Central Venous Pressure: Principles, Measurement, and Interpretation
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Chapter 20 *Lecture Powerpoint the Circulatory System: Blood Vessels and Circulation
Chapter 20 *Lecture PowerPoint The Circulatory System: Blood Vessels and Circulation *See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Introduction • The route taken by the blood after it leaves the heart was a point of much confusion for many centuries – Chinese emperor Huang Ti (2697–2597 BC) believed that blood flowed in a complete circuit around the body and back to the heart – Roman physician Galen (129–c. 199) thought blood flowed back and forth like air; the liver created blood out of nutrients and organs consumed it – English physician William Harvey (1578–1657) did experimentation on circulation in snakes; birth of experimental physiology – After microscope was invented, blood and capillaries were discovered by van Leeuwenhoek and Malpighi 20-2 General Anatomy of the Blood Vessels • Expected Learning Outcomes – Describe the structure of a blood vessel. – Describe the different types of arteries, capillaries, and veins. – Trace the general route usually taken by the blood from the heart and back again. – Describe some variations on this route. 20-3 General Anatomy of the Blood Vessels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillaries Artery: Tunica interna Tunica media Tunica externa Nerve Vein Figure 20.1a (a) 1 mm © The McGraw-Hill Companies, Inc./Dennis Strete, photographer • Arteries carry blood away from heart • Veins -
Blood Volume and Circulation Time in Children
Arch Dis Child: first published as 10.1136/adc.11.61.21 on 1 February 1936. Downloaded from BLOOD VOLUME AND CIRCULATION TIME IN CHILDREN BY H. SECKEL, M.D., Late of the University Children's Clinic, Cologne. This paper is based mainly on the results of the author's own research work on blood volume and circulation time in cases of normal and sick children. The following methods were used:- 1. The colorimetric method for determining the circulating plasma volume, and the haematocrit method for estimating the volume of the total circulating blood; and 2. The histamine rash method for estimating the minimum circulation time of the blood. By means of these two methods there is determined only that portion of the total blood volume which is in rapid circulation, the other part, the so-called stored or depot blood, which is moving slowly or is almost stationary, being neglected. The organs which may act as blood depots are the spleen, the liver, the intestines, the sub-papillary plexus of the skin http://adc.bmj.com/ and possibly the muscles. The greater part of the capillary system of these organs is quite extensive enough to supply stored-up blood as and when required to the more rapid circulation or alternatively, withdraw rapidly circulating blood and store it. This action is regulated by the autonomic nervous system. The circulating blood volume as de-termined by the above methods is not absolutely fixed in quantity but chatnges within wide limits, according to the physiological or pathological conditions under on September 25, 2021 by guest. -
High Blood Pressure
KNOW THE FACTS ABOUT High Blood Pressure What is high blood pressure? What are the signs and symptoms? Blood pressure is the force of blood High blood pressure usually has no against your artery walls as it circulates warning signs or symptoms, so many through your body. Blood pressure people don’t realize they have it. That’s normally rises and falls throughout the why it’s important to visit your doctor day, but it can cause health problems if regularly. Be sure to talk with your it stays high for a long time. High blood doctor about having your blood pressure pressure can lead to heart disease and checked. stroke—leading causes of death in the United States.1 How is high blood pressure diagnosed? Your doctor measures your blood Are you at risk? pressure by wrapping an inflatable cuff One in three American adults has high with a pressure gauge around your blood pressure—that’s an estimated arm to squeeze the blood vessels. Then 67 million people.2 Anyone, including he or she listens to your pulse with a children, can develop it. stethoscope while releasing air from the cuff. The gauge measures the pressure in Several factors that are beyond your the blood vessels when the heart beats control can increase your risk for high (systolic) and when it rests (diastolic). blood pressure. These include your age, sex, and race or ethnicity. But you can work to reduce your risk by How is it treated? eating a healthy diet, maintaining a If you have high blood pressure, your healthy weight, not smoking, and being doctor may prescribe medication to treat physically active. -
Blood Vessels: Part A
