INTRODUCTION
Critically ill patients require continuos assessment of their
cardiovascular system to diagnose and manage their complex
medical conditions.This is most commonly achieved by the use
of direct pressure monitoring systems,often refered to as
hemodynamic monitoring.Heart function is the main focus of
hemodynamic
studies.
Hemodynamic
pressure
monitoring
provides information about blood volume , fluid balance and how
well the heart is pumping. Nurses are responsible for the
collection measurement and interpretation of these dynamic
patient status parameters.
HEMODYNAMICS
Hemodynamics
are the forces which
circulate blood through the body.
Specifically, hemodynamics is the term
used to describe the intravascular
pressure and flow that occurs when the
heart muscle contracts and pumps blood
throughout the body.
DEFINITION
Hemodynamic monitoring refers to
measurement of pressure, flow and
oxygenation of blood within the cardiovascular
system.
OR
Using invasive technology to provide
quantitative information about vascular
capacity, blood volume, pump effectiveness
and tissue perfusion.
OR
Hemodynamic monitoring is the measurement
and interpretation of biological sytems that
describes the performance of cardiovascular
system
PURPOSES
Early detection, identification and
treatment of life threatening conditions
such as heart failure and cardiac
tamponade.
Evaluate the patient’s immediate response
to treatment such as drugs and
mechanical support.
Evaluate the effectiveness of
cardiovascular function such as cardiac
output and index.
INDICATIONS
Any deficits or loss of cardiac function: such
as myocardial infarction, congestive heart
failure, cardiomyopathy.
All types of shock; cardiogenic
shock, neurogenic shock or anaphylactic
shock.
Decreased urine output from
dehydration, hemorrhage. G.I bleed, burns or
surgery.
SPECIALISED EQUIPMENTS NEEDED
FOR INVASIVE MONITORING
A CVP,pulmonary artery ,arterial catheter
A flush system composed of intravenous solution,tubing stop cocks
and a flush device which provides for continous and manual flushing of
system.
A pressure bag placed around the flush solution that is maintained at
300 mmhg pressure ;the pressurized flush system delivers 3-5ml of
solution per hour through the catheter to prevent clotting and backflow
of blood into the pressure monitoring system.
A tranducer to convert the pressure coming from artery or heart
chamber into an electrical signal
An amplifier or moniter which increases the size of electrical signal for
display on an occilloscope.
SETUP FOR HEMODYNAMIC
PRESSURE MONITORING
Obtain barrier kit, sterile gloves and correct swan catheter.
Also need extra iv pole, transducer holder, boxes and
cables.
Check to make sure signed consent is in chart , and that
patient and or family understand procedure.
Everyone in the room should be wearing a mask.
Position patient supine and flat if tolerated.
On the monitor , press “change screen” button , then select
“swan ganz” to allow physician to view catheter wave forms
which inserting.
Assist physician in sterile draping and sterile setup for swan
insertion.
Setup pressure lines and transducers. Level pressure flush
monitoring system and transducers to the phlebostatic axis.
Connect tubings to patient when patient is ready to flush the
swann.
While floating the swann, observe for ventricular ectopy on
the monitor.
After swann is in place, assist with cleanup and let patient
know procedure is complete.
Obtain all the values. For cardiac output inject 10mls of D5w
after pushing the start button.
Perform hemocalculations.
Document findings in ICU flow sheet.
NON INVASIVE ARTERIAL BP
MONITORING
With manual or automated devices
Method of measurement
Oscillometry (most common)
MAP most accurate DP least accurate
Auscultatory (korotkoff sounds)
Combination
LIMITATIONS
Cuff must be placed correctly and must be
appropriately sized
Auscultatory method is very inaccurate
(Korotkoff sound is difficult to hear)
Significant
underestimation
in
low
flow
(shock)
Oscillometric also mostly in accurate
( >5mmhg off directly recorded pressures)
DIRECT INTRA ARTERIAL BP
MONITORING
Intra-arterial BP monitoring is used to
obtain direct and continuous BP
measurements in critically ill patients who
have severe hypertension or hypotension
PROCEDURE
Once
an
arterial
site
(radial, brachial, femoral,
is
selected
or dorsalis
pedis), collateral circulation to the area must
be confirmed before the catheter is placed.
This is a safety precaution to prevent
compromised arterial perfusion to the area
distal to the arterial catheter insertion site. If
no collateral circulation exists and the
cannulated
artery
became
occluded, ischemia and infarction of the area
distal to that artery could occur.
Collateral circulation to the hand can be
checked by the Allen test
With the Allen test, the nurse compresses the
radial and ulnar arteries simultaneously and
asks the patient to make a fist, causing the
hand to blanch.
