The cardiovascular system Flashcards
Hypotension
low bp BELOW 90 SYSTOLIC
Causes of hypertension
Low fluid volume (hypovolemia)
prolonged immobilization
medications (diuretics…)
Neurological disease/damage
Signs and symptoms of hypotension
*lightheadedness,
dizziness,
fainting (syncope),
pallor,
diaphoresis,
visual disturbances.
Severe hypotension will cause heart attack and death
Treatment for hypotension
*fluid bolus blood transfusion or fluid volume, expanders
Orthostatic (postural) hypotension
also called postural hypotension
abnormal drop in systolic bp when changing postition from lying down or sitting to a standing position of at least 20 mm hg or diastolic blood pressure of 10 mm hg
Vasovagal response/ hypotension
a reflex of the vagus nerve
causes the heart to slow down bradycardia which in turn affects the nerves to the blood vessels in the legs permitting those vessels to dilate
Results in the heart putting less blood out and the blood pressure drops and what blood is circulating tends to go into the legs rather than the head. the brain is deprived of oxygen which causes fainting
Main characteristics of orthostatic hypotension
-blood pressure drops due to hypovolemia
-tachycardia results in the heart’s attempt to compensate for low b/p
-give IV or oral fluids until low b/p is normal
-treat the cause of hypovolemia
-maintain patient safety (fall precautions)
Main characteristics of vasovagal hypotension
-Blood pressure drops due to stimulation of the vagus nerve
-bradycardia results from stimulation of the parasympathetic system
-self resolving no tx needed
-maintain patient safety (if patient hates needles and might pass out take proper precautions)
Characteristics of SHOCK
Always causes hypotension
-hypotension is most often due to hypovolemia
-hypovolemia (low volume) causes poor perfusion
-poor perfusion means blood is not getting into body tissues so Oxygen is not delivered
-no O2 leads to organs stop functioning and body dies
3 stages of shock
Compensatory stage
progressive stage
irreversible/ refractory stage
Compensatory stage of shock
Mechanisms are activated to maintain perfusion to heart and brain (epinephrine and norepinephrine are excreted to activate the fight or flight part of the adrenergic nervous system)
Progressive stage of shock
Starts because compensating mechanisms fail to maintain homeostasis. Tissues become hypoxic because of poor perfusion
Cells switch to anaerobic metabolism leads to lactic acid begins to build up and produces metabolic acidosis *also cells die/ break open/ release potassium which makes acidosis even worse
Depressed myocardial function leads to hypoxia which then promotes the *release of endothelial mediators. These chemical mediators cause vasodilation and endothelial abnormality leading to venous pooling and increase capillary permeability increase risk of DIC
Irreversible/ refractory stage of shock
Permanent organ damage occurs which leads to cell death. Hypotension results from increase capillary permeability. Lactate builds up due to anaerobic metabolism, so a *HIGH lactate level is an indicator of POOR prognosis
Oliguria or anuria indicate kidney failure due to low perfusion
CIRCULATORY AND RESPIRATORY FAILURE OCCURS DEATH IS INEVITABLE
Signs and Symptoms of SHOCK
-change in level of consciousness (restlessness and irritability due to cerebral hypoxia)
-Tachycardia and tachypnea
-Cool pale (vasoconstriction in limbs in order to squeeze blood to the core)
-Diaphoretic skin (cool/clammy feeling)
-HYPOTENSION
-low urine output (OLGURIA) due to poor kidney perfusion
-Acidosis leads to CNS depression
-HEART DYSRHYTHMIAS due to poor cardiac perfusion
-RESPIRATORY FAILURE due to poor lung perfusion
Treatment for SHOCK
-intubate as needed (airway)
-Give oxygen (breathing)
-cardiac monitoring (circulation)
-maintain perfusion w/ drugs and fluids (CIRC)
-treat underlying cause
TX PRIORITY
-airway: intubation, suctioning
-breathing: oxygen
-cardiac/ circ: Monitor heart, pump fluids to keep adequate B/p
3 second assessment
a complete head-to-toe rapid assessment of all major body system in 3 seconds
Airway/Breathing: look for chest rise. If present, the person has an open airway and is ventilating adequately
Cardiac/ circulation: feel radical pulse. If present then person has at least an 80 systolic B/P which is adequate to perfuse the brain. Note dysrhythmias; character of pulse (weak or pounding). Feel temp and moisture on skin
Deficit of NEURO functions: Ask person to move feet. This assesses the acoustic nerve; the ability of the brain to process information; brain’s ability to send a signal down the spinal cord; and ability of the spinal cord to send nerve impulses to the most distal nerves in the body.
