Hypovolemiaan

Hypovolemiaan, or reduced intravascular volume, is a condition in which the circulating blood plasma volume falls below normal. It can result from fluid losses or shifts of fluid from the blood into interstitial spaces. It is related to dehydration but not identical; dehydration refers to water losses with relatively preserved plasma electrolytes, while hypovolemia emphasizes a decreased circulating volume.

Common causes include external losses such as bleeding (hemorrhage), vomiting, diarrhea, excessive sweating, and burns, as well as internal or third‑space losses seen in pancreatitis, peritonitis, severe illness, or trauma. Inadequate fluid intake, diuretic use, and fluid shifts during illness can also contribute. The resulting decrease in venous return lowers cardiac output and arterial pressure, and in severe cases may progress to hypovolemic shock.

Clinical features depend on severity and speed of onset. Early signs include tachycardia, normal or low blood pressure (or orthostatic drop), cool and clammy skin, dry mucous membranes, reduced skin turgor, and decreased urine output. Mental status may be altered in more advanced cases.

Diagnosis relies on history and examination, supported by laboratory and imaging tests as needed. Lab findings may show hemoconcentration (elevated hematocrit), elevated blood urea nitrogen, and electrolyte abnormalities. Urine output and urinalysis help assess kidney perfusion; point‑of‑care ultrasound may aid evaluation of volume status and response to fluids.

Management focuses on restoring circulating volume and treating the underlying cause. Initial therapy typically uses isotonic crystalloids (for example, normal saline or lactated Ringer’s) given as rapid IV boluses (often 20 mL/kg) with frequent reassessment. If blood loss is present, blood products are indicated. Invasive monitoring and vasopressors may be needed if shock persists after adequate fluid resuscitation. Prognosis improves with prompt recognition and treatment, while prevention centers on maintaining adequate fluids in high‑risk patients and careful fluid management during illness.