Bowel plus anastomotic perfusion and oxygenation in colorectal surgery: variables to predict anastomotic leakage?

Anastomotic leakage remains a serious complication following colorectal
surgery. Its reported prevalence varies widely from 1% to 39%. Inadequate bowel
perfusion at the anastomosis is thought to be one of the factors involved
causing these anastomotic leaks.

Primary objective:
1. To investigate a correlation between perfusion measured by the
laser-Doppler-spectrophotometry O2C-device and anastomotic leakage in elective
colorectal surgery with a primary anastomosis.

Secondary objectives:
1. To investigate a correlation between the subjective evaluation of bowel
viability by the surgeon and the objective perfusion by the
laser-Doppler-spectrophotometry O2C-device.

2. To investigate reduction in bowel perfusion measured by the
laser-Doppler-spectrophotometry O2C-device at the anticipated site of
anastomosis after the colon is mobilized.

3. To investigate whether an inadequate anastomotic perfusion will result in a
long-term
morbidity such as incontinence and stricture.

All patients planned to undergo a left or right hemicolectomy, a sigmoid
resection, an anterior resection or a partial small bowel resection at the Vumc
will be asked to participate. An informed consent form will be obtained prior
to surgery.
Bowel perfusion, in terms of oxygen saturation of haemoglobin, the relative
amount of haemoglobin, blood flow and blood velocity, is measured during
surgery on the serosa at the anticipated site of anastomosis with the
laser-Doppler-spectrophotometry O2C-device: (1) before bowel mobilization, (2)
after bowel mobilization and (3) after the anastomosis is made. Parallel to the
measurements with the laser-Doplper-spectrophotometry O2C-device blood is drawn
for saturation and haemoglobin level measurements. In addition, functional
recovery of bowel perfusion and oxygenation in the distal and proximal bowel
limb is measured in the following manner: circulation to exactly 5 cm of the
distal and proximal bowel is cut off by a non-traumatic surgical clamp,
subsequently after clamp-release (=reperfusion) kinetics and time to full bowel
perfusion and oxygenation is measured.
The anastomosis must be tension free. At the time of measurements with the
laser-Doppler-spectrophotometry O2C-device the surgeon will be asked to
subjectively estimate bowel perfusion in terms of *good, reasonable, moderate
or poor perfusion*.
Patients will receive standard post-operative care as described in hospital
protocol. Patients are monitored for clinical signs of anastomotic dehiscence,
which would subsequently be objectified by abdominal CT scan. In addition,
patients will be monitored for stricture of the anastomosis.

No substantial risk or burden will be added to patients participating in this
study. The laser-Doppler-spectrophotometry O2C-device used in this study is
non-invasive and CE-approved, therefore allowed to be operated on humans. All
probes used are sterilized as described by the manufacturer and hospital
protocol. Predicting anastomotic leakage in patients undergoing colorectal
surgery with a primary anastomosis will decrease serious morbidity and even
mortality following this type of surgery.