Imaging tracks changes in gastric microcirculation during surgery

Last Updated: 2017-07-12

By David Douglas

NEW YORK (Reuters Health) - Laser speckle contrast imaging (LSCI) during esophagectomy shows that changes in gastric microcirculation have more to do with surgery than thoracic epidural anesthesia (EA) or use of vasopressors, according to Danish researchers.

As Dr. Rikard Ambrus explained in an email to Reuters Health, "Real-time changes of the microcirculation over large tissue areas during surgery have been restricted by technical challenges. With LSCI, visualization of the microcirculation is simple and reliable."

As reported June 29 online in the Journal of the American College of Surgeons, Dr. Ambrus of the University of Copenhagen and colleagues studied 45 patients undergoing open esophagectomy.

Their aim was to explore the effect of EA on gastric microcirculation. They believed the microcirculation would be affected by EA-induced hypotension and use of vasopressors to maintain blood pressure.

In all, 25 patients were randomized to receive intraoperative activation of EA (just after induction of general anesthesia); the remaining 20 patients did not receive activation until the end of surgery. The LSCI operator was blinded to the timing of EA.

Antrum microcirculation was lower in the EA group at baseline. But regardless of when thoracic EA (TEA) was established, “gastric microcirculation decreased during surgery and the decrease was most pronounced at the body of the stomach," the authors found.

Moreover, they say, the decrease "seemed related to the surgical procedure including ligation of proximal vascular supply to the stomach rather than to when TEA was established." A similar decrease in LSCI-determined antrum and corpus microcirculation was seen in the delayed EA group.

The researchers note that the LSCI technique cannot determine absolute flow, and results are expressed as a flux in arbitrary laser speckle perfusion units (LSPU), which are linearly related to flow.

For example, in the delayed EA group, antrum microcirculation fell from 1265 to 1097 LSPU and in the EA group, the drop was from 1150 to 1064 LSPU. There was no difference between groups during the remaining laparotomy.

Given these findings, the researchers conclude that LSCI “is suitable for real-time and non-contact assessment of microcirculation in a clinical setting and may be a valuable tool in studies examining factors affecting splanchnic microcirculation."

In fact, Dr Ambrus added, "The technique will most likely find its way to the operating theater assisting surgeons during decision making. Also, the technique offers an opportunity for studying real-time effects of (for example) different drugs and treatments on the microcirculation, thus identifying the most optimal option for a specific situation or procedure."

SOURCE: http://bit.ly/2teIGtN

J Am Coll Surg 2017.