Precision, Accuracy, and Managed Care Implications of a Hand-Held Whole Blood Analyzer in the Prehospital Setting

Abstract

Hand-held portable clinical analyzers permit the rapid measurement of whole blood electrolytes, glucose, blood urea nitrogen (BUN) and hematocrit. Knowledge of these values in the field might aid radio telemetry emergency department physicians in the field treatment and triage of patients. The purpose of this study was determine if the analyzer could function in the hostile prehospital environment. In phase 1, analyses of control electrolyte (n = 30) and hematocrit (n = 28) solutions were performed in a moving ambulance by paramedics to determine precision performance. The F-statistic was used to compare variances against reference values and no significant differences were found. In phase 2, prospective split-sample testing of 57 whole blood samples drawn in the field were analyzed on 2 machines by paramedics in a moving ambulance, and then again within 10 minutes of arrival at the receiving hospital emergency department. Regression analysis between ambulance and emergency department venues revealed high correlation (r) values: sodium (Na)+ (0.93), potassium (K)+ (0.99), chloride (Cl)- (0.89), BUN (0.99), glucose (0.99), hematocrit (0.95), and hemoglobin (0.92). A hand-held whole blood analyzer can be reliably used in the field to obtain blood chemistry and hematocrit values. There was excellent correlation between field and hospital emergency department values. Clinical pathologists extend their oversight and consider encouraging emergency physicians to obtain field blood chemistry values in research studies aimed at improving medical treatment and patient triage in the prehospital setting. We speculate that these results might be important to managed care groups because knowledge of blood chemistry values in the field might provide physicians with objective, criteria-based data on which to triage patients to the emergency department, to an ambulatory care setting, or to a community health center with attendant cost savings.