Skip to main content

Table 1 The basic characteristics of studies included in this review

From: Efficacy and safety of prone position in COVID-19 patients with respiratory failure: a systematic review and meta-analysis

First author, published year

Study design

Study setting

Study location

Enrollment period

Total sample size (prone/non-prone)

Age (year, IQR or SD) (prone/non-prone)

Male (%) (prone/non-prone)

Oxygen therapy methods

Proning protocol

Location of proning

Proning duration in prone group

Daily

Total

Ehrmann [22]

RCT

Multicenter

Canada, France, Ireland, Mexico, USA, Spain

2020.4.2.–2021.1.26

1121 (564/557)

61.5 (13.3)/60.7 (14.0)

67/66

HFNC

As long and as frequently as possible each day

ICU, Ward, ER

5 (IQR 1.6–8.8) h

NR

Jayakumar [25]

RCT

Multicenter

India

NR

60 (30/30)

54.8 (11.1)/57.3 (12.1)

83.3/83.3

Nasal prongs, face mask, non-rebreather mask, HFNC, or NIV

≥ 6 h/day (cumulative)

ICU

 ≥ 6 h in 43% of intervention group

NR

Kharat [26]

RCT

Single center

Switzerland

2020.4.6.–2020.4.25

27 (10/17)

54 (14)/60 (11)

60/65

Nasal cannula

≤ 12 h/day

Ward

295 (SD 216) m

NR

Rosén [27]

RCT

Multicenter

Sweden

2020.10.7.–2021.2.7

75 (35/39)

66 (53–74)/65 (55–70)

64/82

HFNC, NIV

≥ 16 h/day

Ward, ICU

9.0 (IQR 4.4–10.6) h

4.2 (1.7–5.7) d

Taylor [28]

RCT

Single center

US

2020.6.1.–2020.8.31

40 (27/13)

56 (45–66)/60 (54–63)

63/77

Nasal cannula, MFNC

As long as possible and allowed to return to the supine position as necessary

Ward

NR

NR

Fralick [23]

RCT

Multicenter

Canada, US

2021.3.-2021.5

248 (126/122)

59.5 (45–68)/54 (44–62)

65/63

Nasal cannula, mask, HFNC

Four sessions/day (up to 2 h/sessions), encouraged to sleep in pone position overnight

Ward

NR

From randomization to first 72 h: 6 (1.5–12.8) h, from 72 h to 7 d: 0 (0–12) h

Gad [24]

RCT

Single center

Egypt

2020.6.-2020.9

30 (15/15)

49.0 (38–62)/46.0 (33–51)

60.0/53.3

High flow with non-rebreathing facemask

Each session for 1–2 h according to patient to tolerability with 3 h apart during waking hours

Critical care isolation

NR

NR

Ibarra-Estrada [11]

RCT

Multicenter

Mexico

2020.5.5.–2021.1.26

430 (216/214)

58.6 (15.8)/58.2 (15.8)

61.1/58.9

HFNC

As long as possible

Intermediate or intensive care unit

4 sessions/d (3–5) 3.4 (3–3.6) h/session

9.4 (5.6–12.9) h for 6 (3.7–9) ds

Alhazzani [12]

RCT

Multicenter

Multicountry

2020.5.19–2021.5.13

400 (205/195)

56.8 (12.5)/58.3 (13.2)

73/69

HFNC, LFNC, NPPV

8 h/d–10 h/d with 2 to 3 breaks (1–2 h each), if needed

ICU or a monitored acute care unit

NR

3 (1–5) d

Musso [30]

NRCT

Single center

Italy

Int 2020.12.16.–2021.5.30. Cont 2020.4.1.–2020.12.15

243 (81/162)

68 (60–75)/69 (61–78)

76/72

NIV

As long as possible, at least 1 session/day lasting ≥ 8 h scheduled overnight

Subintensive care unit

12.2 (10.1–13.8) h, 2 session/d

6 (5–8) d

Qian [29]

