From the Research
Hypovolemia significantly affects both CBC and BMP results due to hemoconcentration, leading to elevated hemoglobin, hematocrit, and platelet counts, as well as increased BUN and creatinine levels, reflecting pre-renal acute kidney injury from decreased renal perfusion 1.
Effects on CBC
- Elevated hemoglobin and hematocrit levels due to reduced plasma volume, creating a false impression of polycythemia
- Platelet counts may also appear elevated for the same reason
Effects on BMP
- Increased blood urea nitrogen (BUN) and creatinine levels, reflecting pre-renal acute kidney injury from decreased renal perfusion
- The BUN:creatinine ratio often exceeds 20:1, a hallmark of pre-renal causes
- Electrolyte abnormalities may include hypernatremia from free water loss, though hyponatremia can occur with sodium losses
- Metabolic alkalosis may develop from contraction of extracellular fluid volume, while metabolic acidosis can result from lactic acid accumulation due to tissue hypoperfusion
Clinical Implications
- These laboratory changes reflect the body's compensatory mechanisms to maintain intravascular volume and tissue perfusion during fluid depletion
- They typically normalize with appropriate fluid resuscitation
- It is essential to consider the effects of hypovolemia on CBC and BMP results to avoid misinterpretation and ensure proper management of patients with decreased intravascular volume 2.
- The most recent study 1 highlights the importance of careful fluid management to prevent complications such as intra-abdominal hypertension and abdominal compartment syndrome.