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Published on: October 2, 2020
Osmolal gap in hemodialyzed uremic patients
Ioannis Griveas1, Athina Gompou, Ilias Kyritsis
1Nephrology Department 401 Military Hospital of Athens, Nephroiatriki Renal Unit, Athens, Greece. giannisgriv@hotmail.com
Artificial Organs
|August 19, 2011
Summary
Uremic patients undergoing hemodialysis have higher serum osmolality and osmolal gap compared to healthy individuals. Hemodialysis reduces these values, but the osmolal gap remains elevated, suggesting unidentified solutes.
Area of Science:
- Nephrology
- Clinical Chemistry
Background:
- Osmolality reflects the concentration of particles in a solution.
- The osmolal gap, the difference between measured and calculated osmolality, can indicate the presence of unmeasured osmoles.
Purpose of the Study:
- To determine measured and calculated osmolality and the osmolal gap in hemodialyzed uremic patients pre- and post-hemodialysis.
- To compare these values with those of healthy controls.
Main Methods:
- Serum osmolality was measured using an osmometer and calculated using the formula: 2xNa + UN/2.8 + glucose/18.
- Blood samples were collected from 24 uremic patients pre- and post-hemodialysis and from 22 healthy controls.
Main Results:
- Uremic patients had significantly higher measured and calculated osmolality compared to controls, both pre- and post-hemodialysis.
- Hemodialysis significantly reduced osmolality and the osmolal gap in patients, but these remained higher than in controls.
- The pre- and post-hemodialysis osmolal gap in patients (11 ± 2.08 and 7.29 ± 1.94, respectively) was significantly higher than in controls (3.18 ± 1.46).
Conclusions:
- Uremic hemodialyzed patients exhibit elevated serum osmolality and osmolal gap, even after dialysis.
- The persistent high osmolal gap suggests the presence of unidentified endogenous osmoles in uremic patients' serum.
- Hemodialysis partially removes these unidentified osmoles, leading to a decrease in the osmolal gap.
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