Progressive cellular dehydration and proteolysis in critically ill patients

Area of Science:

• Critical care medicine
• Human physiology
• Nutritional biochemistry

Background:

• Critically ill patients exhibit profound body protein loss.
• A hypothesis suggests cell shrinkage from dehydration triggers and maintains this protein loss.
• This study investigates the link between cellular dehydration and protein/potassium loss in critical illness.

Purpose of the Study:

• To test the hypothesis that cellular dehydration drives protein loss in critically ill patients.
• To examine sequential changes in body composition, including intracellular water, total body protein, and total body potassium.
• To assess intracellular potassium concentration and its relation to protein loss.

Main Methods:

• Studied 20 intensive care unit patients (9 blunt trauma, 11 sepsis) over 21 days.
• Measured intracellular water using bromide and tritium dilution, and bioimpedance spectroscopy.
• Quantified total body protein via neutron activation analysis and total body potassium by whole-body counting.

Main Results:

• Intracellular water decreased by 15-20%, total body protein by 15%, and total body potassium by ~20%.
• Intracellular potassium concentration remained stable and comparable to healthy individuals.
• Tissue analysis in trauma patients indicated water loss exceeded expected levels based on protein loss.

Conclusions:

• Major trauma and sepsis are associated with progressive cellular dehydration.
• Cellular dehydration is a key factor accompanying the loss of body protein and potassium.
• Understanding this mechanism may lead to novel therapies to mitigate protein catabolism in critical illness.