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Med Surg: Hemodynamic Monitoring

Terms in this set (57)

Systole
tense, contracted, SQUEEZING
Diastole
relaxed, dilated, FILLING
preload
all about the FILL, end of diastole before the next contraction
How is preload determined?
venous blood return, vascular tone, myocardial compliance (MORE FILLED=MORE CONTRACTION)
*WE WANT A HIGH PRELOAD*
afterload
all about RESISTANCE, we want LOW afterload for less resistance for blood flowing out
Causes for increased afterload
valve stenosis (narrow/rigid valve)
hypertension
vasoconstriction
Results of increased afterload
decreased stroke volume, increased cardiac workload
contractility
the "squeeze"
depends on Av synchrony, metabolic state (pH), scar tissue and cardio myopathy, coronary perfusion and electrolytes (K, Mg, Ca)
inotropic agents
drugs that stimulate the heart to increase the force of contractions
can improve contractility in a damaged heart, force the muscle to contract
examples of inotropic agents:
epinephrine
milrinone
dobutamine
cardiac output
heart rate x stroke volume
volume of blood pumped by heart in 1 minute
cardiac index
cardiac output adjusted for body size (BSA) and is patient dependent
stroke volume
volume ejected with each heartbeat
determined by preload, afterload and contractility
stroke volume index
SV adjusted for body size (BSA)
systemic vascular resistance
determined by the AMOUNT OF CONSTRICTION OR DILATION OF THE ARTERIES
* Increase in SVR, increase BP
* Decrease in SVR, decrease BP
measures LEFT ventricular afterload
pulmonary vascular resistnace
measures RIGHT ventricular afterload
central venous pressure
-right ventricular preload or right ventricular end-diastolic pressure under normal conditions, measured in right atrium or in vena cava close to heart
pulmonary arterial wedge pressure (PAWP)
reflects left ventricular end-diastolic pressure (preload) under normal conditions
hemodynamic monitoring
-measurement (over time) of pressure, flow and oxygenation with the cardiovascular system
-assess heart function, fluid balance and the effects of fluids/medications on cardiac output
-provides a "picture" of patient's hemodynamic status and the effects of therapy (can follow trends)
Noninvasive Arterial Oxygenation Monitoring
pulse ox
-continuous method of determining arterial oxygenation (SpO2)
-normal is 95-100%
-accurate measurements may be difficult d/t hypothermia, receiving vasopressors or in a shock state
-consider alternate sites for pulse ox probe
-used to evaluate the effectiveness of O2 therapy
Invasive Pressure Monitoring System
-equipment must b referenced and zero balanced to environment and dynamic response characteristics optimized
referencing
placing transducer so zero-reference point is at level of atria of heart or phlebostatic axis
zeroing
confirms when pressure within system is zero, monitor will read zero
how to zero reference
-open up reference stopcock to room air (off to patient)
-with initial setup and periodically thereafter
-delivers continuous flush irrigation system (1-3mL of saline/hour)
-maintains line patency and limits thrombus formation
arterial pressure monitoring
-catheter thread through peripheral artery
-can be used for BP monitoring
-can be used for blood draws
-DO NOT INFUSE ANYTHING!!!!
Arterial sites
radial
femoral
dorsalis pedis
brachial (ischemia to lower arm, thrombus around line inside artery)
Arterial Pressure Monitoring nursing management
-set up line/pressure bad/transducer (300mmHg, primed, zeroed, at axis, notch wave form)
-level to phlebostatic axis and zero line
-assess waveform on monitor for accuracy
-monitor BP
-set alarm limits on monitor
Arterial Pressure Monitoring Risks/Complications
-hemorrhage
-infection (although usually low)
-thrombus formation
-neurovascular impairment
-loss of limb (checks at bedside and assessments!!)
central venous pressure monitoring
monitoring through the central venous catheter or Swan Ganz PA catheter
right ventricular preload
(or right ventricular end-diastolic pressure)
-measured in right atrium or in vena cava close to the heart
-direct measurement of pressure entering the right side of the heart
Normal CVP values
2-8mmHg
low CVP
indicates hypovolemia (so give fluids)
high CVP
indicates high-volume overload (give diuretics)
CVP nursing management
-set up line, pressure bag/transducer
-measured through distal port of CVC (blue port on Swan)
-level to phlebostatic axis and zero line
-assess waveform on monitor for accuracy
-set alarm limits
-evaluate response to interventions
pulmonary artery (PA) catheter indications
-alteration in cardiac output or fluid volume status
-sits in pulmonary artery, risk of bleeding risk thrombosis, risk of infection too
-guides management of patients with complicated heart and lung problems
-used less due to risk assoc. with invasive monitoring and development of less invasive techniques
-inserted at bedside by APP/MD with nursing support
pulmonary artery catheter
-continuous CVP
-continuous PA pressure monitoring
-allows therapeutic manipulation of preload
-CO and CI (in L/min)
-continuous SvO2
-systemic vascular resistance (SVR) (afterload)
-core temperature
CO and CI monitoring
can be measured continuously or intermittently it depends on the type of PA catheter inserted
normal CO values
4-8 L/min
normal CI values
2.2-4 L/min/m2
low CO/CI
-based on body surface area
-heart is not pumping effectively so you need to administer inotrope and give volume
PAWP monitoring
LV + diastolic pressure
-measurements obtained at end expiration
-balloon-tipped catheter is "wedged" into a pulmonary artery branch and inflated (make sure is deflated)
-inflated slowly with 1.5mL of air
-indirect measurement of LV end diastolic pressure
Normal PAWP values
6-15mmHg
low PAWP
indicates volume depletion
high PAWP
heart failure, fluid overload
systemic vascular resistance (SVR) monitoring
-resistance to blood flow by the vessels
-forces opposing ventricular ejection
-measure of LEFT ventriclular afterload
normal SVR values
800-1200 dynes/sec/cm-5
high SVR
indicates vasoconstriction
low SVR
indicates vasodilation
venous oxygenation saturation monitoring
indicator of O2 delivery and O2 consumption
measuring O2 sats of hemoglobin in venous blood can determine adequacy of tissue oxygenation
ScvO2
measured from a central venous catheter
SvO2
measured from a PA Swan Ganz catheter
normal venous oxygenation values
60-80%
high venous oxygenation
-clinical interventions worked (like increasing FiO2, give RBCs and increase CO)
-sepsis can cause abnormally high SvO2 because of inappropriate extraction of O2 at tissue level
low venous oxygenation
-low CO, low hemoglobin, increased O2 consumption (fever) or metabolic state, decreased arterial oxygenation
PA catheter nursing management
-set up line/pressure bad/transducer
-assist MD in sterile insertion
-level to phlebostatic axis and zero line
-assess waveforms on the monitor for accuracy
-monitor CVP, PAP, CO/CI, SVR, PVR
-keep balloon DEFLATED bw PAWP readings
-set alarm limits on monitor
-monitor line insertion site for infection and maintain dressing
-report bleeding, signs of infection, malposition of line to APP/MD
-can use for medication, blood, TPN infusion; can also draw blood
PA catheter complications
dysrhythmias
infection
vessel/ RA/ RV perforation
pneumothorax
pulmonary infarction
balloon rupture= air embolism
DO NOT INFLATE W MORE THAN 1.5ML AIR
pulmonary artery rupture
endocarditis
What to use instead of PA catheter
-impedance cardiography (noninvasive)
-use arterial line already in place (invasive)
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