SEE BASIC SCIENCES : A & P Review Flashcards
Carotid sinus located where
internal carotid artery
Why is the carotid sinus important?
They have receptors that are responsible to normal BP to the brain
PEA causing factors include H & Ts
Hypoxia H+ (acidosi) Hyperkalemia Hypovolemia Hypothermia PE Tension Pneumothorax Tamponade Toxins
Can PEA be treated with defibrillation
NO
Treatment options for PEA
Epi 1mg 3-5 minss
Vasopression 40 units IV
Drugs that can be give through ETT tube with people with no IV access? (LANE) or NEAL
Lidocaine
ATropine
Narcan
Epinephrine
Maximum delivery for monophasic defibrillation?
360 J
Adenosine given paroxysmal SVT, what may occur with admin of that drug?
Bradycardia with brief asystole
How does Adenosine work?
Slow the electrical conduction of signals through the AV node to afford a reset of heart rhythm to a normal rhythm
What is the best description of a 2nd degree HB type II (Morbitz II)
A constant and set PR interval, the ventricular is slower than the atrial rate.
In HB type 2 Mobitz type II , P-R interval is______but what about the P wave?
constant; not every P wave is followed by a QRS complex. , atrial rate is greater than ventricular rate.
3 tx options for 2nd degree HB
Isoproterenol
Dopamine
Trascutaneous pacemaker
Epi 2-10 mcg/min
What is the goal of treatment for a patient with Mobitz type II?
Increasing the HR, as needed to achieve adequate cardiac output
In 2nd degree type I (wenckebach) , where is the pathology ?
AV node
What describe 2nd degree type I?
Progressing lengthening or increase in P-R interval until a QRS is lost due to lack of impulse conduction through the AV node.
Torsades is a disturbance of the _____Phase of the cardiac cycle and is associated with ______QT
repolarization ; prolonged
Vfib , no pulse , no respiration, 1st action?
Defibrillate
How do you know when the pacemaker is not capturing?
Pacemaker is not followed by QRS and occur randomly .
What is the THRESHOLD potential?
Potential to which a membrane must be depolarized to initiate an action potential.
Cardiac membrane depolarization occurs at what phase?
phase 0
Threshold potential is achieved to produce an
action potential represented by the QRS complex.
In what phase of the cardiac action potential has a reduction in Na+ permeability , a transient outword K curent and an outward Cl- current?
Phase 1
Outflow of which ion that inactivates the fast Na+ channels?
K+ and Cl-
What is the mechanism of tachydysrhythmias?
Increased automaticity in normal conduction tissue or in ectopic focus rather than the SA node
Parasympathetic NS stimulation results in which of the following?
A decrease in the SLOPE of PHASE 4 depolarization resulting in a slower HR
Which of the following is true regarding dysrhythmias 2nd to an ectopic focus? (onset)
they have a gradual onset. It insidiously take over the normal generation of the cardiac cycle.
Which of the following are true about re-entrant dysrhythmias ?
They occur along embryological remnants of tissue around the AV node.
What is the most common of premature beats as well as tachydysrythmias, originate secondary to
re-entry pathways of electrical stimuli in the myocardium
In normal pacemaker sites within the heart, the conductime through the _____is the slowest in the heart?
Purkinje fibers
SA node is directly innervated by the
Vagus nerve
SA node stimulation rate
60-100
AV node stimulation rate
40-60
Purkinje stimulation rate
20-40
Variation of the HR in response to changes in intrathoracic pressure during inspiration and expiration is due to which of the following?
Bainbridge reflex
Bainbridge reflex aka
Atrial reflex
What is the Bainbridge (Atria) reflex?
Its a reflex that is triggered by input from atrial stretch receptors resulting in a compensatory increase in HR.
What is the most common supraventricular dysrhythmias associated with acute MI?
Sinus Tachycardia
What is GU symptoms associated with SVT?
Polyuria
What is the mechanism of Polyuria with SVT?
Increase in the secretion of ANP in response to increase atrial pressure from contraction of the atria against closed AV valves.
