Objective: To assess the impact of continuous venovenous hemodiafiltration (CVVHDF) initiation on central hemodynamics, oxygen transport and gastric mucosal energy metabolism Design: Prospective clinical study. Setting: University Hospital medical intensive care unit. Subjects: Fourteen critically ill patients with acute renal failure. Methods: Gastric mucosal PCO2 (pgmCO2) was measured using gastric tonometry at baseline and then at 1,2,3 and 6 hours after starting CVVHDF and gastric mucosal to arterialPCO2 gradient (PCO2gap) was calculated. Whole body hemodynamics was measured invasively (arterial and pulmonary arterial catheters). Results: PCO2gap remained stable during the first 6 hrs of CVVHDF treatment. Mean arterial pressure, cardiac output, systemic vascular resistance and global oxygen consumption remained also unaltered although systemic vascular resistance increased. Conclusions: CVVHDF initiation in hemodynamically stable critically ill patients has minor effects on the whole body hemodynamics without influencing gastric mucosal energy balance.

        Key words: CRRT – acute renal failure – gastric tonometry – monitoring – critically ill