411 Microcirculatory Parameters as Early Markers for Infection in Preterm Infants

Abstract

Background We have previously shown that orthogonal spectral imaging (OPS imaging) can be used to measure microcirculatory parameters such as Red Blood Cell Velocity (RBC Vel) and Functional Capillary Density (FCD). As neonatal infections often manifest unspecificly in e. g. paleness and prolonged capillary refill time we examined if a decrease in FCD can predict neonatal infection.Methods in 25 preterm infants (gestational age of 28 (26,18 - 27,58) wks; birth weight 900 (807,9 - 992,8) g) RBC Vel and FCD was determined from d 3 till d 30 of life. OPS imaging was applied to the upper arm near the axilla, images were stored on videotape and analyzed off-line with the CapiScope Program.Results There were 17 episodes of proven infections (PosInf) with either increased C-reactive Protein or increased interleukine-6. The day when antibiotic treatment was started was defined as d 0 of infection and the evaluation was concentrated on five days before (d -5 until d -1) and five days after (d +1 until d +5). In nine cases the suspected infection was not confirmed biochemically (NegInf). Four infants had no episode of infection for entire time. In PosInf we found a statistical significant decrease in FCD from d -5 to d -1 (mean (95% CI) 231 (187 - 236) cm/cm2 versus 234 (190 - 257) cm/cm2 ; p = 0,0127), but not for NegInf ( p = 0,58). RBC Vel did not change from d -5 to d -1 nor during infection.Conclusion A decreasing FCD correctly identified episodes of infections already one day earlier than changes in laboratory parameters. OPS-Imaging could be used for early diagnosis of secondary infection in preterm infants. However, these changes in FCD during infection are not represented by absolute values, but must be identified by daily intra-individually.