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Table 1 Physiological effects of flow settings during HFNC treatment for healthy volunteers

From: The effects of flow settings during high-flow nasal cannula support for adult subjects: a systematic review

Author/year

Study design

N

Position

Breathing pattern

Flow (L/min)

RR (breaths/min)

\(\Delta\)EELIglob (units)

VT (ml)

PEEP (cmH2O)

PTP (cmH2O s/min)

Others

Okuda et al., 2017 [15]

Randomized crossover

10

Supine 30°

Not specified

0

15.1 ± 2.1

NA

685.6 ± 236.6

NA

NA

MV: 10.1 ± 3.0

\(\Delta\) Pes:4.2 ± 1.9

30

11.6 ± 3.1

NA

929.8 ± 434.7

NA

NA

MV: 10.1 ± 3.9

\(\Delta\) Pes: 6.9 ± 2.9

50

11.1 ± 2.3

NA

968.8 ± 451.1

NA

NA

MV: 10.1 ± 4.0

\(\Delta\) Pes: 7.48 ± 3.1

Moigne et al. 2021 [38]

Prospective

10

Supine 30°

RMO

0

NA

NA

526 (503, 604)

NA

NA

NA

RMC

NA

NA

529 (480,726)

NA

NA

NA

HMO

NA

NA

540 (356, 663)

NA

NA

NA

HMC

 

NA

NA

417 (331, 553)

NA

NA

NA

RMO

30

NA

NA

688 (629, 844)

NA

NA

NA

RMC

NA

NA

815 (511, 959)

NA

NA

NA

HMO

NA

NA

633 (538, 678)

NA

NA

NA

HMC

NA

NA

516 (405, 698)

NA

NA

NA

RMO

60

NA

NA

753 (650, 1208)

NA

NA

NA

RMC

NA

NA

913 (680, 1166)

NA

NA

NA

HMO

NA

NA

664 (634, 1046)

NA

NA

NA

HMC

NA

NA

696 (351, 896)

NA

NA

NA

Plotnikow et al. 2018 [19]

Prospective

16

Supine

RMC

0

16 ± 2.6

Baseline

NA

NA

NA

NA

Setting 45°

15 ± 3.6

1.05 (0.72, 1.34)

NA

NA

NA

NA

30

11 ± 3.6

1.12 (0.8, 2.01)

NA

NA

NA

NA

50

9 ± 2.8

1.44 (1.05, 2.16)

NA

NA

NA

NA

Ritchie et al. 2011 [13]

Prospective

10

Not specified

RMC

30

8.4 (4,15)b

NA

NA

2.5 (0.8, 4.7)b

NA

NA

40

6.8 (4,7)b

NA

NA

4.0 (2.4, 7.8)b

NA

NA

50

7.6 (4.9, 8.0)b

NA

NA

5.2 (3.5, 7.0)b

NA

NA

RMO

30

10 (6.9, 19)b

NA

NA

0.1 (− 0.2, 1)b

NA

NA

40

9.9 (5.5, 19)b

NA

NA

0.8 (− 0.8, 1.2)b

NA

NA

50

11.3 (7, 21.5)b

NA

NA

1.1 (− 0.9, 2.4)b

NA

NA

Parke et al. 2015 [18]

Prospective

15

Not specified

RMC

0

13.8 (9.8, 17.9)b

Baseline

NA

0.5 ± 0.3a

NA

NA

30

8.9 (5.8,11.9)b

0.5 ± 0.3a,c

NA

2.7 ± 0.7a

NA

NA

40

7.7 (4.5, 11.1)b

0.5 ± 0.4a,c

NA

3.8 ± 0.8a

NA

NA

50

7.3 (4.4, 10.3)b

0.7 ± 0.5a,c

NA

4.9 ± 1.1a

NA

NA

60

7.4 (3.8, 11.1)b

0.9 ± 0.6a,c

NA

6.1 ± 1.4a

NA

NA

70

6.9 (3.2,10.7)b

1.0 ± 0.8a,c

NA

7.6 ± 1.5a

NA

NA

80

7.7 (3.6, 11.8)b

1.2 ± 0.8a,c

NA

9 ± 1.9a

NA

NA

90

6.9 (3.3, 10.4)b

1.4 ± 0.8a,c

NA

10.1 ± 2.1a

NA

NA

100

7.5 (2.6,12.5)b

1.6 ± 0.8a,c

NA

11.9 ± 2.7a

NA

NA

Delorme et al. 2020 [16]

Randomized crossover

10

Semi-recumbent position

RMC

0

16 (15, 18)

NA

337 (272, 443)

NA

NA

Comfort: 10 (10, 10)

VA: 3,343; VD/VT: 45

Dead space ventilation: 2431

Dead space washout: 0

5

13 (12, 15)

NA

358 (287, 458)

NA

NA

Comfort: 9 (6, 10)

VA: 3,343; VD/VT: 39

Dead space ventilation: 1823

Dead space washout: 863

20

10 (10, 13)

NA

448 (345, 580)

NA

NA

Comfort: 10 (9, 10)

VA: 3,343; VD/VT: 38

Dead space ventilation: 1546

Dead space washout: 1140

40

9 (8, 12)

NA

450 (307, 480)

NA

NA

Comfort: 9 (7, 10)

VA: 3,343; VD/VT: 34

Dead space ventilation: 1276

Dead space washout: 1191

60

8 (7, 10)

NA

520 (470, 626)

NA

NA

Comfort: 8 (8, 9)

VA: 3,343; VD/VT: 31

Dead space ventilation: 1276

Dead space washout: 1160

Garofalo et al. 2019 [20]

