Gastric tonometry in patients with cardiogenic shock and intra-aortic balloon counterpulsation

Objective: To study the course of gastric regional PCO2 (PrCO2) in patients with cardiogenic shock requiring intra-aortic balloon (IAB) counterpulsati on and the prognostic value of PrCO2 in this patient population. Design:A prospective, observational clinical study. Setting: Medical intensive care unit in a university hospital. Patients: Twenty-six consecutive patients with cardiogenic shack requiring mechanical support with an IAB counterpulsation undergoing mechanical venti lation Interventions: None. Measurements and Main Result. Hemodynamic variables, tonometric variables, arterial blood gases, and arterial lactate were assessed before insertion o f IAB (baseline), and 1, 2, 3, 8, 16, 24, and 48 hrs thereafter. A subset o f these patients (n = 14) were studied just before and 1, 8, 24, and 32 hrs after IAB removal; 12/26 patients (46.2%) died. Cardiac index increased fr om baseline to 1 hr after insertion of IAB (1.7 +/- 0.3 to 2.6 +/- 0.8 L/mi n/m(2), p < .05), PrCO2 did not change between admission (47 +/- 13 torr [6 .3 +/- 1.7 kPa]) and 8 hrs after placement of IAB but increased to 63 +/- 2 2 torr (8.4 +/- 2.9 kPa) at 16 hrs (p < .05) without any further alteration until 48 hrs. CO2 gap showed a similar pattern with 15 +/- II torr (2.0 +/ - 1.5 kPa) at baseline and an increase to 28 +/- 22 torr (3.7 +/- 2.9 kPa) 16 hrs later. PrCO2 and CO2 gap remained at high levels (59 +/- 11 torr [7. 7 +/- 1.5 kPa] and 22 +/- 10 torr [2.9 +/- 1.3 kPa], respectively), before IAB removal without further improvement or deterioration thereafter. PrCO2, values showed no difference between survivors and nonsurvivors at any time point. Conclusion: Patients with cardiogenic shock developed high PrCO2 within the first 24 hrs, which reflects gastric mucosal ischemia. Persistently high l evels of PrCO2 were indicative for prolonged hypoperfusion of the gut Gastr ic tonometry failed to discriminate between survivors and nonsurvivors.