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Table 1 Patients characteristics at low and high positive end-expiratory pressure

From: Intracranial pressure responsiveness to positive end-expiratory pressure is influenced by chest wall elastance: a physiological study in patients with aneurysmal subarachnoid hemorrhage

 

Low PEEP (5 cmH2O)

High PEEP (15 cmH2O)

p

ICP and hemodynamic parameters

 ICP (mmHg)

4.0 (2.0–10.0)

7.0 (5.8–11.0)

<  0.001

 MAP (mmHg)

81.0 (75.6–92.1)

76.2 (67.4–90.0)

0.002

 CPP (mmHg)

74.7 (69.6–86.8)

68.7 (60.6–82.7)

<  0.001

 CVP (mmHg)

8.0 (5.0–10.0)

12.0 (10.0–14.0)

<  0.001

Respiratory mechanics parameters

 VT (mL/kg)

7.7 (7.1–8.3)

7.7 (7.1–8.2)

0.304

 ∆PAW (cmH2O)

6.8 (6.5–9.5)

9.5 (7.8–10.9)

<  0.001

 ∆PCW (cmH2O)

2.7 (1.4–3.1)

2.7 (2.7–4.1)

0.003

 ∆PL (cmH2O)

4.8 (4.1–5.8)

6.8 (4.1–8.2)

0.003

 ERS (cmH2O/L)

15.3 (12.5–18.6)

20.1 (16.2–23.9)

<  0.001

 ECW (cmH2O/L)

5.5 (2.9–6.9)

6.2 (5.4–10.2)

0.001

 EL (cmH2O/L)

9.4 (7.9–12.1)

12.9 (8.5–15.6)

0.004

 ECW/ERS ratio

0.33 (0.25–0.43)

0.40 (0.29–0.47)

0.247

 Resistance (cmH2O/L/sec)

13.0 (9.9–14.2)

12.6 (10.1–15.0)

0.894

Blood gas analysis parameters

 pH

7.40 (7.36–7.44)

7.42 (7.38–7.45)

0.951

 PaO2 (mmHg)

105.5 (78.0–153.5)

115.5 (78.4–163.5)

0.058

 PaO2/FiO2

264 (180–384)

289 (185–388)

0.061

 PaCO2 (mmHg)

35.3 (32.6–36.7)

35.3 (33.6–38.2)

0.052

 PETCO2 (mmHg)

29.5 (27.8–31.2)

29.0 (25.8–30.3)

0.003

 VDalv/VT (%)

13.2 (8.5–19.9)

18.8 (11.9–27.7)

<  0.001

  1. Data are shown as median (interquartile range)
  2. ICP intracranial pressure; MAP mean arterial pressure; CPP cerebral perfusion pressure; CVP central venous pressure; VT tidal volume; ∆PAW airway driving pressure; ∆PCW chest wall driving pressure; ∆PL: transpulmonary driving pressure; ERS respiratory system elastance; ECW chest wall elastance; EL lung elastance; PETCO2 end-tidal carbon dioxide partial pressure; VDalv/VT: ratio of the alveolar dead space to the tidal volume