The elusive microcirculation

Excerpt

In the current issue of Intensive Care Medicine, Bracht and colleagues present a study in sheep intestines where they investigate the response of the microcirculation to ischemia as measured by two techniques aimed at the microcirculation: OPS imaging and laser Doppler flowmetry [1]. Their goal was to investigate how sensitive the two techniques aimed at the microcirculation were able to detect a progressive flow reduction to the intestines. To this end they applied a tourniquet around the superior mesenteric artery and progressively restricted arterial blood flow to the intestine. The results of their study showed that the laser Doppler signal deviated at less arterial flow reduction (45%) than did microcirculatory flow as detected by direct observation of capillary red blood cell flow using OPS imaging. Alterations in capillary red blood cell flow could not be detected until an arterial flow reduction of 75 % had been reached. Because of this difference they concluded that OPS imaging was insensitive in being able to detect gut ischemia. …