Microcirculatory perfusion alterations in severe burn injury

There are valid concerns that resuscitation in burns shock is inadequate. A
tendency to over resuscitate patients seem to exist. Current guidelines were
developed 35 years ago and clinical burn resuscitation had not advanced
significantly, despite ongoing research. The main goal of resuscitation is
achieving organ perfusion and tissue oxygenation. Inadequate fluid
resuscitation of severe acute burns may result in hypovolemic shock and death.
Excessive fluid resuscitation may result in fluid overload, lung edema,
intra-abdominal hypertension, abdominal compartment syndrome and burn depth
conversion with increased requirement for escharotomies, fasciotomies and skin
grafting.
Hypo perfusion caused by insufficient resuscitation may result in glycocalyx
shedding, aggravation of the inflammation and oxidative stress too which may
finally deteriorate outcome of a burn patient.
To date, the Parkland formula is the most used formula worldwide for
resuscitation of the acute burn patient. In this formula, 4cc/kg/% lactated
Ringers solution per percentage total body surface area (TBSA) is administered
in 24 hours of which the half in the first 8 hours. However, this formula has
some well-known restrictions; this formula necessitates large amount of fluids,
which need a close monitoring of clinical and laboratory parameters for the
control of the massive fluid infusion
Monitoring of adequacy of resuscitation in burns patients have always been
guided by systemic hemodynamic variables (macro circulation) like blood
pressure, heart rate, stroke volume and urinary output, being urine output the
major indicator of successful resuscitation. Whether these end points are
successful in achieving adequate perfusion and oxygen transport to the tissues
is unknown and relies on the assumption that there is a hemodynamic coherence
between the macro and microcirculation whereby improving the macro circulation
causes a parallel improvement in the microcirculation. However, emerging
evidence shows that targeting systemic hemodynamic variables gives inadequate
guarantee for correction of tissue perfusion by fluid therapy. Very recently,
Hernekamp et al described that stabilisation of the macrodynamic conditions did
not neccessarilay have a positive effect on the macro circulation in severe
burned rats (TBSA 30%).
Tissue monitoring devices have been described by Venkatesh et al. They found
that despite acceptable clinical indices of global perfusion during
resuscitation of severely burned patients, the splanchnic circulation in both
burned and normal skin remained compromised. In the past it was very difficult
to monitor the microcirculation at bedside. However, due to recent
technological advances it is possible to easily assess microcirculatory
perfusion of critically ill patients. Observation of the microcirculation adds
important measurements to conventional systemic monitoring of the
macrocirculation. Blood flow in the microcirculation can be assessed at the
bedside by means of a handheld sublingual microscope (Cytocam IDF) and Laser
Speckle Imaging. Cytocam IDF is a technologically new advanced version of hand
held microscopes (Cyto Cam, Braedius Medical, Huizen, The Netherlands) and able
to perform sublingual microcirculatory images. Laser Speckle imaging (LSI) is a
non-invasive non-contact method which can be used to evaluate blood flow in the
microcirculation in burns of different depths. Applying these non-invasive
bedside techniques in the clinical setting of severe burns patients will allow
us to see how the current resuscitation regime based on targeting systemic
macro circulatory targets effects the microcirculation and tissue perfusion.

Primary Objective: To assess the incidence of microcirculatory perfusion
alterations, according to a predefined arbitrary cut off value, in patients
with severe burns injury (>15%TBSA) during standard resuscitation in the first
24 hours.

Study design: The design is a monocenter, prospective, observational clinical
study in the Maasstad Hospital.

negligable risk of participation in this study.
Sublingual cytocam measurement is non invasive and the probe is covered with a
sterile disposable cap for each patient
laser speckle image in non contact non invasive
blood samples are withdrawn via a standard inserted arterial canula (so no
extra burden) . Only risk is theoretical risk of anemia for sampling blood.