Hemodynamic Monitoring
Part I
(ABP, CVP, Ao)
MICU Competencies
2006-2007
1
What is Hemodynamic Monitoring?
• Non-invasive = clinical assessment & NBP
• Direct measurement of arterial pressure
• Invasive hemodynamic monitoring
2
Noninvasive Hemodynamic Monitoring
• Noninvasive BP
• Heart Rate, pulses
• Mental Status
• Skin Temperature
• Capillary Refill
• Urine Output
• Mottling (absent)
3
Proper Fit of a Blood Pressure Cuff
• Width of bladder = 2/3 of upper arm
• Length of bladder encircles 80% arm
• Lower edge of cuff approximately 2.5 cm
above the antecubital space
4
Why A Properly Fitting Cuff?
• Too
small
causes false-high reading
• Too
LARGE causes false-low reading
5
Indications for
Arterial Blood Pressure
• Frequent titration of vasoactive drips
• Unstable blood pressures
• Frequent ABGs or labs
• Unable to obtain Non-invasive BP
6
Supplies to Gather
• Arterial Catheter
• Pressure Tubing
• Pressure Bag
• Flush – 500cc NS
• Pressure Cable
7
Supplies to Gather
• Sterile Gown (2)
• Suture (silk 2.0)
• Sterile Towels (3)
• Chlorhexidine Swabs
• Sterile Gloves
• Mask
8
Leveling and Zeroing
• Leveling
– Before/after insertion
– If patient, bed or transducer move
• Zeroing
– Performed before insertion & readings
• Level and zero at the insertion site
9
Potential Complications
Associated With Arterial Lines
• Hemorrhage
• Air Emboli
• Infection
• Altered Skin Integrity
• Impaired Circulation
10
Documentation
• Insertion procedure note
• ABP readings as ordered
• Neurovascular checks every two hours
(in musculoskeletal assessment of HED)
• Pressure line flush amounts (3ml/hr)
• Tubing and dressing changes
11
Central Venous Pressure Assesses . . .
• Intravascular volume status
• Right ventricular function
• Patient response to drugs &/or fluids
12
Central Venous Pressure (CVP)
• Central line or pulmonary artery catheter
• Normal values = 2 – 8 mm Hg
• Low CVP = hypovolemia or ↓ venous return
• High CVP = over hydration, ↑ venous return,
or right-sided heart failure
13
Leveling and Zeroing
• Leveling
– Before/after insertion
– After patient, bed or transducer move
– Aligns transducer with catheter tip
• Zeroing
– Performed before insertion & readings
• Level and zero transducer at the phlebostatic
axis
14
Phlebostatic Axis
• 4th intercostal space, mid-axillary line
• Level of the atria
(Edwards Lifesciences, n.d.)
15
More on Leveling and Zeroing
• HOB 0 – 60 degrees
• No lateral positioning
• Phlebostatic axis with
any position (dotted line)
(Edwards Lifesciences, n.d.)
16
Dynamic Flush
Dynamic flush ensures the integrity
of the pressure tubing system.
Notice how it ascends - forms a
square pattern - and bounces below
the baseline before returning to
the original waveform.
•Check dynamic flush after zeroing
any pressure tubing system
17
System Maintenance
• Change tubing and fluid bag q 96hrs
• No pressors through CVP port
• Antibiotics, NS boluses, blood, & IV pushes
are allowed through the CVP line
18
Troubleshooting
• Improper set-up and equipment malfunction
are the primary causes for hemodynamic
monitoring problems
• Retracing the set-up process or tubing
(patient to monitor) may identify the problem
and solution quickly
• Use your staff resources: Help All, Charge
Nurse, Educator, Preceptors, MICU experts
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Troubleshooting
Damped Waveforms
Pressure bag inflated to 300 mmHg
Reposition extremity or patient
Verify appropriate scale
Flush or aspirate line
Check or replace module or cable
20
Troubleshooting
Inability to obtain/zero waveform
Connections between cable & monitor
Position of stopcocks
Retry zeroing after above adjustments
21
Continuous Airway Pressure (Ao)
• Also known as Paw, Ao
• Purpose:
– Improves accuracy of hemodynamic
waveform measurements
– Identification of end-expiration
• Positive waveform deflections = positive
pressure ventilation
• Negative deflections = spontaneous
inspiratory effort
22
Supplies to Gather
• Pressure Cable
• Pressure Tubing
• Connector
(Edwards Lifesciences, n.d.)
23
Setting up the Ao
• Discard infusion spike end & cap port
• Connect pressure tubing to vent tubing
(using connector opposite heating cable)
• Connect cables
• Zero the tubing (leveling not necessary)
24
Troubleshooting Ao
• Do not prime tubing with fluids!
• Damping will occur with fluid or secretions
• To evacuate any fluids, disconnect pressure
tubing from vent tubing and push air through
the pressure tubing with a 10 ml syringe
connected at one end until fluid-free
25
Pressure Measurement
1) Record Ao and CVP on the same strip
2) Find end-expiration by drawing a vertical line with a
straight edge 200 ms prior to the rise or dip in Ao (1
large box) associated with a breath.
3) Draw a horizontal line through the visually assessed
average vascular pressure starting at end-expiration
going backward 200 ms (1 large box).
4) Read the pressure at the horizontal line.
15
10
5
0
-5
CVP=13
26
Assist-Control
{
CVP
{
Ao
200 ms
200 ms
27
CPAP with Pressure Support
{
{
Ao
200 ms
CVP
200 ms
28
CPAP without Pressure Support
{
Ao
{
200 ms
CVP
200 ms
29
40
30
20
10
0
-10
Incorrect method!
This point was
identified as endexpiration for a pt.
who did not have an
Ao set up.
Correct method!
30 sec after the above
tracing, Ao was added & true
end-expiration clearly
identified.
30
Same patient 20 minutes later
4040
3030
2020
1010
00
-10
-10
31
15
10
5
0
-5
CVP=13
32
Summary
•Record Ao with CVP
•Read mean CVP at end-expiration as
described. No need read vascular pressure at
any particular time in the cardiac cycle
33
Documentation of CVP
• Include on waveform strip
–
–
–
–
–
–
Position of the HOB
Vasopressors and rates
Amount of PEEP
Scale
CVP measurement
Signature of the nurse
(post in green chart behind graphics tab)
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References & Resources
Burns, S. M. (2004). Continuous airway pressure monitoring. Critical Care Nurse, 24(6), 70-74.
Chulay, M., & Burns, S. M. (2006). AACN Essentials of critical care. McGraw-Hill: New York.
Edwards. (2006). Pulmonary Artery Catheter Educational Project. http://www.pacep.org
Edwards Lifesciences. (n.d.) Educational videos. www.edwards.com
MICU Routine Practice Guidelines. www.vanderbiltmicu.com
MICU Bedside Resource Books
MICU Education Kits (Red cart in conference room)
MICU Preceptors, Help All Nurses, & Charge Nurses
VUMC policies. http://vumcpolicies.mc.vanderbilt.edu
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