Chapter 19 The Cardiovascular System: Blood Vessels: Part A Blood Vessels • Delivery system of dynamic structures that begins and ends at heart – Arteries: carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus – Capillaries: contact tissue cells; directly serve cellular needs – Veins: carry blood toward heart Structure of Blood Vessel Walls • Lumen – Central blood-containing space • Three wall layers in arteries and veins – Tunica intima, tunica media, and tunica externa • Capillaries – Endothelium with sparse basal lamina Tunics • Tunica intima – Endothelium lines lumen of all vessels • Continuous with endocardium • Slick surface reduces friction – Subendothelial layer in vessels larger than 1 mm; connective tissue basement membrane Tunics • Tunica media – Smooth muscle and sheets of elastin – Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels • Influence blood flow and blood pressure Tunics • Tunica externa (tunica adventitia) – Collagen fibers protect and reinforce; anchor to surrounding structures – Contains nerve fibers, lymphatic vessels – Vasa vasorum of larger vessels nourishes external layer Blood Vessels • Vessels vary in length, diameter, wall thickness, tissue makeup • See figure 19.2 for interaction with lymphatic vessels Arterial System: Elastic Arteries • Large thick-walled arteries with elastin in all three tunics • Aorta and its major branches • Large lumen offers low resistance • Inactive in vasoconstriction • Act as pressure reservoirs—expand -
Central Venous Pressure Venous Examination but Underestimates Ultrasound Accurately Reflects the Jugular
Ultrasound Accurately Reflects the Jugular Venous Examination but Underestimates Central Venous Pressure Gur Raj Deol, Nicole Collett, Andrew Ashby and Gregory A. Schmidt Chest 2011;139;95-100; Prepublished online August 26, 2010; DOI 10.1378/chest.10-1301 The online version of this article, along with updated information and services can be found online on the World Wide Web at: http://chestjournal.chestpubs.org/content/139/1/95.full.html Chest is the official journal of the American College of Chest Physicians. It has been published monthly since 1935. Copyright2011by the American College of Chest Physicians, 3300 Dundee Road, Northbrook, IL 60062. All rights reserved. No part of this article or PDF may be reproduced or distributed without the prior written permission of the copyright holder. (http://chestjournal.chestpubs.org/site/misc/reprints.xhtml) ISSN:0012-3692 Downloaded from chestjournal.chestpubs.org at UCSF Library & CKM on January 21, 2011 © 2011 American College of Chest Physicians CHEST Original Research CRITICAL CARE Ultrasound Accurately Refl ects the Jugular Venous Examination but Underestimates Central Venous Pressure Gur Raj Deol , MD ; Nicole Collett , MD ; Andrew Ashby , MD ; and Gregory A. Schmidt , MD , FCCP Background: Bedside ultrasound examination could be used to assess jugular venous pressure (JVP), and thus central venous pressure (CVP), more reliably than clinical examination. Methods: The study was a prospective, blinded evaluation comparing physical examination of external jugular venous pressure (JVPEXT), internal jugular venous pressure (JVPINT), and ultrasound collapse pressure (UCP) with CVP measured using an indwelling catheter. We com- pared the examination of the external and internal JVP with each other and with the UCP and CVP. -
Central Venous Pressure: Uses and Limitations
Central Venous Pressure: Uses and Limitations T. Smith, R. M. Grounds, and A. Rhodes Introduction A key component of the management of the critically ill patient is the optimization of cardiovascular function, including the provision of an adequate circulating volume and the titration of cardiac preload to improve cardiac output. In spite of the appearance of several newer monitoring technologies, central venous pressure (CVP) monitoring remains in common use [1] as an index of circulatory filling and of cardiac preload. In this chapter we will discuss the uses and limitations of this monitor in the critically ill patient. Defining Central Venous Pressure What is the Central Venous Pressure? Central venous pressure is the intravascular pressure in the great thoracic veins, measured relative to atmospheric pressure. It is conventionally measured at the junction of the superior vena cava and the right atrium and provides an estimate of the right atrial pressure. The Central Venous Pressure Waveform The normal CVP exhibits a complex waveform as illustrated in Figure 1. The waveform is described in terms of its components, three ascending ‘waves’ and two descents. The a-wave corresponds to atrial contraction and the x descent to atrial relaxation. The c wave, which punctuates the x descent, is caused by the closure of the tricuspid valve at the start of ventricular systole and the bulging of its leaflets back into the atrium. The v wave is due to continued venous return in the presence of a closed tricuspid valve. The y descent occurs at the end of ventricular systole when the tricuspid valve opens and blood once again flows from the atrium into the ventricle. -
Angiotensin II Protocol
