Detection of neonatal sepsis using dynamic light scattering skin sensors

Current hemodynamic monitoring in the neonatal intensive care unit (NICU) is
focused on the central systemic circulation. It is however known that the
microcirculation is one of the systems which are affected already in the early
phase of certain diseases, such as late-onset sepsis. The microcirculation
could therefore be an important indicator of the severity of sepsis and the
response to therapy. Currently there is no continuous clinical parameter which
indicates the microcirculatory state. Recently, a new miniaturised dynamic
light scattering (DLS) sensor has become available which enables measurement of
the microcirculatory blood velocity. We hypothesise that with this measurement
technology, differences in microcirculatory blood velocity can be found between
septic neonates and neonates in whom a suspicion of sepsis is not proven.

The primary objective is to determine the difference in median red blood cell
velocity (RBV) measured within a time interval of half an hour with dynamic
light scattering technology between neonates with and without neonatal
late-onset sepsis.

This pilot study is a prospective observational cohort study. When neonatal
(late-onset) sepsis is suspected and informed consent is obtained, blood
velocity measurements using one or two dynamic light scattering sensors will be
performed. Blood velocity measurements will be continued until cessation of
antibiotic treatment.

The sensor will be attached to the skin using double- sided adhesives, custom
adhesive rings and/or commercially available adhesive rings that are used for
regular care transcutaneous blood gas monitoring. With these adhesives, the
sensors can be kept in place for several days. The DLS sensor contains a class
1 laser source and is safe for the human retina. Several studies have shown
these lasers to be safe for the neonatal retina in particular. As preterm
neonates still develop the ability to focus their eyes, they have a much
smaller effective capacity to focus which is the main reason that the intensity
of the DLS laser will be substantially less in premature neonates. Moreover,
class 1 lasers are characterised to cause no thermal effects on the retinal
tissue when fully focussed on the retina, regardless of the exposure time.
Both the suboptimal capacity of focusing in preterm neonates and the use of a
class 1 laser, lead to no additional risk of the DLS laser in preterm neonates.