Hypovolemia is very common in the ederly for two reasons:
1. The elderly have a decreased thirst response...in other words, it takes longer for them to develop thirst in the setting of dehydration.
2. The elderly have a decreased renal vasopressin response to hypovolemia.
From a treatment standpoint, one should always assume an elderly patient is hypovolemic. Hydration is incredibly important during resuscitation of the elderly patient.
