iabp when , why and how ?
TRANSCRIPT
When to use this !
Ongoing ischemia refractory to medical therapy.
Prophylactic placement for high-risk patients with critical coronary
disease
High-risk patients undergoing off-pump surgery to maintain
hemodynamic stability during lateral wall or posterior wall grafting.
Unloading for cardiogenic shock or mechanical complications of
myocardial infarction (acute mitral regurgitation, ventricular septal
rupture).
Postcardiotomy low cardiac output syndrome unresponsive to
moderate doses of multiple inotropic agents.
Postoperative myocardial ischemia.
Acute deterioration of myocardial function to provide temporarysupport or serve as a bridge to transplantation.
*2 Primary Benefits of IABP
The primary purpose of the IABP is to increase Coronary
Oxygen Supply during Diastole.
The next purpose of the IABP is to Decrease Coronary
Oxygen Demand during Systole.
*Secondary Benefits of IABP
Decreased Heart Rate
Decreased Blood Pressure
Increased Cardiac Output.
Superior
Vena
Cava
Inferior
Vena
Cava
Aorta
Pulmonary
Artery
Right
Atrium
Left
Atrium
Right
Ventricle
Left
Ventricle
Blood
moves by
pressure
gradient
Inferior
Vena
Cava
Cardiac Anatomy
Cardiac Output = Stroke Volume x Heart Rate
normal: 4 – 8 L/min
Cardiac Index =
normal: 2.5 – 4.0 L/min/m 2
CO
BSA
Hemodynamics
CO = HR x SV
HRSinus Node
Endocrine
CNS
Baroreceptors
SV
Preload
Afterload
Contractility
Myocardial Oxygen Balance
Preload
Afterload
Heart Rate
Contractility
O2 Extraction
Diastolic Time
Diastolic Pressure
Coronary Artery Flow
Demand Supply
Principle of Counterpulsation
*Counterpulsation
Synchronization of the pumping of the IABP with diastole
(Inflation) and Systole (Deflation) is called
counterpulsation.
Balloon Placement
To pump
Left Subclavian
Descending
Thoracic
Aorta
Kidney
Deflated Inflated
90%
Occlusive
IAB OCCLUSIVITY
Balloons exert their hemodynamic effect by
volume displacement
*Inflation during Diastole
The primary purpose of the IABP is to increase Coronary Oxygen
Supply during Diastole.
Benefits of Inflation
• Increased coronary blood flow
• Increased diastolic pressure
• Potential for increased coronary
collateral circulation
• Increased systemic perfusion
Deflation at Onset of Systole
*Deflation During Systole
The next purpose of the IABP is to Decrease Coronary Oxygen
Demand during Systole
Benefits of Deflation
• Decreased Afterload
• IVC Phase Shortened
• Increased Stroke Volume
• Enhanced Forward Cardiac
Output
Signs of Improved Clinical Condition
Increased cardiac output, 0.5 – 1 L/min
Increased urine output
Decreased preload
Decreased pulmonary congestion
Improved mentation
Decreased heart rate
Decreased lactic acidosis
Increased pulse pressure and pulse rate
Inflation Deflation
ECG
Electrical Event
Arterial
Pressure
Mechanical Event
Cardiac Cycle
Absolute Contraindications
• Aortic Insufficiency
• Dissecting Aortic Aneurysm
Relative Contraindications
• End-Stage Cardiomyopathy in a patient not
a candidate for transplant
• End-stage Terminal Disease
• Abdominal Aortic Aneurysms, not resected
Complications
Increased Complication Risk
PVD
Female Gender
Diabetes
Hypertension
Nicotine Use
Obesity
Shock
SVR
Complications
Aortic WallDissection
Rupture
Local Vascular Injury
EmboliThrombus
Plaque
Air
Complications
IAB RuptureHelium Embolus
Catheter Entrapment
Compromised circulation due to catheter
– Limb ischemia– compartment syndrome
In nearly all circumstances the IABP will be inserted via the Femoral
Artery.
Pre-Insertion Assessment
1. Skin color of both legs
2. Skin temperature of both legs
3. Capillary refill ability of both legs
4. Quality of pulses in both arms & legs
5. Baseline sensation and movement of both legs
6. Complete neuro check
Adult IAB Sizing Recommendations
DiastoleSystole
<162cm
<5’4”
<1.8m2
<182cm
<6’0”
>1.8m2
>182cm
>6’0”
Height
BSA
30cc 40cc 50cc
Access Femoral Artery
May be done
with or
without a
syringe
Timing
How is proper timing achieved?
• Always performed using the arterial
pressure waveform as the guide
Arterial Pressure Waveform
PSP
Dicrotic Notch
PSP
Dicrotic Notch
AVOAVO
AEDP
IVC
25% SV75% SV
XX
Patient
Aortic
End
Diastolic
Pressure
Dicrotic
Notch
Assisted
Peak
Systolic
Pressure
Peak
Systolic
Pressure
Balloon
Aortic End
Diastolic
Pressure
Augmentation
APSP
AUG
PSP
PAEDP
BAEDP
DN
Arterial Pressure Waveform
Without IABP
With IABP
assist 1:2
Assist Ratios
1:1
1:2
1:3
DN DN
Correct Inflation: Just prior to DN
When inflation timing is correct there
should be a sharp “V” shape at the
dicrotic notch.
