Study on comparison of electrolytes in hospitalized patients of critical care medicine by automated biochemistry analyzer and arterial blood gas analyzer

Abstract

Critical care medicine department has to assess electrolytes accurately and quickly to initiate the treatment. Blood samples are analyzed in a matter of seconds by arterial blood gas analyzers (ABG), albeit their accuracy is still up for debate. The current study objectives were to estimate and compare the levels of electrolytes (sodium, potassium, and chloride) in hospitalized critical care patients as determined by automated biochemistry analysis and blood gas analyzer and to assess the degree of agreement between the two instruments and obtain information on whether these values can be interchanged. A prospective hospital based observational study was undertaken after obtaining institutional ethical committee clearance. The study included a total of 195 paired venous and arterial samples from the patients admitted to Critical Care Medicine Unit of NIMS Hospital, Jaipur, India in whom electrolytes were analysed on Arterial Blood Gas (ABG) analyzer and Automated Biochemistry Analyzer (ABA). Analysis was done on ABL555 blood gas analyzer located in the critical care medicine unit and vitros 5600, located in Clinical Biochemistry. Statistical analysis was done using Student’s t test and Pearson’s correlation coefficient test.A total of 195 samples were analyzed. The mean levels of sodium, potassium and chloride were 136.64 ± 5.44 mmol/L, 3.87 ± 0.523 mmol/L and 100.79 ± 6.65 mmol/L respectively analyzed by ABG analyzer. The mean levels of sodium, potassium and chloride were 136.65 ± 5.81mmol/L, 88 ± 0.543 mmol/L and 100.47 ± 6.41 mmol/L respectively analyzed by ABA. Student’s t test comparison p values for sodium, potassium and chloride were 0.458 (Not Significant), 0.1867 (Not Significant) and 0.0438 (Significant) between the two instruments. The strength of agreement between the two instruments for sodium, potassium and chloride were analyzed using pearsons correlation coefficient. There was strong agreement for all the three parameters between the two instruments and the p value was 0.00001 (highly significant) for all the three parameters.The results of this investigation showed no discernible differences between the automated biochemistry analyzer and arterial blood gas analyzer measurements of sodium, potassium, and chloride. Clinicians can make critically important decisions by relying on the results of arterial blood gas analysis.