Volume replacement in trauma patients within the first 24 h and its impact on the interpretation of biochemical data

Patients of the same and particularly of different trauma studies are primarily incomparable due to different volume replacements. The aim of this prospective study was to analyze the amount of initially administered fluids in trauma patients during the first 24 h and to estimate the impact of dilution on plasma protein concentrations (PPCs) of prostanoids. These substances are vascular endothelium-derived and are thus influenced by blood pressure.

Sixty-nine casualties suffering from multiple injuries were enrolled in the study. The amount of any fluid administered was scrutinized during the first 24 h. Patients were divided into subsets according to trauma severity by Injury Severity Score (ISS) (group=G-I: < or = 9; G-II: 10-18; G-III: 19-32; G-IV: >32) and between survivors and non-survivors. At corresponding time points, hemoglobin, hematocrit (Hct) and PPC as well as prostaglandins (PGI, TxA, PGF2a) were evaluated at the site of accident, at hospital admission, and every hour thereafter for the first 24 h.

During this period, the total amount of infused fluids ranged between 0.51 (G-I) and >481 (G-IV). The higher the trauma severity, the greater the volume infused (G-III/IV P=0.0003 vs G-I/II). Simultaneously, PPC dropped markedly (P<0.01). Patients who died within 36 h required higher volumes (P<0.003) than survivors. PPC was linearly related (r2=.6685, P<0.001) to Hct. During the first 24 h, the time course of prostanoid concentration was altered when dilution is not taken into account.

PPC proved a suitable parameter to estimate dilution effects and to adjust plasma concentrations of prostanoids. We recommend that consideration be given to possible dilution effects during the first 24 h when interpreting biochemical data in trauma patients.