How to objectively assess dehydration

Four parameters can be measured to objectively assess dehydration.

1. PCV and Total Protein should be interpreted together. An increase in both suggests fluid loss except that resulting from acute haemorrhage.
2. Lactate. Hypoperfusion of tissue increases the concentration of lactate due to anaerobic metabolism of cells. A portable lactate meter quickly and cheaply measures blood lactate in the clinical setting and functions similarly to a glucometer. Lactate <2 mmol/l is normal. Increased lactate correlates with outcome and is a poor prognostic indicator in dogs. Serial lactate measurements can be used to monitor and guide fluid therapy.
3. Blood gas analysis. The equipment for measuring blood gas analysis is expensive and not usually available in general practice.