Affiliation

• ¹Department of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Sigmund- Freud-Str. Bonn, Germany
• ²Department of Rehabilitation and Special Education, University of Cologne, Herbert-Lewin-Str. Köln, Germany
• ³Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Sigmund- Freud-Str. Bonn, Germany
• ⁴Center Clinician Scientist, Emergency Department, University Hospital Bonn, Sigmund- Freud-Str. Bonn, Germany

Corresponding Author

Ramona Dolscheid-Pommerich, MD, Sigmund-Freud- Str. 25, 53127 Bonn, Germany, Tel: +49 228 287 12180/ Fax +49 228 287 12159; E-mail: ramona.dolscheid-pommerich@ukbonn.de

Citation

Dolscheid-Pommerich, R.C., et al. Retrospective Evaluation of the Accuracy of Point of Care Versus Central Laboratory Sodium Measurements at a Supra Maximal Care Hospital. (2018) J Anesth Surg 5(1): 22- 40.

Copy rights

© 2018 Dolscheid-Pommerich, R.C. This is an Open access article distributed under the terms of Creative Commons Attribution 4.0 International License.

Keywords

Abstract

Background: Sodium is most frequently requested by the emergency department (ED). It can be measured by direct or indirect ion-selective electrodes (ISE). Aim: Comparison of sodium values obtained from POCT under proven concept conditions and Central Laboratory (CL) analyzers in an accredited laboratory in a large collective of patients. Do significant differences exist in sodium values obtained by direct/indirect ISE?
Methods: In 1941 patients, sodium values were established with POCT-blood gas analyzers in parallel with CL-analyzers. Differences between values were calculated. Clinical relevant outliers were evaluated according to reference and alarm ranges. Data were analyzed with correlation analysis, Bland-Altman plot and outlier evaluation.
Results: Average age was 55.7 years. Male-to-female ratio was 1149:792. Mean value of the absolute difference between POCT and CL sodium was 0.9 mmol/l. POCT sodium mean value was 137.9 mmol/l (SD 4.7) and CL sodium mean value was 139.6 mmol/l (SD 4.2). POCT sodium and CL sodium correlated significantly (r = 0.81, p < 0.0001). Bland-Altman´s mean difference of the measurement values was 1.6 (limits of agreement -3.8 to +7.1). 433 patients had sodium values outside of reference ranges. In 197, both values resulted in the same diagnosis. McNemar´s test revealed significant differences (p < 0.0001). 9 patients had values outside alarm ranges, in five of these cases, both values resulted in the same diagnosis.
Conclusion: We showed that in a large ED-collective of a supra maximal care hospital more than 85% of the patients had no clinically relevant discrepancies regarding their sodium values obtained with direct or indirect ISE.