Evaluation of gastric tube microcirculation with Sidestream Dark Field imaging during minimally invasive esophagectomy and the influence of tissue radiation and the position of the gastric tube in the body on microcirculatory parameters.

Esophagectomy is a high risk surgical procedure with high peri-operative
morbidity and a mortality rate of up to 3-4 % in large centers. Nowadays
patients undergo neoadjuvant chemoradiation therapy to improve postoperative
survival, but although the majority of operations is performed minimally
invasive, the incidence of complications associated with the anastomosis such
as leakage (4-26%) and stenosis (12-40%) remains high (1,2).
During oncologic resection and gastric tube formation, multiple arteries are
ligated and blood supply of the gastric tube depends on only one artery. This
compromised arterial blood supply but also venous congestion after tube
reconstruction has been suggested as causes of early anastomotic complications
(leakage) and late anastomotic complications (stenosis). Moreover the
anastomosis is made in the fundus where blood flow is most compromised. The
fluid status and use of vasopressors might be an influencing factor. In
addition, local damage to the tissues because of radiation therapy might
aggravate the damage to the microcirculation and thus may increase the risk of
leakage and stenosis of the anastomosis. The effect of radiation on
microcirculatory parameters has never been studied and might influence
microvascularisation of the gastric tube.
Various methods to measure the adequacy of microvascular blood flow in the
gastric tube have been tried out peri-operatively through reflection
spectrophotometry, laser Doppler flowmetry and Clark-type tissue oxymetry (2).
However, these are all indirect methods and the interpretation of the data can
be difficult. Originally, sublingual Sidestream Dark Field imaging has been
used to visually assess the microcirculation as a surrogate for the
microcirculation of other more remote tissues (3-5). However, it is also
possible to directly assess the microvascularisation in the target organ. For
example, this method has been used safely to examine the bowel mucosa in post
cardiac surgery and septic patients and the cortical microcirculation during
brain surgery. Therefore it might also be of additional value during gastric
tube reconstruction (6-8).
During minimally invasive esophagectomy, the patient is placed in head up
positioning to improve visualization of the upper abdomen. Postoperatively
patients are bound to stay in 30 degrees head up position to prevent reflux.
This positioning however, might affect the blood flow in the gastric tube. Thus
far it is unknown if positioning of the patient influences the microcirculation
of the gastric tube.

To directly evaluate the gastric tube microcirculation with Dark Sidestream
imaging during minimal invasive esophageal resection on several locations, i.e.
from best arterial blood supply (antrum) to worst (fundus). Furthermore, to
evaluate the influence of fluid balance and vasopressor use, tissue radiation
and positioning during operation on gastric tube microcirculation

Single-center pilot observational study

Benefits and risks

There is no additional risk related to participation in this trial. Sidestream
darkfield imaging has used to measure intestinal perfusion in other
investigations (6,7¬). In addition, this method has been used safely to
directly measure cortical microcirculation in patients with decompressive
craniectomy (8). No side effects of risks were reported. A sterile cover is put
over the probe and the probe will not be inserted inside a body cavity.
Patients will receive standard care concerning anaesthesia and fluid
management. No extra interventions are performed. Each measurement at each
location will take about thirty seconds to record, with a maximal total of 10
minutes.

Benefits

This study is observational only. Participating will not give direct benefits
to the patient. At this time no intervention or change in surgical or
anesthetic management will take place. However, the results might influence
the placement of the anastomosis in future populations and give more insight in
the etiology of anastomotic failure. In addition, the results might influence
anesthesiologic managment concerning the use of vasorpressors and fluids.

Burden

The measurements will cause no damage to the tissues. The probe will be held
very lightly on the tisse, as less pressure gives better results. All
measurements will be done while the patient is under anesthesia.