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Solutions of stroma-free hemoglobin have been investigated for their potential as blood replacement fluids for more than 70 years. Despite many attempts to overcome their unwanted side effects through chemical modification of the hemoglobin molecule, none of the potential solutions has been approved for clinical use in Europe or the United States. In recent years, the vasoconstrictive activity of hemoglobin in the plasma was identified as the pivotal problem of hemoglobin-based blood substitutes, compromising nutritional perfusion and thus impeding oxygen unloading at the site of the microcirculation. One of the prevailing assumptions is that the precapillary vasoconstriction and the ensuing tissue underperfusion is caused by the high affinity of free hemoglobin for nitric oxide. To resolve this problem, a number of recombinant techniques involving site-directed mutagenesis as well as several chemical approaches involving polymerization and pegylation have been developed. This volume summarizes the latest research on the effects of some of these new hemoglobin solutions on the microvasculature and tissue oxygenation. It is recommended reading for all those interested in finding alternatives for donor blood in transfusion medicine, including emergency specialists, anesthesiologists, surgeons, trauma surgeons and other clinicians who are frequently confronted with blood loss and the need for blood replacement.

This book introduces orthogonal polarized spectral (OPS) imaging, a new technique for examining the microcirculation in both animals and humans during surgery and in other clinical setups. OPS imaging creates an image by using the sub-surface scattering of polarized light to create a ‘virtual‘ light source within the tissue being observed. Thus, the microcirculation can be visualized without the use of fluorescent dyes or transillumination, making it possible to observe the human microcirculation in real time. The technology has been incorporated into a small, hand-held device called a CYTOSCANTM video microscope, which can be used in both research and clinical settings. Several validation studies comparing OPS imaging against standard intravital fluorescence microscopy in animal models demonstrate that it is possible to make quantitative measurements of relevant parameters (vessel diameter, red blood cell velocity and functional capillary density) from these images. Further studies show the feasibility of making such measurements in various human organs such as the skin, intestine, and brain. In addition, this book presents several clinical applications including use in cardiopulmonary bypass, neurosurgery, intensive care, general surgery and plastic surgery. The book should be read by anyone concerned with microvascular perfusion. This includes not only those involved in microcirculation research but clinicians interested in nutritive perfusion. The technique described here will be of aid to a variety of surgical specialists from cardiac and neurosurgeons to plastic surgeons. It will likewise be of interest to angiologists, anesthesiologists, neonatologists, dermatologists, and general surgeons.

TThis volume contains expert articles on the physiology and function of the microvascular and microlymphatic systems, the physiology of microvascular fluid filtration and reabsorption, interactions between blood cells and the microvascular endothelium, and molecular mechanisms of leukocyte activation. The therapeutic goals in chronic venous insufficiency include reduction of postischemic leukocyte-endothelial cell interaction, repair of microvascular barrier and improvement of microlymphatic drainage. In addition to measures to counteract inflammatory reactions elicited by local ischemia, surgical procedures such as transplantation of lymph vessels and subfascial division of perforating veins by an endoscopic approach are reviewed. Written by leading experts in the field, this book provides the first synopsis of the role of microcirculatory disturbances in chronic venous insufficiency. It will be of particular interest to phlebologists, angiologists, dermatologists, gerontologists, vascular, plastic and reconstructive surgeons, and general physicians.

Compromised perfusion indicates the inability of the cardiovascular system to sustain the normal distribution of blood flow within the entire body and can be defined as a reduction of perfusion pressure leading to the exclusion of single capillaries or groups of capillaries. Occurring in patients subjected to shock, trauma, extensive surgery and organ transplantation, it reduces the surface area available for exchange of nutrients and metabolites with the consequence of tissue hypoxia and accumulation of waste products. To counteract compromised perfusion hypertonic/hyperoncotic saline/dextran solutions are used efficiently. This book presents an overview of the most recent findings from studies investigating compromised perfusion. The selected contributions discuss the mechanistic effects and side effects of small volume resuscitation, as well as specific effects of dextran in the field of organ conservation and post-ischemic leukocyte/endothelium interaction. Furthermore, specific aspects of the biology and pathophysiology of microvascular endothelium are considered. Providing a critical review of recent advances, this volume serves as an excellent source of information for all those interested in both clinical and experimental microcirculation research.