Assessment of splanchnic perfusion by gastric tonometry in patients with acute hypovolemic burn shock

Objective To compare the changes in pHi and intramucosal–arterial CO2-gap with invasive haemodynamic and global perfusion measurements during hypovolemic burn shock and to evaluate the sensitivity of these parameters as an early predictor of mortality in patients with extensive burns. Design Prospective, controlled, clinical study. Setting An eight-bed intensive burn care unit in a university-affiliated hospital. Patients Fifty severely burned patients with TBSA burned >25% BSA. Methods During the first 48 h after burn, gastric intramucosal CO2 was measured every 8 h using automated air tonometry. pHi and intramucosal–arterial CO2-gap were calculated. Simultaneously invasive haemodynamic data were registered by the transpulmonary thermodilution technique, using the mean of triplicate injections. The intramucosal–arterial CO2-gradient and pHi were compared with haemodynamic and global perfusion data by regression analysis. Mean pHi and CO2-gap values at 8 and 24 h after injury were compared between survivors and non-survivors to evaluate the prognostic significance of this parameter. Results Regression analyses revealed no or a negligible correlation between intramucosal and haemodynamic or perfusion data, even during the critical low flow–high resistance phase of resuscitation. Mean pHi and PCO2-gap at 8 and 24 h did not differ significantly between survivors and non-survivors. Conclusion Gastric tonometry is a poor indicator of splanchnic perfusion in patients with burn shock, even when all precautions are taken to prevent methodological errors. The intramucosal–arterial PCO2-gap and pHi do not distinguish survivors from non-survivors. Therefore, gastric tonometry does not seem to improve the ability to anticipate and avert regional anaerobic metabolism during burn shock and its routine use in these patients cannot be recommended