Hemodynamics, HTN Crises, Valvular Disease & Aneurysms quiz 2
Afterload - Right Ventricle High---> increased PVR resistance Interventions?
"clamped down" & "vasoconstricted" •Oxygen •Vasodilate -->Nitric Oxide -->Other medications •Equipment -->VADs
Afterload Low ---> decreased SVR or PVR resistance Interventions?
"vasodilated" •Vasopressors -->Norepinephrine -->Phenylephrine -->Dopamine
PAP Pulmonary Artery Pressures •PAP pressures Normal
-20-30 mmHg/8-15 mmHg
Preload Low--> decreased CVP/RAP or PCWP "wedge" pressures -Fluid volume deficit "dry" Relative:
-3rd spacing -Vasodilation as in some shock states -Side effects of some medications
What guidelines must you follow when interpreting PA data?
-Always assess patient trends rather than an isolated reading. -Question abnormal readings. Recheck the reading after zeroing and calibrating the equipment. Assess the patient for additional data to support the reading. -Compare the readings with the patient's normal valus and not with the normal values listed in a textbook. -Do not be fooled by normal readings. The patient may have normal readings temporarily because of compensatory mechanisms. Continue to assess the patient. -Assess the interrelationships among the readings. The goal is to obtain a picture of the patient's hemodynamic status, not simply a number.
Invasive Lines in the ICU •Arterial Lines
-Continuous blood pressure -Draw labs - ABGs •Ventilated patients -Minimally invasive hemodynamic monitoring
Preload •High --> increased CVP/RAP or PCWP "wedge" pressures Indicates what?
-Fluid Volume Overload (CVP: edema and Wedge: crackles)
Preload •Low--> decreased CVP/RAP or PCWP "wedge" pressures Indicates what?
-Fluid volume deficit "dry"
Preload Low--> decreased CVP/RAP or PCWP "wedge" pressures -Fluid volume deficit "dry" Absolute:
-Hemorrhage -Dehydration
CO/CI In Critically ill patients
-Monitor hemodynamic status -Ensure adequate tissue & organ perfusion -Unable to compensate on their own -Nurses provide supportive care dependent on patient presentation hemodynamic values, orders & protocols •Give medications; diuretics •Give fluids, blood •Monitor closely
PAP Pulmonary Artery Pressures •PA Diastolic Pressure Normal
-PAD 8-15 mmg Hg •Used in place of PCWP, aka wedge for left heart preload
PAP Pulmonary Artery Pressures •PA Systolic Pressure Normal
-PAS 20-30 mmHg
What is the purpose of the pulmonary artery catheters?
-To determine the direct pressures or volumes within the right heart and PA, and for the indirect measurement of left heart pressures -To determine cardiac output (CO) -To sample pulmonary artery mixed venous blood (SvO,) -To provide various therapies (e.g., IV fluids, medications, or temporary cardiac pacing)
Invasive Lines in the ICU •Central Venous Catheters (CVCs)
-Viscous medications -Draw labs -Hemodynamic monitoring •Central Venous Pressure (CVP) -Various placement •Internal jugular •Subclavian •Femoral
Read thru the paragraph on p. 190-191 treatment of elevated PAP.
-diuretics -restricting sodium and fluid intake -pulmonary vascular vasodilation medications
What are some interventions to reduce elevated wedge pressures?
-diuretics -vasodilators -restricting sodium and fluid intake -control of dysrhythmias help the heart pump more effectively -IABP -contractility is enhanced by using inotropic medications
What 3 steps must a nurse follow in hemodynamic assessment of patient with a PA catheter?
1. Obtain accurate data 2. correctly analyze the waveform 3. Integrate the data with the patient assessment
What is the normal range for CVP?
2 to 6 mmHg
What is the normal range for RAP?
2-6 mmHg
What is the pressure bag for and what mmHg must it be at?
300 mmHg
What is a normal Mean arterial pressure (MAP)?
70-90 mmHg
What is the apical-radial pulse deficit?
A count of the apical heart rate is useful to determine the total heart rate. Usually these two rates are equal, but there may be a deficit between the apical rate and the radial rate caused by irregular heart rhythms that result in stroke volume varying from beat to beat, which results in some beats being too weak to be felt at the radial artery (the apical-radial pulse deficit).
If we cannot use the "wedge" or PAWP/PAOP pressure, is the PAD an acceptable measurement of left ventricular preload?
After the PAD pressure has been demonstrated to correlate with the PAWP, it is used to monitor left ventricular preload status. Certain cardiovascular disorders (e.g., mitral stenosis, heart rate greater than 125 / min) and pulmonary disorders (e.g., chronic obstructive pulmonary disease, pulmonary embolism) alter the relationship of PAD to PAWP, and in such cases PAD cannot be used to monitor PAWP.
