title: Efficacy of reductive ventricular osmotherapy in a swine model of traumatic brain injury.
abstract: BACKGROUND
  The presence of osmotic gradients in the development of cerebral edema and the effectiveness of osmotherapy are well recognized. A modification of ventriculostomy catheters described in this article provides a method of osmotherapy that is not currently available. The reductive ventricular osmotherapy (RVOT) catheter removes free water from ventricular cerebrospinal fluid (CSF) by incorporating hollow fibers that remove water vapor, thereby providing osmotherapy without increasing osmotic load.
  
  
  OBJECTIVE
  To increase osmolarity in the ventricular CSF through use of RVOT in vivo.
  
  
  METHODS
  Twelve Yorkshire swine with contusional injury were randomized to external ventricular drainage (EVD) or RVOT for 12 hours. MR imaging was obtained. Serum, CSF, and brain ultrafiltrate were analyzed. Histology was compared using Fluor-Jade B and hematoxylin and eosin (H & E) stains.
  
  
  RESULTS
  With RVOT, CSF osmolality increased from 292 ± 2.7 to 345 ± 8.0 mOsmol/kg (mean ± SE, P = 0.0006), and the apparent diffusion coefficient (ADC) in the injury region increased from 0.735 ± 0.047 to 1.135 ± .063 (P = 0.004) over 24 hours. With EVD controls, CSF osmolarity and ADC were not significantly changed. Histologically, all RVOT pigs showed no evidence of neuronal degeneration (Grade 1/4) compared to moderate degeneration (Grade 2.6 ± .4/4) seen in EVD treated animals (P = 0.02). The difference in intracranial pressure (ICP) by area under the curve approached significance at P = .065 by Mann Whitney test.
  
  
  CONCLUSIONS
  RVOT can increase CSF osmolarity in vivo after experimental traumatic brain injury (TBI). In anticipated clinical use, only a slight increase in CSF osmolarity may be required to reduce cerebral edema.
authors.affiliation: Twin Star Medical, Minneapolis, Minnesota, USA. odlan007@umn.edu
authors.forename: Rick M
authors.initials: RM
authors.lastname: Odland
authors.forename: Sandya
authors.initials: S
authors.lastname: Venugopal
authors.forename: John
authors.initials: J
authors.lastname: Borgos
authors.forename: Valerie
authors.initials: V
authors.lastname: Coppes
authors.forename: Alexander M
authors.initials: AM
authors.lastname: McKinney
authors.forename: Gaylan
authors.initials: G
authors.lastname: Rockswold
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.forename: Scott
authors.initials: S
authors.lastname: Panter
mesh_terms: D000818:Animals; D001929:Brain Edema / Q000134:cerebrospinal fluid / Q000517:prevention & control / Q000601:surgery; D001930:Brain Injuries / Q000134:cerebrospinal fluid* / Q000601:surgery*; D057785:Catheters; D004195:Disease Models, Animal; D009994:Osmolar Concentration; D013552:Swine; D014696:Ventriculostomy / Q000295:instrumentation* / Q000379:methods