PATHOPHYSIOLOGY Dr Wasfi Dhahir Abid Ali Department of
PATHOPHYSIOLOGY Dr. Wasfi Dhahir Abid Ali Department of medical sciences –College of Nursing – University of Basrah
HEMODYNAMICS DISORDERS
Definition of hemodynamics The study of the forces and physical mechanisms concerned with the circulation of the blood, The dynamics of blood flow that ensures the transportation of nutrients, hormones, metabolic wastes, O 2 and CO 2 throughout the body to maintain cell-level metabolism the regulation of the p. H, osmotic pressure and temperature of the whole body, and the protection from microbial and mechanical harms
Blood flow The study of the properties of the blood flow is called Hemorheology Blood flow is : The quantity of blood flowing through a vessel, region or organ in unit time. Dependent on the arterial blood pressure and the resistance to flow in the local vascular be determined by the state of constriction/dilatation mainly of the arterioles, influenced intern by chemical (local and hormonal) and neural (sympathetic) effects on the vascular smooth muscle
Blood circulation Systemic circulation is the portion of the cardiovascular system which transports oxygenated blood away from the heart through the aorta from the left ventricle where the blood has been previously deposited from pulmonary circulation, to the rest of the body, and returns oxygen-depleted blood back to the heart. The cardiac output is simply the amount of blood pumped by the heart per minute. Necessarily, the cardiac output is the product of the heart rate, which is the number of beats per minute, and the stroke volume, which is amount pumped per beat. CO = HR X SV. The cardiac output is usually expressed in liters/minute
Hemodynamic determined by 1. Preload: describes the pressure at the given space during diastole 2. Contractility: describes the strength of the heart muscle to eject blood 3. After load: describe the pressure that the fluid have to overcome to allow a forward flow. 4. Compliance : The ability of vessels to distended
Hemodynamic disorders Edema defined as abnormal excessive accumulation of fluid in interstitial tissue and serous cavities. Types of edema � Hydro pericardial: a condition where excessive fluid accumulates in the pericardial cavity. Fluid accumulation within the pericardial sac may lead to fibrous thickening and opacity of the pericardium if prolonged � Ascites: ascites refers to abnormal accumulation fluid in the abdominal (peritoneal) cavity. The most common cause of ascites is cirrhosis of the liver. � Hydrothorax: is a type of pleural effusion in which transudate accumulates in the pleural cavity. This condition is most likely to develop secondary to congestive heart following an increase in hydrostatic pressure within the lungs. More rarely, � Anasarca : s a medical condition characterized by widespread swelling of the skin due to effusion of fluid into the extracellular space
Transudes due to, secondary to hydrodynamics impairments 1. Non inflammatory edema 2. Protein-poor. 3. Low specific gravity 4. Contain mesothelial cells and debris Exudate due to secondary to inflammation and increased vascular permeability 1. Inflammatory edema 2. Protein-rich 3. High specific gravity 4 -Contain inflammatory cells and parenchyma cell specific gravity
Hyperemia and Congestion Hyperemia defined as an active process of arteriolar dilation leading to local increase in blood volume. Congestion defined as a passive process of increase in blood volume due to impaired outflow. Hemorrhage Defined as an extravasations of blood because of vessel rupture. Accumulation is a hematoma. Hemostasis Normal Hemostasis: due to 1. Vasoconstriction 2. platelet adherence and activation - primary hemostatic plug 3. coagulation due to activation of thrombin - secondary hemostatic plug 4. permanent plug
Thrombosis Systemic Thromboembolism Clinical: 80% arise from intracardiac mural thrombi remainder arise from aortic aneurysms, plaques or valve vegetation. 75% go to lower extremities and 10% go to the brain. Fat embolism Pathophysiology: Mechanical obstruction and biochemical injury. Free fatty acids cause local toxic injury to endothelium, platelet activation. Prognosis: Syndrome fatal in 10%. Air embolism Pathophysiology: Formation of gases bubbles within skeletal muscle, soft tissues and joints causes pain. (Focal ischemia to brain and heart. )
Infarction Defined as an area of ischemic necrosis caused by occlusion of either arterial supply or venous drainage. Types of infarction 1 -Red Infarct (hemorrhagic): venous occlusions, loose tissues (lung), congested, when flow reestablished 2 -White Infarcts (anemic): arterial occlusions or solid organs (heart, spleen, kidney).
- Slides: 11