Intestinal and gastric tonometry during experimental burn shock

Introduction The occurrence of organ failure following thermal injury, despite restoration of hemodynamic parameters and urine output during resuscitation, has led to efforts to measure end-organ perfusion. The purpose of this 24-h study was to evaluate the utility of gastrointestinal (GI) tonometry during burn shock and resuscitation. Methods Male swine (n = 11, 23.3 ± 0.9 kg) were anesthetized with ketamine and propofol. A 70% full thickness burn was caused by immersion in 97 °C water for 30 s. Resuscitation with lactated Ringerʹs, 4 ml/kg/% burn, was begun at hour 6 and titrated to urine output (UO). Arterial blood gases and pulmonary artery catheter data were measured every 6 h. Gastric and ileal regional PCO2 (PrCO2) were measured continuously by air tonometry, and the gastric and ileal intramucosal pH (pHi) and PCO2 gap (PrCO2 − PaCO2) were calculated every 6 h. Results Gastric pHi, ileal PrCO2, ileal pHi, and ileal PCO2 gap (but not gastric PrCO2 or PCO2 gap) all decreased with shock and were restored to baseline levels by resuscitation. Changes in ileal PrCO2 were of greater magnitude and demonstrated decreased variability than those in gastric PrCO2. Conclusions In this model, ileal tonometry outperformed gastric tonometry during burn shock and resuscitation.