Microvascular flow is compromised early in neonatal infection

Background and Aims: The early diagnosis of neonatal infection remains a challenge. Recent studies using Orthogonal Polarization Spectral (OPS) imaging techniques, have reported microcirculatory alterations in adult patients with severe sepsis and septic shock^1,2. The objective of this study was to compare microcirculatory flow and vascular density between healthy (H) and sick newborns (I) with neonatal infection.

Methods: We obtained prospectively OPS images from the ear conch of 46 infants on their 1^st, 2^nd and 3^rd day of life. Infection was defined as IL–6>50pg/mL and CRP>0,5mg/dL. The OPS sequences were analyzed off-line, blinded to clinical status of the infant, using a semiquantitative assessment of flow based on the work of Sakr² and Boerma³.

Results: In the 16 infants of group I the percentage of vessels with impaired flow was significantly elevated (mean I [95%CI]: 31% [19–44] vs. H: 9% [6–13] p=0,0003) whereas the trend to lower vascular density did not reach statistical significance (I: 5,9 [5,5–6,5]vs. H: 6,5 [6,2–6,8] vessels/mm). Most episodes of infection were not severe (median CRP: 1, 05mg/dL; median IL–6: 98,2 pg/mL). In 69% of the infection cases, microcirculatory changes were seen a day before CRP was elevated. Birth weight an gestational age did not differ between the groups.

Conclusion: Even in infants with mild to moderate signs of infection, microcirculatory flow is impaired in a large proportion of vessels early in the course of disease. Since these changes can be easily recognized at the external ear, an on-line evaluation of microcirculatory flow could be an important screening tool for infection in the future.