USEFULNESS OF GASTRIC INTRAMUCOSAL PH FOR MONITORING HEMODYNAMIC COMPLICATIONS IN CRITICALLY ILL CHILDREN

Objective: To assess the efficacy of gastric intramucosal pH for the e valuation of tissue perfusion and prediction of hemodynamic complicati ons in critically ill children. Design: Open prospective study without controls. Setting: Pediatric intensive care unit (ICU) of a tertiary care university pediatric hospital. Patients: Thirty critically ill ch ildren (16 boys and 14 girls), age range: 3 months-12 years. Measureme nts and results: A tonometry catheter was placed in the stomach of all patients on admission to the pediatric ICU. Simultaneous tonometry an d arterial gas measurements were made on admittance and every 6-12 h t hroughout the study; a total of 202 measurements were made. The cathet er was removed after extubation and/or when the patient was hemodynami cally stable. Intramucosal pH was calculated using the Henderson-Hasse lbalch equation based on the pCO(2) of the tonometer and arterial bica rbonate. Intramucosal pH values between 7.30 and 7.45 were considered to be normal. The patient's condition was analyzed using the Pediatric Risk Mortality Score (PRISM). The relations between intramucosal pH a nd the presence of major hemodynamic complications (cardiopulmonary ar rest, shock), minor hemodynamic complications (hypotension, hypovolemi a or arrhythmia), death, PRISM score and the duration of the stay in t he pediatric ICU were analyzed. Intramucosal pH on admission was 7.48 +/- 0.15 on average (range 7.04-7.68). Five patients (16%) had an intr amucosal pH lower than 7.30 on admission: these patients did not have a higher incidence of hemodynamic complications. The 16 patients (53%) who had an intramucosal pH of less than 7.30 at some time during the course of their disease had more hemodynamic complications than the pa tients who did not have pH lower than 7.30 (p < 0.0001), Every case of cardiopulmonary arrest and shock was related to intramucosal pH of le ss than 7.30, Patients with major complications (cardiopulmonary arres t and shock) had lower intramucosal pHs than those with minor hemodyna mic complications (p = 0.03); similarly, they had low intramucosal pH readings more often than those with minor complications (p = 0.0032). Intramucosal pH values less than 7.30 had a sensitivity of 90% and a s pecificity of 98% as a predictor of hemodynamic complications. There w as no relation between intramucosal pH lower than 7.30 and either PRIS M or the duration of the stay in the pediatric ICU, Patients with intr amucosal pH less than 7.20 had a higher PRISM than the patients who di d not have pH lower than 7.20 (p < 0.05). A patient who died during th e study due to cardiopulmonary arrest had prior intramucosal pH measur ements of 7.23 and 7.10, and three patients died of late complications after the end of the study. Hemodynamic complications were not detect ed with arterial pH. Gap pH (arterial pH-intramucosal pH) and standard pH measurements yielded the same results as gastric intramucosal pH. Conclusion: Intramucosal pH could provide a useful early indication of hemodynamic complications in critically ill children.