Gastric tonometry and direct intraabdominal pressure monitoring in abdominal compartment syndrome

Background/Purpose: Abdominal compartment syndrome (ACS) may complicate abdominal closure in patients with abdominal wall defects, abdominal trauma, intraperitoneal bleeding, and infection. Increased intraabdominal pressure (IAP) leads to respiratory compromise, organ hypoperfusion, and a high mortality rate. This study evaluates the efficacy of continuous direct monitoring of IAP and gastric tissue pH in detecting impending ACS. Methods: Ten mongrel puppies weighing 2.8 to 6.4 kg underwent general endotracheal anesthesia, placement of an intraabdominal inflatable balloon to simulate ACS and a Swan-Ganz catheter to measure direct IAP. A gastric tonometer, nasogastric tube, foley catheter, and arterial catheter also were inserted. Half-hourly inflation's of the intraabdominal balloon were used to simulate the development of ACS. Direct intraabdominal (IAP), gastric (GP), bladder (BP), and peak airway pressures (PAP) were measured. Gastric tonometry fluid and arterial blood gas levels were obtained during inflation, and the gastric tissue pH level was calculated. Data were statistically analyzed using Pearson's correlation coefficients. Results: Baseline pressures were 2 to 5 cm H2O in the stomach and bladder catheters, 1 to 3 mm Hg in the intraabdominal catheter, and correlated with a gastric tissue pH level of 7.4. Significantly high correlation coefficients (cc) were observed between IAP versus BP (cc, 0.77; P <.002). IAP versus GP (cc, 0.79; P <.002) and IAP versus PAP (c, 0.83; P <,0004). A high negative correlation coefficient was noted between gastric pH and IAP (cc, 0.61; P <.026). The pH level dropped to 7.0 with BP and GP of 20 cm H2O and IAP of 10 mm Hg, to 6.8 at 30 cm H2O and 20 mm Hg, and 6.5 at 40 cm H2O and 30 mm Hg, respectively. However, correlation coefficients between gastric tissue pH and BP, GP, or PAP were not significant. Conclusions: These data suggest that continuous direct intraabdominal pressure monitoring is a simple and effective method that correlates well with indirect bladder or gastric pressure measurement. Changes in gastric tissue pH in association with increased intraabdominal pressure may be an early indicator of impending abdominal compartment syndrome. These observations indicate that these techniques may be more sensitive than current methods of indirect measurement, which may be associated with delayed recognition of ACS. Copyright (C) 2002 by W B, Saunders Company.