Hemodynamics Flashcards
Hemodynamics is the name given to the ______ that control ______ through the body.
The end goal of hemodynamics is _____________.
forces, blood flow
adequate tissue perfusion
The body has ________________ that will change hemodynamic forces to compensate for ____________________.
compensatory mechanisms
inadequate tissue perfusion
When these compensatory mechanisms fail due to illness, we use _____________________ to identify and address problems to restore adequate blood flow to tissues.
heart rate increase is an example.
when youre sick (septic, buring through o2 demand) your compensatory mechanisms fail.
another way they are taken out is through heart surgery (bypass
hemodynamic monitoring,
END goal of hemodynamics: is the ______ being ________________?
tissue, adequately perfused
how do we monitor tissue perfusion?
(urine output, toes pink and warm)
Give the blood flow pathway through the circulatory system?
Inferior vena cava and superior vena cava
right atrium
tricuspid valve
right ventricle
pulmonic valve
pulmonary artery
lungs
pulmonary vein
left atrium
mitral valve
left ventricle
aortic valve
aorta
body
____________- Strong, elastic, three-layered vessels. Tough outer coating, middle smooth muscle layer, and smooth, slippery connective tissue that allows the blood to flow easily. ____________will dilate or constrict to meet metabolic demand.
Arteries
___________- microscopic vessels, one cell-layer thick walls allow for easy passage of gasses, nutrients, and hormones into and out of the blood.
Capillaries
__________- Weak, elastic, three-layered vessels. Low-pressure system. One-way valves help the__________ return blood back to the heart. 70% of all blood in the body is in the __________ system at any time.
Veins
how many liters of blood do we have normally? What are some variations?
5 L. smaller bodies have less and bigger bodies have more.
Vasopressors and vasodilators act on receptors in the ______________ layer of the arteries and veins to cause them to contract or expand = increasing or reducing the pressure. Remember: the body makes it’s own _________ to change the diameter of arteries and veins as well.
middle muscle (smooth layer), catecholamines
Heart failure arises when?
muscles or the valves start to fail (or malfunction).
Valve function is dependent on _____________ on the valves. they work well until ___________ or _________ valve.
pressures, stenosis, regurgitating
__________ phase of the cardiac cycle
when heart is at rest
Diastolic
_____________________ phase:
The heart is at rest
Blood flows into the right and left _________
The __________________ are open because the ______________________________ are the same when the heart is at rest.
Passive diastolic, atrium, tricuspid and mitral valves, pressures in the atria and ventricles
___________________ phase:
Electrical stimulation from the SA node sends a signal for the atria to contract (P wave on the ECG)
Atria squeeze blood into the ventricles
Once the pressure in the ventricles exceeds the pressure in the atria, the tricuspid and mitral valves close. (This is the______ heart sound)
Complete emptying of the atria into the ventricles makes up ~30% of total cardiac output. (this is sometimes called the “atrial kick”)
Active diastolic, S1
____________ reduce the amount of time chambers have to fill. Less fill equals less pressure.
THE SHORTER THE AMOUNT OF time spent in the ___________________ –THE LESS TIME THEY HAVE TO FILL –LOWERED cardiac output
High heart rates, DIASTOLIC PHASE
____________ of the cardiac cycle
Electrical stimulation down the bundle branches and through the Purkinje fibers sends a signal for the ventricles to contract (QRS complex on the ECG).
Ventricles squeeze and push blood forward through the pulmonic and aortic valves into the lungs and the aorta.
Once the pressure in the arteries exceeds the pressure in the ventricles, the pulmonic and aortic valves snap shut. (this is the ______ heart sound)
Systolic phase, S2
_____ is the highest pressure that occurs in the systolic phase, _____ is the lowest pressure that occurs in the diastolic phase.
SBP, DBP
The heart can only perfuse the coronary arteries during the __________.
diastolic phase
THE HEART CAN ONLY PERFUSE ITS CORONARY ARTERIES DURING THE ____________, NOTTTTTT THE ______________
HIGH HEART RATE WILL SHORTEN THE ____________ AND CAUSE LOW (cardiac output?)
DIASTOLIC PHASE, SYSTOLIC PHASE, DIASTOLIC TIME
What is cardiac output? What chambers are responsible for which percentage?
amount of blood pumped by the heart in 1 minute. 30% atria, 70% Ventricles
What is the formula for cardiac output?
CO = Heart Rate(Stroke volume)
What are ways to increase heart rate?
ANS stimulation, temperature, electrolytes, adrenal stimulation, and catecholamine release can all affect HR
_______ can decrease CO if the body is unable to compensate with an increase in SV
Slow HR
________ can decrease CO because the heart does not have enough time to fill with blood.
Fast HR
What factors affect stroke volume?
Preload, Afterload, and Contractility affect SV
____________ will decrease CO unless the body can compensate with increased HR.
Decreased SV
What is the normal cardiac output in adults?
4-8L in adults
______ –is volume dependent (if you have a dehydrated patient they will be tachycardic to compensate)
preload
___________ increases heart rate via the ANS
atropine
atropine increases heart rate via the ______
ANS
below __________ is when symptomatic bradycardia begins
50 bpm
Preload-
Stretch on the ventricular myocardium at the end of diastole.
preload: _____________________ dependent.
Volume and outside pressure
pneumothorax, hemothorax, cardiac tamponad, high peep. –these things cause increased pressure in the thoracic cavity which pushes against the heart and can potentially cause ____________________
decreased preload
Afterload-
resistance against which the ventricle must overcome to push blood forward.
