Predictive factors associated with high‐flow nasal cannula success for COVID‐19‐related acute hypoxemic respiratory failure

Abstract

During the coronavirus disease 2019 (COVID-19) pandemic, oxygen support management for critically ill patients with acute hypoxemic respiratory failure (AHRF) was a key component of clinical decisionmaking. 1 There is a lack of knowledge regarding the use of high-flow nasal cannula (HFNC) in COVID-19 patients with AHRF. Most hospitals adopted an early-intubation strategy leading to a high intubation rate and the demand for intensive care unit (ICU)-beds overwhelmed hospital resources. With a low ICU bed-to-population ratio in our area, we adopted a large high-flow nasal cannula (HFNC) therapy use in COVID-19 patient-related AHRF. Here, we assessed, retrospectively, the benefit of HFNC use in this population. | METHODSForty-two COVID-19-confirmed patients with AHRF treated with at least 2 hours of HFNC in first line were included in the study between March 1 and May 23, 2020 (Figure 1). The study was declared at European General Data Protection Regulation (Identifier RMR004-25052020). Inclusion criteria were laboratory-confirmed COVID-19 patients over 18 years of age suffering from AHRF treated with HFNC as first-line therapy and admitted to the medical ICU of the Reims University Hospital. Exclusion criteria were under 18 years of age, urgent need to intubate (less than 2 hours after HFNC initiation), previous intubation in the same hospital stay, and presence of a do-not-resuscitate order.HFNC was initiated with a minimum flow of 50 L/min with a FiO 2 of 50%. Then, FiO 2 was titrated targeting an SpO 2 above 92%, and flow rate was adjusted up to 60 L/min or according to the maximum tolerated dose. HFNC failure was defined as the subsequent need for invasive mechanical ventilation. Intubation criteria were left at the discretion of physicians. Respiratory parameters were measured under HFNC conditions. The ROX index was defined as the ratio of SpO 2 /FiO 2 (%) to respiratory rate (breaths/min). In patients with AHRF treated with HFNC, a ROX index higher than 4.88 measured after 12 hours of HFNC was significantly associated with a lower risk of intubation. 2,3 Quantitative parameters were analyzed with nonparametric tests.Differences in categorical variables were assessed with chi-square. All tests were two-sided with a 5% significance level. | RESULTSResults are displayed in Table 1. Twenty-two patients were treated successfully with HFNC (52%) and twenty patients subsequently required IMV support (48%).At ICU admission, patients had a median PaO 2 /FiO 2 ratio of 128 for HFNC success group and 121.5 [88.5-135.5] for

In-Hospital Mortality of COVID-19 Patients Treated with High-Flow Nasal Oxygen: Evaluation of Biomarkers and Development of the Novel Risk Score Model CROW-65

“…The observed difference is probably owing to the discrepancy in clinical characteristics of treated patients, primarily the severity of the disease. Namely, the ROX index at the time of hospital admission, a valuable indicator of poor outcomes in patients with AHRF, was substantially lower in our and Hu’s study in comparison to the studies with lower mortality rates [ 32 , 33 , 40 , 41 , 42 ]. Furthermore, during the time in which the study was conducted, the British variant of SARS-CoV-2 breached our department, thus yielding less favorable outcomes.…”

“…In terms of mortality, our cohort of patients in which HFNO failed yielded similar results as the aforementioned study by Hu et al [ 32 ]. However, other studies reported much lower mortality rates among their patients [ 31 , 34 , 40 ]. The observed difference is probably owing to the discrepancy in clinical characteristics of treated patients, primarily the severity of the disease.…”

Effectiveness of the use of a high-flow nasal cannula to treat COVID-19 patients and risk factors for failure: a meta-analysis

“…After excluding duplicates and evaluating the full texts of articles, we identified 25 eligible studies (1 RCT, 12 case-control studies, and 12 cohort studies). 14 – 38 The search and screening process is described in Figure 1 . The main characteristics of the articles included in the meta-analysis are shown in Tables 1 , 2 , 3 and 4 .…”

“…A total of 586 out of 2055 patients on HFNC from 20 studies 14 , 16 – 24 , 26 – 28 , 30 , 33 – 38 ultimately died, for a mortality rate of 0.23 (95% CI: 0.19–0.29, I 2 = 88%; Figure 3 (b) ) . A total of 529 out of 1124 patients from 14 studies 14 , 16 – 18 , 20 , 23 , 24 , 26 , 29 , 30 , 33 , 35 , 36 , 38 experienced HFNC failure (escalation to NIV or intubation and/or death), for a failure rate of 0.47 (95% CI: 0.42–0.51, I 2 = 56%; Figure 3 (c) ) . When reported, the ROX index after the initiation of HFNC was 5.0 ± 2.4, the duration of HFNC was 4.9 ± 5.0 days, and the length of the hospital stay was 19.6 ± 13.6 days.…”

Factors associated with mechanical ventilation in SARS‐CoV‐2 patients treated with high‐flow nasal cannula oxygen and outcomes

“…Thus, the use of HFNCO led to a decrease in intubation rate and did not increase mortality 3,5–7 . Some studies found a decrease in the length of stay and a decrease in mortality for patients treated with HFNCO 6,8 . However, the use of HFNCO on patients not infected with SARS‐CoV‐2 and presenting acute respiratory failure is associated with greater mortality when HFNCO fails within 48 h after its initiation.…”