How can hemodynamics be measured at the most basic level?
Blood pressure, heart rate, urine output
Cardiac Index (CI) CI = ______
CI = CO/BSA •Volume of blood ejected by the heart over 1 minute based on patients body surface area (BSA) *bases it on the individual and their size
What is the normal ranges for CO/CI?
CI: 2.4-4.0 CO: 4 - 8
Normal Values CO: CI: SV: CVP or RAP: Wedge: PAD: SVR: PVR: PAS:
CO: 4-8 CI: 2.4-4 SV: 50-100 CVP or RAP: 2-6 Wedge: 4-12 PAD: 8-15 SVR: 900-1400 PVR: 100-250 PAS: 20-30
Elevated wedge can be caused by (see table 8-5), what would be your patient's clinical findings? (Subjective or objective data?) Also, table 8-5 on page 192 for causes of elevated Wedge pressures
Clinical Findings. Clinical findings related to an elevated PAWP vary according to the degree of elevation but typically include tachycardia, exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea (PND), crackles in the lung fields, an S3 or S4 gallop at the heart apex, and neck vein distension. Causes: mitral valve stenosis, cardiac tamponade, fluid overload, left ventricular failure, myocardial ischemia
Elevated PAD would present how with your patient?
Clinical findings associated with left-heart failure may result in some or all of the following signs and symptoms: dyspnea, tachycardia, S3 or S4 heart sounds, and bilateral crackles in the lungs. CO is reduced, and PAWP is elevated.
Why must you level and zero the transducer?
Corrects for hydrostatic pressure changes in vessels above and below the heart
Elevated PAD causes include:
Elevated PAD. Conditions that affect the left heart, such as angina or myocardial infarction, fluid overload, mitral stenosis, and left-to-right intracardiac shunts, are associated with a high PAD pressure.
Elevated PAS causes include:
Elevated PAS. The PA pressure is generated by the right ventricle; therefore, any condition that acutely or chronically increases the afterload of the right ventricle (i.e., increases the pulmonary vascular resistance) results in an elevated PAS pressure. Examples include pulmonary hypertension from any cause, including chronic lung disease, pulmonary embolism, and hypoxemia.
Review for causes and possible interventions for both elevated and low SVR.
Elevated SVR -Causes: Hypothermia, hypovolemia (due to compensatory mechanisms--> vasoconstricted), cardiac failure--> hypotension--> constriction -Interventions: Diuretic, vasodilator, positive inotropic agent (milrinone) Low SVR -Causes: drug-induced vasodilation, shock--> hypotension, and anaphylaxis -Interventions: Adjust drug dose, vasoconstricting medications (shock)
PAP What will affect this value?
Generated by the Right Ventricle -Any condition that affects the afterload of the right ventricle (PVR) will affect the PA pressures •Pulmonary hypertension •Chronic lung diseases •Pulmonary embolism •Hypoxemia
What are the two major determinants of cardiac output?
Heart rate and stroke volume
What are some causes of decreased RAP? Symptoms?
Hypovolemia -absolute deficit: hemorrhage or excessive diuresis -relative deficit: drug induced vasodilation or third spacing of fluid *sufficient enough to compromise CO --> shock symptoms
What are some causes of low or high preload?
Low: -Two types of fluid deficient: Absolute (hemorrhage and dehydration) and relative (drugs or conditions that cause severe vasodilation) High: a failing heart or volume overload
Define preload
The pressure or stretch exerted on the walls of the ventricle by the volume of blood filling the ventricle at the end of diastole (ventricular filling).
What about treatment interventions for either decreased or increased RAP? Also look at the table 8-4
Increased RAP -Diuretic therapy -restricting sodium and fluid -vasodilating medications Decreased RAP -Dehydration: IV fluids -Hemorrhage may need surgical intervention -decrease vasodilators
What are some causes of increased RAP?
Increases with fluid volume excess problems (e.g., heart failure or excessive fluid intake) or any pathologic condition that increases the pressures or vascular volumes in the lungs can increase pulmonary resistance
What are hemodynamics?
Is a physiologic term that refers to the forces involved in the flow of blood as it circulates through the cardiovascular system.
What is systemic vascular resistance (SVR)? What are ranges (see table 8-1)
Is an estimate of left ventricular afterload. It represents an average of the resistance of all the vascular beds.
What is PVR and why do you care a high PVR?
Is an estimate of right ventricular afterload. It represents an average of the resistance of pulmonary vascular beds. Is elevated with hypoxemia (causes pulmonary constriction), acute lung injury, acute respiratory distress syndrome, pulmonary hypertension, and pulmonary congestion.
What is cardiac output (CO)?
Is the amount of blood pumped by the heart each minute
What is pulse pressure?