Contractility-
the strength of muscle contraction in the myocardium
When is preload increased?
hypervolemia
regurgitation of cardiac valves
when is afterload increased?
hypertension
vasoconstriction
___________ is often volume-dependent. Increases in intrathoracic pressure also decrease ______, High PEEP, or pneumothorax can affect it. Drugs like ____________ decrease _________ because vesodilation decreases the amount of blood returning to the heart.
Preload, preload, nitroglycerine, preload
The ______ side of the heart is extremely preload dependent. NURSING INTERVENTIONS: ___________ (IS MOST COMMON THING THAT WILL FIX THIS), decrease peep possibly, chest tube for hemothorax.
right, FLUID BOLUS
Afterload is the _____________that the heart must beat against. Stenotic valves, pulmonary hypertension and systemic hypertension, vasopressors, _______________________ all ________ afterload.
downstream resistance , hypoxia, and hypothermia, increase
____________, ____________, and _________ all decrease contractility ( or ______ effect)
hypoxia, acidosis, and hypothermia, (inotropic)
Contractility is increased by positive inotropic meds such as digoxin levophed, dobutamine ________ and _________. Decreased by ___________, negative inotropes like _____________, ______________, ___________, ____________, hypoxia, acidosis, hypothermia. digoxin in a positive inotrope which increases contractility. many blood pressure meds decrease ___________ effects.
milrinone, hypercalcemia,
hypocalcemia
amiodarone, beta blockers calcium channel blockers and ace inhibitors
inotropic
_____________ and ____________ are positive inotropes as well as ____________.
Dobutamine and milarone, CALCIUM
cardiac index. define. give formula.
The volume of blood pumped by the left ventricle in 1 minute divided by body surface area. CO/BSA = Cardiac index
What is a normal cardiac index?
2.5-4.2 L/min/m^2
Is cardiac output or cardiac index preferred to use ? explain why.
Cardiac index is preferred measurement because it is a universal measurement no matter how big the person is.
ANYTHING BELOW _____ IS CARDIOGENIC SHOCK
2.0 (cardiac index scale)
PNEUMOTHORAX, BLEEDING are problems for ?
preload
What are common causes of afterload problems?
hypertensive crisis, someone who doesnt take their Heart failure meds
What are common preload problems?
pneumothorax, bleeding
low preload –_________
high afterload –__________________
fluids
control hypertension
Central Venous Pressure (CVP)
Values and what is it?
2-6 mm Hg
Pressure of blood in the right heart at the end of diastole. Preload of the right ventricle
Pulmonary Artery Pressure (PAP)
what is is and what are values?
Blood pressure in the pulmonary artery. PA diastolic pressure is almost the same as PAOP, so it is often substituted for PAOP. Safer than occluding PA cath.
15-25 mm Hg/8-15 mm Hg
Pulmonary Artery Occlusive Pressure (PAOP)
what is it and what are values?
Pressure of blood in the left heart at the end of diastole. Preload of left ventricle.
8-12 mm Hg
Stroke Volume (SV)
give definition and normal values
Volume of blood ejected from LV with each heartbeat.
60-130 mL/beat
Systemic Vascular Resistance (SVR).
define and give normal values
Resistance that LV must overcome to open aortic valve and push blood forward. Afterload of left ventricle.
770-1500 dynes/sec/m2
Pulmonary Vascular Resistance (PVR)
define and give normal values.
Resistance that RV must overcome to open Pulmonic valve and push blood forward. Afterload of right ventricle.
< 250 dynes/sec/m2
Mean Arterial Pressure (MAP)
define and give normal values.
Average blood pressure over 1 cardiac cycle. Important for end organ perfusion.
70-105 mm Hg
systemic vascular resistance (fancy name for_________ of the left ventricle)
pulmonary vascular resistance (fancy name for _____________)
afterload, pre load
KIDNEYS NEED ___________ MMHG MAP TO GET PERFUSION, ALL OTHER ORGANS CAN GET PERFUSION WITH THIS PRESSURE,
65-75
only difference between central venous O2 and mixed venous oxygen saturation is that ___________________________
Mixed venous oxygen has been through the coronary arteries
Central Venous Oxygen Saturation (ScvO2)
Normal Value ___________
is obtained from __________
65%-85%.
distal port of a central line or PICC line or CVP port of PA catheter.
Mixed Venous Oxygen Saturation (SvO2)
Normal Value ____________
Can be drawn from __________________________
60%-75%.
distal port of PA catheter.
Both values provide an assessment of the balance between oxygen supply and demand. ____________ values indicate an increased oxygen supply, a decreased oxygen demand or the inability to extract oxygen from the blood. ___________ values indicate decreased oxygen supply or increased oxygen demand.
Central venous oxygen saturation and mixed venous oxygen. High. Low.
__________________ is slightly higher because it is measured with blood above the ______________ thus the cardiac sinuses have not returned the oxygenated blood from the myocardium.
Central venous oxygen saturation, right atrium
__________ is drawn from the vena cava. has to be drawn from a ____________________________________
central venous O2, central line or through a port.
________________________ –is drawn from the distal end of a PA catheter only
mixed venous oxygen saturation
low O2 saturation indicates tissue is not picking up O2 (_______ not circulating blood to tissues) or theyre not picking up enough O2
low bp
What are non invasive ways to monitor hemodynamics?
Noninvasive blood pressure
assess for JVD
lactate measurement
urine output or EtCO2