Gastric mucosal gas monitoring and survival in exacerbated chronic obstructive pulmonary disease

摘要

Objectives: Gastric tonometry is an established minimally invasive procedure for measurement of intramucosal pCO_2, and it can foretell hemodynamic instability long before other common signs. The objectives of the present work were to monitor gastric mucosal acidity in patients intensively treated for exacerbated chronic obstructive pulmonary disease (COPD), to examine its relationship with other hemodynamic factors and its correlation with outcome.Design: Prospective uncontrolled study.Settimg: Respiratory and General Intensive Care Units (ICUs) in a general hospital. Subjects: Twenty-two patients were recruited from those admitted to the ICUs with exacerbated COPD requiring ventilation.Interventions: The intramucosal pCO_2 (P_rCO_2) was measured by tonometry from 30 min to 72 hours post admission every 12 hours. At each time point, arterial and venous blood gases and pH, and respiratory variables were also determined. Measurements and main results: During the study period, 17 patients were weaned from the ventilator and five (all males) expired. Linear, positive and mostly statistically significant correlations were observed between the intramucosal P_rCO_2 and the arterial or the venous CO_2 levels during the first 60 hours. The intramucosal pH remained neutral in the surviving patients, while in those who succumbed it was more acidic, with significant differences at t = 12, 60 and 72 hours (p = 0.007, p = 0.026, p = 0.017, respectively). The respiratory variables, the pH_v' P_aCO_2, P_vCO_2, P_rCO_2 and the difference P_rCO_2- P_aCO_2 were similar in both groups, but the latter was consistently lower in the survivors, and at the point of maximum difference (12 hours) it was predictive of 80% of the mortalities and 65% of the survivals. Conclusions: This preliminary study suggests that gastric mucosal tonometry can provide early diagnostic information on ventilated patients, and it should be considered as an additional tool applied for clinical decision making in ICUs.