Intermittent hemodialysis in critically ill patients with multiple organ dysfunction syndrome is associated with intestinal intramucosal acidosis.

OBJECTIVE: Conventional intermittent hemodialysis in the critically ill patient can be associated with hemodynamic and respiratory instability. Intermittent hemodialysis induced arterial hypotension might be detrimental. We therefore studied the influence of intermittent hemodialysis on systemic and regional oxygen transport in critically ill patients.
DESIGN: Prospective descriptive study.
SETTING: Medical/surgical 24-bed intensive care unit in a university hospital. PATIENTS: Eleven critically ill patients admitted to the intensive care unit (APACHE III score: 82 +/- 12) and developing multiple organ dysfunction syndrome with acute renal failure. All patients were mechanically ventilated and hemodynamically stable with inotropic support. Systemic oxygen transport variables were calculated, and arterial blood lactate concentration was measured before, during, and after intermittent hemodialysis. Tonometer PCO2 was measured using a tonometer, and arterial-tonometer CO2 gap was used as an indicator of intestinal intramucosal acidosis.
RESULTS: Intermittent hemodialysis induced an increase in calculated systemic oxygen consumption (P < 0.01). During intermittent hemodialysis there was a significantly higher need of inotropic support (P < 0.05) to maintain arterial blood pressure, cardiac index, and calculated systemic arterial oxygen delivery. The arterial-tonometer CO2 gap increased significantly during and after the procedure.
CONCLUSION: In critically ill patients with multiple organ dysfunction syndrome intermittent hemodialysis induces an increase in oxygen consumption. Despite higher inotropic support to maintain systemic calculated oxygen delivery intestinal intramucosal acidosis occurs during intermittent hemodialysis and may even persist after the procedure is terminated.