau pressures <30 cmH2O, PEEP ≥5 cmH2O, and SpO2 targets of 92-97%. 1, 2

General Ventilation Principles for CVICU

• Use standard full-featured ventilators rather than basic flow generators or resuscitation devices for optimal control and monitoring 1
• Implement lung-protective ventilation strategies to prevent ventilator-induced lung injury 2, 3
• Monitor pressure-time and flow-time scalars to optimize ventilator synchrony 1
• Measure peak inspiratory pressure, plateau pressure, mean airway pressure, and PEEP regularly 1
• Consider measuring transpulmonary pressure and dynamic compliance in complex cases 1

Initial Ventilator Settings

Ventilation Parameters

• Tidal Volume: 4-8 mL/kg predicted body weight 2, 3
• Plateau Pressure: Maintain <30 cmH2O (may tolerate up to 35 cmH2O in patients with stiff chest wall) 2, 3
• PEEP: Start at ≥5 cmH2O, titrate higher (≥10 cmH2O) for moderate-severe ARDS 1
• Respiratory Rate: 20-35 breaths per minute, adjusted to maintain pH >7.20 1, 2
• Driving Pressure: Minimize the difference between plateau pressure and PEEP 3

Oxygenation Targets

• SpO2: Target 92-97% (avoid hyperoxia) 1
• FiO2: Titrate to maintain target SpO2, avoid prolonged exposure to high FiO2 2
• PaO2: Target >55 mmHg 4
• PaCO2: 35-45 mmHg for healthy lungs; higher values acceptable in acute pulmonary conditions 1
• pH: Target >7.20 (maintain normal pH for patients with pulmonary hypertension) 1

Special Considerations for Post-Cardiac Surgery Patients

• Post-ECPR Patients: Use low ventilatory pressure and respiratory rate with PEEP >10 cmH2O to maintain alveolar inflation and prevent pulmonary edema 1
• Avoid Rapid PaCO2 Changes: Large drops in PaCO2 (>20 mmHg) are associated with intracranial hemorrhage and poorer survival in VA-ECMO patients 1
• LV Distension Prevention: Consider appropriate inotropic support and mechanical circulatory support devices to prevent LV distension during VA-ECMO 1
• Harlequin Syndrome Prevention: Maintain adequate oxygenation through mechanical ventilation in VA-ECMO patients 1

Ventilation Strategies for Specific Conditions

For ARDS Patients

• Prone Positioning: Implement for 12-16 hours daily when PaO2/FiO2 <150 mmHg 1, 4
• Complete (180°) Prone Position: Preferred over incomplete positioning for better oxygenation 1, 4
• PEEP Strategy: For ARDS, target SpO2 92-97% when PEEP <10 cmH2O and 88-92% when PEEP ≥10 cmH2O 1
• Consider ECMO: For refractory hypoxemia despite optimal mechanical ventilation and prone positioning 4, 5

For Post-Cardiac Surgery Patients

• Hemodynamic Monitoring: Closely monitor cardiac output and filling pressures during ventilator adjustments 1
• Positive Pressure Effects: Be aware of the impact of positive pressure ventilation on right ventricular afterload and left ventricular preload 3
• Upper Body Elevation: Maintain head of bed elevated 30-45° to reduce risk of ventilator-associated pneumonia 1

Monitoring and Adjustments

• Regular Assessment: Measure arterial blood gases, lactate, and central venous saturation in moderate-to-severe disease 1
• End-tidal CO2: Monitor in all ventilated patients 1
• SpO2: Continuous monitoring in all ventilated patients 1
• Pressure Monitoring: Regularly assess peak inspiratory pressure, plateau pressure, and driving pressure 1, 3
• Daily Weaning Assessment: Perform daily extubation readiness testing 1

Weaning Considerations

• Early Weaning: Start weaning process as soon as clinically appropriate 1
• Daily Assessment: Perform daily extubation readiness testing 1
• Consider NIV: Non-invasive ventilation may be beneficial post-extubation in selected patients 1
• Cuff Pressure: Maintain endotracheal tube cuff pressure ≤20 cmH2O 1

Common Pitfalls to Avoid

• Excessive Tidal Volumes: Avoid volumes >8 mL/kg predicted body weight which can cause volutrauma 2, 3
• Inadequate PEEP: Too low PEEP can lead to atelectasis and worsening oxygenation 1, 2
• Hyperoxia: Early hyperoxia (PaO2 >300 mmHg) is associated with increased mortality and poor neurological outcomes 1
• Rapid PaCO2 Changes: Avoid large drops in PaCO2 (>20 mmHg) which can lead to cerebral injury 1
• Ventilator Asynchrony: Failure to optimize patient-ventilator interaction can increase work of breathing and oxygen consumption 6
• Delayed Prone Positioning: Implement prone positioning early when indicated for ARDS patients 4