Introduction: Based on the evidence, the Pedunculopontine Tegmental nucleus (PPT) is involved in cardiovascular function regulation. In this study, the probable role of PPT on cardiovascular parameters in the hypotension induced by Hemorrhage (HEM) was evaluated.  Methods: The study rats were divided up into 5 groups: 1. Control (Saline); 2. Cobalt(II) chloride (CoCl2); 3. HEM; 4. Saline+HEM; ...

We investigate oscillatory blood flow in an elastic artery and in the presence of stenosis, whose form is given analytically. The stenosis is a condition where an artery wall thickens as a result of fatty materials such as cholesterol. We consider the case of very low pulse frequency that can be the case for patients whose hearts beat too slowly, but with arbitrary value of the ratio γ of the a...

Most observers have found that when circulating red cell volume is deduced from measurement of plasma volume and venous hematocrit a higher value is obtained than when the red cell volume is measured directly. It is widely believed that this is because the proportion of red cells in the blood in large vessels is higher than that in the body as a whole and various correction factors have been pr...

Purpose. The gravimetric method of weighing surgical sponges is used to quantify intraoperative blood loss. The dry mass minus the wet mass of the gauze equals the volume of blood lost. This method assumes that the density of blood is equivalent to water (1 gm/mL). This study's purpose was to validate the assumption that the density of blood is equivalent to water and to correlate density with ...

The central mechanisms underlying the transition from compensation to decompensation during severe hemorrhage (HEM) are poorly understood. Furthermore, a lack of consistency in HEM protocols exists in the current literature. This study assessed the cardiovascular response and Fos-like immunoreactivity (FLI) in specific brain regions following severe HEM at three rates (2, 1, or 0.5 ml.kg(-1).mi...

BACKGROUND Skin color changes and mottling are frequently described signs of hemorrhagic shock (HEM). Based on this, we developed a noninvasive, noncontact hyperspectral imaging system (HSI), which quantifies and depicts the surface tissue saturation of oxygen (SHSIO2) for each pixel in a region of interest (ROI). Our purpose was to assess HSI in a porcine HEM model. We hypothesized that HEM wo...

TO THE EDITOR: We appreciate the approach of Drs. Stark and Schuster (13) to elaborate a systematic foundation of the optimal hematocrit concept on physics. However, some corrections and additional information are necessary. It is important to note that the empirical description of Pries et al. (7)—in contrast to the theoretical approaches for bulk viscosity—is based on experiments for tube flo...

BACKGROUND We investigated whether electrical stimulation (STIM) of efferent vagus nerves may suppress nuclear factor (NF)-kappaB activation and the inflammatory cascade in hemorrhagic (Hem) shock. METHODS AND RESULTS Rats were subjected to bilateral cervical vagotomy (VGX) or sham surgical procedures. Hem shock was induced by intermittent withdrawing of blood until mean arterial pressure sta...

The wide-spread assumption that doping with erythropoietin or blood transfusion is only effective by increasing arterial blood O2 content because of rising hematocrit is not self-evident. "Natural blood dopers" (horses, dogs) increase both hematocrit and circulating blood volume during exercise by releasing stored erythrocytes from the spleen. Improvement of aerobic performance by augmenting he...

Equations of blood viscosity provide a prediction of the 'optimal' hematocrit' (hct) as the hct resulting in the highest value of the bell-shaped curve of hematocrit/viscosity ratio h/η. We investigated if overweight and obesity have an influence on these parameters. We compared 32 normal weight subjects, 40 overweight (BMI 25-30) and 38 obese subjects. There was no difference in the theoretica...