JMIR Publications

ABSTRACT

Background:

Type 2 respiratory failure (T2RF) is a common and high-risk presentation in the emergency department (ED). Non-invasive positive pressure ventilation (NIPPV) is a standard first-line therapy for T2RF, particularly in acute exacerbations of chronic obstructive pulmonary disease and cardiogenic pulmonary edema. However, NIPPV has limitations including discomfort, claustrophobia, air leaks, skin injury, and aspiration, which may compromise tolerance and lead to treatment failure or escalation to endotracheal intubation. High-velocity nasal insufflation (HVNI), particularly via a single-prong asymmetric cannula configuration, has been proposed to enhance dead-space washout and improve patient comfort. Despite growing interest, robust evidence evaluating HVNI in heterogeneous, all-cause T2RF populations in the ED remains limited.

Objective:

This study aims to determine whether HVNI delivered via a single-prong nasal cannula is non-inferior to standard NIPPV in improving ventilation among adult ED patients with T2RF from any cause.

Methods:

This is a single-center, open-label, non-inferiority randomized controlled trial conducted in the ED of a tertiary academic center. Adults 21 years and above with T2RF defined as PaCO2 >45 mmHg and pH <7.35, requiring ventilatory support, will be randomized 1:1 to HVNI with single-prong cannula or standard NIPPV. Allocation will be concealed via an independent web-based platform using variable block sizes (4 and 6). The primary outcome is percentage change in PaCO2 from baseline to 60 minutes after initiation of therapy. Eighty-four patients provide 80% power, one-sided alpha 2.5% assuming standard deviation 6.65% and non-inferiority margin 4.3%. Analyses will use intention-to-treat and per-protocol approaches, and sensitivity analyses to address missing arterial blood gas results. Predefined failure criteria (persistent or worsening acidosis, rising PaCO2, refractory hypoxemia, severe intolerance, clinical deterioration) would trigger crossover or escalation per protocol.

Results:

Ethics approval was granted by the local institutional ethics board on 24 February 2025 (reference: 2024-4329). Recruitment commenced in January 2026 and is expected to be completed by June 2027. As of July 2026, 19 participants have been enrolled out of a target sample of 84.

Conclusions:

Should HVNI with single-prong cannula be shown to be non-inferior to NIPPV, it may offer a practical alternative to treatment of T2RF in the ED when mask-based interfaces are poorly tolerated or contraindicated, potentially reducing the need for more invasive interventions like endotracheal intubation and mechanical ventilation. Clinical Trial: This trial was prospectively registered on 15 July 2025 with ClinicalTrials.gov (#NCT07065656).