Blood Pressure Seminar.pdf

Blood Pressure Practical and Seminar Where opportunity creates success Learning Outcomes • Define blood pressure • Compare and contrast hypotension and hypertension • Describe homeostatic regulation of blood pressure • Compare and contrast advantage and disadvantages of direct and indirect...

Blood Pressure Practical and Seminar Where opportunity creates success Learning Outcomes • Define blood pressure • Compare and contrast hypotension and hypertension • Describe homeostatic regulation of blood pressure • Compare and contrast advantage and disadvantages of direct and indirect blood pressure measurement techniques • Describe different blood pressure measurement techniques and equipment, including pros & cons • Measure and record blood pressure using non-invasive techniques (doppler/oscilometric) • Define shock • List and describe types of shock Pre-Learning Quiz Homeostatic Regulation of Blood Pressure In this session (50 mins) • Review what you already know about blood pressure • Understand the complex nature of how blood pressure is regulated • Be able to describe the RAAS and it’s impact on blood pressure • Relate to a clinical scenario (This is not examinable!!!!!!!) • Define and list the symptoms and common causes of hypotension and hypertension Blood Pressure • The pressure or force of the circulating blood against the blood vessel walls • Arterial and venous pressure can be measured • Typically in practice we measure arterial blood pressure • When measuring BP we typically refer to systolic and diastolic pressures • Systolic pressure is the highest measurable pressure and coincides with contraction of the heart • Diastolic pressure is the lowest measurable pressure and coincides with the filling/relaxation of the heart • Many internal and external factors and physiological processes can affect blood pressure The Cardiovascular Centre Can cause increase or decrease in CO and vascular tone via neural and hormonal pathways Baroreceptors – measure stretch of BVs Chemoreceptors – measures chemical composition Impulses are sent to the Cardiovascular Centre Cardiac Output Blood Pressure Peripheral Resistance - Vasoconstriction – narrowing of blood vessels (increases BP) - Vasodilation – widening of blood vessels (decreases BP) HR Stroke Volume Hormonal Regulation Renin Angiotensin Aldosterone System (RAAS) – increase BP Adrenaline (Epinephrine) – increase BP Anti Diuretic Hormone (ADH) – increase BP Atrial Natriuretic Peptide – decrease BP Action via various mechanisms What is the RAAS? RAAS - step by step… Angiotensinogen A ‘Drop’ Blood Pressure Detected by Kidney Releases Renin Cleaves Angiotensin I Angiotensin Converting Enzyme (ACE) Converts Angiotensin II RAAS - step by step… Nervous System Angiotensin II Vasoconstriction Stimulates Arterioles Adrenal Cortex Pituitary Gland Sodium and Water Retention Release Aldosterone Kidney Water Reabsorption Release ADH Cardiac Output Blood Pressure HR A decrease in BP activates RAAS Peripheral Resistance Stroke Volume Vasoconstriction Sodium and Water Retention RAAS Renin • An enzyme released from the glomerulus (kidney) in response to a decrease in renal perfusion • Release of renin is necessary for RAAS to be activated • When BP normalises renin is no longer released – feedback mechanism Angiotensin(s) Angiotensinogen – precursor of angiotensin I – produced in liver – cleaved by renin to form angiotensin I Angiotensinogen Angiotensin I – becomes angiotensin II – Converted by Angiotensin Converting Enzyme (ACE) – Occurs mostly in lungs as ACE produced there Angiotensin II – binds to various receptors to trigger effects Angiotensin I Angiotensin II Aldosterone – Steroid hormone (mineralocorticoid) – Released from adrenal cortex in response to angiotensin II – Acts on collecting ducts in nephron – Increased reabsorption of Na+ – Increased excretion of K+ Effects of angiotensin II • Vasoconstriction Arterioles • Na+ reabsorption Kidney • Increased noradrenaline (NA) Sympathetic nervous system • Aldosterone release Adrenal cortex • Increases thirst Hypothalamus • Stimulates anti-diuretic hormone (ADH) Hypothalamus https://www.google.com/url?sa=i&url=https%3A%2F%2Fcommons.wikimedia.org%2Fwiki%2FFile%3ARAAS_System.png&psig=AOvVaw1Y hCDXbl6BXGGTgn7OvKP&ust=1697730894735000&source=images&cd=vfe&opi=89978449&ved=0CBAQjRxqFwoTCKDog8n6_4EDFQAAAAAdAAAAABAr Relevance in Practice ACE inhibitors in practice Treatment of congestive heart failure in dogs . The RAAS system and it’s effects are eliminated! Congestive Heart Failure in Dogs • The heart pumps blood around the pulmonary and systemic circulation…… • The circulatory system backs up whilst blood volume is asked to increase….. • If the valves in the heart start to fail, what happens to the efficiency of the pump? • Where does all the extra fluid go? • If the pump is less effective what happens to cardiac output? • If CO drops, what happens to BP? • When BP drops what compensatory mechanism kicks in? • What does RAAS do? (2 things!) • The heart is asked to work harder (& faster) and blood volume increases! • Into the lungs and abdomen. • What symptoms do we see in the dog? • Coughing, lethargy, depression, exercise intolerance, swollen abdomen, collapse, death • Why would an ACE inhibitor help? • Reduces peripheral resistance and reduces volume retention, easing symptoms. • Used as part of a multimodal treatment plan. Variation in Blood Pressure Using Padlet – Consider for either – • Hypotension Define …… List the potential causes of……. List the symptoms of ……. Why are you seeing these symptoms? Be prepared to share your findings. • Hypertension Compare and Contrast the Advantages and Disadvantages of Indirect and Direct Blood Pressure Measurement Investigate On flipcharts – Define indirect blood pressure measurement. What equipment is used in vet practice to measure indirect BP? Define direct blood pressure measurement. What equipment is used in vet practice to measure direct BP? What are the pro and cons of each technique? Be prepared to share your findings. (Flipcharts will be uploaded to Blackboard after session) Practical Session Measure Indirect BP Shock Exercise What is shock? Shock, a definition Shock is a life-threatening manifestation of circulatory failure. Circulatory shock leads to cellular and tissue hypoxia resulting in cellular death and dysfunction of vital organs. Effects of shock are reversible in the early stages, and a delay in diagnosis and/or timely initiation of treatment can lead to irreversible changes, including multiorgan failure and death. Group Exercise Types of Shock Using Padlet describe – - Cardiogenic shock - Distributive shock What is it? - Hypovolaemic shock What causes it? (human and vet) - Obstructive shock What are the symptoms and signs? Be prepared to share your findings. Learning Outcomes • Define blood pressure • Compare and contrast hypotension and hypertension • Describe homeostatic regulation of blood pressure • Compare and contrast advantage and disadvantages of direct and indirect blood pressure measurement techniques • Describe different blood pressure measurement techniques and equipment, including pros & cons • Measure and record blood pressure using non-invasive techniques (doppler/oscilometric) • Define shock • List and describe types of shock