Accuracy of Prehospital Intravenous Fluid Volume Measurement by Emergency Medical Services

Abstract

Prehospital treatment protocols call for intravenous (IV) fluid for patients with shock, yet the measurement accuracy of administered fluid volume is unknown. The purpose of the current study was to assess the accuracy of documented and self-reported fluid volumes administered to medical patients by paramedics during prehospital care. We conducted a pilot, observational study nested within a parent cohort study of prehospital biomarkers in a single EMS agency transporting patients to a tertiary care hospital in Pittsburgh, Pennsylvania over 8 months. Among eligible nontrauma, noncardiac arrest patients, we studied the self-reported IV fluid volume on ED arrival by paramedics, documented fluid volume in the EMS record, and compared those to the mass-derived fluid volume. We quantified the absolute error between methods, and determined EMS transport times or initial prehospital systolic blood pressure had any effect on error. We enrolled 50 patients who received prehospital IV fluid and had mass-derived fluid volume measured at ED arrival. Of these, 21 (42%) patients had IV fluid volume subsequently documented in EMS records. The median mass-derived fluid volume was 393 mL [IQR: 264–618 mL]. Mass-derived volume was similar for subjects who did (386 mL, IQR: 271–642 mL) or did not (399 mL, IQR: 253–602) have documented fluid administration (p > 0.05). The median self-reported fluid volume was 250 mL [IQR: 150–500 mL] and did not differ by documentation (p > 0.05). The median absolute error comparing self-reported to mass-derived fluid volume was 109 mL [IQR: 41–205 mL], and less than 250 mL in more than 80% of subjects. The median absolute error comparing documented fluid to mass-derived fluid volume was 142 mL [IQR: 64–265 mL], and was less than 250 mL in 71% of subjects. No difference in absolute error for either self-reported or document fluid volumes were modified by transport time or prehospital systolic blood pressure. Prehospital IV fluid administration is variably documented by EMS, and when recorded is typically within 250 mL of mass-derived fluid volume. Key words: emergency medical services; prehospital resuscitation; intravenous fluids; fluids