Kinetic Method to Detect Dehydration

• Fifteen healthy male volunteers are subjected to 4 experiments. They drink 800 ml of water at 6:00 AM to make sure they are not dehydrated when the experiments begin.
• On two occasions the volunteer receives, at 9:00 AM, an intravenous infusion of acetated Ringer´s solution being either 5 ml/kg or 10 ml/kg, over 15 min. The blood hemoglobin concentration is measured during 16 occasions during 120 min by invasive blood sampling and also non-invasively by a pulse oximeter (Masimo´s Radical 7).
• On two other occasions, the infusions are preceded for 2 hours of deliberate dehydration. Doses of furosemide 5 mg are repeated 3-4 times with the goal of creating dehydration amounting to approximately 2 liters of fluid. Excreted urine is collected and the volume measured.
• The kinetics of each infusion is calculated by volume kinetics, and the data compared pairwise from the experiments with and those without dehydration.
• The accuracy and precision of the non-invasive monitoring of Hgb can be determined.
• The study is ended with that the Hgb response between the lying and sitting position is compared and with that the fluid balance is restored by ingestion of water.
• Experiments are performed in the Department of Intensive Care at Linköping University Hospital, Sweden.

Inclusion criteria

• Healthy male.

Exclusion criteria

• Disease for which daily medication is required.
• Poor peripheral perfusion; defined as a perfusion index, as measured by Masimo´s Radical 7, of 2 or less.