Transcript Airgas template

Assessment of Cardiovascular
Function
Hemodynamic Monitoring
1
Copyright © 2008 Lippincott Williams & Wilkins.

Overview of Anatomy and
Physiology
of
the
Heart
Three layers of the heart:
 Endocardium (inner lining)
 Myocardium (muscle fibers)
 Epicardium (exterior layer)
 Heart is encased in the pericardium
 Four chambers
 2 atria, 2 ventricles
 Heart valves
 2 atrioventricular valves, 2 semilunar valves
 Coronary arteries
 Cardiac conduction system
2
Copyright © 2008 Lippincott Williams & Wilkins.
Structure of the Heart
3
Copyright © 2008 Lippincott Williams & Wilkins.
The Cardiac Cycle
 During systole, the heart muscle contracts
and blood is ejected from the chambers
 During diastole, the heart muscle relaxes
and the chambers fill with blood
4
Copyright © 2008 Lippincott Williams & Wilkins.
The Cardiac Cycle
 Muscle contraction is initiated by action potentials the
normally originate in the sinoatrial node
 Ventricular contraction causes the AV valves (tricuspid
and mitral) to close, which indicates the beginning of
ventricular systole.
 The semilunar valves (aortic and pulmonic) were closed
during the previous filling (diastole) period and remain
closed during this time
 Continued contraction raises pressure in the ventricles
above the pressure in the aorta and pulmonary trunk,
causing the semilunar valves to open
 Blood is ejected from the ventricles, through the semilunar
valves, into the pulmonary artery (right) and aorta (left)
Copyright © 2008 Lippincott Williams & Wilkins.
5
The Cardiac Cycle
 Once the ventricles relax and pressures decrease, blood
flowing back (from the pulmonary artery and aorta)
towards the relaxed ventricles causes the semilunar valves
to close.
 This is the beginning of ventricular diastole
 The AV valves remain closed
 When the ventricular pressure becomes lower than the
pressure within the atria, the AV valves open and blood
flows from the atria into relaxed ventricles. This represents
approximately 75% of ventricular filling.
 The atria then contract and complete the remainder of 6
ventricular filling
Copyright © 2008 Lippincott Williams & Wilkins.
Coronary Arteries
7
Copyright © 2008 Lippincott Williams & Wilkins.
Cardiac Conduction System
8
Copyright © 2008 Lippincott Williams & Wilkins.
Terms: Cardiac Action Potential
 Depolarization: electrical activation of a cell
caused by the influx of sodium into the cell while
potassium exits the cell
 Repolarization: return of the cell to the resting
state caused by re-entry of potassium into the cell
while sodium exits
 Refractory periods:
 Effective refractory period: phase in which cells are
incapable of depolarizing
9
Copyright © 2008 Lippincott Williams & Wilkins.
Cardiac Action Potential
10
Copyright © 2008 Lippincott Williams & Wilkins.
Great Vessel and Heart Chamber
Pressures
11
Copyright © 2008 Lippincott Williams & Wilkins.
Cardiac output
 Cardiac output refers to the amount of blood
pumped by each ventricle during a given
period
 Average human cardiac output is 5 liters per
minute (4-8 is normal)
 Stroke volume (SV) refers to the amount of
blood ejected per heartbeat
 CARDIAC OUTPUT = SV x HR
12
Copyright © 2008 Lippincott Williams & Wilkins.
Terms: Cardiac Output
 Stroke volume: the amount of blood ejected with each
heartbeat
 Cardiac output: amount of blood pumped by the
ventricle in liters per minute
 Preload: degree of stretch of the cardiac muscle fibers at
the end of diastole
 Contractility: ability of the cardiac muscle to shorten in
response to an electrical impulse
 Afterload: the resistance to ejection of blood from the
ventricle
13
 Ejection fraction: the percent of end-diastolic volume
Copyright © 2008 Lippincott Williams & Wilkins.
 CO = HR x SV
14
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic MonitoringNoninvasive
 Blood pressure
 Orthostatic vital signs
15
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Blood Pressure Measurement
 Systemic blood pressure is exerted on the walls
of the arteries during ventricular systole and
diastole
 Affected by factors such as cardiac output,
distension of the arteries, and the volume,
velocity and viscosity of blood
 Normal: 100/60-135-85
16
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Orthostatic (postural) blood pressure/HR measurements
 The patient should be supine and flat for 5-10 minutes, then the
initial BP and HR are measured
 The patient is then placed in the sitting position, with feet
dangling. Repeat measurements are taken within 1-3 minutes of
position change
 Repeat the procedure with the patient in the standing position
 Record BP and HR, as well as the patient position that
each was taken
 Be sure to ask about symptoms of dizziness or feeling
faint during position changes - record this as well 17
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic MonitoringInvasive
CVP
Pulmonary artery pressure
Intra-arterial BP monitoring
18
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Critically ill patients may require continuous
assessment of their hemodynamic status
 Special Equipment: see slide 27
 Catheter, which is introduced into the appropriate
vessel
 Flush system for continuous flushing of the catheter
 Pressure bag around the flush system to prevent
backflow of blood
 A transducer to convert the pressure from the vessel
into an electrical signal
 A monitor to display the signal and reading
19
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Nursing responsibilities
 Ensuring that the system is set up and
maintained properly
 Prior to taking a measurement, ensuring that the
stopcock of the transducer is at the level of the
right atrium - referred to as the phlebostatic axis
(4th intercostal space, midaxillary line
 Monitoring for complications
20
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Central Venous Pressure Monitoring (CVP)
 Normal 2-8 mmHg
 Pressure in the vena cava and right atrium
 Used to assess right ventricular function and venous blood
return to the right side of the heart
 Very useful in the assessment of volume status
 High CVP may indicate volume overload
 Low CVP may indicate volume depletion
 Measured via a central line catheter positioned in the vena
cava via the internal jugular or subclavian vein
21
Copyright © 2008 Lippincott Williams & Wilkins.
Phlebostatic Level
22
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Central Venous Pressure Monitoring (CVP)-Nursing
Interventions
 Ensure that dressing maintains clean, dry and STERILE
 Xray confirmation of catheter placement
 Dressing and pressure monitoring system are maintained according
to hospital policy
 Monitor for signs of infection
 Ensure appropriate transducer placement before measurements are
recorded
 Document CVP
 Monitor for other complications: pneumothorax, air embolism
23
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Pulmonary arterial pressure monitoring (Swan Ganz)
 Normal PA pressure 20-30/8-15 mmHg; mean 12-18 mmHg
 Normal pulmonary capillary wedge pressure 6-12 mmHg
 Used to evaluate right and left sided cardiac function:






