High Velocity Nasal Insufflation versus Noninvasive Positive Pressure Ventilation for Moderate Acute Exacerbation of Chronic Obstructive Pulmonary Disease in the Emergency Department

Review Author: Auryan Esfandiari

High Velocity Nasal Insufflation versus Noninvasive Positive Pressure Ventilation for Moderate Acute Exacerbation of Chronic Obstructive Pulmonary Disease in the Emergency Department: A Randomized Clinical Trial 

David P. Yamane MD; Christopher W. Jones MD; R. Gentry Wilkerson MD; Joshua J. Oliver MD, MPH; Soroush Shahamatdar BS; et al. 

What are High Velocity Nasal Insufflation (HVNI) and Noninvasive Positive Pressure Ventilation (NIPPV)? 

HVNI is a type of high-flow nasal cannula that delivers heated, humidified oxygen at high flow rates through nasal prongs. This high flow flushes out dead space, improves oxygenation, and provides a small amount of positive pressure support. 

NIPPV is another noninvasive form of respiratory support delivered through a tightly fitted mask that provides pressurized air during both inspiration and expiration, thereby reducing the work of breathing and improving gas exchange. 

Why are these therapies considered for acute COPD exacerbation? 

In COPD, airflow limitation due to loss of elastic recoil leads to air trapping, impaired CO₂ clearance, and increased work of breathing, which may result in respiratory muscle fatigue. Both HVNI and NIPPV help by maintaining airway and alveolar patency during expiration, reducing air trapping, and promoting more effective CO₂ clearance. 

Why this study? 

NIPPV is commonly used in emergency departments to treat COPD exacerbations but is often limited by patient intolerance due to discomfort, aspiration risk, or poor mask seal. HVNI offers potential advantages, including improved comfort, easier communication, ability to eat, and better secretion clearance. This study aimed to determine whether HVNI is noninferior to NIPPV in relieving dyspnea among ED patients with acute hypercapnic respiratory failure. 

Study Design 

This was a prospective, multicenter, randomized, noninferiority trial conducted from November 2020 to May 2023 across 7 U.S. emergency departments (3 community hospitals, 3 academic hospitals, and 1 military hospital). Sixty-three patients were enrolled after meeting eligibility criteria. Following randomization, patients were assigned to HVNI or NIPPV and assessed at baseline, 30 minutes, 60 minutes, and 4 hours. All other management was left to the treating team. 

● Inclusion criteria: age >18, known or suspected COPD, venous pCO₂ >60 mmHg, and pH 7.0–7.35. 

● Exclusion criteria: need for immediate intubation, respiratory or cardiac arrest, dyspnea unlikely due to COPD, intolerance to either therapy, altered mental status, or pregnancy. 

The primary outcome was dyspnea at 4 hours measured by the Borg scale (0 = no dyspnea, 10 = unbearable dyspnea). A secondary outcome was patient-reported comfort on a 10-point visual analog scale (VAS).

Results 

Groups were well matched for demographics, comorbidities, and baseline physiology (average pH 7.27, pCO₂ ~77 mmHg, Borg score ~5.5). No patients in either group required intubation. 

● Primary outcome: At 4 hours, HVNI was noninferior to NIPPV in reducing dyspnea (Borg score 3.17 ± 2.59 vs. 3.34 ± 2.04, p = 0.03). Noninferiority was also demonstrated at 30 and 60 minutes. ● Dyspnea resolution: A greater proportion of HVNI patients achieved minimal dyspnea within 60 minutes (41% vs. 8%, p = 0.01). 

● Disposition: More HVNI patients were admitted to the ICU (38% vs. 27%, p = 0.42). Four HVNI patients were discharged directly from the ED; none were discharged in the NIPPV group. ● Comfort: HVNI patients reported significantly less discomfort (VAS 20.1 vs. 43.3, p = 0.003). 

Conclusion 

HVNI was noninferior to NIPPV in reducing dyspnea at 4 hours among ED patients with moderate COPD exacerbations and hypercapnia. Both therapies achieved similar improvements in pH and pCO₂. Given its favorable comfort profile, HVNI may be a reasonable alternative, especially in patients who cannot tolerate NIPPV. 

Limitations 

1. Participants, providers, and assessors were not blinded to treatment assignment. 2. Many patients presented with undifferentiated dyspnea presumed to be COPD, reflecting typical ED practice. 

3. Only patients not in imminent respiratory arrest and able to consent were included. 4. All patients also received standard care per treating clinicians, which may have introduced variability. 

5. The primary outcome relied on a subjective dyspnea score, though supported by objective pH and pCO₂ measurements.