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Evaluation of i-STAT portable clinical analyzer in a neonatal and pediatric intensive care unit
J N Murthy1, J M Hicks, S J Soldin
1Department of Laboratory Medicine, Children's National Medical Center, Washington, DC 20010, USA.
Insights
The Point-of-Care (POC) i-STAT system accurately measures blood gases and electrolytes in neonatal and pediatric intensive care units. This reliable analyzer offers a marginal improvement in turnaround time compared to traditional laboratory methods.
Area of Science:
- Clinical Chemistry
- Point-of-Care Testing
- Critical Care Diagnostics
Background:
- Traditional blood gas analysis requires laboratory processing, leading to potential delays in critical care settings.
- Point-of-care testing (POCT) offers rapid results at the patient's bedside, improving clinical decision-making.
- The i-STAT system is a handheld POCT device for various blood analyses.
Purpose of the Study:
- To evaluate the accuracy and reliability of the i-STAT system for blood gas and electrolyte measurements in neonatal and pediatric intensive care units (NICU/PICU).
- To assess the performance of the i-STAT system when operated by non-laboratory personnel.
- To determine the necessity of routine quality control (QC) for the i-STAT system in a clinical setting.
Main Methods:
- The i-STAT system's imprecision and linearity were assessed using aqueous standards and whole blood samples.
- Patient samples were analyzed using both the i-STAT system and a Ciba Coming 288 blood gas analyzer for comparison.
- The impact of operator (nurses vs. lab personnel) and routine QC on i-STAT results was evaluated.
Main Results:
- The i-STAT system demonstrated good precision (%CVs < 3.5) and linearity for pH, pCO2, Na+, K+, and iCa2+.
- Excellent correlation (r > 0.95) was observed between i-STAT and Ciba Coming 288 for pH, pCO2, pO2, Na+, and K+; iCa2+ showed moderate correlation (r = 0.73).
- No significant difference in results was found between NICU/PICU nurses and laboratory personnel, and routine QC was deemed unnecessary.
Conclusions:
- The i-STAT system is a reliable point-of-care alternative to traditional blood gas analyzers for neonatal and pediatric critical care.
- The system provides a marginal improvement in turnaround time compared to central laboratory services.
- Careful cost management is essential for the effective implementation of the i-STAT system.
Objective:
To evaluate the Point-of-Care (POC) i-STAT system for measuring blood gases (pH, pCO2, pO2) and whole blood electrolytes (sodium, Na+, potassium, K+ and ionized calcium, iCa2+) in the neonatal and pediatric intensive care units.
Design And Methods:
The i-STAT system was evaluated for imprecision, necessity of running quality control and accuracy. Comparison of patients' samples analyzed by the i-STAT system and the Ciba Coming 288 blood gas analyzer were performed. The reliability of the i-STAT system when performed by non-laboratory personnel was assessed.
Results:
The system was evaluated for imprecision and linearity using three concentrations of aqueous standards. Except for pO2, the %CVs were < 3.0 for all the analytes (pH, pCO2, Na+, K+ and iCa2+) at all the three concentrations. Using whole blood studies the precision data gave %CVs that were < 3.5 for all the analytes. Linearity studies showed good linearity over the five different concentrations tested. Comparison of the i-STAT and the Ciba Coming 288 blood gas analyzer was assessed by split sample measurement. Patients' results from the i-STAT correlated well with the Ciba Coming 288 blood gas analyzer (r = 0.99 for pH, pCO2 and pO2 and 0.95 to 0.99 for Na+ and K+) with the exception of iCa2+ (r = 0.73). There was no significant difference in the results when operated by PICU/NICU nurses or laboratory personnel. A further study was made to assess whether routine quality control (QC) samples are necessary when using the i-STAT system. The regression analysis (slope and correlation coefficient) of the results from instruments run with and without QC samples gave results close to 1, indicating that there is no need to run additional quality control (QC).
Conclusion:
The POC testing analyzer i-STAT is a reliable alternative to the traditional blood gas analyzers and provides marginal improvement in turnaround time when compared with the service received from the PICU/NICU laboratory. Costs need to be carefully controlled.