Inhaled Nitric Oxide via High-Flow Nasal Cannula in Patients with Acute Respiratory Failure Related to COVID-19.

INTRODUCTION: Limited evidence exists regarding use of inhaled nitric oxide (iNO) in spontaneously breathing patients. We evaluated the effectiveness of continuous iNO via high-flow nasal cannula (HFNC) in COVID-19 respiratory failure. METHODS: We performed a multicenter cohort study of patients with respiratory failure from COVID-19 managed with HFNC. Patients were stratified by administration of iNO via HFNC. Regression analysis was used to compare the need for mechanical ventilation and secondary endpoints including hospital mortality, length of stay, acute kidney injury, need for renal replacement therapy, and need for extracorporeal life support. RESULTS: A total of 272 patients were identified and 66 (24.3%) of these patients received iNO via HFNC for a median of 88 h (interquartile range: 44, 135). After 12 h of iNO, supplemental oxygen requirement was unchanged or increased in 52.7% of patients. Twenty-nine (43.9%) patients treated with iNO compared to 79 (38.3%) patients without iNO therapy required endotracheal intubation (P = .47). After multivariable adjustment, there was no difference in need for mechanical ventilation between groups (odds ratio: 1.53; 95% confidence interval [CI]: 0.74-3.17), however, iNO administration was associated with longer hospital length of stay (incidence rate ratio: 1.41; 95% CI: 1.31-1.51). No difference was found for mortality, acute kidney injury, need for renal replacement therapy, or need for extracorporeal life support. CONCLUSION: In patients with COVID-19 respiratory failure, iNO delivered via HFNC did not reduce oxygen requirements in the majority of patients or improve clinical outcomes. Given the observed association with increased length of stay, judicious selection of those likely to benefit from this therapy is warranted.

High-Flow Nasal Cannula Therapy in COVID-19: Using the ROX Index to Predict Success.

BACKGROUND: Optimal timing of mechanical ventilation in COVID-19 is uncertain. We sought to evaluate outcomes of delayed intubation and examine the ROX index (ie, [[Formula: see text]]/breathing frequency) to predict weaning from high-flow nasal cannula (HFNC) in patients with COVID-19. METHODS: We performed a multicenter, retrospective, observational cohort study of subjects with respiratory failure due to COVID-19 and managed with HFNC. The ROX index was applied to predict HFNC success. Subjects that failed HFNC were divided into early HFNC failure (≤ 48 h of HFNC therapy prior to mechanical ventilation) and late failure (> 48 h). Standard statistical comparisons and regression analyses were used to compare overall hospital mortality and secondary end points, including time-specific mortality, need for extracorporeal membrane oxygenation, and ICU length of stay between early and late failure groups. RESULTS: 272 subjects with COVID-19 were managed with HFNC. One hundred sixty-four (60.3%) were successfully weaned from HFNC, and 111 (67.7%) of those weaned were managed solely in non-ICU settings. ROX index >3.0 at 2, 6, and 12 hours after initiation of HFNC was 85.3% sensitive for identifying subsequent HFNC success. One hundred eight subjects were intubated for failure of HFNC (61 early failures and 47 late failures). Mortality after HFNC failure was high (45.4%). There was no statistical difference in hospital mortality (39.3% vs 53.2%, P = .18) or any of the secondary end points between early and late HFNC failure groups. This remained true even when adjusted for covariates. CONCLUSIONS: In this retrospective review, HFNC was a viable strategy and mechanical ventilation was unecessary in the majority of subjects. In the minority that progressed to mechanical ventilation, duration of HFNC did not differentiate subjects with worse clinical outcomes. The ROX index was sensitive for the identification of subjects successfully weaned from HFNC. Prospective studies in COVID-19 are warranted to confirm these findings and to optimize patient selection for use of HFNC in this disease.

Outcomes of mechanically ventilated patients with COVID-19 associated respiratory failure.

PURPOSE: The outcomes of patients requiring invasive mechanical ventilation for COVID-19 remain poorly defined. We sought to determine clinical characteristics and outcomes of patients with COVID-19 managed with invasive mechanical ventilation in an appropriately resourced US health care system. METHODS: Outcomes of COVID-19 infected patients requiring mechanical ventilation treated within the Inova Health System between March 5, 2020 and April 26, 2020 were evaluated through an electronic medical record review. RESULTS: 1023 COVID-19 positive patients were admitted to the Inova Health System during the study period. Of these, 164 (16.0%) were managed with invasive mechanical ventilation. All patients were followed to definitive disposition. 70/164 patients (42.7%) had died and 94/164 (57.3%) were still alive. Deceased patients were older (median age of 66 vs. 55, p <0.0001) and had a higher initial d-dimer (2.22 vs. 1.31, p = 0.005) and peak ferritin levels (2998 vs. 2077, p = 0.016) compared to survivors. 84.3% of patients over 70 years old died in the hospital. Conversely, 67.4% of patients age 70 or younger survived to hospital discharge. Younger age, non-Caucasian race and treatment at a tertiary care center were all associated with survivor status. CONCLUSION: Mortality of patients with COVID-19 requiring invasive mechanical ventilation is high, with particularly daunting mortality seen in patients of advanced age, even in a well-resourced health care system. A substantial proportion of patients requiring invasive mechanical ventilation were not of advanced age, and this group had a reasonable chance for recovery.