NRCT

Multicenter

US

2020.5.13.–2020.12.11

501 (243/258)

61.6 (15.4)/60.3 (15.2)

56.6/56.8

HFNC, LFNC, NIV

Encouraged as often and consistently as possible

NR

4.2 (1.8–6.7) h

NR

Ferrando [32]

Prospective cohort study

Multicenter

Spain, Andorra

2020.3.12.–2020.6.9

199 (55/144)

60.0 (54.0–70.0)/63.0 (55.0–71.0)

75.9/72.7

HFNC

 > 16 h regardless of the number of sessions

ICU

NR

NR

Ni [5]

Prospective cohort study

Single center

China

2020.1.31.–2020.2.15

52 (17/35)

60 (12)/64 (12)

64.7/60

NR

≥ 4 h/day for 10 days

Provisional ICU

NR

NR

Zang [35]

Prospective cohort study

Single center

China

2020.2.1.–2020.4.30

60 (23/37)

63 (59–71)/66 (60–72)

56.5/70.3

O2 storage mask

1–2 h/session, 3–4 sessions/day for more than 5 consecutive days

NR

NR

13.4 (SD 8.0) h

Bahloul [7]

Prospective cohort study

Single center

Tunisia

2020.9.1.–2020.12.4

38 (21/17)

61 (10)/60 (12)

76.2/NR

Facial mask, HFNC

2–4 h followed by 2 h of supine positioning during the day, and to sleep in a proning at night, when possible

ICU

NR

NR

Esperatti [31]

Prospective cohort study

Multicenter

Argentina

2020.6.–2021.1

335 (187/148)

57 (47–66)/66.5 (56.5–75)

76/72

HFNC

≥ 6 h/day, no time limits for prone position

ICU

12 (IQR 9–16) h

5 (IQR 3–8) d

Sryma [34]

Prospective cohort study

NR

India

NR

45 (30/15)

50.9 (10.1)/57.5 (12.2)

96.7/60

NIV, HFNC, COT

≥ 2 h/session, target duration of 8 h/day

NR

7.5 (range 4–12) h on the first day

NR

Pierucci [33]

Prospective cohort study

Single center

Italy

2020.3.11.–2020.4.30

32 (16/16)

59 (11)/70 (15)

81/62

Int: spontaneously breathing Cont: HFNC, CPAP, NIV

As long as possible with intervals for meals and other personal care

   

Jagan [39]

Retrospective cohort study

Single center

US

2020.3.24.–2020.5.5

105 (40/65)

56.0 (14.4)/65.8 (16.3)

50/56.9

Non-intubation

≥ 1 h/day for at least 5 sessions, ≥ 1 h/overnight

NR

NR

NR

Padrão [42]

Retrospective cohort study

Single center

Brazil

2020.3.1.–2020.4.30

166 (57/109)

51.8 (13)/61.4 (13.6)

70/66

Nasal cannula, venturi mask, non-rebreather mask

≥ 4 h in the first session, stimulated twice daily to maintain proning

NR

First session < 1 h 6%, 1–2 h 14%, 2–3 h 12%, 3–4 h 10%, > 4 h 58%

NR

Barker [37]

Retrospective cohort study

Single center

UK

2020.3.26.–2020.6.26

20 (10/10)

59 (55–63)/65 (55–71)

60/60

NIV (Int 90%, Con 70%)

30 m–2 h, repeated as many times as comfortable

ICU

NR

120 (IQR 76–161) m, 4 (IQR 1–7) sessions/patient

Jouffroy [6]

Retrospective cohort study

Multicenter

France

2020.2.20.–2020.4.24

379 (40/339)

59.5 (56–64)/62 (53–69)

90/75.2

HFNC

3–6 h/session, twice a day

ICU

NR

2.5 (IQR 1.6–3.4) d, 3 (IQR 2–5) sessions

Loureiro-Amigo [8]

