Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests - 08/12/12
Abstract |
Purposes |
Outcome prediction for out-of-hospital cardiac arrest (OHCA) is of medical, ethical, and socioeconomic importance. We hypothesized that blood ammonia may reflect tissue hypoxia in OHCA patients and conducted this study to evaluate the prognostic value of ammonia for the return of spontaneous circulation (ROSC).
Methods |
This prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2008. The subjects consisted of OHCA patients who were sent to the emergency department (ED). The primary outcome was ROSC. The prognostic values were calculated for ammonia levels and the partial pressure of ammonia (pNH3), and the results were depicted as a receiver operating characteristics curve with an area under the curve.
Results |
Among 119 patients enrolled in this study, 28 patients (23.5%) achieved ROSC. Ammonia levels and pNH3 in the non-ROSC group were significantly higher than those in the ROSC group (167.0 μmol/L vs 80.0 μmol/L, P < .05; 2.61 × 10−5 vs 1.67 × 10−5 mm Hg, P < .05, respectively). The predictive capacity of area under the curve for ammonia and pNH3 for non-ROSC was 0.85 (95% confidence interval, 0.75-0.95) and 0.73 (95% confidence interval, 0.61-0.84), respectively. The multivariate analysis confirmed that ammonia and pNH3 are independent predictors of non-ROSC. The prognostic value of ammonia was better than that of pNH3. The cutoff level for ammonia of 84 μmol/L was 94.5% sensitive and 75.0% specific for predicting non-ROSC with a diagnostic accuracy of 89.9%.
Conclusions |
Hyperammonemia on ED arrival is independently predictive of non-ROSC for OHCA patients. The findings may offer useful information for clinical management.
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☆ | Disclosures of conflict of interest: The authors disclose no conflicts. |
☆☆ | Ethical adherence: The study procedures were in accordance with the ethical standards and were approved by the institutional review board in the hospital. |
☆☆☆ | Funding and support: No financial support was granted. |
★ | Writing assistance: None. |
★★ | Author contributions: CHL conceived and supervised the study. All authors were involved in acquisition of data. CHL and SYW interpreted the data and performed statistical analysis. CHL drafted the manuscript, and all authors contributed substantially to its revision. CHL and CHC offered administrative and technical supports. CHL is the corresponding author who takes responsibility for the manuscript as a whole. |
Vol 31 - N° 1
P. 8-15 - janvier 2013 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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