The utility of high-flow nasal oxygen for severe COVID-19 pneumonia in a resource-constrained setting: A multi-centre prospective observational study

Abstract

Background The utility of heated and humidified high-flow nasal oxygen (HFNO) for severe COVID-19-related hypoxaemic respiratory failure (HRF), particularly in s``ettings with limited access to intensive care unit (ICU) resources, remains unclear, and predictors of outcome have been poorly studied. Methods We included consecutive patients with COVID-19-related HRF treated with HFNO at two tertiary hospitals in Cape Town, South Africa. The primary outcome was the proportion of patients who were successfully weaned from HFNO, whilst failure comprised intubation or death on HFNO. Findings The median (IQR) arterial oxygen partial pressure to fraction inspired oxygen ratio (P a O2/FiO 2 ) was 68 (54–92) in 293 enroled patients. Of these, 137/293 (47%) of patients [P a O2/FiO 2 76 (63–93)] were successfully weaned from HFNO. The median duration of HFNO was 6 (3–9) in those successfully treated versus 2 (1–5) days in those who failed ( p <0.001). A higher ratio of oxygen saturation/FiO2 to respiratory rate within 6 h (ROX-6 score) after HFNO commencement was associated with HFNO success (ROX-6; AHR 0.43, 0.31–0.60), as was use of steroids (AHR 0.35, 95%CI 0.19–0.64). A ROX-6 score of ≥3.7 was 80% predictive of successful weaning whilst ROX-6 ≤ 2.2 was 74% predictive of failure. In total, 139 patents (52%) survived to hospital discharge, whilst mortality amongst HFNO failures with outcomes was 129/140 (92%). Interpretation In a resource-constrained setting, HFNO for severe COVID-19 HRF is feasible and more almost half of those who receive it can be successfully weaned without the need for mechanical ventilation.

High-Flow Nasal Cannula Treatment in Patients with COVID-19 Acute Hypoxemic Respiratory Failure

“…Moreover, they found that a high ROX index (per point increase) at 6 hours to be signi cantly associated with HFNC success cases (adjusted HR, 0.42; 95% CI [0.33-0.54]; p < 0.001). However, the mortality in patients who failed HFNC treatment was very high (92%) [23]. This considerably high rate is inconsistent with neither previous studies nor the current study ndings, which might be attributed to several reasons, including resourceconstrained setting, the majority (64%) of their cohort were admitted to the ward in a non-critical care environment, and limited access to ICU expertise [23].…”

“…Most recently, a prospective multicenter study that involved 293 patients has reported 53% HFNC failure rate, in which half of the patients did not require mechanical ventilation [23]. Moreover, they found that a high ROX index (per point increase) at 6 hours to be signi cantly associated with HFNC success cases (adjusted HR, 0.42; 95% CI [0.33-0.54]; p < 0.001).…”

“…However, the mortality in patients who failed HFNC treatment was very high (92%) [23]. This considerably high rate is inconsistent with neither previous studies nor the current study ndings, which might be attributed to several reasons, including resourceconstrained setting, the majority (64%) of their cohort were admitted to the ward in a non-critical care environment, and limited access to ICU expertise [23]. Besides, there was a signi cant difference between the admitting settings of the two groups, where 45% of successfully treated patients were admitted to ICU setting compared to only 28% of the failed HFNC cases were treated in ICU setting (p = 0.004) [23].…”

Prolonged treatment of COVID-19 pneumonia with high-flow nasal oxygen: A story of oxygen and resilience

“…In the cohort from GSH and TBH, it was shown that in a resource-constrained setting, HFNO for COVID-19 hypoxic respiratory failure is feasible even outside the ICU and averts death or the need for mechanical ventilation in almost half of those who receive it. [10] Over the course of our patient's 40 days on HFNO, she averaged an FiO 2 of 77% at a flow rate of 52 L/min. This equates to the consumption of 40 L of gaseous oxygen per minute or a total of 2.3 million L of gaseous oxygen over the 40 days.…”

“…In a cohort of 293 patients with COVID-19 hypoxic respiratory failure enrolled at GSH and Tygerberg Hospital (TBH) during the pandemic, the median (interquartile range) time on HFNO in those successfully weaned was 6 (3 -9) days. [10] The 40 days described above is the longest time any patient has spent on HFNO in this cohort -by a considerable margin. We have been unable to find another case of HFNO used for this duration before in a patient with a good outcome.…”