Critical care lecture 2 (shock, SIRS, MODS) Flashcards
What is shock
physiologic state characterized by significant reduction of systemic tissue perfusion from decreased tissue oxygen delivery
if prolonged oxygen deprivation continues without compensation, what could the complications be
cellular hypoxia and derangement of critical biochemical processes that could turn into systemic consequences
what are the determinants of systemic tissue perfusion
cardiac output and systemic vascular resistance
blood pressure
pressure against the wall of a blood vessel exerted by circulating blood and is a major factor in tissue oxygenation and perfusion
vasoplegic
patient who is extremely vasodilated
mean arterial pressure
average pressure seen in the systemic circulation (or organs)
what is the normal range of MAP
70-100mmhg
what are the determinants of cardiac output (amount of blood pumped by the left ventricle each minute)
- heart rate
- stroke volume
what are the detrminants of stroke volume
- pre-load
- after-load
- contractility
what is the normal cardiac output
4-8L/min
what is cardiac index
cardiac output but takes into account body surface
pre-load
- amount of stretch exerted on the myocardial fibers at the end of distaole which represents the volume of blood in the ventricle
- uses pressure to estimate volume
afterload
- ventricular wall tension or stress during systolic ejection or as the resistance against which the ventricle pump blood
what is the difference between Blood pressure and afterload
Blood pressure is the force against artery and afterload is the reistance the blood encounters to pump
what happens if there is no resistance
no flow of blood
contractility or inotropy
ability of the myocardium to contract that is independent of afterload and preload
what can affect contractility
- electrolytes
- level of fitness
- damage to myocardium
- obstruction
what is the broad-spectrum of what a shock state looks like
- unmet metabolic demands
- tissue hypoxia that leads to cells death
- anaerobic metabolism with high levels of lactate
- organ dysfunction
- supply and demand for oxygen is imbalanced
inital stage of shock
- a trigger events causes cardiac output to decrease and tissue perfusion decreases
compensatory stage of shock
- helps increase cardiac output and oxygen dilvery
- increase HR and contractility, vasoconstricton, abdnormal redirection of blood (shunting) to vital organs
- hormonal compensation (vasoconstrictionand fluid retention)
- adrenal medulla stimulated to release epinephrine and norepinephrine
progressive stage of shock
- compensatory mechanisms inadequate
- major dysfunction of organs
- low blood flow, poor tissue perfusion, metabolic waste build up
refractory stage of shcok
- shock stage is so deep that death is inevitable
- intractable circulatory failure and death
early stages of shock
- fever and chills
- skin warm and flushes
- tachycardia and tachypnea
- known as warm shock