Most common post operative tachydysrythmias after cardiac surgery?
Atrial fibrillation
Independent risk factors for afib after cardiac surgery?
DM
Valvular disease
CHF
Age, (elderly)
When giving anesthesia to a patient with a known hx of WPW , anesthesia provider should do the following? Avoid what medications
Avoid Digoxin, and CCB
When giving anesthesia to a patient with a known hx of WPW , anesthesia provider should do the following? Avoid what ?
Stimulation of SNS is avoided
When giving anesthesia to a patient with a known hx of WPW , anesthesia provider should do the following? What do you do with fluids?
Limit IV fluids because Atrial-ventricular dyssynchrony may cause acute fluid overload.
Wolff Parkisons white syndrome is characterized by inappriate
ANTEROGRADE conduction of cardiac impulses via an accessory pathway.
With WPW , anesthetist should avoid to
Enhanced aberrant conduction
Consideration for asthma patient with long QT syndromes
PREOP incremental loading dose of METOPROLOL 5mg IVP
Possible mechanisms of asystole during spinal and epidural anesthesia include which of the following.
The BEZOLD-JArisch response
The Bezold Jarisch reflex , results from
initiation of vagal reflex arcs by the decrease venous return associated with spinal or epidural to result in a REFLEX- induced bradycardia.
Profound bradycardia and cardiac arrest during neuraxial anesthesia is
Less common than cardiac arrest during GA
Characteristics of BBB: –> RBBB
rSR’ QRS complex in leads V1-V2
Deep S wave in I and V6
Does RBBB always imply cardiac disease?
No
Which is more common in patient without structural HD?
RBBB vs LBBB
RBBB
Characteristics of BBB: –> LBBB
Absence Q wave in I and V6
ST and T waves changes are already present (repolarization abnormality)
PA contraindicated in patients with
LBBB; may lead to RBBB
SVT combined with this BBB can be mistaken for ____
Left BBB; VTACH
Single MOST important factor that increases survical in patient with VFib
Defibrillaiton within 3-5 minutes of onset
Atrial systole (atrial kick) accounts for ______% of CA
20-30%
Maximization of CO occurs as the result of
Atrial contraction
Where is the Effective Refractory period?
Period that extends from the QRS complex to near the top of the T wave.
What is the Effective Refractory period?
Period of time when no contraction will occur no matter how strong the stimulus.
what is the relative refractory period?
Late stage of repolarization during which a second action potential may be generated by a sufficiently large stimulus.
In a normal distribution of blood volume, where does the major %of blood exist?
Venous circulation. Systemic circulatory circulation, the venous network is more compliant and distensible, with the greatest capability
Most of the deoxygenated blood from the myocardium drains into a large vascular sinus called the ________
Coronary sinus
The Coronary sinus empties in the
Right Atrium
The semilunar valves allow the ejection of blood from the _________ into the _______through valves that consists of ______cusps each
Ventricles: artery ; 3
How many cusps in semilunar valves
3 cusps
Which layer of the valve is responsible for the major pumping action of the ventricles?
Myocardium
What are the 2 most important preop risk factors for about about to have a surgical procedure?
Unstable Coronary syndrome
CHF
Assessment of which system is paramount for the patient going for surgery?
Cardiac
Pt SV of 70ml, HR 80, pulmonary artery mean pressure of 20mmHg. and a CVP of 15 will have which CO ?
5.6
Formula for CO
SV x HR
Which fibers primarily innervates the atria and conducting tissues?
Parasympathetic
Innervation of the SA comes via the
right vagus EFFERENT FIBERS
Stimulation of Parasympathetic system results in
negative chronotropic
dromotropic
inotropic effects
Vascular tone and autonomic influences on the HR are controlled by vasomotor centers in which area?R
Reticular formation of the medulla oblongata and lower pons
Chemoreceptors in the carotid and aortic bodies detect all the following except?
Blood pressure
Receptors that detect change in BP
Baroreceptors
What stimulates chemoreceptors?
