Stimulation of the autonomic nervous system to improve postoperative recovery after colorectal surgery

We hypothesized that stimulation of the autonomic nervos system via de vagal
nerve reduces the postoperative inflammatory response after colorectal surgery.
In this way, complications such as postoperative ileus will be reduced and
recovery after surgery is enhanced. Experimental studies already showed that
vagal nerve stimulation reduces postoperative ileus and decreases the
inflammatory response following hemorrhagic shock, endotoxemia and ischemia/
reperfusion. Stimulation of the autonomic nervous system releases acetylcholine
that binds to nictotinic receptors located on inflammatory cells. Hereby,
production of inflammatory mediators is directly inhibited. It is thought that
the chewing of gum activates the autonomic nervous system vai de vagus nerve.

To study the occurrence of postoperative ileus and the extend of the
postoperative inflammatory response either systemic as well as locally in the
bowel in patients receiving chewing gum before and after colorectal surgery.

A prospective, randomized controlled trial

Patients in this study will be divided into two groups. Group one will receive
chewing gum three hours preoperatively until time of surgery. Three hours
postoperatively chewing gum will be distributed again to the patients until the
start of enteral nutrition. All patients in group two, the placebo controlled
group, will receive a dermal patch three hours preoperatively. This dermal
patch will be removed until the first moment of oral nutrition is achieved.
Preoperatively the vagal activity of all patients will be measured by variation
of the heartbeat via blood pressure measurements, electrocardiographs and
impedance cardiographs.

Patients included in this study will be seen one extra time at the outpatient
clinic. There will be taken 10 ml extra venous blood preoperatively additional
to the regular blood samples. There will be a vagal activity measurement by use
of electrocardiography and blood pressure measurements. These measurements are
without any known health risks, non invasive en take about one hour in total.
Biopsy will be done from the removed bowel to assess bowel damage. This causes
no extra inconvenience or risk for the patients. In the postoperative phase
blood samples (in total 36 ml) will be collected at six different time-points
till 48 hours postoperatively from an intravenous line, that is standard for
this kind of surgery. The collected amount of blood is not much and patients
have besides the vena puncture no other discomfort.