OBJECTIVE: To compare the changes in pHi and intramucosal-arterial CO(2)-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 48h after burn, gastric intramucosal CO(2) was measured every 8h using automated air tonometry. pHi and intramucosal-arterial CO(2)-gap were calculated. Simultaneously invasive haemodynamic data were registered by the transpulmonary thermodilution technique, using the mean of triplicate injections. The intramucosal-arterial CO(2)-gradient and pHi were compared with haemodynamic and global perfusion data by regression analysis. Mean pHi and CO(2)-gap values at 8 and 24h 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 PCO(2)-gap at 8 and 24h 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 PCO(2)-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.
OBJECTIVE: To compare the changes in pHi and intramucosal-arterial CO(2)-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 48h after burn, gastric intramucosal CO(2) was measured every 8h using automated air tonometry. pHi and intramucosal-arterial CO(2)-gap were calculated. Simultaneously invasive haemodynamic data were registered by the transpulmonary thermodilution technique, using the mean of triplicate injections. The intramucosal-arterial CO(2)-gradient and pHi were compared with haemodynamic and global perfusion data by regression analysis. Mean pHi and CO(2)-gap values at 8 and 24h 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 PCO(2)-gap at 8 and 24h 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 PCO(2)-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.