Hypovolemic shock
Deficient circulating vascular volume (hemorrhage)
Cardiogenic shock
obstructive secondary to heart failure
-inability of the heart to fill properly (pericarditis)
-obstruction preventing “outflow” from the heart
-pump failure
Distributive: septic, anaphylactic, neurogenic
altered regulation of vascular tone
-septic shock: infection caused by gram negative bacteria toxin leads massive vasodilation
-Anaphylactic shock: overwhelming immune response (vasodilation) to an allergen
-Neurogenic shock: loss of blood vessel tone, lead to displacement of the vascular vol. away from the heart and central circulation. EX: spinal shock - spinal cord injury
Hypertension
B/P is consistently higher than 140/90
The vicious cycle
Major cause of hypertension is arterial injury (blood clots) that causes arterial constriction. Narrowed arteries increase the resistance the heart has to pump against. Pressure goes up in the heart because it is pushing so hard to get the blood out. Ironically the forceful blood flow then causes more arterial injury.
Normal BP for adult
100/60 - 120/80
BP categories
Normal
elevated
high bp (hypertension) stage 1
High blood pressure (hypertension) stage 2
Hypertensive Crisis
Normal (bp category)
less than 120 systolic and less then 80 diastolic
Elevated (bp category)
120-129 systolic and less than 80 diastolic
High bp stage one (bp category)
130-139 systolic or 80-89 diastolic
High bp stage 2 (bp category)
140 or higher systolic and 90 or higher diastolic
Hypersensitive crisis (bp category)
higher than 180 systolic and higher than 120 diastolic
Arteriosclerosis
an INFLAMMATORY PROCESS that causes abnormal thickening and hardening of arterial wall from deposition of collagen into vessel wall leads to diminished distensibility
Atherosclerosis
is the NARROWING OF THE ARTERY because of plaque build up it is a form of arteriosclerosis resulting from fat being deposited in vessel wall that reduce lumen size
Steps of atherosclerosis development in a blood vessel
1 - ulceration of vessel
2 - fatty streak
3 - fibrous plaque
4 - complicated lesion (thrombosis)
5 - thrombus to embolus
Ulceration of vessel
vessel injury can be due to inflammation, high bp, infections, etc
Fatty streak
initial deposit of cholesterol to cover the ulceration in the vessel lining - a “band-aid”
Fibrous plaque
the fatty streak becomes surrounded by collagen and muco-protein matrix leading to protrusion into the vessel that then causes luminal narrowing
Complicated lesion (thrombosis)
the fibrous plaque becomes calcified and penetrates into the vessel’s muscular layer as well as extending into the lumen producing occlusion leading to a thrombus
thrombus to embolus
when the calcified fibrous plaque chip off and float freely through the vascular system it is termed and “embolus” these fragments can block smaller vessels and stop blood flow which could result in everything from localized tissue necrosis to death from a pulmonary embolism that lodges in the lungs
Primary hypertension
etiology (cause) : UNKNOWN (genetic and environmental)
*High risk groups: inherited, race, age, insulin resistance, diet, obesity, alcohol, and smoking
Incidence: ACCOUNTS FOR 90-95% OF HTN
Pathophysiology: hypovolemia, vasoconstricion, resistance in vessels
S/S: USUALLY NONE, morning HA, fatigue,
Rx: DIET, EXERCISE, MEDICATION (LIFE-LONG)
Secondary HTN
Etiology: ATTRIBUTABLE TO ANOTHER DISEASE PROCESS
Incidence: accounts for <5% of HTN
pathophysiology: it has many different causes including ENDOCRINE DISEASES, KIDNEY DISEASES, and TUMORS. it also can be a SIDE EFFECT of many MEDICATIONS
S/S: same as primary HTN and those associated with disease process
Rx: treat underlying cause