The ventilatory effect of high velocity nasal insufflation compared to non-invasive positive-pressure ventilation in the treatment of hypercapneic respiratory failure: A subgroup analysis.

PURPOSE: Oxygen delivery by high flow nasal cannula (HFNC) is effective in providing respiratory support. HFNC has utility in clearing the extra-thoracic dead space, making it potentially beneficial in the treatment of hypercapnic respiratory failure. This study compares high velocity nasal insufflation (HVNI), a form of HFNC, to non-invasive positive pressure ventilation (NIPPV) in their abilities to provide ventilatory support for patients with hypercapnic respiratory failure. METHODS: This is a pre-defined subgroup analysis from a larger randomized clinical trial of Emergency Department (ED) patients with respiratory failure requiring NIPPV support. Patients were randomized to HVNI or NIPPV. Subgroup selection was done for patients with discharge diagnoses of acute hypercapnic respiratory failure or acute exacerbation of chronic obstructive pulmonary disease. The primary outcomes were change in pCO2 and pH over time. Secondary outcomes were treatment failure and intubation rate. RESULTS: 65 patients with hypercapnic respiratory failure were compared. 34 were randomized to HVNI and 31 to NIPPV. The therapeutic impact on PCO2 and pH over time was similar in each group. The intubation rate was 5.9% in the HVNI group and 16.1% in the NIPPV group (p = 0.244). The rate of treatment failure was 23.5% in the HVNI group and 25.8% in the NIPPV group (p = 1.0). CONCLUSION: HVNI may provide ventilatory support similar to NIPPV in patients presenting with acute hypercapnic respiratory failure, but further study is needed to corroborate these findings.