Table 1.
Baseline characteristics of the included studies.
| Study | Country | Study design | Number | Setting | Oxygen therapy method | SpO2/FiO2 of prone position | SpO2/FiO2 of usual care | Prone position duration | Intervention | Control |
|---|---|---|---|---|---|---|---|---|---|---|
| Alhazzani et al.[15] | Canada/Kuwait/Saudi Arabia/USA | RCT | 400 | ICU | High flow, low flow, NIV | 132 (103 -174) | 136 (110-181) | 4.8 (1.8–8.0) h/day | The target duration of prone positioning was 8 h/day to 10 h/day. | Not to prone position |
| Ehrmann et al.[24] | Mexico/France/USA/Spain/Ireland/Canada | Multicenter RCT | 1126 | ICU and general wards | HFNC | 147.9 ± 43.9 | 148.6 ± 43.1 | 5.0 (1.6–8.8) h/day | Lie in the prone position for as long and as frequently as possible each day | Standard care with HFNC |
| Ibarra-Estrada et al.[23] | Mexico | RCT | 430 | COVID-19 unit | HFNC | 134.7 ± 38.7 | 135.5 ± 37.9 | 9.4 (5.6–12.9) h/day | HFNC + APP | HFNC+ standard care |
| Fralick et al.[28] | Canada, USA | Multicenter RCT | 248 | General ward | Nasal cannula, HFNC, face mask | 303 (261-336) | 305 (267-339) | 6 (1.5–12.8) h/72 h | Recommended to adopt a prone position four times a day | Received usual care |
| Jayakumar et al.[32] | India | Multicenter RCT | 60 | ICU | Nasal cannula, face mask, non-rebreather mask, HFNC, or NIV | 185.6 ± 126.1 | 201.4 ± 118.8 | NA | Patients were encouraged to lie prone for a minimum of 6 h in a day | APP was not encouraged |
| Johnson et al.[31] | USA | RCT | 30 | General ward | Room air, nasal cannula | >300 | >300 | 1.6 (0.2–3.1) h/72 h | Patients were instructed to position themselves in prone and lateral position | Usual care |
| Kharat et al.[30] | Switzerland | RCT | 27 | General ward | Nasal cannula | 318 (284–341) | 336 (303–388) | NA | Patients used their mobile phone “timer” function to alternate their body position every 4 h | Nasal cannula+usual care |
| Garcia et al.[33] | USA | Multicenter RCT | 239 | General ward | Room air, nasal cannula, mask, or HFNC | 396 (308-457) | 402 (311-457) | NA | Smartphone-based recommendation to self-prone position during hospitalization | Usual care |
| Rosén et al.[27] | Sweden | Multicenter RCT | 75 | ICU and general ward | HFNC or NIV | 151(131–174) | 157(136–175) | 9.0 (4.4–10.6) h/day | A protocol targeting at least 16 h APP per day was initiated | APP was not encouraged |
| Taylor et al.[29] | USA | RCT | 40 | General ward | Room air, nasal cannula, HFNC, or NIV | >200 | >200 | NA | APP | Usual care |
Data are expressed as mean ± SD or median (interquartile range).APP: Awake prone positioning; COVID-19: Coronavirus disease 2019; HFNC: High-flow nasal cannula oxygenation; ICU: Intensive care unit; NIV: Non-invasive ventilation; RCT: Randomized controlled trial; SD: Standard deviation.