Hemoconcentration and Hemodilution

Introduction

• Importance of understanding hemoconcentration and hemodilution in lab analysis.
• Assess if the patient is dehydrated (hemoconcentrated) or fluid overloaded (hemodiluted) before treating lab results.

Hemoconcentration

• Definition: Loss of water in the blood, not the overall whole blood, leading to concentrated lab results.
  • Example: Loss due to diuresis.
  • Can cause falsely elevated results for BUN, creatinine, RBC, hemoglobin, hematocrit.
• Management:
  • Rehydrate the patient to normalize blood volume.
  • Re-evaluate labs post-rehydration before treatment.
• Risks:
  • Treating falsely elevated labs may cause imbalances, e.g., hypokalemia.

Hemodilution

• Definition: Excess water in the blood, diluting blood components.
  • Results in falsely low lab values.
• Management:
  • Patient may need diuresis or fluid restriction.
  • Labs should be re-assessed post-treatment.

Osmosis, Diffusion, and Filtration

• Understanding fluid and solute shifts across semi-permeable membranes.
• Examples:
  • Hypertonic solutions can pull fluid out of brain cells (reduce cerebral edema).
  • Hypotonic solutions can rehydrate brain cells.

IV Solutions

• Isotonic: Same concentration as blood, no fluid shifts.
• Hypotonic: Lower concentration, fluid shifts into cells.
• Hypertonic: Higher concentration, fluid shifts out of cells.

Critical Lab Results

• Definition: Lab results critically dangerous to the patient.
• Response Protocol:
  • Immediate attention required.
  • Contact provider within 60 minutes.
• Chain of Command:
  • Follow hierarchy: Provider, charge nurse, nurse manager, house supervisor, and chief medical officer.
  • Do not skip levels.
• Examples:
  • Potassium levels: Critical is around 7-8, typical normal range is 3.5-5.

Case Study

• Example of a patient with severe dehydration showing critical lab results.
• Importance of rehydrating before accurately assessing and treating lab results.

Summary

• Always verify lab results are true and not affected by hemoconcentration or hemodilution.
• Understand the physiological principles behind fluid and solute shifts to manage lab values effectively.