Decreasing O2 tension and increasing {H+} concentration , which results in increase pulmonary ventilation and BP with decreased HR
Chemoreceptors respond to
Alteration in chemical component, their concentration, and acidity and alkalinity to communicate.
Where are baroreceptors found?
Carotid sinus and aortic arch
What are baroreceptors innervated by ?
Sinus nerve of Herring
Role of baroreceptors? What do they monitor?
Regulate the autonomic control of heart and blood vessels.
They monitor pressure and volume changes and communicating those changes to the CNS via the sinus nerve of herring, CN IX , and CN X
3 nerves that baroreceptors communicate via
Sinus Nerve of Herring
CN IX
CN X
What is the CAUSE of the greatest myocardial O2 requirement?
Pressure work (to force blood through the body , 64%.
T/F As a determinant of myocardial blood flow, MAP is more important than Arterial diastolic pressure?
False; Coronary perfusion pressure is actually determined as the difference between aortic diastolic pressure ( ADP) and LVEDP. CPP = ADP-LVEDP
Coronary Artery blood flows from
Epicardial to ENDOCARDIAL
Coronary arteries receive blood for the myocardium as they emergy from the aorta and traverse the outside of the heart the _______ to branch and infiltrate the heart muscle, eventually terminally reaching the
Epicardium; inside of the heart, the endocardium
83 yo pt with HR of 46, and takes no medication that that would slow the HR. Which part of the electrical system is acting as the cardiac pacemaker?
AV nodes.
Right atrial pressure is
0-8 mmHg
Left atrial pressure is
3-12 mmHg
RV systolic pressure
15-25 mmHg
Pulmonary artery diastolic pressure
8-15 mmHg
Close approximation of the left atrial pressure is obtained through
Pulmonary capillary wedge.
What is the normal coronary artery blood flow at rest?
225- 250ml/min
When is the LV perfused?
Almost entirely during diastole
The RV is perfused when?
Both systole and diastole
Is coronary perfusion continous ?why or why not?
Not continuous ; it is interrupted with every contraction, Coronary perfusion is intermittent.
Which alpha receptor subtype is responsible for vasoconstriction?
Alpha 2B
Chief functions for alpha 2A adenoceptors are
Sedation
Hypnosis
Analgesia
And sympatholysis
Chief functions for alpha 2B adenoceptors are
Mediate vasoconstriction
Clonidine alpha 2 to alpha 1
200 time more specific for alpha 2 than alpha 1
Terminal elimination half life of Dexmedetomidine?
2 hours
What is elimination of Half life?
time required for 50% of a dose of medication to be removed from the plasma.
Clonidine and dexmedetomidine are part of which chemical class of Alpha 2 adrenergic agonists?
IMIDAZOLINES
IMIDAZOLINES compound found in precedex contain
Nitrogen andamine bonds.
act on CNS to decrease spasticity with significantly less muscle weakness.
Clonidine advantage prior to giving anesthesia reduces
Myocardial energy requirements and improves myocardial oxygen balance.
Clonidine and LA
Increase the duration of action when used with LA for neuraxial blockade.
Clonidine and TEMP
clonidine affect thermoregulatory control.
Clonidine and IV and VA
Decrease requirement , originally used from HTN crisis.
Abrupt discontinuation clonidine can lead to
Rebound HTN
Which medication can be given with patient with rebound HTN from clonidine?
Labetalol.
Following abrupt discontinuation of adrenergic blockers, which is beneficiai?
Labetalol is beneficial in a hyperadrenergic state following abrupt withdrawal of adrenergic blockers.
Class of dexmedetomidine?
It is a full alpha-2 agonist
Dexmedetomidine vs clonidine?
7-10 times more alpha 2 selective than clonidine.
Action of precedex ( in ICU or anesthesia)
Sedation
Analgesia
Action of precedex on sympathetic
Centrally mediated sympatholysis
CCB bind to voltage gated ion channels resulting in
A closed , inactive state
How does voltage gated ion channels work?
They receive a chemical signal from a neurotransmitter presynaptically and delivers that signal rapidly by converting it to a post-synaptic electrical signal . action
may be affected by ligands, ions, membrane potentials
Endocarditis is 3 to 8 times more prevalent in
MVP
MVP put at risk for
Dysrhythmias, stroke, MR, sudden death.
