Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests

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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.

Original languageEnglish
Pages (from-to)8-15
Number of pages8
JournalAmerican Journal of Emergency Medicine
Volume31
Issue number1
DOIs
Publication statusPublished - 2013 Jan 1

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Out-of-Hospital Cardiac Arrest
Partial Pressure
Ammonia
Blood Pressure
Area Under Curve
Hospital Emergency Service
Confidence Intervals
Hyperammonemia
Information Management
Tertiary Care Centers
ROC Curve
Observational Studies
Multivariate Analysis
Prospective Studies

All Science Journal Classification (ASJC) codes

  • Emergency Medicine

Cite this

@article{aadfe6139b62437c86c00465104e3cbe,
title = "Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests",
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.",
author = "Chih-Hao Lin and Chih-Hsien Chi and Wu, {Shyu Yu} and Hsiang-Chin Hsu and Ying-Hsin Chang and Yao-Yi Huang and Chih-Jan Chang and Ming-Yuan Hong and Tsung-Yu Chan and Hsin-I Shih",
year = "2013",
month = "1",
day = "1",
doi = "10.1016/j.ajem.2012.04.037",
language = "English",
volume = "31",
pages = "8--15",
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TY - JOUR

T1 - Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests

AU - Lin, Chih-Hao

AU - Chi, Chih-Hsien

AU - Wu, Shyu Yu

AU - Hsu, Hsiang-Chin

AU - Chang, Ying-Hsin

AU - Huang, Yao-Yi

AU - Chang, Chih-Jan

AU - Hong, Ming-Yuan

AU - Chan, Tsung-Yu

AU - Shih, Hsin-I

PY - 2013/1/1

Y1 - 2013/1/1

N2 - 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.

AB - 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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