Biomedical Engineering Reference
In-Depth Information
this procedure is not 100% effective. Studies made with 2,980 patients that has
this procedure, show that the leakage through the anastomosis was 5.1% [
3
].
A gastroesophageal anastomotic leak after cancer resection, for example, has a
mortality rate of up to 60% and significant morbidity, no matter what type of
treatment is applied after it [
4
]. A perfect anastomosis depends to a high degree
on the surgeon's skill [
5
], whereas some robot-assisted surgeries, as they do not
need direct contact between patient and surgeon, are shown to be more accurate
[
6
]. Therefore, an anastomotic leak has the potential of representing a problem for
surgeons [
7
] and will increase the duration of hospital stay, which is associated
with remedial treatment and recovery, causing, as a result, a negative financial
impact [
2
,
8
].
Normally leakages can be identified during surgery just after the surgeon finishes
the construction of the anastomosis. A number of research techniques to detect,
treat, and even prevent an anastomotic leakage are under investigation. However,
studies show that these techniques are not always able to prevent an anastomotic
leak from occurring [
2
]. Applying saline through the rectum is a technique widely
discussed in previous studies. Gilbert and Trapnell [
9
] developed this technique
and reported it in 1988 in the Annals of the Royal College of Surgeons. However,
despite the fact that this technique demonstrated simplicity in its execution, further
studies showed that it is not 100% guaranteed that there will be no occurrence of an
anastomotic leakage in the future. Instead of applying saline there is also a method
that applies air through the rectum. This technique is widely known as “The bubble
test”. This test is performed by filling the pelvis with saline and the next step is to
insufflate air through the rectum. If air bubbles appear, that is an indication that the
anastomosis is compromised and further strengthening is required. It was concluded
that an air-tight anastomosis is unlikely to leak, but it was recognized that the test is
not 100% reliable.
An alternative approach to the problem is presented in this paper and uses a gas
sensor and a trace gas to evaluate the leakage rate through the anastomosis. This
paper discusses the dynamic behavior of N
2
O gas through different sized leakages
as detected by an Infra-Red gas sensor and how the sensors response time changes
depending on the leakage size. Tests were made experimentally and also using a
Computational Fluid Dynamics (CFD) package called FloWorks. The results will
be compared and discussed in this paper.
2
The SUSIE Method
The problem with previous techniques is that it was not possible to estimate
or calculate the maximum pressure that can be applied safely to the bowel. By
distending the bowel by increasing the pressure in the area of the anastomosis might
bring about a leakage of bowel faecal contents into the cavity of the abdomen. An
alternative method to previous research is discussed in this paper which, instead of