After the patient opens the fist, the nurse
releases the pressure on the ulnar artery
while maintaining pressure on the radial
artery. The patient’s hand will turn pink if the
ulnar artery is patent.
NURSING INTERVENTIONS
Before insertion of a catheter, the site is
prepared by shaving if necessary and by
cleansing with an antiseptic solution. A local
anesthetic may be used.
Once the arterial catheter is inserted, it is
secured and a dry, sterile dressing is applied.
The site is inspected daily for signs of
infection. The dressing and pressure
monitoring system or water manometer are
changed according to hospital policy.
In general, the dressing is to be kept dry and air
occlusive.
Dressing changes are performed with the use of sterile
technique.
Arterial catheters can be used for infusing intravenous
fluids, administering intravenous medications, and
drawing blood specimens in addition to monitoring
pressure.
To measure the arterial pressure, the transducer (when
a pressure monitoring system is used) or the zero mark
on the manometer (when a water manometer is used)
must be placed at a standard reference point, called
the phlebostatic axis .
After locating this position, the nurse may make an ink
mark on the chest
CENTRAL VENOUS PRESSURE
MONITORING
The CVP, the pressure in the vena cava
or right atrium, is used to assess right
ventricular function and venous blood
return to the right side of the heart. The
CVP can be continuously measured by
connecting either a catheter positioned in
the vena cava or the proximal port of a
pulmonary artery catheter to a pressure
monitoring system
PROCEDURE
Before insertion of a CVP catheter, the site is
prepared by shaving if necessary and by
cleansing with an antiseptic solution.
A local anesthetic may be used. The
physician threads a single lumen or
multilumen catheter through the external
jugular, antecubital, or femoral vein into the
vena cava just above or within the right
atrium
NURSING INTERVENTIONS
Once the CVP catheter is inserted, it is secured and a
dry, sterile dressing is applied.
Catheter placement is confirmed by a chest x-ray, and the
site is inspected daily for signs of infection. The dressing
and pressure monitoring system or water manometer are
changed according to hospital policy.
In general, the dressing is to be kept dry and air occlusive.
Dressing changes are performed with the use of sterile
technique.
CVP catheters can be used for infusing
intravenous fluids, administering intravenous
medications, and drawing blood specimens
in addition to monitoring pressure.
To measure the CVP, the transducer (when a
pressure monitoring system is used) or the
zero mark on the manometer (when a water
manometer is used) must be placed at a
standard reference
phlebostatic axis .
point,
called
the
After locating this position, the nurse may
make an ink mark on the chest
PULMONARY ARTERY PRESSURE
MONITORING
Pulmonary artery pressure monitoring is an important
tool used in critical care for assessing left ventricular
function, diagnosing the etiology of shock, and
evaluating
the
patient’s
response
to
medical
interventions (eg, fluid administration, vasoactive
medications). Pulmonary artery pressure monitoring
is achieved by using a pulmonary artery catheter and
pressure monitoring system.
PULMONARY ARTERY CATHETER
Development of the balloon-tipped flow
directed catheter has enabled continuous
direct monitoring of PA pressure.
Pulmonary artery catheter otherwise
known as “swan- ganz catheter”.
INSERTION OF PAC
PA monitoring must be carried out in a critical
care unit under careful scrutiny of an
experienced nursing staff.
Before insertion of the catheter , explain to
the client that;
The procedure may be uncomfortable but not
painful.
A local anesthetic will be given at the
catheter insertion site. Support
of the
critically ill client at this time helps promote
cooperation and lessen anxiety.
Procedure
This procedure can be performed in the
operating room or cardiac catheterization
laboratory or at the bedside in the critical care
unit.Catheters vary in their number of lumens
and their types of measurement (eg, cardiac
output, oxygen saturation) or pacing
capabilities.
All types require that a balloon-tipped, flowdirected catheter be inserted into a large vein
(usually the subclavian, jugular, or femoral
vein); the catheter is then passed into the
vena cava and right atrium.
In the right atrium, the balloon tip is
inflated, and the catheter is carried rapidly by
the flow of blood through the tricuspid
valve, into the right ventricle, through the
pulmonic valve, and into a branch of the
pulmonary artery.
(During insertion of the pulmonary artery
catheter, the bedside monitor is observed for
waveform andECG changes as the catheter
is movedthrough the heart chambers on the
right side and into the pulmonary Artery)
When the catheter reaches a small pulmonary
artery, the balloon is deflated and the catheter is
secured with sutures.
Fluoroscopy may be used during insertion to
visualize the progression of the catheter through
the heart chambers to the pulmonary artery.
After the catheter is correctly positioned, the
following pressures can be measured:
CVP or right atrial pressure
pulmonary artery systolic and
diastolic pressures, mean pulmonary artery
pressure, and pulmonary artery wedge
pressure).
