Intraabdominal pressure and gastric intramucosal pH: Is there an association?

This study evaluated the potential association between increased intraabdominal pressure (IAP) and abnormally low gastric intramucosal pH (pHi) (less than or equal to 732) in postoperative patients and assessed its effect on patient outcome, Altogether 73 patients undergoing major abdominal surgery over a 9-month period were studied prospectively: All underwent gastric tonometry and intravesical IAP measurements three time daily. An IAP of greater than or equal to 20 mmHg and a pHi of less than or equal to 7.32 were considered abnormal. The development of the following complications were also documented: hypotension [mean aortic pressure (MAP) < 80 mmHg], abdominal sepsis, renal impairment, and death. The median APACHE II score was 16 (range 5-34). Twenty-two patients had upper gastrointestinal (GI) surgery, 27 lower GI surgery, and 24 aortic surgery; 13 of these patients underwent emergency surgery. Abnormal pHi (less than or equal to 7.32) occurred in 36 patients while on the intensive care unit. Compared to patients with normal pHi, abnormal pHi patients were 11.3 times (3.2-43.5) [odds ratio +/- 95% CI] more likely to have an increased IAP. Abnormal pHi was significantly associated with hypotension (chi(2) = 6.8; p = 0.009), sepsis (chi(2) = 3.7; p = 0.06), renal impairment (chi(2) = 28.3; p = 0.0000001), relaparotomy (chi(2) = 4.1; p = 0.04), and death (chi(2) = 9.7; p = 0.002). This study demonstrated a significant clinical association between increased IAP and abnormal pHi. An abnormally low pHi was associated with poor outcome.