Heart murmurs from valve insufficiency occur when the blood goes backwards and
The ventricles are contracting
The valve is closed.
What produces the heart murmur?
retrograde blood flow when ventricle contract to force blood out toward the lungs or systemic circulation. The retrograde flow results from the inability of the valves between the atria and the ventricles to withstand the pressure generated by the ventricles
What is mitral regurgitation?
Retrograde back flow of blood , decreases quantity of blood flow pump to systemic circulation , small volume insignificant, larger volume, increase the work of the heart to maintain forward flows
Implication of mitral regurgitation
increase the workload of the heart to maintain forward flow, may lead to changes in the heart and HF.
Slightly FAST HR better for which heart condition?
Valve Regurgitation (help minimize the regurgitation)
Mnemonic to remember mitral regurgitation treatment?
Mr. FAR
Fast HR
Adequate Intravascular volume (preload)
Reduction in Afterload
Mnemonic to remember mitral regurgitation treatment?
MR. FAR
Fast HR
Adequate Intravascular volume (preload)
Reduction in Afterload
Abrupt cessation of this drug can causes rebound HTN (2)
Propranolol
Alpha 2 agonists
What can happen with abrupt cessation of beta blocking agents and/or Alpha 1 agonists
Rebound HTN possible HTN crisis
What position are the valves of the heart in during ventricular filling with a DIASTOLIC MURMUR?
Aortic and pulmonic closed
mitral and tricuspid open
What are the 2 types of Diastolic murmurs?
Early decrescendo
Rumbling diastolic murmur
First type of diastolic murmur : EARLY DESCRECENDO is caused by what?
Significant retrograde flow through incompetent semilunar valves.
2nd type of diastolic murmur : RUMBLING DIASTOLIC murmur caused by?
retrograde flow through stenotic mitral valve.
What is the most common manifestation of hypertrophic obstructive Cardiomyopathy in patients younger than 30 years of age?
Sudden CARDIAC Death
Sudden death among pre-adolescent and adolescent children is more often due to
Hypertrophyic Cardiomyopathy (HCM)
Describe Hypertrophic cardiomyopathy?
Asymmetrical hypertrophy frequently involving any portion of the LV and even more involves the interventricular septum.
A normal aortic valve area (cross-sectional area)
2.5- 3.5
Aortic regurgitation, what happens to pulse pressure?
Widened pulse pressure.
What is pulse pressure?
Difference between systolic and diastolic pressure.
Widening pulse pressure in cardiac suggest
Aortic Regurgitation
4 Treatment for acute MR with severe LV dysfunction ?
DDAMDS
DDAMDS Dobutamine Decrease Afterload Milrinone Sodium Nitroprusside
Main goals in Mitral Regurgitaiton
Effectively minimize the quantity of regurgitation by REDUCING AFTERLOAD to afford greater cardiac output
3 main medication in the treatment of MR (NiMD)
Nitroprusside
Milrinone
Dobutamine
Anesthetic management goals for Mitral stenosis are
Ms. Avoid (TPH
AVOID TACHYCARDIA
Avoid hypovolemia (loss of SV and CO)
Normal SR on the lower side of normal
Maximize effectivenss of each contraction
Why is tachycardia best avoided in MS?
because decreased diastolic filling time, leading to decreased CO and increase in left atrial pressure.
Continue those medication
Digoxin, CCBs, and Beta blockers
Which of the following is the only cardiac valve stenotic or regurgitative state that necessitates a DECREASED preload?
