The Microcirculation as a Therapeutic Target in the Treatment of Sepsis and Shock

Vanina S. Kanoore Edul, M.D.; Arnaldo Dubin, M.D., Ph.D.; Can Ince, Ph.D.

Disclosures

Semin Respir Crit Care Med. 2011;32(5):558-568. 

In This Article

Evaluation of the Microcirculation

Depending on the scenario, there are several techniques available to evaluate the functional state of the microcirculation.[35] O2 electrodes inserted into the tissues of patients and animals, although invasive, have been conventionally used to provide information regarding tissue O2 tension.[36] Infusion of the oxygen sensitive dye Pd-porphyrin has been used in experimental studies to measure noninvasively and quantitatively the microcirculatory pO2 in vivo by measuring the oxygen-dependent quenching of its phosphorescence. The unique feature of this technique is that it is noninvasive and becomes more sensitive at lower pO2 values.[35] As mentioned earlier, we recently identified the use of endogenously available mitochondrial Pp IX to quantitatively measure mitochondrial pO2 in vivo by the use of delayed fluorescence.[22] The combination of these techniques now provides a powerful tool to follow the passage of oxygen from the microcirculation to the mitochondria in experimental models in vivo.

Based on the previous work of Slaaf et al[37] and Sherman et al[38] using microscopes for observation of the microcirculation in vivo, orthogonal polarization spectral (OPS) imaging[39] and later sidestream dark field (SDF)[40] were developed to fit in hand-held microscopes for study of the human microcirculation at the bedside. SDF imaging consists of a light guide surrounded by green light-emitting diodes (530 nm) whose light penetrates the tissue and illuminates the microcirculation. The green light is absorbed by RBC hemoglobin, and a magnifying lens projects the image onto a video camera. Placed on organ surfaces, SDF imaging provides images of RBCs flowing in the microcirculation (Fig. 2). The introduction of these techniques at the bedside opened a new field of research, monitoring, and potential therapeutic targets. The introduction of these techniques at the bedside, opened a new field of research, monitoring, and potential therapeutic targets, and also highlighted the significance of this physiological compartment in the perioperative patient.

Figure 2.

Sidestream dark-field (SDF) imaging. This imaging technique is a method of observing the human microcirculation at the bedside. (a) SDF imaging consists of a light guide surrounded by green light-emitting diodes (LEDs; wavelength 530 nm) whose light penetrates the tissue and illuminates the microcirculation. The light is absorbed by hemoglobin of the red blood cells and scattered by leukocytes. A magnifying lens projects the image onto a video camera. Placed on organ surfaces, SDF imaging provides crisp images of the red blood cells and leukocytes flowing through the microcirculation (for real-time films, see www.sdfimaging.net). (b) As an example of the improved image quality provided by SDF imaging, the sublingual microcirculation of a volunteer is shown, with a magnified inset showing several leukocytes. Reproduced with permission from Ince.[13]

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....