Is the difference between diastolic and systolic blood pressures. It reflects how much the heart is able to raise the pressure in the arterial system with each beat.
Why is cardiac index (CI) a more useful piece of data as opposed to cardiac output?
It relates the CO to the patient's body size. -considers BSA
What is a transducer?
It translates mechanical energy sensed by the catheter into electrical energy, displayed on the screen as a waveform.
Review box 8-2 for guidelines for prevention of CLABSI.
Keeping the dressings clean and the lines patent are huge factors. Hand hygiene is another.
PAD or wedge
Left side
Review in book Review table on 8-4 for conditions that alter RAP(CVP for our purposes) Wagner & Hardin-Pierce, 2017, p. 188
Review table on 8-4 for conditions that alter RAP(CVP for our purposes) Wagner & Hardin-Pierce, 2017, p. 188 Increased RAP: Conditions causing fluid excess: -chronic or severe left heart failure -excessive fluid intake Conditions causing increased pulmonary afterload: -pulmonic valve stenosis -pulmonary hypertension Condition that apply external pressure on the heart--> increasing right ventricular filling -cardiac tamponade and tension pneumothorax Decreased RAP: conditions causing fluid volume deficit Absolute: hemorrhage, diuresis, dehydration relative: vasodilation, certain shock staters, third spacing
Afterload - Right Ventricle High---> increased _______
PVR resistance
What are some complications of central lines?
Pneumothorax, catheter fracture and occlusion, artery puncture, air embolism, cardiac dysrhythmias
How can we measure preload? Which measures the right ventricle and which measures the left ventricle?
Preload is reflected in two PA catheter measurements, the right atrial pressure (RAP) and the pulmonary artery wedge pressure (PAWP). The RAP directly measures right ventricular preload, and the PAWP measures left ventricular preload.
Afterload Definition
Pressure or RESISTANCE the ventricle has to overcome to open the aortic or pulmonic valves to eject the blood into the systemic or pulmonary circulation
Contractility
Property of myocardial muscle fibers that allows them to shorten (p. 152) "squeeze" •A weak contraction or squeeze that will happen with heart failure or hypovolemia (Starlings Law) decreases your CO because your SV is decreased—remember CO = HR x SV •Increased contractility assessments: bounding & vigorous pulse; increased pulse pressure •Decreased contractility assessments: weak & thready pulse; decreased pulse pressure
Preload •Pulmonary Artery Wedge pressure (PAWP) or Pulmonary Artery Diastolic (PAD) pressure Normal Values and what does it measure?
Pulmonary Artery Wedge pressure (PAWP) or Pulmonary Artery Diastolic (PAD) pressure -Left heart measure -4-12 mmHg Wedge; 8-15 mmHg PAD *After the PAD pressure has been demonstrated to correlate with the PAWP, it is used to monitor left ventricular preload status.
Invasive Lines in the ICU •Pulmonary Artery (PA) Catheters -Aka Swan Ganz or Swan
RAP, RV PA Pressures "wedge" Cardiac Output Temporary pacemaker
What does the pulmonary artery SYSTOLIC (PAS) pressure reflect? And what are its normal ranges?
Reflects the highest pressure generated by the RV during systole, with a normal range of 20 to 30 mmHg.
What does the pulmonary artery DIASTOLIC (PAD) pressure reflect? And what are its normal ranges?
Reflects the lowest pressure within the pulmonary artery and has a normal range of 8 to 15 mmHg.
Why is it important a patient have an "adequate cardiac output"?
Required for the delivery of oxygen to tissues and organs
Where is the tip of the central line located in vascular anatomy?
Requires only that a central venous catheter (CVP) line be inserted with the distal tip located in the superior vena cava near the entrance of the right atrium
Preload Right atrial pressure (RAP) or (CVP) central venous pressure (CVP) Normal values and what does it measure?
Right atrial pressure (RAP) or (CVP) central venous pressure (CVP) which is measured in the SVC-values differ slightly -Right heart measure •-2-6 mmHg
Afterload- Left Ventricle High --> increased________
SVR
Elevated PAS would present how with your patient?
The clinical findings of elevated PAS pressure vary according to the cause, severity, and duration of the elevated pressure. Assessment of the patient with pulmonary hypertension may reveal signs of right-heart failure, including distended neck veins, peripheral edema, a tender liver, and ascites. Palpation of the chest may reveal a right ventricular lift, and auscultation may reveal S3 and S4 heart sounds. The patient with a pulmonary embolus may present as a medical emergency with dyspnea, chest pain, hemoptysis, and hemodynamic instability.
Stroke Volume Definition
Stroke Volume - "the amount of blood ejected by each heartbeat"
What is stroke volume?