Left ventricular performance
Volume status
Cardiac output
Condition of vascular system (SVR)
Response to cardiovascular infusions
Effects of treatments on cardiac functioning
 Inserted via the subclavian or jugular vein, occasionally the
femoral vein
24
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Pulmonary arterial pressure monitoring
 Pulmonary artery pressures reflect volume status,
right heart function
 Pulmonary capillary wedge pressure reflects left
heart function ; the catheter is “wedged” in the
pulmonary artery and the balloon is inflated ,
temporarily obstructing blood flow
 This creates a static fluid column, and the catheter
senses the pressure in the pulmonary vein - this allows
us to estimate the left atrial pressure
25
Copyright © 2008 Lippincott Williams & Wilkins.
Pulmonary Artery Catheter
26
Copyright © 2008 Lippincott Williams & Wilkins.
Pulmonary Artery Catheter and
Pressure Monitoring System
27
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
Nursing responsibilities of a PA catheter:
 Ensure that dressing maintains clean, dry and STERILE
 Xray confirmation of catheter placement
 Dressing and pressure monitoring system are maintained according to
hospital policy
 Monitor for signs of infection
 Ensure appropriate transducer placement before measurements are
recorded
 Document hemodynamic measurements as ordered
 During insertion: monitor EKG for dysrhythmias
 NEVER leave balloon inflated (risk of PA rupture)
 Monitor for other complications: PA rupture, PA embolism,
pulmonary infarction, catheter migration, dysrhythmias, air embolus,
28
pneumothorax
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Intra-arterial Blood Pressure Monitoring
 Used to obtain direct and continuous BP measurements
in critically ill patients
 Placed in the radial, femoral or brachial artery
29
Copyright © 2008 Lippincott Williams & Wilkins.
Hemodynamic Monitoring
 Intra-arterial Blood Pressure Monitoring
 Nursing Interventions
 Ensure that dressing remains clean, dry and sterile
 Ensure patency of pressure monitoring and flushing systems,
maintain per hospital policy
 Ensure appropriate transducer placement when measurements are
recorded
 Document BP as ordered
 Monitor for complications: distal ischemia, hemorrhage, massive
ecchymosis, dissection, air embolism, pain, infection
 NEVER inject anything into the arterial line
30
Copyright © 2008 Lippincott Williams & Wilkins.
Arterial Pressure Monitoring
System
31
Copyright © 2008 Lippincott Williams & Wilkins.