From the Guidelines
Non-invasive ventilation (NIV) is a crucial therapy in managing respiratory distress, particularly in patients with acute exacerbations of COPD, cardiogenic pulmonary edema, and immunocompromised patients with respiratory failure, as it reduces the need for intubation, frequency of complications, hospital length of stay, and mortality rate compared with standard therapy 1.
Indications for NIV
NIV is primarily indicated for conditions where it can provide significant benefits in reducing the work of breathing, improving gas exchange, and preventing complications associated with invasive ventilation. These conditions include:
- Acute exacerbation of COPD
- Cardiogenic pulmonary edema
- Immunocompromised patients with respiratory failure
Mechanism and Modes of NIV
NIV works by delivering positive pressure through a mask, which helps in reducing the work of breathing, improving gas exchange, decreasing respiratory rate, and preventing alveolar collapse. Common NIV modes include:
- CPAP (Continuous Positive Airway Pressure), which maintains constant pressure throughout the respiratory cycle
- BiPAP (Bi-level Positive Airway Pressure), which provides higher pressure during inspiration and lower pressure during expiration
Initiation and Monitoring of NIV
NIV should be initiated early in respiratory distress, with close monitoring of vital signs, work of breathing, and arterial blood gases. Typical initial settings for BiPAP include IPAP of 8-12 cmH2O and EPAP of 3-5 cmH2O, which can be titrated based on patient response 1.
Contraindications and Physiological Benefits
Contraindications for NIV include decreased consciousness, inability to protect airways, facial trauma, and hemodynamic instability. The physiological benefits of NIV include reduced respiratory muscle fatigue, improved ventilation-perfusion matching, and decreased left ventricular afterload, all contributing to its effectiveness in relieving respiratory distress and potentially avoiding intubation 1.
Evidence Supporting NIV
The use of NIV in selected groups of patients presenting with respiratory failure has been supported by considerable evidence, showing reductions in the need for intubation, frequency of complications, hospital length of stay, and mortality rate compared with standard therapy 1. However, the application of NIV in patients following extubation has shown mixed results, with some studies indicating a potential benefit in reducing reintubation rates, while others have found no significant effect or even an increase in ICU mortality in certain contexts 1.
From the Research
Role of NIV in Respiratory Distress
- Noninvasive ventilation (NIV) is a crucial intervention in treating acute respiratory failure caused by various conditions, including acute cardiogenic pulmonary edema (ACPE) and acute exacerbations of chronic obstructive pulmonary disease (COPD) 2, 3.
- The use of NIV has been shown to reduce the rate of endotracheal intubation, mortality, and length of hospital stay in patients with respiratory distress 3, 4.
- NIV is currently the first-line treatment for moderate-to-severe COPD exacerbation, as well as for acute cardiogenic pulmonary edema, and should be considered in immunocompromised patients with acute respiratory insufficiency 2, 4.
- The appropriate selection of patients and adaptation to the technique are key to the success of NIV 2.
- NIV can be used in a wide range of acute settings, including critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care 2, 5.
- The literature suggests that NIV may be beneficial in other respiratory pathologies, such as asthma exacerbation, pediatric patients, and community-acquired pneumonia, although the evidence is not as strong 5, 6.
- NIV eliminates morbidity related to the endotracheal tube and is associated with a better outcome in selected conditions, such as COPD exacerbation, acute cardiogenic pulmonary edema, and immunosuppressed patients with pulmonary infiltrates and hypoxia 4.
- However, NIV is associated with complications, especially minor complications related to the interface, and major complications like aspiration pneumonia, barotrauma, and hypotension are infrequent 4.