ABDOMINAL PRESSURE PROFILING IN ADULT HORSES

Measurement of intra-abdominal pressure (IAP) is essential for documentation and monitoring of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). IAH and ACS are two linked conditions significantly associated with morbidity and mortality in critically ill humans. Documented risk factors for the development of ACS in people may be applicable to horses and IAH has been described within the equine literature. Consensus statements are available in human critical care advising on optimal IAP acquisition methodologies and monitoring because many variables can affect the results obtained. Guidelines are also published for the treatment of IAH and ACS in people. Such information is currently unavailable in equine medicine. The purpose of this study was to undertake abdominal pressure profiling in normal horses to investigate species-specific characteristics. We hypothesized that intra-abdominal pressure is both location and body position dependent in normal horses. We further hypothesized that sedation would not affect IAP in normal standing horses. Direct abdominal pressures were measured from 3 different locations in nine healthy, standing, adult horses (2 flank positions and the ventral abdomen). Direct arterial blood pressure was concurrently obtained. Abdominal perfusion pressure was calculated (mean arterial pressure – IAP). Identical variables were recorded after administration of intravenous sedation (xylazine hydrochloride). Each horse then underwent short-term total intravenous anesthesia (diazepam, ketamine, guaifenesin guaiacolate) to facilitate patient positioning. All hemodynamic and abdominal pressures were measured with horses in left lateral/right lateral (LR) and dorsal recumbencies (DR). We demonstrated that flank IAP was subatmospheric and significantly lower than ventrum IAP in standing horses (P < 0.001). Ventrum calculated abdominal perfusion pressure (APP) was lower than flank calculated APP (P = 0.029). Administration of intravenous sedation did not affect IAP, APP, direct arterial blood pressure, heart rate or respiratory rate in normal standing horses (P > 0.05 for each variable). Ventrum IAP was significantly lower (subatmospheric) with horses in DR compared to values obtained in LR (P < 0.0001). Ventrum APP was not different with horses in all 3 recumbencies. MAP was significantly lower when horses were positioned in DR compared to LR (P < 0.0001). Flank (left and right) IAP was significantly lower and flank (left and right) APP was significantly higher with horses in LR compared to DR (P = 0.002 for all comparisons).The abdominal pressure profiling undertaken in this study showed that direct IAP and APP are both location and body position dependent in normal horses. Direct arterial blood pressure also varies with recumbency. Sedation with xylazine hydrochloride does not affect hemodynamic and abdominal pressures in standing normal horses. These effects should be considered when evaluating abdominal pressure profiles and visceral perfusion in horses.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Comparative and Veterinary Medicine

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Scott, Victoria HL

Contributors dc:contributor

• Hurcombe, Samuel

• Veterinary Services
• Medicine
• abdominal pressure
• horses
• intra-abdominal hypertension
• abdominal compartment syndrome
• abdominal perfusion pressure
• sedation
• anesthesia
• body position

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365493966

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365493966