Evaluation of the ROX index in SARS-CoV-2 Acute Respiratory failure treated with both High-Flow Nasal Oxygen (HFNO) and Continuous Positive Airway Pressure (CPAP)

Abstract

Background: Non-invasive respiratory support including high-flow nasal oxygen (HFNO), and continuous positive airway pressure (CPAP) have been used to provide therapy in selected SARS-CoV-2 patients with acute respiratory failure (ARF). The value of the ROX index, a validated benchmark for outcomes in HFNO is unknown in CPAP. Objective: Can the ROX, a validated benchmark in HFNO be used for measuring treatment outcomes of CPAP in SARS-COV-2 ARF? Study Design and Methods: A non-randomised prospective protocol driven observational non-intensive care unit study in 130 SARS-COV-2 patients with ARF treated with non-invasive therapy from March 2020 to January 2021. The primary end point was failure of therapy (death or escalation). Secondary outcomes included time to failure including invasive mechanical ventilation (IMV) or death, the effect of escalation to CPAP from HFNO and the utility of ROX in ARF. Results: HFNO was better than CPAP in treating SARS-COV-2 ARF: 17/35 (48.5%) with successful HFNO therapy versus 24/95 (25.2%) with CPAP. The ROX index was more sensitive to outcomes with CPAP compared to HFNO and distinguished treatment failure early at 1, 4, 6, 12, and 24 hours with the highest sensitivity at 24 hours (ROX-24h). The AUC for the ROX-24h was 0.77 for HFNO (P<0.0001), and 0.84 for CPAP (P<0.0001). The ROX-24h cut-points predicted failure with HFNO when < 3.9 (PPV 71%, NPV 75%) and CPAP < 4.3 (PPV 75%, NPV 91%). For success, ROX-24h cut-points of 7.6 for HFNO (PPV 85%, NPV 48%) and 6.1 for CPAP (PPV 88%, NPV 62%) were observed. Escalation from HFNO to CPAP was mostly not successful. Conclusion: ARF in SARS-COV-2 can be successfully managed by non-invasive support. The ROX index, validated for HFNO, provides a timely, low resource measure for both HFNO and CPAP avoiding delayed intubation. Trial registration: Study approved by NHS HRAREC (20/HRA/2344;ethics 283888)

Comparison between high-flow nasal cannula and noninvasive ventilation in COVID-19 patients: a systematic review and meta-analysis

“…A total of 6394 relevant studies were obtained from the databases. After excluding duplicates and evaluating the full texts of articles, we identified 23 eligible studies 9 , 11 – 32 (3 RCTs, 20 , 24 , 26 8 prospective observational studies, 13 , 16 , 18 , 19 , 22 , 25 , 28 , 30 and 12 retrospective observational studies). 9 , 11 , 12 , 14 , 15 , 17 , 21 , 23 , 27 , 29 , 31 , 32 The process of searching and screening is described in Figure 1 .…”

“…Two studies were considered to have an unclear risk of bias. The 20 observational 9 , 11 – 19 , 21 – 23 , 25 , 27 – 32 studies were assessed using the NOS checklist, and the results are shown in the Table 2 . All studies were of medium quality (⩾5 stars) or above, and 10 were considered high quality (⩾8 stars).…”

“…A total of 5354 patients participated in the 23 studies 9 , 11 – 32 of the present meta-analysis, all of whom were adult COVID-19 patients. The patients were admitted to different hospital settings and received noninvasive respiratory support at the time of admission.…”

“…The patients were admitted to different hospital settings and received noninvasive respiratory support at the time of admission. In 4 studies, 11 , 17 , 20 , 25 a helmet was applied, in 11 studies, 9 , 13 – 15 , 18 , 19 , 26 , 28 , 29 , 30 , 32 a face mask was used, 1 study 22 reported applying both a helmet and a face mask, 7 studies 12 , 16 , 21 , 23 , 24 , 27 , 31 did not report whether a helmet or a facemask was used, in 6 studies, 9 , 20 , 22 , 24 , 27 , 29 BiPAP was applied, 7 studies 11 , 17 – 19 , 25 , 26 , 30 featured CPAP, 4 studies 14 – 16 , 23 reported applying both BiPAP and CPAP, and 6 studies 12 , 13 , 21 , 28 , 31 , 32 did not report whether they applied BiPAP or CPAP ( Table 1…”

“…A total of 5196 patients participated in 20 studies 9 , 12 – 20 , 23 – 32 that reported mortality, and the pooled estimates demonstrated that mortality rate was lower in HFNC groups than in NIV groups [OR = 0.66, 95% CI: 0.51–0.84, p = 0.0008, I 2 = 60%, Figure 4(a) ]. However, in subgroup analysis, no significant differences in mortality were observed in the HFNC group relative to NIV-helmet group [OR = 1.21, 95% CI: 0.63–2.32, p = 0.57, I 2 = 0%, Figure 5(a) ] or the NIV-CPAP group [OR = 0.77, 95% CI: 0.51–1.17, p = 0.23, I 2 = 65%, Figure 5(b) ], but significant differences in mortality were observed in the HFNC group relative to the NIV-facemask group [OR = 0.58, 95% CI: 0.41–0.81, p = 0.001, I 2 = 63%, Figure 5(a) ] or the NIV-BiPAP group [OR = 0.60, 95% CI: 0.45–0.79, p = 0.0003, I 2 = 5%, Figure 5(b) ].…”