Aside from its use in pulmonary edema, noninvasive ventilation (NIV) has demonstrated repeated benefit in the subset of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).
The positive pressure works to reduce the collapse of small and medium-sized airways during expiration. It also reduces the workload of the muscles of inspiration and expiration, allowing for more efficient breathing in a time of distress.
How does positive pressure NIV benefit patients with COPD?
Before the routine use of NIV in patients with COPD, or chronic obstructive pulmonary disease, in-hospital mortality rates were quoted up to 33%. These patients were given nebulizers, steroids, and antibiotics—and when those measures failed, patients were intubated and heavily sedated.
With the adoption of NIV as a routine treatment for COPD, we see a range of benefits:
- Improved respiratory rate
- Improved PaCO2
- Improved pH
- Decreased in-hospital complications
- Decreased hospital stays
- Reduced rate of intubation
- Reduced mortality rate
Which ventilator mode should I choose for my patients with COPD?
The primary mode of NIV used in patients with COPD is bilevel positive airway pressure (BPAP).
The positive end-expiratory pressure (PEEP) works to stent open airways during expiration when the bronchi are most at risk of collapse and airflow obstruction. The additional pressure support (PS) during inspiration allows larger volume breaths that work to increase the minute ventilation. The PS also reduces the work done by accessory muscles to take in breaths and allows greater efficiency of breathing.
Could I use CPAP instead of BPAP for my patients with COPD?
In patients with COPD, continuous positive airway pressure (CPAP) can provide a pressure that would stent open the airways in expiration, but since there is no added pressure support, it doesn’t help with inspiratory work. Plus, this mode really has not been well studied for use in COPD.
So, since the preponderance of literature supports the use of BPAP in acute COPD, that’s what you need to reach for the next time you have a patient with COPD.
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Bott, J, Carroll, MP, Conway, JH, et al. 1993. Randomised controlled trial of nasal ventilation in acute ventilatory failure due to chronic obstructive airways disease. Lancet. 341: 1555–1557. PMID: 8099639
Brochard, L, Mancebo, J, Wysocki, M, et al. 1995. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med. 333: 817–822. PMID: 7651472
Ram, FSF, Picot, J, Lightowler, J, et al. 2004. Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease. Cochrane Database Syst Rev. CD004104. PMID: 15266518