Ambulatory care of non-invasive mechanical ventilation in COPD patients with global decompensated respiratory acidosis

Introduction:

An indication that is firmly established for use of Non-invasive Mechanical Ventilation (NIV) is respiratory failure with respiratory acidosis secondary to exacerbation of COPD (Chronic Obstructive Pulmonary Disease). However, there are COPD patients with clinically well tolerated respiratory acidosis who could benefit from an easily accessible NIV consultation.

Material and methods:

Prospective observational study of a cohort of 32 patients with decompensated severe COPD and hypercapnic respiratory failure with respiratory acidosis, but well tolerated clinically (absence of signs of hypercapnic encephalopathy, absence of laboured breathing and hemodynamic stability). Patients were treated at the NIV Unit. In addition to the clinical evaluation, venous blood gases and occasionally spirometry were performed. Those who already had NIV at home adjusted the parameters of their respirator. And those who still were not treated with NIV, were introduced to the same routine protocol. Ventilation was maintained for two hours, after which a new venous blood gas analysis was performed. Patients who previously had NIV were discharged with the new set of parameters. The rest were given a home respirator prescription and the device was installed at their home the same day. Patients were reviewed in consultation in two weeks. The progression in all patients was favourable.

Results:

Thirty-two patients were assessed (84.4% males), ages 71 ± 8.7. A total of 53% were prescribed NIV previously. In the joint analysis of the two blood gases, early NIV was associated with an increase in pH (1: pH 7.30//2: pH 7.35; p < 0.001) and reduction of pCO2 (1: pCO2 69.7 mmHg//2: pCO2 55.9 mmHg; p < 0.001). No respiratory complications occurred within 15 – 20 days after the start of NIV.

Conclusions:

Early ambulatory care for the establishment or adjustment of NIV in severe or very severe COPD cases with decompensated and well tolerated respiratory failure can be a useful tool for quick resolution of the condition, thus avoiding hospital admissions.