Contribution of serum ethanol concentration to the osmol gap: a prospective volunteer study

Carstairs, Shaun D.; Suchard, Jeffrey R.; Smith, T. Lynn; Simon, L; Kalynych, Colleen; Shimada, Masatoshi; Tanen, D. A.

doi:10.3109/15563650.2013.791695

Cited by 11 publications

(5 citation statements)

References 9 publications

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“…When examining the mean difference, there was no significant difference between Formula 5a and measured ethanol, but there were constant and proportional differences between the measurement and the Formula 5a result. Our results indicating that the coefficient for ethanol should be greater than 1/4.6 agreed with the findings of several studies [9][10][11]. But it may vary with increasing ethanol concentrations, as ethanol may affect the solubility of solutes in serum as a solvent.…”

Section: Discussionsupporting

confidence: 81%

Comparison of measured ethanol and calculated ethanol using osmolal gap and osmolarity formulas

Börü¹

2017

Int J Med Biochem

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Comparison of measured ethanol and calculated ethanol using osmolal gap and osmolarity formulasO smolality is the concentration of the osmoles of solute dissolved per kilogram of pure water (mOsmol/kg H 2 O), whereas osmolarity is the concentration of the osmoles of solute dissolved per liter of solution (mOsmol/L). These 2 terms can be used interchangeably, but osmolality is a more accurate term thermodynamically. Solution concentrations are expressed on the basis of weight, and therefore, it is independent of temperature and pressure. In contrast, solution concentrations are expressed on the basis of volume in osmolarity, and changes in volume can occur depending on the thermal expansion of the solution. As a result, osmolarity can lead to incorrect results in cases of hyperlipidemia or hyperproteinemia, or in the presence of osmotically active substances, such as alcohol or mannitol [1][2][3].The osmolal gap is the difference between measured osmolality and calculated osmolality. Normally, the osmolal gap is less than 10 mOsmol/kg H 2 O [4].A high concentration of alcohol, such as ethanol, methanol, isopropanol, ethylene glycol, or propylene glycol causes hyperosmolality and a high osmolal gap in proportion with the Objectives: Osmolality can be measured with an osmometer, and it can also be calculated using formulas that include the level of some osmotically active serum components. The difference between measured and calculated osmolality is referred to as the osmolal gap. The osmolal gap indirectly indicates the presence of osmotically active substances other than sodium, urea, and glucose. The aim of this study was to calculate the osmolal gap using 6 osmolarity formulas published in the literature and compare the measured ethanol concentrations with various ethanol calculation formulas that include the osmolal gap. Methods: Serum ethanol, glucose, potassium, sodium, and urea levels were measured. Serum osmolarity was calculated with 6 formulas and converted to osmolality (mOsmol/L-mOsmol/kg H 2 O) using a converting factor. The osmolal gap was determined using measured and calculated osmolality with 6 different formulas for each sample. The osmolal gap values were multiplied by the ethanol coefficient used to ascertain the effect of ethanol on serum osmolality in order to obtain the amount of ethanol in the samples. Results: A positive correlation was observed between the 24 calculated ethanol levels and measured ethanol levels. No statistically significant difference was seen between the measured ethanol levels and 1 of the formulas, but there were systematic differences between them. Conclusion: Estimating the ethanol concentration with this type of approach is particularly inappropriate in forensic cases. The osmolal gap should only be used for screening toxic alcohols as an adjunct to clinical decision-making in emergency departments when ethanol cannot be measured, as in a case of alcohol intoxication.

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Section: Discussionsupporting

confidence: 81%

Comparison of measured ethanol and calculated ethanol using osmolal gap and osmolarity formulas

Börü¹

2017

Int J Med Biochem

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“…The osmol gap was divided by the blood ethanol to determine the mean coefficient of ethanol's contribution to serum osmolality, yielding 4.25 (95 % CI,. This divisor is smaller than that predicted by molecular weight of ethanol, indicating that it contributes more to total osmolality than predicted for an ideal solute [191]. The study has been criticized for proposing a mean coefficient when the underlying individual subjects had coefficients that were substantially inconsistent [193].…”

Section: Mass Unitsmentioning

confidence: 82%

“…Two more recent studies have studied the effect of ethanol on the osmol gap [191,192]. Carstairs and colleagues gave ten healthy volunteers up to 140 mL 100 % ethanol in sugar-free soda (n = 8) or plain sugar-free soda (n = 2).…”

Section: Mass Unitsmentioning

confidence: 99%

Acid–Base Balance in the Poisoned Patient

Borron¹

2016

Critical Care Toxicology

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“…The differing results reported by various investigators may be related to the varying characteristics of study samples (e.g., presence and absence of ethanol intake, or healthy volunteers) or data manipulation (compared with ethanol and osmolality which diminished ethanol contribution) 6,13,14) . The present study was conducted to validate the formula derived by Purssell et al 5,15) that linked ethanol concentration with OG.…”

Section: Discussionmentioning

confidence: 99%

“…We found that the correlation between the calculated ethanol level using OG and the measured ethanol level in patients with suspected acute poisoning was 0.704 (range in subgroups, 0.412-0.835). In previous studies, Pearson correlation coefficients were ranged from 0.93 to 0.994 for healthy volunteers or patients poisoned with known toxic alcohols 1,4,5, 13,14,17) . Chang et al 19) reported that the correlation between OG and measured ethanol level was 0.916 in all non-trauma and trauma patients; 0.939 non-trauma without shock patients; 0.917 in trauma without shock patients; and 0.844 trauma patients with shock.…”

Section: A B C Dmentioning

confidence: 99%

Discrepancies and Validation of Ethanol Level Determination with Osmolar Gap Formula in Patients with Suspected Acute Poisoning

Haewon¹,

Lee²,

jaewan³

et al. 2019

JKSCT

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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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Contribution of serum ethanol concentration to the osmol gap: a prospective volunteer study

Abstract: In this volunteer study, the coefficient describing the contribution of ethanol to serum osmolality (k) was found to be 4.25. This indicates that ethanol contributes more to total serum osmolality than would be predicted for an ideal solute.

Cited by 11 publications

References 9 publications

Comparison of measured ethanol and calculated ethanol using osmolal gap and osmolarity formulas

Comparison of measured ethanol and calculated ethanol using osmolal gap and osmolarity formulas

Acid–Base Balance in the Poisoned Patient

Discrepancies and Validation of Ethanol Level Determination with Osmolar Gap Formula in Patients with Suspected Acute Poisoning

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