Class 6 & 7 - Perfusion Flashcards
Central perfusion: Electrical
SA node -> Av node -> Bundle of His -> Purkinje fibers
Central perfusion: Mechanical Systole
Ventricular contraction
Ventricles contract -> Mitral and Tricuspid valves close -> Pressure increases in venitrlces -> Aortic and Pulmonic valves open -> Blood ejected into Arota and Pulmonary arteries -> Ventricular pressure decreases -> Aortic and Pulmonic valves close
Central perfusion: Mechanical Diastole
Ventriular filling
Ventricles relax -> Mitral and Tricuspid valves are closed already -> Atrias fill -> Pressure in atrias increases -> Mitral and Tricuspid valves open -> Ventricles fill as Aortic and Pulmonic valves are still closed
Cardiac output
4-6 L/min
Impacted by stroke volume and heart rate
CO = SV x HR
Stroke volume
Amount of blood ejected from each ventricle during contraction/systole
Preload = amount of blood in the ventricles at the end of diastole
Contractility = strength of myocardial contraction
Afterload = force the ventricles must exert to open aortic/pulmonic valves
Afterload = resistance L ventricle overomces to circulate blood
Systemic vascular resistance
In SV
Resistance to the ejected blood created by the diameter of the blood vessels receiving the blood
Arterial BP
Determined by CO and SVR
Ventricular contraction creates pressure - pushes blood through arteries, capillaries, and into niterstitial spaces
Delivers oxygen, fluid and nutirents to the cells
BP is maintained by constricting or dialting arteries and arterioles in response to stimuli
Venous BP
Blood is returned through veins and venules (less sturdy)
More stretchy - lower pressure than arteries
Veins contain vlaves to keep blood flowing forward to the heart
Peripheral arterial disease
Systemic atherosclerosis
Partial or total arterial occlusion
PAD in lower legs is Lower extremity arterial disease (LEAD)
Peripheral venous disease
Chronic venous insufficiency
- Defective valves
- Thrombus formation
- Skeletal muscle mobility
PAD: Stage 1
Asymptomatic
- No claudication
- Bruit or aneurysm may be present
- Pedal pulses are decreased or absent
PAD: Stage 2
Claudication
- Mucle pain, cramping, burning occurs with exercise… relieves with rest
- Symptoms are reproducible with exercise
PAD: Stage 3
Rest pain
- Pain while resting commonly awakens the patient at night
- Pain described as numbing, burning, toothache-type pain
- Pain usually in distal part of extremity
- Pain is relieved by placing the extremity in a dependent position
PAD: Stage 4
Necrosis/Gangrene
- Ulcers and blackened tissue occur on the toes, forefoot, heel
- Distinctive gangrenous odor
PAD Clinical Manifestations
- Loss of hair to lower leg
- Dry, scaly/dusky pale or mottled skin
- Thickened toe nails
- Decreased or absent pulses
- Pain at rest, leads to worsening at night
- Cold and cyanotic or darkened skin (pallor with elevation, dependent rubor when lowered)
- Muscle atrophy with chornic cases
- Ulcer to toes, metatarsal heads, heels, and lateral ankle (ulcers have pale ischemic base, well-defined edges, and no bleeding)