NORMAL RESULTS
Normal pulmonary artery pressure is
25/9 mm Hg, with a mean pressure of 15
mm Hg.
Pulmonary capillary wedge pressure is
a mean pressure and is normally 4.5 to 13
mm Hg.
NURSING INTERVENTIONS
Catheter site care is essentially the same as for a CVP
catheter. As in measuring CVP, the transducer must be
positioned at the phlebostatic axis to ensure accurate
readings .
The nurse who obtains the wedge reading ensures that
the catheter has returned to its normal position in the
pulmonary artery by evaluating the pulmonary artery
pressure waveform.
The pulmonary artery diastolic reading and the wedge
pressure reflect the pressure in the ventricle at enddiastole and are particularly important to monitor in
critically ill patients, because they are used to evaluate
left ventricular filling pressures (preload)
At end-diastole, when the mitral valve is
open, the wedge pressure is the same as
the pressure in the left atrium and the left
ventricle, unless the patient has mitral
valve disease or pulmonary hypertension.
Critically ill patients usually require higher
left ventricular filling pressures to optimize
cardiac output. These patients may need
to have their wedge pressure maintained
as high as 18 mm Hg.
DERIVED PARAMETERS
Cardiac o/p measurements may be combined with systemic
arterial, venous, and PAP determinations to calculate a number
of variables useful in assessing the overall hemodynamic status
of the patient.
They are,
Cardiac index = Cardiac output / Body surface area
Systemic vascular resistance = [(Mean arterial pressure -
resistance CVP or rt atrial pressure)/Cardiac output] x 80
Pulmonary vascular resistance = [(PAP - PAWP) / Cardiac
vascular resistance output] x 80
Mixed venous oxygen saturation (SvO2)
(SvO2 = SaO2 - [VO2 / (1.36 x Hb x CO)]
(6)
NURSING RESPONSIBILITIES
Site Care and Catheter Safety:
A sterile dressing is placed over the insertion site
and the catheter is taped in place. The insertion
site should be assessed for infection and the
dressing changed every 72 hours and prn.
The placement of the catheter, stated in
centimeters, should be documented and assessed
every shift.
The integrity of the sterile sleeve must be maintained
so the catheter can be advanced or pulled back
without contamination.
The catheter tubing should be labeled and all the
connections secure. The balloon should always be
deflated and the syringe closed and locked unless
you are taking a PCWP measurement
Patient Activity and
Positioning:
Many physicians allow stable patients who
have PA catheters, such as post CABG
patients, to getout of bed and sit. The nurse
must position the patient in a manner that
avoids
dislodging
the
catheter.
Proper
positioning during hemodynamic
readings will ensure accuracy.
Dysrhythmia Prevention:
Continuous EKG monitoring is essential
while the PA catheter is in place.
Do not advance the catheter unless the
balloon is inflated.
Antiarrhythmic medications should be
readily available to treat lethal
dysrhythmias.
Monitoring Waveforms for
Proper Catheter Placement:
The nurse must be vigilant in assessing
the patient for proper catheter placement.
If the PA waveform suddenly looks like the
RV or PCWP waveform, the catheter may
have become misplaced. The nurse must
implement the proper procedures for
correcting the situation.
Monitoring Hemodynamic
Values for Response to
Treatments:
The purpose of the PA catheter is to assist
healthcare team members in assessing
the patient’s condition and response to
treatment.
Therefore,
accurate
documentation of values before and after
treatment changes is necessary.
Assessing the Patient for Complications
Associated with the PA Catheter:
Occluded ports
Balloon rupture caused by overinflating the balloon or
frequent use of the balloon.
Pneumothorax - may occur during initial placement.
Dysrhythmias - caused by catheter migration
Air embolism - caused by balloon rupture or air in the
infusion line.
Pulmonary thromboembolism - improper flushing
technique, non-heparinized flush solution.
Pulmonary artery rupture - perforation during
placement, overinflation of the balloon, overuse of the
balloon.
Pulmonary infarction - caused by the catheter migrating
into the wedge position, the balloon left inflated, or
thrombus formation around the catheter which causes
an occlusion.
CONCLUSION
Hemodynamics is the forces involved in blood circulation.
Hemodynamic monitoring started with the estimation of heart rate
using the simple skill of 'finger on the pulse' and then moved on to
more and more sophisticated techniques
like stethoscope,
sphygmomanometer, ECG etc. The status of critically ill patients
can be assessed either from non-invasive single parameter
indicators or various invasive techniques that provide multiparameter
hemodynamic
measurements.
As
a
result,
comprehensive data can be provided for the clinician to proactively
address hemodynamic crisis and safely manage the patient instead
of reacting to late indicators of hemodynamic instability