Table 2.
The summary of outcomes and GRADE quality assessments.
| Quality assessment | No of patients | Effect | Quality | Importance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of studies | Design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other consideration | HFNC | COT | Relative RR (95% CI) | Absolute (95% CI) | ||
| Intubation rate | ||||||||||||
| 4 | RCTs | Seriousa | Not serious | Not serious | Seriousb | None | 10/296 (3.4%) | 17/275 (6.2%) | 0.53(0.26–1.09) | −32 per 1000 (from −69 to 4) | ⊕⊕Low | Critical |
|
| ||||||||||||
| Mortality rate | ||||||||||||
| 2 | RCTs | Not serious | Not serious | Not serious | Seriousb | None | 36/228 (15.8%) | 24/203 (11.8%) | 1.25(0.79–1.99) | 32 per 1000 (from −32 to 95) | ⊕⊕⊕Moderate | Critical |
|
| ||||||||||||
| ICU admission rate | ||||||||||||
| 2 | RCTs | Not serious | Not serious | Not serious | Seriousb | None | 17/213 (8%) | 15/190 (7.9%) | 1.11(0.58–2.12) | 8 per 1000 (from −43 to 59) | ⊕⊕⊕Moderate | Critical |
|
| ||||||||||||
| ED discharge rate | ||||||||||||
| 2 | RCTs | Not serious | Not serious | Not serious | Seriousb | None | 23/111 (20.7%) | 23/117 (19.7%) | 1.04(0.63–1.72) | 8 per 1000 (from −93 to 109) | ⊕⊕⊕Moderate | Critical |
|
| ||||||||||||
| Need for escalation | ||||||||||||
| 4 | RCTs | Seriousa | Not serious | Not serious | Not serious | None | 13/296 (4.4%) | 29/275 (10.5%) | 0.41(0.22–0.78) | −62 per 1000 (from −105 to −19) | ⊕⊕⊕Moderate | Critical |
|
| ||||||||||||
| Length of ED stay (hour) | ||||||||||||
| 3 | RCTs | Not serious | Seriousc | Not serious | Seriousb | None | 276 | 255 | — | MD 1.66 hours (from −0.95 to 4.27) | ⊕⊕Low | Critical |
|
| ||||||||||||
| Length of hospital stay (day) | ||||||||||||
| 2 | RCTs | Not serious | Seriousc | Not serious | Seriousb | None | 228 | 203 | — | MD 0.9 days (from −2.06 to 3.87) | ⊕⊕Low | Critical |
|
| ||||||||||||
| Patient dyspnea score | ||||||||||||
| 2 | RCTs | Seriousd | Seriousc | Not serious | Not serious | None | 83 | 85 | — | MD −0.82 point (from −1.45 to −0.18) | ⊕⊕Low | Critical |
|
| ||||||||||||
| Patient comfort score | ||||||||||||
| 3 | RCTs | Seriousd | Not serious | Not serious | Not serious | None | 131 | 137 | — | SMD −0.76 SD (from −1.01 to −0.51) | ⊕⊕⊕Moderate | Critical |
RCT, randomized controlled trial; HFNC, high-flow nasal cannula; COT, conventional oxygen therapy; CI, confidence interval; RR, risk ratio; MD, mean difference; SMD, standardized mean difference. aAll inclusion trials lacked blinding (performance bias), so escalation or intubation may be subjective. bInsufficient evidence of clear benefit or harm because of a wide CI. cSignificant heterogeneity among the included trials (I2 > 50%). dSubjective outcome. ⊕, very low quality; ⊕⊕, low quality; ⊕⊕⊕, moderate quality; ⊕⊕⊕⊕, high quality.