University of Georgia Veterinary Teaching Hospital
There are several methods to measure portal pressures in veterinary patients; however, there is a paucity of literature regarding the accuracy and precision of these techniques. The objective of this study was to investigate the accuracy and precision of four pressure measurement devices (water manometer with built-in gauge [WMg], water manometer with ruler [WMr], arterial pressure transducer [APT], and Compass CT [CCT]) in an ex vivo model. A second APT was used to set the model to five predetermined pressures. Each device was tested at each pressure in a randomized order by three investigators. Bland-Altman plots were used to assess agreement between devices and intra-class correlation coefficients were calculated for both intra- and inter-observer reliability. Pressures measured with WMr were significantly different than APT (P<.001) and WMg (P=.005); no other devices were different from each other. Interobserver agreement was excellent (0.998) and intraobserver agreement was excellent (0.995, 0.990, 0.987 for each observer). The mean difference ± SD compared to the set pressure was -0.296 ± 0.303 (WMr), -0.622 ± 2.037 (CCT), -1.024 ± 0.568 (WMg), and -1.244 ± 0.435 (APT), with WMr having the best accuracy and precision, APT having the least accuracy, and CCT having the least precision. Interobserver and intraobserver agreement for all four devices were excellent. Although the WMr was the most accurate and precise measurement device, all devices were within 1.2 mmHg of the set pressure, indicating possible clinical utility for in vivo pressure measurements based on the results of this ex vivo model.
