@article{ref1,
title="Gravitational valves in supine patients with ventriculo-peritoneal shunts",
journal="Acta neurochirurgica",
year="2009",
author="Deininger, Martin H. and Weyerbrock, Astrid",
volume="151",
number="6",
pages="705-709; discussion 709",
abstract="BACKGROUND: In the subgroup of bedridden hydrocephalic patients with ventriculo-peritoneal shunts and gravitational valves, we occasionally observed persisting hydrocephalic complaints even when mechanical or infection-related obstruction was excluded. METHODS: To investigate the cause of these hydrocephalic symptoms, in vitro and in vivo analyses were used to determine valve opening, intra-abdominal and hydrostatic pressure of an Aesculap-Miethke 10/40 cm H2O gravitational valve at different angles of upper body and head inclination. FINDINGS: Since hydrostatic pressure is lacking, the resulting intra-ventricular pressures are shown to peak up to 27 cm H2O in supine patients with head, but not upper body inclined. CONCLUSIONS: We conclude that in the subgroup of bedridden patients with ventriculo-peritoneal shunts and gravitational valves, upright posture is a prerequisite for proper cerebrospinal fluid drainage.<p /><p>Language: en</p>",
language="en",
issn="0001-6268",
doi="10.1007/s00701-009-0291-8",
url="http://dx.doi.org/10.1007/s00701-009-0291-8"
}