Search results for "Circulation"

Precapillary Servo Control of Blood Pressure and Postcapillary Adjustment of Flow to Tissue Metabolic Status

1996

Background There are several shortcomings in current understanding of how the microvasculature maintains tissue homeostasis. Presently unresolved issues include (1) integration of the potentially conflicting needs for capillary perfusion and hydrostatic pressure regulation, (2) an understanding of signal transmission pathways for conveying information about tissue energetic status from undersupplied tissue sites to the arterioles, (3) accounting for the experimentally observed interrelations between precapillary and postcapillary resistances, and (4) an explanation of how precise local adjustment of perfusion to metabolic demands is achieved. Methods and Results A novel conceptualization o…

Role of Ischemia/Reperfusion Injury in Organ Transplantation

1997

Reperfusion of oxygenated blood into previously ischemic tissue is essential to prevent the progression of cellular injury due to the decreased nutritional blood flow, i.e., the decreased delivery of oxygen and metabolic substrates, as well as the removal of harmful metabolic byproducts. However, it has become obvious that reperfusion also initiates a complex series of pathologic events that contribute to, rather than prevent, further tissue damage. Moreover, a growing body of evidence indicates that ischemia/reperfusion injury is initiated by events that occur at the level of the microcirculation. In the first part of this overview, we will delineate the major components of the microcircul…

“Small Volume Resuscitation” as Treatment of Cerebral Blood Flow Disturbances and Increased ICP in Trauma and Ischemia

1996

“Small volume resuscitation” (SVR) is a promising concept for the treatment of shock and trauma patients. SVR utilizes the fast infusion of a small volume of hypertonic saline to mobilize intraendothelial and parenchymal water to expand and restitute intravascular volume. Therefore it seems warranted to also consider SVR for the treatment of disturbances of the cerebral circulation and of increased intracranial pressure (ICP). The current study uses a rabbit model of global cerebral ischemia combined with mild hemorrhage to test SVR. Somatosensory evoked potentials (SEPs) serve as a short-term outcome parameter. The data demonstrate a beneficial effect on ICP, a better reperfusion, and an i…

The role of the microcirculation in multiple organ dysfunction syndrome (MODS): a review and perspective

1996

Major advances in intensive care medicine during the past two decades have altered the spectrum of disease encountered by intensive care physicians, anaesthesiologists, traumatologists and pathologists. One of the most important manifestations of severe trauma or infections is the multiple organ dysfunction syndrome (MODS), a life-threatening condition that often ends in multiple organ failure (MOF) and death. Evidence gathered from clinical and morphological observations in humans, taken together with experimental animal studies and a vast accumulation of in vitro data, clearly indicate that the microcirculation lies at the centre of this complex process, which results in peripheral vascul…

Study of Post-Infarction Coronary Perfusion Using Quantitative Analysis of Myocardial Echocardiography With Intravenous Injection of Contrast

2005

Introduction and objectives. After a myocardial infarction, damage to the microcirculation indicates a worse prognosis. We compared the usefulness of the quantitative analysis of myocardial contrast echocardiography with intravenous injection of contrast (MCE-iv) with intracoronary injection (MCE-ic) for analyzing coronary perfusion. Patients and method. We studied 42 patients with a first ST-elevation myocardial infarction, single-vessel disease and a patent artery (TIMI 3, stenosis 0.75) and MCE-iv (perfusion of SonoVue, singleimage capture in 1 out of each 6 cycles with trigger set at end-systole, perfusion considered normal if >0.9). Perfusion was considered abnormal if 2 or more segmen…

Erratum to “Anatomical evaluation of oral microcirculation: Capillary characteristics associated with sex or age group” [Ann. Anat. 191(4) (2009) 371…

2009

1043 Evaluation of Pediatric Testes After Surgery by Laser Doppler and White Light Spectroscopy

2012

Aim To evaluate testes after unilateral orchiopexy Laser Doppler and white light spectroscopy and compare microcirculation with contralaterat testis and healthy controls. Methods A combination of the laser Doppler (determination of blood flow) and white light spectroscopy (determination of oxygen saturation and hemoglobin amount) is used to determine microcirculation at two different depth levels non-invasively. Patients were recruited after unilateral orchiopexy. Controls were age-matched boys without relevant disease. Ethical approval was obtained. Results 99 patients were included after unilateral orchiopexy at the age of 3.5 years (+-2.9 years). 65% underwent surgery after their second …

Comparison of Standard Cardiopulmonary Resuscitation Versus the Combination of Active Compression-Decompression Cardiopulmonary Resuscitation and an …

2003

Background— Active compression-decompression (ACD) CPR combined with an inspiratory impedance threshold device (ITD) improves vital organ blood flow during cardiac arrest. This study compared survival rates with ACD+ITD CPR versus standard manual CPR (S-CPR). Methods and Results— A prospective, controlled trial was performed in Mainz, Germany, in which a 2-tiered emergency response included early defibrillation. Patients with out-of-hospital arrest of presumed cardiac pathogenesis were sequentially randomized to ACD+ITD CPR or S-CPR by the advanced life support team after intubation. Rescuers learned which method of CPR to use at the start of each work shift. The primary end point was 1-ho…

Potential Involvement of Impaired Venous Outflow from the Brain in Neurodegeneration: Lessons Learned from the Research on Chronic Cerebrospinal Veno…

2019

About 10 years ago, the so-called chronic cerebrospinal venous insufficiency syndrome was discovered. This clinical entity, which is associated with extracranial venous abnormalities that impair venous outflow from the brain, was initially found exclusively in multiple sclerosis patients. Currently, we know that such venous lesions can also be revealed in other neurological pathologies, including Alzheimer’s and Parkinson’s diseases. Although direct causative role of chronic cerebrospinal venous insufficiency in these neurological diseases still remains elusive, in this paper, we suggest that perhaps an abnormal venous drainage of the brain affects functioning of the glymphatic system, whi…

Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine

1998

Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine. Myogenic, pressure-induced vasoconstriction may amplify the effects of circulating vasoconstrictors. Through intravital microscopy in cremaster arterioles (31 to 115 μm diameter), the relative contribution of myogenic responses (MR) to norepinephrine (NE)-induced constriction and the inhibitor potency of nitric oxide (NO) or a Ca2+ entry blocker (CEB), felodipine (F), were examined. In 24 anesthetized hamsters, a vessel occluder was placed around the aorta to control cremaster vessel inflow pressure (IP). NE infusion increased blood pressure (by 50 ± 2mm Hg) and induced significant constriction …