Reliability of point of care assessments of hemoglobin, hematocrit and electrolytes obtained with blood gas device and central laboratory blood gas analyzer in critical emergency clinical setting 

Background: The point of care blood gas measurements are designed to aid immediate patient management right at their bedside.
Objective:  This study aimed to determine the association of parameters-hemoglobin, hematocrit, sodium, potassium levels obtained with blood gas device versus central laboratory analyzer and to evaluate their co-relation in different ranges of pH, age groups and gender.
Methodology: This cross sectional study was carried out for six months in emergency treatment unit (ETU), National Hospital of Sri Lanka, Colombo. In recruited patients, venous blood samples were obtained at the admission for both measurements of central laboratory and blood gas analysis.
Results: A total of 440 patients were included, of them 49.8% was male. Mean age 56.9 years (SD 22.33). Mean values of sodium, potassium, hemoglobin, hematocrit in blood gas analysis were 137.15(range 97.6-162), 3.99(1.9-7.4), 12.55(5.9-19.2), 35.65(40-58) respectively. In contrast, the laboratory values for the same parameters were 137(98-163), 4.09(1.99-7.0), 12.24(5.66-19.0), 35.94(19.5-56.9). There was a significant difference between the laboratory and blood gas hematocrit values (p=0.04), however mean values were closely lined. Subgroup analysis in gender, values were not statistically significant except hemoglobin levels (p=0.02). Further subgroup analysis among age and pH groups did not show significant difference.
Conclusion:  The critical decision can be made by trusting sodium, potassium and hemoglobin values obtained from blood gas analysis. The hematocrit values need to review once laboratory results are available before making a critical decision.