Acute MR
Acute MR and left atrial pressure
Acute MR leads to increase in LAP that cause a retrograde transmission of that pressure to the pulmonary vasculature to result in pulmonary edema
Critical Aortic stenosis is when the valve area is less than
0.8 (0.7 some books)
Critical Aortic stenosis is when the Transvalvular gradient (at rest) of
50 mmHg
Mild stenosis is valve area
Greater than 1.5
Mild stenosis mean gradient is
less than 25 mmHg
With stenosis the greater the gradient
The worst
Moderate stenosis valve area
between 1.0 and 1.5
What happens with aortic stenosis ?
there is resistance when ventricles try to eject blood from the heart , and there is elevation of the left ventricular systolic pressure. initially, may compensate but eventually lead to elevated LVDP which is transmitted in retrograde fashion to the pulmonary cicuit and leads to reduction of CO
Pressure elevated in Aortic stenosis
LVEDP (preload)
What is 2nd cardiomyopathy?
when it results from other damage factors such as toxins, inflammatory process, autoimmune disease.
Treatment goals for AS (aortic stenosis)
NCHAT
NSR and Volume status Cardiac pacing should be considered(SVT ->direct current cardioversion) Hypotension AVOID (treat with neo) Avoid tachycardia Treatment of ischemia
What is the only valvular lesions associated with an increase risk of perioperative ischemia, MI and death?
Aortic Stenosis
Treating ischemia with AS goal
increase O2 delivery by raising Coronary perfusion pressure
Decrease O2 consumption (Increase BP and lower HR)
Most common genetic cardiovascular disease?
Hypertrophic cardiomyopathy
Pathophysiology of hypertrophyic cardiomyopathy?
excessive growth of heart muscle
particularly of the interventricular septum near the aortic valve, WALLS STIFFENED and the aortic and mitral valve function become impaired which impeded to normal blood flow from the heart.
Hypertrophic Cardiomyopathy features(DSM)
Dynamic LV outflow tract obstruction
Systolic anterior movement of mitral valve
Myocardial ischemia
If a patient with Hypertrophic Cardiomyopathy has HYPOTENSION, it should be treated with
Neosynephrine (phenylepherine)
How does phenylephrine produces vasoconstriction?
direct action WITHOUT INCREASING HR (because increasing HR WOULD INCREASE LV OUTFLOW OBStRUCTION
Vent setting for the patient with Hypertrophic Cardiomyopathy
Greater RR with decrease TV would give adequate ventilation and oxygenation without inducing a DECREASE IN PRELOAD (venous return)
Volume status that can be DETRIMENTAL in HCM patients
Relative hypovolemia
What are the characteristics of DILATED CARDIOMYOPATHY?
Systolic Dysfunction
LV dilation
All the following are causes of dilated cardiomyopathy?
HIV (infectious disease)
Toxins
Viral Coxsackie B
Genetic
Amyloidosis associated with what kind of cardiomyopathy?
restrictive
Tx of restrictive cardiomyopathy?
Pacemaker/ICD Insertion
Restrictive Cardiomyopathy main issue is
impaired effectiveness of contractions.
Final common pathway in the pathophysiology of ESSENTIAL HTN is
Peripheral vascular resistance
In essential HTN, factors leading to increase PVR
SODIUM RETENTION Altered transports humoral factors CNS factors Increased vascular reactivity
What is the most common cause of 2nd HTN?
Renal Artery stenosis
Renal artery stenosis lead to ______. What compensatory change occur?
hypotension to the kidneys, compensatory increase in CO in order to maintain the nominal GFR. Enhanced CO cannot compensate for the structural issue and that results in chronic elevated CO through stenotic renal artery.
If this drug is discontinued prior to surgery, you get REBOUND HTN ?
Atenolol (beta blockers do)
All possible effects of abrupt withdrawal of beta blocker
Tachycardia Palpitations HTN -> HTN crisis angina exacerbation of HF
Why is a patient on long term ACEI therapy at risk for intraoperative hemodynamic instability and HoTN
More likely to have prolonged HoTN during GETA particularly when there is LARGE FLUID SHIFTS with the procedures
ACEI can do this to RAAS
Blunt RAAS
What is the only system intact to support BP in ACEI patients
Vasopressin system
Ideal vasoconstrictor for patients with pulmonary hypertension
Vasopressin
The most important physiological action of AVP (especially during normal physiology) is to
increase water reabsorption in the kidneys by increasing water permeability in the collecting duct, thereby permitting the formation of a more concentrated urine.