Angiotensin II (Giapreza ™) Protocol Background Sepsis and septic shock are medical emergencies that affect millions of people each year and killing as many as 1 in 4.1 The cornerstones of therapy are fluid resuscitation, early appropriate antibiotics, source control if needed and vasopressors. A small portion of patients fail to respond to these therapies and develop refractory shock. The definition of refractory septic shock varies in the literature but is generally considered to be hypotension, with end-organ dysfunction, requiring high-dose vasopressor support.2 The associated mortality of refractory septic shock is up to 60% and as high as 80-90% in patients requiring more than 1 mcg/kg/min of norepinephrine.2,3 Patients who develop refractory septic shock comprise a very small portion of the population in large randomized controlled trials therefore limited data is available regarding outcomes and management. Indications: Angiotensin II (Ang II) is a vasoconstrictor used to increase blood pressure in adults with septic or other distributive shock. Administration: Starting dose of 5 (nanograms) ng/kg/min intravenously via central line only. Titration: Every 5 minutes by increments of 5 ng/kg/min as needed. Maximum dose should not exceed 80 ng/kg/min (During the first 3 hours of administration); after the first 3 hours the maintenance (maximum) dose is 40 ng/kg/min. Monitoring: Critical care setting only with telemetry, arterial blood pressure, and continuous SpO2 monitoring. DVT Prophylaxis should be started (unless contraindicated) -
Cardiovascular Physiology
CARDIOVASCULAR PHYSIOLOGY Ida Sletteng Karlsen • Trym Reiberg Second Edition 15 March 2020 Copyright StudyAid 2020 Authors Trym Reiberg Ida Sletteng Karlsen Illustrators Nora Charlotte Sønstebø Ida Marie Lisle Amalie Misund Ida Sletteng Karlsen Trym Reiberg Booklet Disclaimer All rights reserved. No part oF this book may be reproduced in any Form on by an electronic or mechanical means, without permission From StudyAid. Although the authors have made every efFort to ensure the inFormation in the booklet was correct at date of publishing, the authors do not assume and hereby disclaim any liability to any part For any inFormation that is omitted or possible errors. The material is taken From a variety of academic sources as well as physiology lecturers, but are Further incorporated and summarized in an original manner. It is important to note, the material has not been approved by professors of physiology. All illustrations in the booklet are original. This booklet is made especially For students at the Jagiellonian University in Krakow by tutors in the StudyAid group (students at JU). It is available as a PDF and is available for printing. If you have any questions concerning copyrights oF the booklet please contact [email protected]. About StudyAid StudyAid is a student organization at the Jagiellonian University in Krakow. Throughout the academic year we host seminars in the major theoretical subjects: anatomy, physiology, biochemistry, immunology, pathophysiology, supplementing the lectures provided by the university. We are a group of 25 tutors, who are students at JU, each with their own Field oF specialty. To make our seminars as useful and relevant as possible, we teach in an interactive manner often using drawings and diagrams to help students remember the concepts. -
The Icefish (Chionodraco Hamatus)
The Journal of Experimental Biology 207, 3855-3864 3855 Published by The Company of Biologists 2004 doi:10.1242/jeb.01180 No hemoglobin but NO: the icefish (Chionodraco hamatus) heart as a paradigm D. Pellegrino1,2, C. A. Palmerini3 and B. Tota2,4,* Departments of 1Pharmaco-Biology and 2Cellular Biology, University of Calabria, 87030, Arcavacata di Rende, CS, Italy, 3Department of Cellular and Molecular Biology, University of Perugia, 06126, Perugia, Italy and 4Zoological Station ‘A. Dohrn’, Villa Comunale, 80121, Napoli, Italy *Author for correspondence (e-mail: [email protected]) Accepted 13 July 2004 Summary The role of nitric oxide (NO) in cardio-vascular therefore demonstrate that under basal working homeostasis is now known to include allosteric redox conditions the icefish heart is under the tonic influence modulation of cell respiration. An interesting animal for of a NO-cGMP-mediated positive inotropism. We also the study of this wide-ranging influence of NO is the cold- show that the working heart, which has intracardiac adapted Antarctic icefish Chionodraco hamatus, which is NOS (shown by NADPH-diaphorase activity and characterised by evolutionary loss of hemoglobin and immunolocalization), can produce and release NO, as multiple cardio-circulatory and subcellular compensations measured by nitrite appearance in the cardiac effluent. for efficient oxygen delivery. Using an isolated, perfused These results indicate the presence of a functional NOS working heart preparation of C. hamatus, we show that system in the icefish heart, possibly serving a both endogenous (L-arginine) and exogenous (SIN-1 in paracrine/autocrine regulatory role. presence of SOD) NO-donors as well as the guanylate cyclase (GC) donor 8Br-cGMP elicit positive inotropism, while both nitric oxide synthase (NOS) and sGC Key words: nitric oxide, heart, Antarctic teleost, icefish, Chionodraco inhibitors, i.e. -
What Is High Blood Pressure?
