Journal of The Korean Society of Clinical Toxicology (대한임상독성학회지)

Korean society of Clincal Toxicology (대한임상독성학회)
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Discrepancies and Validation of Ethanol Level Determination with Osmolar Gap Formula in Patients with Suspected Acute Poisoning

급성 중독환자에서 삼투압 계산식으로 추정된 에탄올 농도의 유효성 검증

  • Jung, Haewon (Department of Emergency Medicine, School of Medicine, Kyungpook National University) ;
  • Lee, Mi Jin (Department of Emergency Medicine, School of Medicine, Kyungpook National University) ;
  • Cho, Jae Wan (Department of Emergency Medicine, School of Medicine, Kyungpook National University) ;
  • Ahn, Jae Yun (Department of Emergency Medicine, School of Medicine, Kyungpook National University) ;
  • Kim, Changho (Department of Emergency Medicine, School of Medicine, Kyungpook National University)
  • 정해원 (경북대학교 의과대학 응급의학교실) ;
  • 이미진 (경북대학교 의과대학 응급의학교실) ;
  • 조재완 (경북대학교 의과대학 응급의학교실) ;
  • 안재윤 (경북대학교 의과대학 응급의학교실) ;
  • 김창호 (경북대학교 의과대학 응급의학교실)
  • Received : 2019.06.06
  • Accepted : 2019.11.15
  • Published : 2019.12.31
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Abstract

Purpose: Osmolar gap (OG) has been used for decades to screen for toxic alcohol levels. However, its reliability may vary due to several reasons. We validated the estimated ethanol concentration formula for patients with suspected poisoning and who visited the emergency department. We examined discrepancies in the ethanol level and patient characteristics by applying this formula when it was used to screen for intoxication due to toxic levels of alcohol. Methods: We retrospectively reviewed 153 emergency department cases to determine the measured levels of toxic ethanol ingestion and we calculated alcohol ingestion using a formula based on serum osmolality. Those patients who were subjected to simultaneous measurements of osmolality, sodium, urea, glucose, and ethanol were included in this study. Patients with exposure to other toxic alcohols (methanol, ethylene glycol, or isopropanol) or poisons that affect osmolality were excluded. OG (the measured-calculated serum osmolality) was used to determine the calculated ethanol concentration. Results: Among the 153 included cases, 114 had normal OGs (OG≤14 mOsm/kg), and 39 cases had elevated OGs (OG>14). The mean difference between the measured and estimated (calculated ethanol using OG) ethanol concentration was -9.8 mg/dL. The 95% limits of agreement were -121.1 and 101.5 mg/dL, and the correlation coefficient R was 0.7037. For the four subgroups stratified by comorbidities and poisoning, the correlation coefficients R were 0.692, 0.588, 0.835, and 0.412, respectively, and the mean differences in measurement between the measured and calculated ethanol levels were -2.4 mg/dL, -48.8 mg/dL, 9.4 mg/dL, and -4.7 mg/dL, respectively. The equation plots had wide limits of agreement. Conclusion: We found that there were some discrepancies between OGs and the calculated ethanol concentrations. Addition of a correction factor for unmeasured osmoles to the equation of the calculated serum osmolality would help mitigate these discrepancies.

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References

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