Case report: (Pre)syncopal symptoms associated with a negative internal jugular venous pressure

TY - JOUR

T1 - Case report: (Pre)syncopal symptoms associated with a negative internal jugular venous pressure

AU - Olesen, Niels D

AU - van Lieshout, Johannes J

AU - Fisher, James P

AU - Seifert, Thomas

AU - Nielsen, Henning B

AU - Secher, Niels H

PY - 2014

Y1 - 2014

N2 - A siphon is suggested to support cerebral blood flow but appears not to be established because internal jugular venous (IJV) pressure is close to zero in upright humans. Thus, in eleven young healthy males, IJV pressure was 9 ± 1 mmHg (mean ± SE) when supine and fell to 3 ± 1 mmHg when seated, and middle cerebral artery mean blood velocity (MCA Vmean; P < 0.007) and the near-infrared spectroscopy-determined frontal lobe oxygenation (ScO2; P = 0.028) also decreased. Another subject, however, developed (pre)syncopal symptoms while seated and his IJV pressure decreased to -17 mmHg. Furthermore, his MCA Vmean decreased and yet within the time of observation ScO2 was not necessarily affected. These findings support the hypothesis that a negative IJV pressure that is a prerequisite for creation of a siphon provokes venous collapse inside the dura, and thereby limits rather than supports CBF.

AB - A siphon is suggested to support cerebral blood flow but appears not to be established because internal jugular venous (IJV) pressure is close to zero in upright humans. Thus, in eleven young healthy males, IJV pressure was 9 ± 1 mmHg (mean ± SE) when supine and fell to 3 ± 1 mmHg when seated, and middle cerebral artery mean blood velocity (MCA Vmean; P < 0.007) and the near-infrared spectroscopy-determined frontal lobe oxygenation (ScO2; P = 0.028) also decreased. Another subject, however, developed (pre)syncopal symptoms while seated and his IJV pressure decreased to -17 mmHg. Furthermore, his MCA Vmean decreased and yet within the time of observation ScO2 was not necessarily affected. These findings support the hypothesis that a negative IJV pressure that is a prerequisite for creation of a siphon provokes venous collapse inside the dura, and thereby limits rather than supports CBF.

U2 - 10.3389/fphys.2014.00317

DO - 10.3389/fphys.2014.00317

M3 - Journal article

C2 - 25191276

SN - 1664-042X

VL - 5

SP - 1

EP - 5

JO - Frontiers in Physiology

JF - Frontiers in Physiology

M1 - 317

ER -