Rectal pH measurement in tracking cardiac performance in a hemorrhagic shock model

Objective and Design: We evaluated the utility of rectal mucosal pH measurement for tracking cardiac performance in hemorrhagic shock as compared with gastric tonometry. Materials and Methods: Hemorrhagic shock was induced in five adult swine to a mean arterial pressure of 45-65 mm Hg. Hypotension was maintained for 30 minutes, resuscitation was accomplished with the shed blood and lactated Ringer's solution (3x blood volume). Gastric tonometry, rectal pH, and oxygen transport data were obtained at baseline, 0, and 30 minutes after onset of hypotension and after resuscitation. Results: Intramucosal pH readings from gastric tonometry and rectal mucosal pH both showed a significant change from baseline to 0 and 30 minutes after onset of hypotension. Data after resuscitation were found to be statistically the same as baseline values. Conclusions: Rectal mucosal pH tracks cardiac performance as well as does gastric tonometry in hemorrhagic shock without as many limitations.