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Table 1 Mean inspiratory airway pressure (Paw mean), expiratory pressure time product (PTPexp), and maximum CO2 concentration (CO2 max) within the helmet at a respiratory rate of 15 and 30 breaths per minute

From: High flow biphasic positive airway pressure by helmet – effects on pressurization, tidal volume, carbon dioxide accumulation and noise exposure

Normal lung condition

Respiratory rate

15 breaths/minute

30 breaths/minute

Δ pressure

5 cmH20

15 cmH20

5 cmH20

15 cmH20

Effort

low

high

low

high

low

high

low

high

Paw mean (cmH2O)

HF-BiPAP

10.2 ± 0.3

10.4 ± 0.4

15.2 ± 0.4

14.7 ± 0.3

10.7 ± 0.2

11.1 ± 0.5

15.1 ± 0.5

15.0 ± 0.2

 

BiVent

10.1 ± 0.1

9.8 ± 0.1

14.8 ± 0.3

14.5 ± 0.1

10.6 ± 0.2

9.8 ± 0.2

15.0 ± 0.3

15.2 ± 0.3

 

PSV

8.7 ± 0.2

8.4 ± 0.2

11.9 ± 0.6

11.6 ± 0.7

9.6 ± 0.4

8.7 ± 0.2

12 ± 0.4

13.2 ± 0.9

PTPexp. (cmH20/sec)

HF-BiPAP

4.3 ± 1.1

10.6 ± 3.2

13.9 ± 1.1

21.4 ± 1.7

3.1 ± 0.4

7.4 ± 1.4

2.7 ± 0.7

9.2 ± 1.2

 

BiVent

4.6 ± 0.5

5.7 ± 0.3

18.7 ± 0.7

21.7 ± 0.8

2.8 ± 0.2

2.9 ± 0.8

9.8 ± 0.6

9.4 ± 0.8

 

PSV

1.9 ± 0.5

3.2 ± 0.7

6.7 ± 0.4

7 ± 0.6

1.9 ± 0.9

2.5 ± 0.3

4.4 ± 4.9

2.2 ± 0.7

CO 2 max (%)

HF-BiPAP

0.1 ± 0

0.1 ± 0

0.1 ± 0

0.1 ± 0

0.1 ± 0

0.1 ± 0

0.2 ± 0

0.2 ± 0

 

BiVent

4.2 ± 0

4.0 ± 0.1

2.1 ± 0

3.2 ± 0

3.9 ± 0.1

2.6 ± 0

1.9 ± 0

1.4 ± 0.2

 

PSV

0.2 ± 0

1.2 ± 0

1 ± 0

0.8 ± 0

0.9 ± 0

0.7 ± 0

1 ± 0.2

0.5 ± 0

Obstructive lung condition

Respiratory rate

15 breaths/minute

30 breaths/minute

Δ pressure

5 cmH20

15 cmH20

5 cmH20

15 cmH20

Effort

low

high

low

high

low

high

low

high

Paw mean (cmH2O)

HF-BiPAP

10.4 ± 0.1

9.9 ± 0.1

14.1 ± 0.1

14 ± 0.1

10.2 ± 0.1

10.7 ± 0

14.6 ± 0.1

15.6 ± 0.2

 

BiVent

9.9 ± 0.2

10.1 ± 0.1

15.5 ± 0.1

14.9 ± 0

9.9 ± 0.1

10.3 ± 0

15.3 ± 0.2

15.8 ± 0.2

 

PSV

9.3 ± 0.1

9.1 ± 0

11.6 ± 0.1

10.6 ± 0.1

9.1 ± 0.1

9.3 ± 0.1

11.2 ± 0.5

12.3 ± 0.1

PTPexp. (cmH20/sec)

HF-BiPAP

9 ± 0.5

3.4 ± 0.6

15.9 ± 1.1

19.4 ± 0.9

7.7 ± 0.9

5.7 ± 0.8

11.1 ± 2.3

16.9 ± 3.5

 