What is a demand-mode Pacemaker?
It senses the Electrical activity of the heart and provide either impulse or inhibition
What pacemaker competed with the intrinsic rhythm of the heart?
Asynchronous
Does asynchronous pacemaker recognize the instrinsic heart rate or rhythm of the patinet
NO
How does the asynchronous pacemaker work?
initiates impulse at a designated rate without regard to the patient rate or rhythm
What can permanently disable anti-tachycardia therapy in some ICD devices?
Magnet placement over the ICD over 30 seconds
ICDs before induction of anesthesia: What should be done?
Antitachycardia features should be disabled,
ICDs musc be
Reinterrogated and re-enabled immediately after surgery, either in surgery or in PACU
What can happen if the ICDs is not disabled during surgery?
Inappropriate shock
Insertion of CVC and ICD
the CVC guidewire may contact the leads of an ICD and cause the ICD to mistakenly sense a shockable rhythm and it will deliver an inappropriate shock
The blood supply of the spinal cord and nerve roots is derived from
One anterior
2 posterior
2 arteries contributing to the posterior blood supply of the
Radicular artery
Posterior longitudinal artery
Segmental artery of the spinal cord divides into (RAP)
Radicular artery
Anterior longitudinal artery
Posterior longitudinal artery
The anterior blood supply is the
Anterior longitudinal artery
The anterior spinal artery provides the anterior
2/3 of the cord
The posterior spinal arteries provide the posterior
1/3 of the cord
Provide 75% of the blood supply of the spinal cord ?
75%
The anterior artery supplies the
motor tracts
What form the anterior artery?
Vertebral arteries and receives reinforcement of blood supply from 6 to 8 radicular arteries,
Most important of the anterior artery?
the artery of Adamkiewicz is the most important of these
Signs and symptoms of Anterior spinal artery syndrome manifests as
Flaccid paralysis of the lower extremities
Bowel and bladder dysfunction with sparing of proprioception and sensation, due to the selective ischemia to the anterior portion of the cord.
Spared during anterior spinal artery syndrome
Proprioception and sensation
A large artery that comes off the aorta and feeds the spinal column is called the
Artery of Adamkiewicz
Artery of Adamkiewicz provides supply to the
Anterior, lower 2/3 of spinal cord.
In vascular surgery, the risk of paralysis related to Anterior spinal artery syndrome, highest risk is with
40% in the setting of dissection or rupture involving the thoracic cord.
During dissection or rupture involving the thoracici cord,______ is a key determinant of the risk of paraplegia.
The duration of cord clamping
Artery of Adamkiewicz arises from ______ and enter a single intervertebral foramen somehwere between ______ to _____
T7 to L4; T9-T11
What is the most common cause of RV failure ?
LV failure
What is the hallmark of Chronic LV systolic dysfunction ?
Decrease LV EF
When the LV does not completely effect the volume of blood it holds, what happens?
the workload on the ventricle and heart builds up with each heart beat leading to elevated LVEDV and decrease EF , decrease SV
3 hallmarks of Decreased EF
Elevated LVEDV, decrease EF, decreased SV
Symptomatic HF in patient with normal LV systolic function is most likely due to ?
Diastolic dysfunction
What parameter is elevated with diastolic dysfunction? What does it cause?
LVEDP; elevated cardiac work ; back pressure increase in LA and Pulmonary veins.
Causes of high cardiac output failure?
AV fistulas Pregnancy Anemia Hyperthyroidism Glomerulonephritis
Explain the adaptive mechanism of the failing ventricle to maintain normal CO
Atrial natriuretic peptide is released in response to increase atrial pressure.
Increase pressure in atrium releases
ANP
ANP secreted by _______ act as a vaso_______and leads to _______ of the heart
Atrial myocytes
Vasodilator
reducing afterload for the heart.
Strategis to manage diastolic HF?
Beta blockrs
Diuretics
Digoxin
What is the goal for management of diastolic heart failure?
Prevent remodeling of the LV , Which can deteriorate to HF.