Augmentation should be higher than PSP unless:
1. Patient’s SV significantly greater than
balloon volume
2. Balloon is positioned too low
3. Hypovolemia
4. Balloon is too small
5. Improper timing
6. Partial obstruction of gas flow
PSP AUG
APSP < PSP
CORRECT DEFLATION : BAEDP < PAEDP
PSPAPSP
BAEDP
PAEDP
Timing Errors
• Early Inflation
• Late Inflation
• Early Deflation
• Late Deflation
Early Inflation
Early Inflation Correct Timing
move inflation
AUG
DN
Late Inflation
Late Inflation Correct Timing
move inflation
AUG
DN
Early Deflation
Early Deflation Correct Timing
move deflation
PSP APSP
Late Deflation
Late Deflation Correct Timing
move deflation
BAEDP
PAEDP
# 1
Inflation is Good
Deflation is early
# 2
Inflation Is early
Note that the Dicrotic Notch on inflation appears higher than
non-inflation
Deflation is normal
# 3
Inflation is Good
Deflation is Good
# 4
Appears Good but we really cannot make comparisons on 1:1
timing.
# 5
Inflation is Early
Deflation is Early
# 6
Inflation is late
Deflation is good
Helium Delivery
Balloon Inflation
0
transducer
pumphelium
BPW
compressor
Vacuum /
compressor
system
Balloon Deflation
0
transducer
pumphelium
BPW
vacuum
Vacuum /
compressor
system
Heart Rate Variations
BPW in Irregular Diastole (Afib)
Pressure Variations
Fill Failure
Pump did not fill adequately with helium to establish the
balloon pressure waveform baseline
Verify helium tank not empty, all catheter connections intact
Gas Loss
0
300
Classic BPW of an IAB too large for the aorta
Triggering
Definition
Options
FOR GOOD, CONSISTANT TRIGGERING IT IS IMPORTANT TO
PROVIDE THE PUMP WITH A GOOD ECG SIGNAL
Good Choices –
Unidirectional QRS with minimal
artifact
Poor Choices –
Biphasic QRS, tall T or P waves, wandering baseline, artifact
present
This lead will give you both
triggering and timing problems
ECG
Newer Systems will automatically initiate
Arrhythmia Timing when several irregular
diastolic intervals occur.
Arrhythmia Timing allows for more
consistent and appropriate deflation of the
IAB during irregular rhythms.
Timing with Irregular Rhythms
Arrhythmia Timing
Conventional Timing
V Pacer
Arterial Trigger
The IABP will detect changes in arterial pressure to
initiate inflation and deflation.
It is the trigger of choice when CPR is in progress.
Internal
The balloon inflates and deflates at a
preset rate regardless of the patient’s
cardiac activity.
This mode is only to be used when there
is no cardiac output and no ECG but
many newer systems can detect pressure
differences from CPR
Cardiac Arrest
What do you do with the IABP?
Augmentation
Augmentation refers to how full we fill the IABP balloon during operation.
During normal operation the IABP will be operated at 100% augmentation
The IABP should never be operated below 50% augmentation.
Low augmentation can result in the peak diastolic
augmentation being lower than unassisted systole and
the wave form will look irregular.
Augmentation is frequently used in conjunction with
timing to wean the patient from the IABP.
Other Complications Of IABP
Balloon Rupture
Balloon Rupture can allow a large gas embolism to enter the body.
The IABP must never be operated if a Balloon rupture is suspected.
The classic sign of a balloon rupture is rust colored specs inside the
IABP helium tubing in conjunction with loss of helium pressure.
It the rupture is large it may be RED.
Gas Loss
Transducer Position
The transducer should be placed in line with the phlebostatic axis.
During transport it is critical that the transducer be secured at a fixed
point on the patient.
For every inch variance to the phlebostatic axis there is a 2 mm/HG
inverse change in pressure.
Increase height by 4 inches and pressure reads 8 mm/HG lower
All of the transducer connections must be tight to prevent rapid
blood loss.
There must not be any air in the transducer lines.
weaning
Criteria for weaning
Ratio , augmentation and heparin
weaning
IABP support can be withdrawn when the cardiac output is satisfactory
on minimal inotropic support (usually 1 mg/min of epinephrine or 5
mg/kg/min of either dopamine or dobutamine). However, earlier
removal may be indicated if complications develop, such as leg
ischemia, balloon malfunction, thrombocytopenia, or infection.
weaning
Weaning is initiated by decreasing the inflation ratio from 1:1 to 1:2
for about 2– 4 hours, and then to 1:3 or 1:4 for 1–2 more hours.
Once it is determined that the patient can tolerate a low inflation
ratio with stable hemodynamics, the IABP should be removed.
If there is an anticipated delay in removal of more than a few hours
for manpower reasons or because of the need to correct a
coagulopathy, the ratio should be increased to at least 1:2 to
prevent thrombus formation.
Removal of the ballon
Hussein Khairy ElkhayatLecturer (consultant) of Cardiothoracic Surgery
Faculty of Medicine, Assiut university,
Assiut,Egypt.
P.Box 71526
Mobile : + 2 010 0 55 49 6 53
Work : + 2 088 241 37 73
Fax : +2 088 2333327
Website: http://www.aun.edu.eg/membercv.php?M_ID=4489
For more information , please contact me : [email protected]
Thank you