Evaluation of gastric pressures as an indirect method for measurement of intraabdominal pressures in the horse.

This research aimed to develop an indirect method for measuring intraabdominal pressures in horses by measuring gastric pressures, but concluded that there was no statistical correlation between the two measurements, indicating that direct measurement of intraperitoneal pressures may be more reliable.

Objective and Methodology

• This research was conducted to attempt to establish an indirect, less invasive technique for gauging intraabdominal pressures in standing horses. The proposed method was to calculate gastric pressures and compare these measurements to the traditional method, direct monitoring of pressures from within the peritoneal cavity (a space within the abdomen housing several organs).
• The study was prospective and experimental, carried out at a university-owned equine research facility.
• For this investigation, 10 healthy adult horses were evaluated, including 7 geldings and 3 mares.
• The gastric pressures were measured employing a nasogastric tube with a U-tube manometry method, while intraperitoneal pressures were calculated with a peritoneal cannula.

Measurement and Analysis

• Intraabdominal pressure measurements were concurrently obtained using both the proposed and the traditional methods. The evaluations took place over five stages, each with increasing volumes of fluid infused into the horse’s stomach (0, 400, 1,000, 2,000, and 3,000 mL).
• The differences and agreement between these two methods were determined using Bland-Altman analysis and Lin’s concordance correlation coefficients.

Results

• The mean gastric pressure observed was 14.44 ± 4.69 cm H2O, ranging from 0 to 25.8 cm H2O. The intraperitoneal pressure measurements were generally subatmospheric, ranging from -6.6 to 3.1 cm H2O, with an average of -1.59 ± 2.09 cm H2O.
• The measurements of intraperitoneal pressures were repeatable, but there was larger intra- and interindividual variance for the measurements of gastric pressures.
• The mean and relative bias for comparison between the two techniques was high with 15.9 ± 5.3 cm H2O and 244.3 ± 199.2% respectively. Furthermore, the Lin’s concordance correlation coefficient between gastric and intraperitoneal pressures was -0.003, but this was not statistically significant (P=0.75).

Conclusion

• The study concluded that there was no statistical concordance between intraabdominal pressure measurements conducted through gastric and intraperitoneal pressure measurement.
• This result suggests that gastric pressures cannot be used as a substitute for intraperitoneal pressure measurement. Hence, the direct measurement of intraperitoneal pressures may be considered a more consistent method for comparing intraabdominal pressures among horses due to less variability within and between individuals.