Table 1: Systemic and cerebral circulatory and jugular venous responses to continuous positive airway pressure (CPAP) at different body positions.

PositionSupineProneProne w/head turned
CPAP 0 cmH2O 10 cmH2O 0 cmH2O10 cmH2O 0 cmH2O10 cmH2O

ΔMCA 𝑉 mean (%)0 ± 0−6.8 ± 2.5−2.0 ± 2.4−4.4 ± 2.8−3.9 ± 2.6−8.6 ± 3.2
ΔSV (%)0 ± 0−3.0 ± 0.8−5.4 ± 1.5*−9.3 ± 1.3−5.7 ± 1.6*−9.0 ± 1.4
ΔCO (%)0 ± 0−3.4 ± 1.4−2.3 ± 1.9*−7.2 ± 2.4−2.6 ± 1.6*−6.4 ± 1.7
HR (bpm)59 ± 259 ± 261 ± 261 ± 262 ± 261 ± 2
MAP (mmHg)78 ± 279 ± 280 ± 3*84 ± 384 ± 3*87 ± 2
𝐴 jugR(cm2)1.0 ± 0.51.4 ± 0.51.9* ± 0.82.1 ± 0.90.9* ± 1.11.2 ± 1.0
𝐴 jugL (cm2)0.7 ± 0.40.9 ± 0.51.3* ± 0.71.2 ± 0.61.1* ± 0.61.2 ± 0.6

Changes in middle cerebral artery mean blood velocity (ΔMCA 𝑉 mean), mean arterial pressure (MAP), cardiac stroke volume (ΔSV), cardiac output (ΔCO), heart rate (HR), and right and left internal jugular vein cross-sectional area ( 𝐴 jugR, 𝐴 jugL) during CPAP 0 cmH2O and 10 cmH2O. *Significant different from supine, 𝑃 < 0 . 0 5 . Significant different from 0 cmH2O CPAP.