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Make the Diagnosis: Hypovolemia, Adult

Prior Probability

Hypovolemia occurs for a variety of causes. There are no reasonable estimates for the prior probability that would be uniformly helpful. Clinicians should use their best judgment in assessing the probability of intravascular volume depletion according to the patient's medical history and findings that suggest the possibility of fluid losses.

Population for Whom Hypovolemia Disease Should Be Considered

  • Acute blood loss

  • Illness with fluid loss

  • Decreased oral intake

  • “Unmeasured” losses as might occur with heat-induced illness

See Tables 24-8 and 24-9 for the likelihood of hypovolemia caused by blood loss.

Table 24-8.Detecting the Likelihood of Hypovolemia Not Caused by Blood Loss
Table 24-9.Detecting the Likelihood of Hypovolemia Caused by Blood Loss

Reference Standard Tests

Intravascular volume depletion typically relies on a clinical diagnosis, with appropriate laboratory measures that correct with rehydration. In controlled settings, blood volume and total body water can be measured indirectly with radiolabeled agents.

Original Article: Is This Adult Patient Hypovolemic?

Clinical Scenarios

In each of the following clinical scenarios, clinicians need to identify which physical signs reliably and accurately indicate volume depletion or dehydration.

Case 1

A 54-year-old man, taking ibuprofen for knee arthritis, presents with a 1-day history of melena. Physical examination reveals a pulse of 80/min and blood pressure (BP) of 140/82 mm Hg when supine and 115 and 132/86 mm Hg when standing. There is mild epigastric tenderness and a positive result on a guaiac test for occult blood in the stool. The hematocrit level is 39%.

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