title: Efficacy of Intravenous Mannitol in the Management of Orbital Compartment Syndrome: A Nonhuman Primate Model.
abstract: OBJECTIVE
  To report the efficacy of intravenous mannitol in the treatment of orbital compartment syndrome.
  
  
  METHODS
  An experimental study was conducted on 4 nonhuman primates (8 orbits). Orbital compartment syndrome was simulated by injecting autologous blood into both orbits of each nonhuman primate until a pressure of 80 mm Hg was reached (time 0). After 10 minutes, nonhuman primates were randomized to receive an infusion of either mannitol or saline, given over 15 minutes. Five minutes after the infusion was complete, lateral canthotomy and cantholysis was performed on both orbits in isolated steps every 5 minutes. During the study protocol, orbital and intraocular pressures were recorded every 5 minutes, with a final set of measurements at 60 minutes. The primary outcome measures were the mean change in pressure from time 0 to 60 minutes, as well as the mean change in pressure during the infusion period.
  
  
  RESULTS
  There was no statistically significant difference in the mean changes in orbital or intraocular pressure from time 0 to 60 minutes of the protocol. However, during the infusion period there was significantly greater decrease in both orbital and intraocular pressure in the mannitol compared with saline group (-34.0 vs. -9.3 mm Hg for orbital pressure [p = 0.03]; -34.8 vs. -9.7 mm Hg for intraocular pressure [p = 0.04]).
  
  
  CONCLUSIONS
  While the definitive treatment of orbital compartment syndrome is lateral canthotomy and cantholysis, mannitol results in a rapid and clinically meaningful drop in orbital and intraocular pressure. The authors believe that their data support the routine use of mannitol in orbital compartment syndrome, especially when there is a delay in timely surgical management.
authors.affiliation: *Department of Ophthalmology, †Office of the University Veterinarian, Queen's University, Kingston, Ontario, Canada.
authors.forename: Davin
authors.initials: D
authors.lastname: Johnson
authors.forename: Andrew
authors.initials: A
authors.lastname: Winterborn
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kratky
mesh_terms: D000818:Animals; D003161:Compartment Syndromes / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D004195:Disease Models, Animal; D004234:Diuretics, Osmotic / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D007262:Infusions, Intravenous; D007429:Intraocular Pressure; D008252:Macaca fascicularis; D008297:Male; D008353:Mannitol / Q000008:administration & dosage*; D009915:Orbit / Q000000981:diagnostic imaging*; D009916:Orbital Diseases / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D004234:Diuretics, Osmotic; D008353:Mannitol