Background Early recognition of early onset sepsis (EOS) in neonates is difficult. Conventional markers like CRP rise late. Interleukin 6 (IL-6) is an early reliable marker. These methods require blood sampling. Non-invasive methods in early recognition of EOS would be useful.
Methods Prospective, single centre study in neonates at risk of EOS. Standard septic workup was undertaken (blood culture, WBC, PC, CRP). Clinicians were blinded to IL-6 results (100 μl serum, Picoscan, Milenia Biotec, FRG). Within 2 h white-light spectroscopic measurement (Mediscan, MBR Messtechnik, FRG) of the microcirculation at the forearm was performed obtaining baseline, then a defined pressure of 5N for 5s was applied and the circulatory response measured. The gradient of the tangent to the curve was used as determinant of vascular response and classified as septic or normal. Sensitivity, specificity, positive predictive and negative predictive values were calculated.
Results 15 neonates (median: 39 weeks, 3.38 kg) were included of whom 11 were treated with antibiotics until blood culture results were available (all negative). 7 neonates had abnormal IL-6 results compared to 6 patients with abnormal Mediscan. 8 patients had normal IL-6 results compared to 5 normal Mediscan. Sensitivity, specificity, positive predictive and negative predictive values were: 86%, 63%, 67% and 83%. When comparing conventional markers to IL-6 sensitivity, specificity, positive predictive and negative predictive values were: 29%, 100%, 100% and 83%.
Conclusions Conventional markers are unreliable as screening tools for EOS. Mediscan measurements agree well with IL-6 suggesting a potential use as a non-invasive screening tool.