Table 2.
Effects of head elevations of 30°, 15°, and 0° (flat) on systemic and brain variables during the three experiments (exp1, exp2, and exp3) after admission to the ICU
| Variables | Exp1 | Exp2 | Exp3 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Head posture (°) | 30 | 15 | 0 | 30 | 15 | 0 | 30 | 15 | 0 |
| MAP, right atrium (mm Hg) | 91 (83–98) | 90 (81–94) | 90 (82–97) | 85 (80–101) | 85 (79–102) | 83 (76–101) | 86 (81–100) | 83 (81–100) | 83 (80–98) |
| MAP, Monro (mm Hg) | 82 (75–94) | 83 (79–94) | 90 (81–100) | 81 (72–92) | 81 (75–99) | 83 (77–99) | 80 (72–93) | 81 (75–95) | 83 (80–98) |
| ICP (mm Hg) | 15 (11–18) | 15 (12–22) | 22 (16–26) | 15 (10–18) | 16 (13–21) | 18 (17–24) | 13 (9–18) | 16 (12–22) | 20 (17–26) |
| CPP (mm Hg) | 70 (60–75) | 70 (60–75) | 70 (60–75) | 65 (63–75) | 65 (64–75) | 65 (63–71) | 65 (59–80) | 69 (59–80) | 66 (59–80) |
| PbtO2 (mm Hg) | 22 (17–28) | 24 (18–30) | 25 (21–31) | 25 (22–30) | 25 (23–29) | 25 (23–29) | 27 (25–30) | 27 (25–30) | 28 (26–31) |
| FVm (cm/s) | 58 (47–87) | 58 (51–82) | 60 (52–94) | 73 (63–109) | 79 (65–101) | 80 (71–111) | 74 (64–83) | 74 (59–91) | 71 (65–91) |
| FVd (cm/s) | 36 (27–51) | 35 (30–58) | 35 (29–64) | 41 (33–65) | 47 (35–69) | 52 (43–74) | 48 (36–58) | 43 (39–56) | 43 (38–56) |
| PI | 1.1 (0.8–1.5) | 1.1 (0.7–1.6) | 1.0 (0.7–1.3) | 1.2 (0.5–1.6) | 1.1 (0.5–1.8) | 1.0 (0.6–1.6) | 1.1 (0.6–1.7) | 1.1 (0.6–1.7) | 1.2 (0.6–1.8) |
| PaO2 (mm Hg) | 104 (93–122) | 105 (95–124) | 106 (91–119) | 98 (82–116) | 97 (82–119) | 97 (82–120) | 107 (101–118) | 112 (99–124) | 114 (95–132) |
| PaCO2 (mm Hg) | 38 (35–40) | 37 (34–39) | 37 (35–38) | 39 (37–41) | 38 (37–42) | 38 (36–42) | 37 (35–41) | 38 (35–41) | 38 (35–41) |
| Hemoglobin (g/dl) | 11 (10–12) | 11 (10–12) | 11 (10–12) | 11 (10–12) | 11 (10–12) | 11 (9–12) | 10 (9–11) | 10 (9–11) | 10 (9–11) |
| Temperature (°C) | 37 (35–37) | 36 (35–37) | 36 (35–37) | 37 (36–38) | 37 (36–37) | 37 (36–37) | 37 (36–38) | 37 (36–38) | 37 (36–38) |
| Norepinephrine (μg/kg/h) | 16 (5–31) | 13 (6–31) | 12 (6–26) | 21 (7–33) | 19 (7–31) | 12 (5–43) | 16 (6–26) | 13 (5–26) | 15 (5–26) |
Experiments were performed 24 h after admission to the ICU (exp1), and then repeated 24 h (exp2) and 96 h later (exp3). Data are expressed as median (25–75th percentile). See text for statistically significant results
CPP, cerebral perfusion pressure; FVd, diastolic blood flow velocity; FVm, mean blood flow velocity; ICP, intracranial pressure; ICU, intensive care unit; MAP, mean arterial pressure; PaCO2, partial pressure of carbon dioxide, arterial; PaO2, partial pressure of oxygen, arterial; PbtO2, brain tissue oxygenation pressure; PI, pulsatility index