ANSWERS Lifestyle + Risk Reduction by heart High Blood Pressure BLOOD PRESSURE SYSTOLIC mm Hg DIASTOLIC mm Hg What is CATEGORY (upper number) (lower number) High Blood NORMAL LESS THAN 120 and LESS THAN 80 ELEVATED 120-129 and LESS THAN 80 Pressure? HIGH BLOOD PRESSURE 130-139 or 80-89 (HYPERTENSION) Blood pressure is the force of blood STAGE 1 pushing against blood vessel walls. It’s measured in millimeters of HIGH BLOOD PRESSURE 140 OR HIGHER or 90 OR HIGHER mercury (mm Hg). (HYPERTENSION) STAGE 2 High blood pressure (HBP) means HYPERTENSIVE the pressure in your arteries is higher CRISIS HIGHER THAN 180 and/ HIGHER THAN 120 than it should be. Another name for (consult your doctor or immediately) high blood pressure is hypertension. Blood pressure is written as two numbers, such as 112/78 mm Hg. The top, or larger, number (called Am I at higher risk of developing HBP? systolic pressure) is the pressure when the heart There are risk factors that increase your chances of developing HBP. Some you can control, and some you can’t. beats. The bottom, or smaller, number (called diastolic pressure) is the pressure when the heart Those that can be controlled are: rests between beats. • Cigarette smoking and exposure to secondhand smoke • Diabetes Normal blood pressure is below 120/80 mm Hg. • Being obese or overweight If you’re an adult and your systolic pressure is 120 to • High cholesterol 129, and your diastolic pressure is less than 80, you have elevated blood pressure. High blood pressure • Unhealthy diet (high in sodium, low in potassium, and drinking too much alcohol) is a systolic pressure of 130 or higher,or a diastolic pressure of 80 or higher, that stays high over time. -
Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: a PET Study with the Acetazolamide Test in Cerebrovascular Disease
CLINICAL INVESTIGATIONS Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: A PET Study with the Acetazolamide Test in Cerebrovascular Disease Hidehiko Okazawa, MD, PhD1,2; Hiroshi Yamauchi, MD, PhD1; Hiroshi Toyoda, MD, PhD1,2; Kanji Sugimoto, MS1; Yasuhisa Fujibayashi, PhD2; and Yoshiharu Yonekura, MD, PhD2 1PET Unit, Research Institute, Shiga Medical Center, Moriyama, Japan; and 2Biomedical Imaging Research Center, Fukui Medical University, Fukui, Japan Key Words: acetazolamide; cerebrovascular disease; cerebral The changes in cerebral blood flow (CBF) and arterial-to- blood volume; vasodilatory capacity; cerebral perfusion pressure capillary blood volume (V0) induced by acetazolamide (ACZ) are expected to be parallel each other in the normal circula- J Nucl Med 2003; 44:1875–1883 tion; however, it has not been proven that the same changes in those parameters are observed in patients with cerebro- vascular disease. To investigate the relationship between changes in CBF, vasodilatory capacity, and other hemody- namic parameters, the ACZ test was performed after an The ability of autoregulation to maintain the cerebral 15O-gas PET study. Methods: Twenty-two patients with uni- blood flow (CBF), which resides in the cerebral circulation lateral major cerebral arterial occlusive disease underwent despite transient changes in systemic mean arterial blood 15 PET scans using the H2 O bolus method with the ACZ test pressure, has been shown to occur via the mechanism of 15 after the O-gas steady-state method. CBF and V0 for each arteriolar vasodilatation in the cerebral circulation (1). The subject were calculated using the 3-weighted integral vasodilatory change in the cerebral arteries is assumed for method as well as the nonlinear least-squares fitting method. -
Arteries to Arterioles
• arteries to arterioles Important: The highest pressure of circulating blood is found in arteries, and gradu- ally drops as the blood flows through the arterioles, capillaries, venules, and veins (where it is the lowest). The greatest drop in blood pressure occurs at the transition from arteries to arterioles. Arterioles are one of the blood vessels of the smallest branch of the arterial circula- tion. Blood flowing from the heart is pumped by the left ventricle to the aorta (largest artery), which in turn branches into smaller arteries and finally into arterioles. The blood continues to flow through these arterioles into capillaries, venules, and finally veins, which return the blood to the heart. Arterioles have a very small diameter (<0.5 mm), a small lumen, and a relatively thick tunica media that is composed almost entirely of smooth muscle, with little elastic tissue. This smooth muscle constricts and dilates in response to neurochemical stimuli, which in turn changes the diameter of the arterioles. This causes profound and rapid changes in peripheral resistance. This change in diameter of the arteri- oles regulates the flow of blood into the capillaries. Note: By affecting peripheral resistance, arterioles directly affect arterial blood pressure. Primary function of each type of blood vessel: - Arteries - transport blood away from the heart, generally have blood that is rich in oxygen - Arterioles - control blood pressure - Capillaries - diffusion of nutrients/oxygen - Veins - carry blood back to the heart, generally have blood that is low in oxygen.