Histophysiological effects of fluid resuscitation on heart, lung and brain tissues in rats with hypovolemia

New perspectives of volemic resuscitation in polytrauma patients: a review

Nowadays, fluid resuscitation of multiple trauma patients is still a challenging therapy. Existing therapies for volume replacement in severe haemorrhagic shock can lead to adverse reactions that may be fatal for the patient. Patients presenting with multiple trauma often develop hemorrhagic shock, which triggers a series of metabolic, physiological and cellular dysfunction. These disorders combined, lead to complications that significantly decrease survival rate in this subset of patients. Volume and electrolyte resuscitation is challenging due to many factors that overlap. Poor management can lead to post-resuscitation systemic inflammation causing multiple organ failure and ultimately death. In literature, there is no exact formula for this purpose, and opinions are divided. This paper presents a review of modern techniques and current studies regarding the management of fluid resuscitation in trauma patients with hemorrhagic shock. According to the literature and from clinical experience, all aspects regarding post-resuscitation period need to be considered. Also, for every case in particular, emergency therapy management needs to be rigorously respected considering all physiological, biochemical and biological parameters.

Immunolocalization of VEGF, VEGFR-1 and VEGFR-2 in lung tissues after acute hemorrhage in rats

In treatment of hypovolemia it is important to reestablish normal tissue hemodynamics after fluid resuscitation. Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) have been identified as important in many physiological and pathological processes. In this study, we aimed to investigate the histo-physiological effects of VEGF, VEGFR-1 (flt-1) and VEGFR-2 (KDR/flk-1) in resuscitation with different plasma substitutes on lung tissues after acute hemorrhage in rats. Male Sprague-Dawley rats (n=25) were used in this study. The left femoral vein and artery were cannulated for the administration of volume expanders and for direct measurement of mean arterial blood pressure (MAP) (Power-Lab) and heart rate (HR). Fifteen rats were bled (5 ml/10 min) and infused (5 ml/5 min) with one of three randomly selected fluids: (a) dextran-70 (Macrodex); (b) gelatin (Gelofusine); or (c) physiological saline (PS, 0.9% isotonic saline) solutions. Five rats were bled and none were infused (hypovolemia group) and five rats were untreated as the control group. At the end of the experiment, rats were sacrificed and lung tissues were removed for routine processing and paraffin wax embedding. Sections of tissue were stained with hematoxylin and eosin (H&E) and selected blocks were then prepared for indirect immunohistochemical labeling for anti-VEGF, anti-VEGFR-1 and anti-VEGFR-2 primary antibodies. It was observed that both MAP and HR decreased parallel to blood withdrawn in this time interval. The MAP and HR were restored in the following periods. In the control rats, positive immunoreactivity of VEGF and its receptors (VEGFR-1 and VEGFR-2) were detected in respiratory epithelial cells, respiratory and vascular smooth muscle cells, alveolar cells and endothelial cells. While strong immunoreactivities of VEGF and VEGFR-1 were observed in the hypovolemia group, only moderate immunoreactivity of VEGFR-2 was seen in this group. Moderately strong immunolabeling of VEGF and VEGFR-1 were observed in the dextran-70, gelatin and PS resuscitated groups, whereas only weak immunolabeling of VEGFR-2 was observed in these groups. In summary, the vascular protecting effects of these factors were observed with fluid resuscitation, contributing to the pathophysiological changes seen in hypovolemia.