From the Guidelines
Dehydration increases hematocrit levels as blood becomes more concentrated due to fluid loss. When the body loses water through sweating, vomiting, diarrhea, or inadequate fluid intake, plasma volume decreases while red blood cell count remains constant, resulting in an elevated hematocrit percentage. Management primarily involves fluid rehydration, either orally or intravenously depending on severity. For mild to moderate dehydration, oral rehydration with water or electrolyte solutions is recommended at a rate of approximately 5-10 mL/kg/hour 1. Severe dehydration requires intravenous fluid administration, typically with isotonic solutions such as normal saline (0.9% NaCl) or lactated Ringer's solution at initial rates of 20-30 mL/kg over 1-2 hours, followed by maintenance fluids.
Key Considerations
- The underlying cause of dehydration should also be addressed.
- Monitoring hematocrit levels during rehydration helps assess treatment effectiveness, with values typically returning to the patient's baseline as fluid balance is restored.
- Prevention strategies include regular fluid intake, especially during hot weather, illness, or physical activity, with the general recommendation being 2-3 liters daily for adults under normal conditions.
Management Approach
- Aggressive intravenous hydration is not recommended for patients with non-severe acute pancreatitis, as it may increase the risk of fluid overload while not improving clinical conditions 1.
- Subcutaneous rehydration can be an effective alternative to intravenous rehydration for mild to moderate dehydration, with similar rates of adverse effects 1.
- Parenteral hydration should be considered as a medical treatment rather than basic care, with its benefits and risks carefully balanced 1.
From the Research
Effect of Dehydration on Hematocrit Level
- Dehydration can lead to an increase in hematocrit (Hct) level due to a decrease in plasma volume 2.
- However, a study found that mild dehydration did not cause significant changes in hemoglobin or hematocrit levels in humans 2.
- In contrast, another study found that dehydration in hamadryas baboons resulted in no significant changes in hematocrit or hemoglobin concentration, despite a 10% loss of body mass and 12.5% loss of total body water 3.
Management of Dehydration and Hematocrit Level
- Rehydration can lead to a decrease in hematocrit level due to hemodilution 4, 5.
- A study found that intravenous rehydration with normal saline resulted in a significant decrease in hematocrit level, but this effect was temporary and the level returned to baseline over time 4.
- Another study found that rehydration did not prevent orthostatic hypercoagulability, despite causing hemodilution and a decrease in hematocrit level 5.
Clinical Implications
- Dehydration has been found to be a strong predictor of long-term prognosis in patients with acute ischemic stroke, and hydration status may be an important factor in patient outcomes 6.
- The relationship between dehydration and hematocrit level is complex and may depend on various factors, including the severity and duration of dehydration, as well as individual patient characteristics 2, 4, 5, 6, 3.