title: Effects of gastric distension on intraabdominal pressures in horses.
abstract: OBJECTIVE
  To determine the effect of gastric distension on intraabdominal pressures (IAP) measured directly from the intraperitoneal space.
  
  
  METHODS
  Prospective, experimental study.
  
  
  METHODS
  A university-based equine research facility.
  
  
  METHODS
  Ten healthy adult horses, 5 males and 5 females.
  
  
  METHODS
  Intraabdominal pressures were measured through an intraperitoneal cannula zeroed at a height midway between the height of the tuber ishii and point of the shoulder at 6 time points: at rest, after placement of a nasogastric tube, and after instillation of each 5 L increment up to a total of 20 L of water. Simultaneously, mean arterial pressures (MAP) were obtained using a tail cuff, and abdominal perfusion pressures (APP) were calculated using the measured IAP minus the measured MAP.
  
  
  RESULTS
  Baseline direct IAP measurements were subatmospheric (-4.5 ± 3.0 cm H2 O). IAPs were not significantly affected by placement of a nasogastric tube (-2.69, 95% CI [-3.24, -2.14], P = 0.4195), but were significantly increased after placement of 5 L (-1.73, 95% CI [-2.28, -1.18], P = 0.0015), 10 L (-0.54, 95% CI [-1.09,0.01], P = 0.0001), 15 L (0.89, 95% CI [0.34, 1.44], P = 0.0001), or 20 L (3.08, 95% CI [2.53, 3.63], P = 0.0001) of water into the stomach. APPs were not significantly different for any volume of fluid infused into the stomach (P = 0.05 for all comparisons).
  
  
  CONCLUSIONS
  IAPs were significantly increased when > 5 L of water was infused into the stomach. These results indicate the need for further research in clinical cases to determine the relationship between gastric pressures and the development of intraabdominal hypertension in horses.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 35849, USA.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Barrett
authors.forename: Amelia S
authors.initials: AS
authors.lastname: Munsterman
authors.forename: R Reid
authors.initials: RR
authors.lastname: Hanson
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000818:Animals; D005260:Female; D006736:Horses / Q000502:physiology*; D008297:Male; D008365:Manometry / Q000662:veterinary; D011312:Pressure
keywords: abdomen; acute; colic; compartment syndrome