The amount of blood ejected by each heart beat
Preload Definition
The pressure or stretch exerted on the walls of the ventricle by the VOLUME of blood filling the ventricle at the end of diastole
How can we measure afterload? Which measures the left side of the heart and which measures the right side of the heart?
The left sided afterload is know as the systemic vascular resistance (SVR); the right sided afterload is known as the pulmonary vascular resistance (PVR)
What anatomic position is the landmark for leveling a transducer? *note we also have to use transducers for any central line if we want a CVP reading or any arterial line for a BP reading
The phlebostatic axis approximates the level of the right atrium and represents the level of the catheter tip
Define afterload
The resistance to ventricular contraction
Why is an increased afterload concerning?
The ventricle does not fully empty, which translates into a reduced SV and low CO
Lizzy, 45-year-old female, presents to the ED at 1000 9/8/2020 with chief complaint of chest tightness, cough and fever 101.5 F x 2 days. She says she is unable to keep any fluids down. Her skin is dry and skin turgor "tent's when assessed. Her pulse is weak and thready, BP is 80/56. O2 sats 93% on RA. Her extremities are cool/pale, BLE pulses are 1+ at best. COVID test is pending. Monitor is placed and her telemetry shows this rhythm:
What is this rhythm? -sinus tachy Based on her symptoms, what you expect her physical assessment to reveal? -low fluid status The physician will be placing a CVC catheter. What hemodynamic measures can be obtained from this catheter? -low CVP (right heart venous) What do expect her value to be? -fluids (LR) -blood culture -CBC, ABGs, lactatae
How can you measure Central Venous Pressure? (CVP)
Used to measure central blood volume, right ventricular filling pressure, and central venous oxygenation status.
When might an arterial line be placed? For what? *Be familiar with the arterial waveform, but do not have to memorize the components of at this level
When a patient requires frequent monitoring of systemic blood pressure and mean arterial pressure (MAP) or frequent arterial blood gases (ABGs)
If the patient's heart rate increases, will that affect stroke volume?
Yes, because HR will affect preload, afterload, contractility.
Define contractility
a property of myocardial muscle fibers that allows them to shorten.
LHC vs RHC
arterial side (high pressure) --> LHC venous side (low pressure)--> RHC
•Increased contractility assessments:
bounding & vigorous pulse; increased pulse pressure
CVP or right side
fluid status/venous return
What symptoms would you anticipate seeing in your patients (increased RAP)?
generally those of fluid volume excess
What 3 factors affect stroke volume?
preload, contractility, afterload
•Decreased contractility assessments:
weak & thready pulse; decreased pulse pressure (difference between systolic and diastolic BPs)
Afterload- Left Ventricle High --> increased SVR Goal of therapy *target reducing_______ Interventions?
workload •Vasodilate -->Nitroglycerin -->Nipride •Equipment -->IABP (creates a vacuum in the aorta to decrease resistance) -->VADs
Afterload- Left Ventricle High --> increased SVR
•"clamped down" & "vasoconstricted" •Heart has to work hard -Increases myocardial oxygen demand Goal of therapy *target reducing workload •Vasodilate -->Nitroglycerin (venous system more) -->Nipride (arterial system more) •Equipment -->IABP -->VADs
PAD Pressure & Wedge-Preload Wedge pressure Normal
•- 4 - 12 mmHg
PAD Pressure & Wedge-Preload PAD pressure Normal
•8-15 mmHg
Invasive Lines in the ICU
•Arterial Lines •Central Venous Catheters •Pulmonary Artery Catheters (aka Swan Ganz) •Goal is to get the overall picture of what is happening with the patient -by looking at the data & the patient's presentation
Hemodynamics Defined
•Heme "blood" •Dynamics "force or change within a system" Text "Forces involved in the flow of blood as it circulates through the cardiovascular system"
Afterload •Systemic Vascular Resistance (SVR) What does it measure? Normal values?
•Left heart measure •900 - 1400 dynes/sec/cm-5
Cardiac Index (CI) Normal
•Normal 2.4 - 4 L/min/m2
Stroke Volume Normal
•Normal 50 to 100 mL/beat
Afterload •Pulmonary Vascular Resistance (PVR) What does it measure? Normal values?
•Right heart measure •100-250 dynes/sec/cm-5
Heart Rate
•Sympathetic Nervous System •Parasympathetic nervous system Affected by: -fever -Pain -Anxiety -volume status -vagal nerve stimulation
Afterload Includes
•Systemic Vascular Resistance (SVR) •Pulmonary Vascular Resistance (PVR) -higher the number the worse the resistance -higher --> constricted blood vessels
Cardiac Output (CO) Definition/Normal value
•Volume of blood ejected by the heart over 1 minute •Liters/minute •4 to 8 L/min