1. Intra Aortic Balloon Pump (IABP)
Yan Wing Wa
Department of Intensive Care
Pamela Youde Nethersole Eastern Hospital
Spring 2009

2. What is an IABP?
The Intra-Aortic Balloon Counterpulsation system is a volume displacement device.
It should be positioned so that the tip is approximately 1 to 2 cm below the origin of the left subclavian artery and above the renal arteries.
On chest x-ray the tip should be visible in the 2nd or 3rd intercostal space.

3. Purpose of IABP Hemodynamic support in medical conditions
Prophylactic hemodynamic support
Cardiac support for hemodynamically challenged patients with mechanical defects PRIOR to correction
Hemodynamic support in medical conditions such as:
Cardiogenic Shock
Threatening Extension of MI
Unstable Angina
Intractable Ventricular Dysrhythmias
Septic Shock Syndrome
Cardiac Contusion
Prophylactic hemodynamic support for:
Coronary Angiography
Coronary Angioplasty
Thrombolysis
High-risk interventional procedures (stents)
Cardiac support for hemodynamically challenged patients with mechanical defects PRIOR to correction:
Valvular Stenosis
Mitral Valve Insufficiency
Ruptured Papillary Muscle
Ventricular Septal Defect (VSD)
LV Aneurysm
Bridging Device to other mechanical assist, such as Ventricular Assist Device (VAD)
Support During Transport

4. Surgical Indications Post surgical myocardial dysfunction
Support for weaning from cardiopulmonary bypass (CPB)
Cardiac support following correction of anatomical defects
Maintenance of graft patency post CABG
Pulsatile flow during CPB

5. IABP Kit Contents Introducer needle Guide wire Vessel dilators Sheath
IABP (34 or 40cc)
Gas tubing
60-mL syringe
Three-way stopcock
Arterial pressure tubing (not in kit)

6. IAB Sizing Chart
The IAB Should be selected according to the following chart (chart located on every box).
Note: The 50cc balloons are no longer made by Datascope 6

7. Insertion Techniques Percutaneous Surgical insertion Sheath less
Femoral cut down
Trans-thoracic

8. Positioning
The end of the balloon should be just distal to the takeoff of the left subclavian artery
Position should be confirmed by fluoroscopy or chest x-ray

9. Insertion Position
On chest x-ray the tip should be visible in the 2nd or 3rd intercostal space

10. Pressure Waveforms Red wave = normal arterial pressure trace
                                                                                                                                                
DEFLATED
INFLATED
Red wave = normal arterial pressure trace
Blue wave = arterial pressure trace on IABP

11. Desired Outcome
Appropriately timed blood volume displacement (30 – 50 mL) in the aorta by the rapid shuttling of helium gas in and out of the balloon chamber, resulting in changes in inflation and deflation hemodynamics

12. Inflation The goal of inflation is to increase or augment perfusion
The principles of counterpulsation state that the balloon should be inflated at the start of diastole, just prior to the Dicrotic Notch. Aortic volume and pressure are increased through displacement principles causing:
Increased coronary perfusion pressure
Increased systemic perfusion pressure
Increased O2 supply to both the coronary and peripheral tissue
Increased baroreceptor response
Decreased sympathetic stimulation causing decreased Heart Rate, decreased Systemic Vascular Resistance, and increased Left Ventricular function

13. Inflation of IABP Results In:
Increased coronary perfusion pressure
Increased systemic perfusion pressure
Increased O2 supply to both the coronary and peripheral tissue
Increased baroreceptor response
Decreased sympathetic stimulation causing decreased HR, decreased SVR, and increased LV function

14. Deflation The goal of deflation is to reduce LV workload
Deflation creates a "potential space" in the aorta, reducing aortic volume and pressure
The principles of counterpulsation state that the balloon should be deflated at the start of systole, during Isovolumetric Contraction.

15. Deflation of the IABP Results In:
Afterload reduction and therefore a reduction in MVO2
Reduction in peak systolic pressure, therefore a reduction in LV work
Increased cardiac output
Improved ejection fraction and forward flow

16. How do you Know? Afterload reduction? Change in diastolic pressures
Unassisted and assisted
Decreased workload?
Change in systolic pressures
Improved cardiac output?
Increase in pulse pressures

17. Review of Arterial Pressure Landmarks
AVO = Aortic valve opens, beginning of systole
PSP = Peak systolic pressure, 65-75% of stroke volume has been delivered
DN = Dicrotic notch, signifies aortic valve closure and the beginning of diastole
AEDP = Aortic end diastolic pressure

18. IABP Waveform Zero baseline (on console) Balloon pressure baseline
Rapid inflation
Peak inflation artifact
Balloon pressure plateau (IAB fully inflated)
Rapid deflation
Balloon deflation artifact
Return to baseline (IAB fully deflated)
Duration of balloon cycle

19. Inflate just prior to the dicrotic notch
To accomplish the goals of inflation, the balloon must be inflated at the onset of diastole
The result of properly timed inflation is a pressure rise during diastole
The PDP/DA influences the gradient for coronary artery perfusion

20. Review of Arterial Pressure Landmarks in 1:2 Assist
Patient AEDP
PSP (unassisted systole)
PDP/DA (diastolic augmentation)
Balloon AEDP
APSP (assisted systole)
PAEDP = Patient aortic end diastolic pressure, this is the patient's unassisted diastole
PSP = Peak systolic pressure, this is the patient's unassisted systole
PDP/DA = Peak diastolic pressure or diastolic augmentation, this is the pressure generated in the aorta as the result of inflation
BAEDP = Balloon aortic end diastolic pressure, this is the lowest pressure produced by deflation of the IAB
APSP = Assisted peak systolic pressure, this systole follows balloon deflation and should reflect the decrease in LV work

