|
Parameter
|
Mode
|
PEEPe0%
|
PEEPe40%
|
PEEPe80%
|
PEEPe120%
|
P*
|
|---|
|
P̅aw (cm H2O)
|
PSP
|
10.9 (10.3, 11.3)
|
12.9 (12.3, 13.3)a
|
15.0 (14.8, 16.3)ab
|
17.4 (16.8, 18.3)abc
|
<0.001
|
| |
PSN
|
11.4 (10.8, 11.6)x
|
13.1 (12.1, 13.3)a
|
15.2 (14.4, 16.4)ab
|
17.5 (16.9, 18.6)abc
| |
|
PEEPe (cm H2O)
|
PSP
|
0.6 (0.4, 1.0)z
|
2.3 (2.2, 2.5)az
|
4.7 (4.2, 5.4)ab
|
7.1 (6.5, 7.5)abc
|
<0.001
|
| |
PSN
|
1.0 (0.5, 1.2)x
|
2.5 (2.3, 3.0)a
|
4.7 (4.4, 5.4)ab
|
7.0 (6.6, 7.5)abc
| |
|
VT (ml/kg)
|
PSP
|
5.4 (4.2, 6.7)z
|
5.8 (4.9, 6.8)z
|
5.9 (5.0, 6.6)abz
|
5.5 (5.2, 7.0)ab
|
<0.001
|
| |
PSN
|
4.6 (4.3, 5.8)x
|
5.0 (4.4, 5.9)a
|
4.9 (4.6, 6.7)ab
|
5.0 (4.6, 7.1)abc
| |
|
BfN (breaths/min)
|
PSP
|
20.2 (17.7, 29.3)z
|
20.5 (17.6, 28.9)z
|
21.5 (17.2, 26.9)z
|
20.9 (17.9, 30.3)
|
0.003
|
| |
PSN
|
26.4 (17.3, 30.7)x
|
24.4 (17.2, 33.2)
|
22.1 (18.1, 31.5)ab
|
20.5 (16.0, 29.6)ab
| |
|
VE (l/min)
|
PSP
|
6.05 (5.25, 8.13)z
|
6.54 (5.47, 8.91)a
|
7.05 (5.67, 9.02)a
|
7.07 (5.70, 11.62)a
|
<0.001
|
| |
PSN
|
6.43 (5.31, 9.54)x
|
6.92 (5.53, 9.98)a
|
7.14 (5.50, 9.20)a
|
7.79 (5.74, 9.66)a
| |
|
VT/TiP (ml/s)
|
PSP
|
424 (390, 446)z
|
429 (389, 472)
|
436 (386, 458)
|
438 (396, 466)
|
0.013
|
| |
PSN
|
414 (302, 491)x
|
443 (334, 508)a
|
452 (338, 526)a
|
479 (361, 513)a
| |
|
TiN (s)
|
PSP
|
0.90 (0.72, 1.03)
|
0.90 (0.74, 0.94)
|
0.84 (0.73, 0.98)
|
0.87 (0.69, 0.93)
|
NS
|
| |
PSN
|
0.84 (0.71, 0.96)
|
0.77 (0.71, 0.86)
|
0.81 (0.74, 0.86)
|
0.84 (0.73, 0.95)
| |
|
TeN (s)
|
PSP
|
2.12 (1.43, 2.60)z
|
2.22 (1.45, 2.93)
|
2.17 (1.58, 3.14)z
|
2.13 (1.53, 2.58)
|
0.050
|
| |
PSN
|
1.76 (1.16, 2.66)x
|
2.09 (1.20, 2.77)a
|
2.02 (1.24, 2.59)a
|
2.14 (1.33, 2.92)a
| |
|
TiN/TtN (%)
|
PSP
|
29.6 (27.5, 36.5)
|
28.7 (24.5, 39.0)
|
27.1 (23.4, 36.3)
|
26.1 (23.0, 36.7)
|
NS
|
| |
PSN
|
31.4 (25.6, 37.8)
|
29.4 (23.9, 38.5)
|
29.7 (24.6, 38.3)
|
30.6 (22.5, 36.8)
| |
|
pH
|
PSP
|
7.36 (7.33, 7.41)
|
7.38 (7.36, 7.41)a
|
7.39 (7.34, 7.44)a
|
7.39 (7.33, 7.42)a
|
0.009
|
| |
PSN
|
7.37 (7.33, 7.40)x
|
7.39 (7.34, 7.42)a
|
7.38 (7.32, 7.45)a
|
7.38 (7.35, 7.42)a
| |
|
PaCO2 (mm Hg)
|
PSP
|
37.9 (32.0, 48.6)
|
35.9 (31.2, 46.1)
|
36.3 (32.1, 46.8)
|
33.5 (32.9, 43.3)
|
NS
|
| |
PSN
|
40.4 (29.8, 47.5)
|
34.2 (31.2, 42.1)
|
35.4 (32.8, 41.8)
|
36.5 (30.7, 41.9)
| |
|
PaO2 (mm Hg)
|
PSP
|
84.0 (79.9, 113.9)
|
94.8 (84.9, 116.7)
|
98.7 (90.0, 124.3)
|
103.9 (84.0, 117.2)
|
NS
|
| |
PSN
|
89.7 (83.5, 122.9)
|
106.6 (81.2, 124.1)
|
99.4 (91.0, 123.9)
|
109.0 (95.0, 125.8)
| |
|
MAP (mm Hg)
|
PSP
|
89.0 (76.0, 92.7)
|
88.0 (77.0, 92.7)
|
86.7 (77.7, 91.7)
|
89.3 (79.0, 91.3)
|
NS
|
| |
PSN
|
88.3 (75.7, 91.3)
|
88.0 (75.3, 90.4)
|
88.7 (78.3, 91.0)
|
86.7 (80.3, 92.0)
| |
- Values are presented as median (25–75 % interquartile range). *P values for one-way repeated measures analysis of variance on ranks for the eight conditions: within the same mode: a
P <0.05 compared to PEEPe0%; b
P <0.05 compared to PEEPe40%; c
P <0.05 compared to PEEPe80%. Between modes: z
P <0.05 compared to PSN at same PEEPe. Comparison of PSN zero PEEP to PSP optimal PEEP: x
P <0.05 PEEPe0% at PSN vs. PEEPe80% at PSP. PSP pneumatically triggered and cycled-off pressure support, PSN neurally triggered and cycled-off pressure support ventilation, P̅aw mean airway pressure (including PEEPe), PEEPe extrinsic PEEP, VT tidal volume, VE minute ventilation, TiN neural inspiratory time, TeN neural expiratory time, Ti/TtotN neural duty cycle, BfN neural breathing frequency, PEEPiSTAT static intrinsic positive end-expiratory pressure, MAP mean arterial pressure, NS not significant
