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Intravenous contrast agents and associated changes in serum osmolality
Mathew George1, Michael Shannon
1Harvard Medical Toxicology Program, Division of Emergency Medicine, Children's Hospital Boston, Boston, MA, USA. drmg456@gmail.com
Pediatric Emergency Care
|September 17, 2009
Summary
Intravenous contrast agents do not significantly increase serum osmolality or create an osmolal gap in pediatric patients. Further evaluation is needed for unexplained osmolal gaps post-CT scan.
Area of Science:
- Radiology
- Clinical Chemistry
- Pediatric Emergency Medicine
Background:
- Intravenous contrast agents used in computed tomography (CT) scans may increase serum osmolality, potentially causing an osmolal gap.
- An unexplained osmolal gap can lead to extensive evaluations for toxic substances, including toxic alcohols.
- The effect of intravenous contrast media on serum osmolality and osmolal gap has not been systematically studied.
Purpose of the Study:
- To investigate whether intravenous contrast agents significantly alter serum osmolality or create an osmolal gap in pediatric patients undergoing CT scans.
- To determine the relationship between contrast agent administration and changes in serum osmolality and osmolal gap.
Main Methods:
- A cohort of pediatric patients (10-18 years) presenting to the emergency department with abdominal pain and requiring contrast-enhanced CT were evaluated.
- Serum osmolality and osmolal gap were measured before and 30 minutes after the administration of Optiray 320 (ioversol).
- Osmolal gap was calculated using standard laboratory values (Na, BUN, glucose).
Main Results:
- No statistically significant increase in mean serum osmolality was observed post-contrast administration (292.75 vs. 292.875 mOsm/L, P = 0.93).
- Mean osmolal gap showed no significant change (9.17 vs. 12.15 mOsm/L, P = 0.133), with a mean difference of 0.125 mOsm/L.
- No significant correlation was found between contrast dose and postcontrast osmolality or osmolal gap.
Conclusions:
- Conventional doses of intravenous contrast agents do not significantly increase serum osmolality or produce an osmolal gap in pediatric patients.
- An osmolal gap identified after a contrast-enhanced CT scan warrants a comprehensive etiological investigation rather than attributing it to the contrast agent.
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