skin autofluorescense in patients undergoing elective colorectal surgery.

Laparotomy causes oxidative stress in the gut because of an increase in
xanthine oxidase, decreased antioxidant status of the gut and a change in
mitochondrial funtioning of enterocytes. Inflammation and ischemia-reperfusion
effects also attribute to this oxidative stress. As a consequence there are
both local and systemic effects notable. Ischemia-reperfusion effects are
normal in any laparotomy, thus not only when bloodvessels are clamped.
Splanchnic vasoconstriction happens during hypovolemia, epidural anesthesia and
manipulation of the gut. This local ischemia-reperfusion causes an enhanced
permeability of the gut, sepsis and a increased systemic inflammatory response.
Local increase in oxidative stress has shown to be related to a higher chance
of anastomotic leakage in animal models. The systemic response to this
ischemia-reperfusion effect leads to an increased rate of cardiopulmonary
complications.

Different methods can be used to detect oxidative stress. One of these is
autofluorescence of the skin. An increased autofluorescense of the skin caused
by oxidative stress is already shown in acute coronary events and sepsis.
Autofluorescense is not only a marker of oxidative stress but it also increases
when Advancced Glycation Endproducts (AGEs) are being formed. AGEs are formed
through biochemical reactions of glucose, lipids, proteins and oxidative
stress. Therefore skin autofluorescense is an indicator of cumulative metabolic
stress. AGEs are related to the genesis of a broad spectrum of systemic
complications such as atherosclerosis, renal failure and M. Alzheimer. AGEs are
able to predict cardiovascular morbidity and mortality. Simm et al have shown
that the level of preoperative AGEs is a predictor of per-operative occurrence
of complications and length of stay in the intensive care unit. One could
assume that the amount of AGEs is related to the vitality of a patient.

To determine if there is an increase of skin-autofluorescense in subjects
undergoing elective colorectal surgery.

This study will be an observational pilot study in the Isala Clinics Zwolle. 75
patients undergoing elective colorectal surgery will be included in the study.
Pre- and post-operative autofluorescense (AFR)-measurement of the skin will be
done. Also patient characteristics (eg indication, comorbidities) will be
looked at. Details of surgery will be noted too, like length of operation,
blood loss, diuresis, saturation, blood pressure and preoperative
complications. Besides the AFR-measurement CRP, leucocytes, kreatinine,
glucose, NK-cells, vital functions, diuresis, length of ileus and complications
will be noted too. In the Isala Clinics these data can be collected through the
already existing colorectal database. After including 75 patients we will
analyse the data in order to specify our hypothesis.

The autofluorescense measurement will be done daily. The meaurement will cost 5
minutes of a patients time and is non-invasive. Also patients don't need to be
transported because the measurement can be done anywhere. The vena-punction
will be one every other day. Undergoing these vena-punctions comprises the
usual burden/risks: pain, tromboflebitis, hematoma.