BiVent

6 ± 0.5

7.4 ± 0.6

18.5 ± 0.7

19.5 ± 0.3

5.9 ± 0.4

6.1 ± 0.1

9.4 ± 0.3

8 ± 0.4

 

PSV

3.7 ± 0.7

2.4 ± 0.3

3.2 ± 0.9

2.2 ± 0.3

3.8 ± 0.4

5.5 ± 0.3

2.5 ± 2

4 ± 0.3

CO 2 max (%)

HF-BiPAP

0.1 ± 0

0.1 ± 0

0.2 ± 0

0.2 ± 0

0.1 ± 0

0.1 ± 0

0.2 ± 0

0.2 ± 0

 

BiVent

2.5 ± 0

3 ± 0.1

2.8 ± 0

3.2 ± 0

4.8 ± 0

4.8 ± 0

2.3 ± 0

2.2 ± 0

 

PSV

0.2 ± 0

0.9 ± 0

0.1 ± 0

0.6 ± 0

0.4 ± 0

0.4 ± 0

0.1 ± 0

0.2 ± 0

Restrictive lung condition

Respiratory rate

15 breaths/minute

30 breaths/minute

Δ pressure

5 cmH20

15 cmH20

5 cmH20

15 cmH20

Effort

low

high

low

high

Low

high

low

high

Paw mean (cmH2O)

HF-BiPAP

9.9 ± 0.3

10.7 ± 0.3

14.6 ± 0.2

14.3 ± 0.3

10.1 ± 0.2

11.5 ± 0.3

14.4 ± 0.1

14.9 ± 0.1

 

BiVent

9.9 ± 0.2

9.9 ± 0.1

14.9 ± 0.1

14.9 ± 0.2

10.0 ± 0.3

9.8 ± 0.1

16.3 ± 0.2

16.3 ± 0.2

 

PSV

11.6 ± 0.6

9.3 ± 0.1

10.1 ± 0.1

9.8 ± 0.1

10.2 ± 0.3

9.1 ± 0

15.9 ± 0.4

11.3 ± 0.1

PTP exp. (cmH20/sec)

HF-BiPAP

6.4 ± 2.9

10.1 ± 3

13.8 ± 1.5

15.0 ± 9.6

3.3 ± 1

4.8 ± 1.1

9.5 ± 2.4

11.7 ± 1.3

 

BiVent

5.4 ± 1.7

6.6 ± 1

9.0 ± 0.6

12.1 ± 0.6

3.0 ± 0.3

2.5 ± 0.3

6.6 ± 0.5

8.9 ± 0.7

 

PSV

5.2 ± 0.5

4.5 ± 0.7

3.1 ± 0.4

3.3 ± 0.4

3.0 ± 0.8

2.5 ± 0.3

5.6 ± 0.8

4.9 ± 0.6

CO 2 max (%)

HF-BiPAP

0.1 ± 0

0.1 ± 0

0.2 ± 0

0.2 ± 0

0.1 ± 0

0.1 ± 0

0.1 ± 0

0.3 ± 0

 

BiVent

4.7 ± 0

4.7 ± 0.1

4.2 ± 0

4.4 ± 0.1

4.1 ± 0

3.0 ± 0.1

3.8 ± 0

2.9 ± 0

 

PSV

0.4 ± 0

0.8 ± 0

0.3 ± 0

0.4 ± 0

0.4 ± 0

0.7 ± 0

1.0 ± 0.1

0.6 ± 0

  1. Measurements were made in normal (compliance 90 ml/cmH2O, resistance 3 cmH2O/l/s), restrictive (compliance 30 ml/cmH2O, resistance 3 cmH2O/l/s) and obstructive (compliance 90 ml/cmH2O, resistance 15 cmH2O/l/s) lung conditions, during varying delta pressure (5 and 15 cmH2O) and inspiratory efforts (low: 2.5 cmH2O, high: 10 cmH2O) at a set positive end-expiratory pressure of 8 cmH2O.
  2. HF-BiPAP = high flow biphasic positive airway pressure ventilation; BiVent = biphasic positive airway pressure delivered by a ventilator; PSV = pressure support ventilation delivered by a ventilator.