A Comparison of the He Ne Laser and Ultrasound Doppler Systems in the Determination of Viability of Ischemic Canine Intestine

Abstract

One of the most challenging intraoperative dilemmas continues to be determination of viability of ischemic bowel. Many techniques and devices are available to help the surgeon, probably the most useful of which is the ultrasound Doppler. A more recently developed system, the laser Doppler, has a flexible optical fiber and fine tip probe that can be approximated onto or endoscopically passed into the gastrointestinal tract. This study was undertaken to experimentally compare the He Ne laser and ultrasound Doppler systems in predicting viability of ischemic canine intestine. Twenty ischemic bowel zones were created in dogs by division of the mesenteric blood supply. Determination of the last site of antimesenteric serosal nor fusion was then marked with each Doppler. Additionally, the fine tip probe was endoscopically passed across the ischemic zone and mucosal perfusion determined. Thus, each zone was marked three times, each indicating the anticipated site of necrosis by each method. The animals were killed 24 hours later and the tissues studied histologically. The results demonstrated that both the serosally applied and endoscopically placed laser Doppler were closer to predicting the point of total transmural necrosis. The possible clinical advantage of this device in prevention of short gun syndromes is readily apparent. The additional asset of a flexible optical fiber than can be endoscopically or laparoscopically passed make it an even more attractive modality. The findings of this study attested to the superior sensitivity, ease of use, and objectivity of the laser Doppler when compared with the ultrasound system.

Laser doppler flowmetry for estimation of bone blood flow: Studies of reproducibility and correlation with microsphere technique

“…Accordingly, LDF has proven useful for measurement of blood flow changes in the cerebral cortex (6,24), gastrointestinal canal (12,18,21,23),myocardial and skeletal muscle (1,10,14),skin (3,11,26), and renal cortex (22). So far, only a few Received December 30,1991; accepted January 18,1993.…”

How to assess intestinal viability during surgery: A review of techniques

“…Doppler ultrasonography resulted in a high rate of false-negative and false-positive results in an experimental study by Dyess et al [14] . The superiority of laser Doppler flowmetry compared with ultrasound studies was shown [35] . Widely discussed limitations of this technique are that it is considered to be vulnerable to the signals from the neighboring large vessels, it requires an artery exposure and a pulsatile blood flow and a tissue contact is required which can impair local blood flow [1,29] .…”

Experimental model to estimate intestinal viability using charge-coupled device microscopy

“…None of these methods, however, is commonly used clinically, because some are invasive and others are time consuming. Other methods to evaluate viability that are considered economical and clinically applicable include fluorescein assessment 6,7 , Doppler ultrasonography 8,9 and a laser Doppler technique 10,11 . However, fluorescein assessment lacks precision and sufficient objectivity, as it is based on a macroscopic impression of the intestinal microcirculation.…”