Chemical monitoring of intensive care patients using intravenous microdialysis

The objective of the study was to evaluate intravenous microdialysis for monitoring of plasma lactate, pyruvate, glucose, creatinine, urea, adenosine, inosine and hypoxanthine in intensive care patients. Microdialysis probes (O.D. 0.9 mm; membrane length 20 mm) were inserted into major veins and perfused with Ringer's solution. Dialysis samples were collected from 4 patients with septic shock in 60 min fractions during 24 h. At the end of every hour a venous blood plasma sample was drawn from the corresponding contralateral vein for comparison. Microdialysate values of all metabolites closely followed the changes in the corresponding blood samples. The in vivo recovery of the probe type used was close to 100% for lactate, creatinine, and urea, and about 90% for glucose. It is concluded that intravenous microdialysis sampling is a suitable method for continuous bedside monitoring of important metabolites in intensive care patients.