NIPPV in Hypoxic Respiratory Failure
A 56 year old male comes to the ED via EMS after noting progressive dyspnea and fever. In the field, the EMS team notes the patient is hypoxic with an SPO2 of 85%. Despite the low oxygen saturation, he is only using minimal accessory muscles and he is alert and oriented. His chest X-ray shows a right lobar pneumonia and he is requiring 6LNC oxygen to maintain a saturation greater than 90%. You know there is significant guideline evidence to support the use of non-invasive positive pressure ventilation (NIPPV) for COPD and CHF exacerbations, but what about patients with other causes of hypoxia such as pneumonia?
A recent systematic review and meta-analysis published in JAMA found a signal of reduced mortality and rates of intubation for patients supported with NIPPV in hypoxic respiratory failure(1). A unique aspect in this publication is the explicit exclusion of studies where patients with COPD and CHF comprised greater than 50% of the subjects. The authors did this to better evaluate the use of NIPPV in patients with hypoxic respiratory failure due to other causes. Twenty-five trials with 3804 patients were included. Most of the causes of respiratory failure were community acquired pneumonia, but a number of them (14 of 25) also included a significant population of immunocompromised patients.
The authors found that using NIPPV in this patient population reduced the risk of mortality and need for intubation using both facemask and helmet NIPPV interfaces. Interestingly, there was a much more significant reduction in mortality and intubation when using helmet interface NIPPV rather than face-mask NIPPV. However, the authors did note that the quality of the studies using helmet interface was lower than the studies using the facemask interface.
Helmet interface NIPPV was only recently approved for use in the United States during the COVID-19 epidemic. So, it remains to be seen if that stronger signal remains after helmet NIPPV is more widely used. For those who are unfamiliar with helmet NIPPV, this YouTube video from JAMA demonstrates how it is applied.
References: Ferreyro BL, Angriman F, Munshi L, et al. Association of Noninvasive Oxygenation Strategies With All-Cause Mortality in Adults With Acute Hypoxemic Respiratory Failure. Jama. 2020;324(1):57-67. doi:10.1001/jama.2020.9524