Retrospective cohort study (SEMI-COVID-19)

Multicenter

Spain

2020.3.1.–2020.8.31

163 (60/103)

66.57 [59.2–72.4]/70.81 [60.6–74.2]

71.7/68.9

Venturi masks, rebreathing masks

NR

Ward

NR

NR

Prud’homme [44]

Retrospective cohort study

Multicenter

France

2020.3.20–2020.4.20

96 (48/48)

62 (11)/61 (18)

77.1/64.6

COT, HFNC

≥ 3 h/day during 3 consecutive days, 1 to 12 h/session

Non-ICU

3–8 h in 67%, > 5 h in 38% of intervention group

6.9 (SD 5.2) d

Shelhamer [9]

Retrospective cohort study

Single center

US

2020.3.25.–2020.5.2

261 (62/199)

60.0 (54.3–66.5)/66.0 (55.0–74.5)

67.7/60.3

IMV

≥ 16 h in the afternoon, supine position the following morning

Traditional ICU, Converted floor ICU

NR

NR

Stilma [45]

Retrospective cohort study

Multicenter

Netherlands

2020.3.1.–2020.6.1

734 (438/296)

Without indication for proning 65.0 (10.3)/64.2 (11.4) With indication for proning 62.6 (11.2)/66.6 (9.1)

72.6/73.3

IMV

NR

ICU

15.0 (IQR 10.5–21.0) h

3 (2–3) d

Tonelli [46]

Retrospective cohort study

Multicenter

Italy

2020.3.1.–2020.6.1

114 (38/76)

61 (32 − 75)/70 (33 − 80)

66/73

HFNC, CPAP, NIV

≥ 3 h before back to supine

ICU

NR

NR

Perez-Nieto [43]

Retrospective cohort study (APRONOX study)

Multicenter

Mexico, Ecuador

2020.5.1.–2020.6.12

827 (505/322)

53.4 (13.9)/55.8 (14.5)

73.3/71.4

LFNC, HFNC or a non-rebreather mask

≥ 2 h continuously

ICU 13% non-ICU 87%

NR

12 (IQR 8–24) h

Koike [40]

Retrospective study

Single center

Japan

Int: 2020.10.1.–2020.12.1. Cont: 2020.12.1.–2020.3.31

58 (27/31)

71 (55–77)/63 (49–70)

90/87

Simple O2, HFNC, NPPV

Discontinued if the patient developed intolerable respiratory distress, tachypnea > 35 bpm, or new unacceptable back pain during proning

ICU

2 (2–3) sessions/d 180 (120–240) m

13 (7–16) d

Altinay [36]

Retrospective study

Single center

Turkey

2020.3.15.–2020.6.15

48 (25/23)

62.4 (10.9)/72.6 (10.1)

44/39.1

Nonrebreather mask oxygen

18 h intermittently in a day

ICU

NR

NR

Numata [41]

Retrospective study

Multicenter

Japan

2020.7–2021.2

108 (54/54)

68 (58–76)/70 (59–79)

68.5/42.6

HFNC

As long as possible, at least 3 times a day and for at least 6 h per day

Severe COVID-19 patient unit

NR

NR

Chen [38]

Retrospective study

Single center

China

2020.1.9.–2020.4.10

40 (17/23)

69 (56–87)/72 (54–89)

64.7/78.3

IMV

NR

ICU

NR

NR

  1. RCT, randomized controlled trial; NRCT, nonrandomized controlled trial; HFNC, high-flow nasal cannula; MFNC, medium-flow nasal cannula; ICU, intensive care unit; ER, emergency room; IQR, interquartile range; SD, standard definition; NR, not reported; NIV, non-invasive ventilation; COT, conventional oxygen therapy; ECMO, extracorporeal membrane oxygenation; IMV, invasive mechanical ventilation; CPAP, continuous positive airway pressure; LFNC, low-flow nasal cannula; NPPV, non-invasive positive pressure ventilation