Prospective

14

Semi-recumbent position

RMC

0

15 (14,16)

NA

NA

0b

NA

Comfort: 10 (10,10

PEIP: 0b

30

15 (14,16)

NA

NA

2.8 (0.8, 7.8)b

NA

Comfort: 10 (10,10)

PEIP: 0.7 (0.3, 0.7)b

40

14 (12,14)

NA

NA

6 (3.2, 11)b

NA

Comfort: 10 (10,10)

PEIP: 0.8 (0.6, 1.3)b

50

12 (12, 13)

NA

NA

7.6 (4.1, 12)b

NA

Comfort: 9 (9,10)

PEIP: 1.1 (0.7, 1.5)b

RMO

0

NA

NA

NA

0b

NA

PEIP: 0b

30

NA

NA

NA

0.7 (0.5, 2.5)b

NA

PEIP: 0.1 (0, 0.4)b

40

NA

NA

NA

1.7 (0.3, 5)b

NA

PEIP: 0.3 (0, 0.3)b

50

NA

NA

NA

2.3 (0.7, 3.9)b

NA

PEIP: 0.3 (0, 0.6)b

Vieira et al. 2022 [17]

Randomized crossover

10

Not specified

RMC

20

9.0 (7.3, 11.7)

90 (43, 160)

458 (364, 557)

1.2 (0.8, 1.3)

94.1 (79.3, 114.5)

MV: 4.4 (3.2, 4.9 Ti:Ttot: 0.31 ± 0.05

40

7.2 (5.9, 9.9)

160 (96, 178)

447 (368, 787)

3.6 (2.8, 4.6)

112.5 (86, 127)

MV: 3.9 (2.7, 4.2)

Ti:Ttot: 0.26 ± 0.06

60

8.5 (5.0, 12.4)

230 (165, 344)

431 (229, 760)

6.78 (5.0, 7.9)

124.8 (72, 138)

MV: 3.2 (2. 7,4.6)

Ti:Ttot: 0.23 ± 0.07

RMO

20

11.6 (9.4, 14.2)

70 (15, 138)

421 (341, 517)

0.13 (0.06, 0.2)

70.0 (50.6, 103)

MV: 5.2 (4.3, 6.1)

Ti:Ttot: 0.33 ± 0.09

40

11.6 (8.9, 12.6)

92 (36, 151)

459 (388, 502)

0.55 (0.3, 0.7)

78.5 (66, 102)

MV:5.2 (4.1–6.7)

Ti:Ttot: 0.3 ± 0.07

60

12.7 (10.4,15.8)

202 (115, 233)

504 (385, 657)

0.83 (0.6, 1.2)

90.4 (70, 111)

MV: 6.0 (4.8, 9.1)

Ti:Ttot: 0.3 ± 0.07

Groves et al. 2007 [39]

Prospective

10

Setting position

RMC

0

NA

NA

NA

0.8 (0.5, 1.3)

NA

MIP: − 1.1 (− 2.0, − 0.6)

10

NA

NA

NA

1.7 (1.2, 2.3)

NA

MIP: − 0.8 (− 1.1, − 0.3)

20

NA

NA

NA

2.9 (2.2, 2.7)

NA

MIP: − 0.2 (− 0.9, 0.2)

40

NA

NA

NA

5.5 (4.1, 7.2)

NA

MIP:1.1 (− 0.1, 1.9)

60

NA

NA

NA

7.4 (5.4, 8.8)

NA

MIP: 1.6 (0.8, 2.7)

RMO

0

NA

NA

NA

0.3 (0.3, 0.5)

NA

MIP: − 0.6 (− 1.1, − 0.4)

10

NA

NA

NA

0.7 (0.6, 0.9)

NA

MIP: − 0.2 (− 0.8, 0.1)

20

NA

NA

NA

1.4 (1.3, 1.8)

NA

MIP: − 0.2 (− 0.9, 0.1)

40

NA

NA

NA

2.2 (2.0, 2.5)

NA

MIP:0.1 (− 0.2, 0.4)

60

NA

NA

NA

2.7 (2.4, 3.1)

NA

MIP:0.5 (0.2, 0.7)

Möller et al. 2017 [40]

Randomized crossover

10

Not specified

RMC

15

NA

NA

NA

NA

NA

Clearance half-time in trachea: 23.73 ± 6.63

30

NA

NA

NA

NA

NA

Clearance half-time in trachea:14.3 ± 13.43

45

NA

NA

NA

NA

NA

Clearance half-time in trachea:10.53 ± 9.85

  1. RR respiratory rate, \(\Delta\) EELIglob global change in end-expiratory lung impedance measured by electrical impedance tomography, VT tidal volume, PEEP positive end-expiratory pressure measured by pharyngeal or tracheal catheter, MV minute ventilation (L/min), PTP esophageal pressure-time product per minute (cmH2O·s/min), \(\Delta\) Pes esophageal pressure swings (cmH2O), RMO regular respiratory rate breathing with mouth opened, RMC regular respiratory rate breathing with mouth closed, HMO high respiratory rate breathing with mouth opened, HMC high respiratory rate breathing with mouth closed. Ti:Ttot duty time (sec), VA alveolar ventilation (ml/min), VD/VT percentage of dead space (%), Dead space ventilation (ml/min), Dead space washout (ml/min), Clearance half-time in trachea (sec), Comfort respiratory comfort level measured by a scale, PEIP positive end-inspiratory pressure, MIP mean inspiratory pressure (cmH2O); NA not available
  2. aValues are calculated
  3. bValues extracted from graph using graph reader Website
  4. cValues are reported as % of change from baseline