Medication that decrease the progress of HF
Beta blockers, Digozin Diuretics Aldosterone antagonists ACEI
Opioids seem to have a particularly beneficial effect in HF patients because of their effects on the
delta on the ventricles.
associated with an increased risk of surgical mortality [
Known CHF is
New York Heart Association Functional Class Class I: Class III: Major limitation of physical activities; comfortable at rest; minimal physical activity results in dyspnoea, fatigue, or angina
Patient has no limitation of regular physical activities
NYHA Class ______Mild limitation of physical activities; comfortable at rest; normal physical activity results in dyspnea, fatigue or angina
NYHA Class II
NYHA Class ____Major limitation of physical activities; comfortable at rest; minimal physical activity results in dyspnoea, fatigue, or angina
NYHA Class III
Inability to perform any physical activity without symptoms; symptoms are present at rest, and are worsened with any activity? NYHA which class?
NYHA Class IV:
One of the fundamental concepts when considering how to protect and optimize cardiac performance is the concept of
myocardial oxygen supply and demand.
Oxygen supply delivered to the myocardium is represented by the
oxygen content of the blood multiplied by the cardiac output
What is demand?
Demand is the consumption of oxygen by the myocardium.
The determination of the amount of blood delivered to tissue is described in a way that is analogous to the mathematical description of ________
OHM’s LAW electrical current driven by voltage, Ohm’s law, where current equals voltage divided by resistance.
In the biologic blood flow model, this equates to:Ohm’s law
Q (flow ) = △P / Resistance
The subendocardial vessels are compressed during systole so that coronary perfusion only occurs during
the diastolic phase.
Conditions that may result in decreased oxygen supply to the left ventricle,
decrease the diastolic blood pressure, decrease diastolic filling time, or increase the diastolic pressure of the left ventricle
The primary determinants of arterial blood oxygen content (CaO2) are
hemoglobin concentration (HgB) and O2 saturation (SaO2):
The relationship between hemoglobin (Hb) and oxygen (O2) is described by the
oxyhemoglobin dissociation curve.
Flow per poiseuille’s Law
Flow is affected by decreases in the arterial radius to the fourth power, so even small decreases can cause significant flow limitation that can impede regional myocardial blood flow significantly.
CaO2 formula is
CaO2 = (HgB x 1.39) (SaO2)+ (PaO2) (0.003)
Factors that affect oxygen demand are the following:
Contractility
Heart rate
Wall tension
is also a key component of the oxygen consumption because this determines the frequency at which work is being done by the myocardium.
Heart rate
According to LaPlace’s law,
ventricular wall tension is directly proportional to the pressure in the chamber multiplied by the radius of the chamber and is inversely proportional to the wall thickness:
La place formula
P x P / 2h (Wall thickness)
Amount of blood delivered to the tissue in 1 min.
Cardiac output (CO)
CO formula
HR x SV
amount of blood ejected by the ventricle with each contraction
SV
SV is determined by
preload, afterload, and contractility.
follows Starling’s law in enhancing the contractile force of the ventricle
Preload, the precontractile fiber length of myocardial fiber augmented by end-diastolic volume (EDV),
Venous return is directly proportional to
EDV
main mechanism which influences the binding strength of actin and myosin filaments that determine the force of myocardial contraction.
Intracellular calcium ion
What is a normal CI?
2.5 to 3.5
Determinants of HR
HR is determined primarily by the rate of spontaneous phase 4 depolarization of the sinoatrial node pacemaker cells, which are influenced by neural and humoral mechanisms.
3 factors that determine preload
Venous return
Ventricular filling
Intrathoracic pressure
SV formula
EDV- ESV
EDV is determined by________while ESV is determined by ______And ______
preload; Afterload and contractility
3 factors that determined afterload?
SVR
Wall tension
Blood Viscosity
3 factors that determine contractility
SNS
Catecholamine drugs
If no obstruction or loss of volume in circulating pathways is present, venous return should equal
CO.
Impedance to ejection is
Afterload is defined
What is the formula for SVR?
80 x (MAP-RAP)/ CO
Afterload, as defined by ventricular wall stress, is represented by which law ?
