Outcomes of Heated High Flow Nasal Cannula in Patients With Severe or Life-Threatening COVID-19 at a Military Treatment Facility—A Retrospective Cohort Study

Dollin, Capt Yonatan P; Elliott, Capt Brian P; Markert, Ronald; Koroscil, Maj Matthew T

INTRODUCTION: The coronavirus-19 (COVID-19) pandemic has forced radical changes in management of healthcare in military treatment facilities (MTFs). Military treatment facilities serve unique patients that have a service connection; thus, research and data on this population are relatively sparse. The purpose of this study was to provide descriptive data on characteristics and outcomes of MTF patients with COVID-19 who are treated with heated high-flow nasal cannula (HHFNC). MATERIALS AND METHODS: We performed a single-center retrospective cohort study at the Wright-Patterson Medical Center, a 52-bed hospital in an urban setting. We received approval from our Institutional Review Board. The cohort included patients admitted from June 1, 2020, through May 15, 2021 with severe or life-threatening COVID-19 from a positive severe acute respiratory syndrome–related coronavirus 2 reverse transcription polymerase chain reaction test who were placed on HHFNC during their hospital stay. Severe disease was defined as dyspnea, respiratory rate ≥30/min, blood oxygen saturation ≤93% without supplemental oxygen, partial pressure of arterial oxygen to fraction of inspired oxygen ratio <300, or lung infiltrates involving >50% of lung fields within 24-48 hours. Life-threatening disease was defined as having septic shock or multiple organ dysfunction or requiring intubation. Patients meeting these criteria were retrieved from a quality improvement cohort that represents a consecutive group of patients with COVID-19 admitted to the Wright-Patterson Medical Center. RESULTS: Our MTF managed 70 cases of severe or life-threatening COVID-19 from June 1, 2020, to May 15, 2021. Of the 70 cases, 19 (27%) were placed on HHFNC. After initiation of HHFNC, median SpO(2)/FiO(2) was 281.8 and at 24 hours 145.4. Median respiratory rate oxygenation at these times were 10.7 and 9.4, respectively. Fifty percent required mechanical ventilation during hospitalization. Median intensive care unit length of stay was 11 days, with a maximum stay of 39 days. Median hospital length of stay was 12 days, with a maximum of 39 days. CONCLUSION: Our retrospective cohort study characterized and analyzed outcomes observed in a MTF population, with severe or life-threatening COVID-19, who were treated with HHFNC. While the study did not have the power to make concrete conclusions on the optimal form of respiratory support for COVID-19 patients, our data support HHFNC as a reasonable treatment modality despite some notable differences between our cohort and prior studied patient populations.