LaPlace’s law:
intrinsic ability of the myocardium to generate force at given end-diastolic fiber length
Contractility
Coronary blood flow formula is
CBF = DBP (aorta) - LVEDP
Neurohormonal Systems Activated in Patients with Heart Failure
SNS
RAAS
ADH
Endothelin
Systolic HF and EF
Systolic function, with a reduced ejection fraction (EF).
Diastolic HF and EF
(HF with preserved EF).
PAD is
narrowed arteries reduce blood flow to your limbs.
PAD associated with this symptoms
Claudication symptoms include muscle pain or cramping in your legs or arms that’s triggered by activity, such as walking, but disappears after a few minutes of rest.
CRPS-1 is a syndrome where chronic pain (normally in an extremity) appears to be associated
with sympathetic nervous system dysfunction after trauma.
Raynaud’s phenomenon
cold temperatures or stress can trigger “Raynaud’s attacks.” During an attack, little or no blood flows to affected body parts.
Cardiac TAMPONADE: VERY IMPORTANT TO KNOW
positive pressure ventilation, combined with tamponade, can further reduce preload and actually cause catastrophic hypotension and even cardiac death.
NEVER to this with TAMPONADE?
initiate positive pressure ventilation until the pericardial space has been drained –
With cardiac tamponade, if general anesthesia is needed, what do you do?
spontaneous ventilation is mandatory, thus ketamine (or sevoflurane) is the drug of choice.
When to Induce with cardiac tamponade?
Induction should not take place until the surgical team is ready to make incision.
Signs of Cardiac tamponade
Beck’s triad
Muffled heart sounds, elevated jugular venous pressure (JVD), HYPOTENSION
ALSO pulsus paradoxus.
The pericardial sac typically has
15-30 ml fluid.
The classic cause of pulsus paradoxus,
Cardiac tamponade
Cardiac tamponade keep the heart
Fast full and strong
Underlying pathology of cor pulmonale?
Pulm HTN
When alpha 1 receptors are activated , what ion increase
Intracellular Calcium
Alpha 2 receptors located
Presynaptically
What are the 3 most common drugs used in treating ISCHEMIC HD
Nitrates
Beta Blockers
CCBs
Mitral stenosis with severe hemodynamic instability with SVT, immediately should undergo
Cardioversion
What is the formula of EF
SV/EDV
Classic triad of AS with critical valve stenosis of less than 1
SAD
Syncope
Angina
Dyspnea
Critical aortic stenosis Anesthesia contraindicated?
SPinal
Which valvular disease is the PCWP and overestimation of LVEDP
Mitral stenosis (because of the abnormal transvalvular gradient)
2 things that decrease coronary perfusion pressure?
Decrease in aortic pressure
Increase in ventricular end-diastolic pressure.
most common cause of myocardial remodeling
Myocardial ischemic injury
Pulse BiSFERIENS associated with
Associated with Severe AR, because of rapid ejection of large SV>
S3 is associated with
heart failure.
Develop as compensatory mechanism of AR
Eccentric Hypertrophy
Eccentric Hypertrophy mnemoic
VES (Volume, Eccentric , series)
MVP most common arrhythmia
Paroxysmal SVT
Cardiac sympathetic or accelerated fibers located where
T1-T4
Aortic pressure has a direct relationship with
Coronary perfusion pressure.
LV perfused almost entirely during
Diastole
THe RV is perfused when
Both systole and diastole
Which factor most NEGATIVELY affect MYOCARDIAL O2 CONSUMPTION?
Heart rate.
Which paradoxical cardiac wall motion is indicative of Myocardial iNFARCTION
Dyskinesia
Relative contraindications to PA catheterization
LBBB
Pa a wave produce by
Atrial contraction
ABsent with afib on PAC
A wave
Giant CANNON a wave on CVP with this heart valve issue
Tricuspid Stenosis
Mitral stenosis
Ventricular hypertrophy
With PE, CVP is ______ , PCWP is _____
high ; normal
LV failure, CVP _____and PCWP is ______
HIgh ,High