21. Inflation Hemodynamics
Coronary artery blood flow and pressure are increased
Increased renal and cerebral blood flow
Increased diastolic pressure increases perfusion to distal organs and tissues

22. Inflation Hemodynamics
Coronary collateral circulation is potentially increased from the increase in coronary perfusion pressure (CPP)
Systemic perfusion pressure is increased

23. Coronary Perfusion Pressure
The pressure at which blood perfuses through the coronary circulation, mainly in diastole
Blood flow to the left ventricle occurs principally during diastole and is largely determined by the driving pressure (diastolic pressure minus left ventricular diastolic pressure), the diastolic interval and the state of coronary vasodilatation
The major vessels of the coronary circulation are the left main coronary that divides into *left anterior descending* and *circumflex* branches, and the right main coronary artery. The *left and right coronary arteries* originate at the base of the aorta from openings called the *coronary ostia* located behind the aortic valve leaflets. The left and right coronary arteries and their branches lie on the surface of the heart, and therefore are sometimes referred to as the *epicardial coronary vessels*. These vessels distribute blood flow to different regions of the heart muscle. When the vessels are not diseased, they have a low vascular resistance <../Hemodynamics/H002.htm> relative to their more distal and smaller branches that comprise the microvascular network <../Microcirculation/M014.htm>. As in all vascular beds, it is the small arteries and arterioles in the microcirculation that are the primary sites of vascular resistance, and therefore the primary site for regulation of blood flow. The arterioles branch into numerous capillaries that lie adjacent to the cardiac myocytes. A high capillary-to-cardiomyocyte ratio and short diffusion distances ensure adequate oxygen delivery to the myocytes and removal of metabolic waste products from the cells (e.g., CO_2 and H^+ ). Capillary blood flow enters venules that join together to form cardiac veins that drain into the *coronary sinus* located on the posterior side of the heart, which drains into the right atrium. There are also *anterior cardiac veins* and *thesbesian veins* drain directly into the cardiac chambers. Although there is _considerable heterogeneity_ among people, the following table indicates the regions of the heart that are generally supplied by the different coronary arteries. This anatomic distribution is important because these cardiac regions are assessed by 12-lead ECGs <../Arrhythmias/A013.htm> to help localize ischemic or infarcted regions, which can be loosely correlated with specific coronary vessels; however, because of vessel heterogeneity, actual vessel involvement in ischemic conditions needs to be verified by coronary angiograms or other imaging techniques. *Anatomic Region of Heart* *Coronary Artery (most likely associated)* Inferior Right coronary Anteroseptal Left anterior descending Anteroapical Left anterior descending (distal) Anterolateral Circumflex Posterior Right coronary artery

24. Deflation Hemodynamics
The pressure that the LV must generate (afterload) is less throughout the systolic phase
Decreases myocardial O2 demands
Isovolumetric contraction (IVC) phase of systole is shortened

25. Deflation Hemodynamics
Reduced afterload allows the LV to empty more effectively so stroke volume (SV) is increased
Enhanced forward cardiac output decreases the amount of blood shunted from left to right in cases of intraventricular septal defects and incompetent mitral valve

26. Triggering
It is necessary to establish a reliable trigger signal before balloon pumping can begin
The computer in the IAB console needs a stimulus to cycle the pneumatic system, which inflates and deflates the balloon
The trigger signal tells the computer that another cardiac cycle has begun

27. Triggering
In most cases it is preferable to use the R wave of the ECG as the trigger signal
There are other trigger options for instances when the R wave cannot be used or is not appropriate

28. Trigger Loss
The console MUST see a trigger to initiate an inflate/deflate cycle
If no trigger is seen when the clinician attempts to start pumping, no pumping will occur and an alarm will be sounded
If the trigger is lost after pumping starts, no further pumping will occur until a trigger is re-established
The pump will go to STANDBY and an alarm will be sounded

29. Trigger Loss
If the current trigger is lost the clinician can choose an alternate, available trigger to resume pumping
For example, if the ECG lead becomes disconnected the arterial pressure (AP) trigger may be selected until the ECG is re-established

30. ECG Trigger
Since triggering on the R wave of the ECG is preferred, it is very important to give the IABP a good quality ECG signal and lead

31. Poor ECG Choices
Note: changing QRS morphology may cause wandering timing
Note: tall T waves may cause double triggering or may alter previously set timing points
Note: wandering baseline may cause skipped trigger
Note: artifact may cause inappropriate triggering 

32. ECG Gain
In addition to selecting a lead with a QRS morphology that provides consistent, appropriate triggering, it is important to ensure the QRS complex has adequate amplitude
The computer has a minimum height requirement to recognize the initial deflection as an R wave, whether upright or negative in configuration

33. Triggering on the Arterial Pressure Waveform
Arterial pressure provides another signal to the IABP to determine where the cardiac cycle begins and ends
It is used when the ECG has too much interference from patient movement or poor lead connection
There are limitations to triggering on the arterial pressure curve
AP trigger should be considered a backup trigger and not the one used as the primary trigger
The PDP/DA influences the gradient for coronary artery perfusion
Irregular heart rates and irregular pulse pressures can cause the pump to not see a trigger where it expects to find one
If this happens, pumping will be temporarily interrupted as the computer relearns the parameters
Late deflation will also cause missed triggers and an interruption in pumping

34. CPR AP trigger is the appropriate choice during CPR
Once chest compressions are started an arterial pressure waveform will be generated
Triggering on the AP will produce pumping in synchrony to chest compression and has been shown to assist with coronary and carotid perfusion
CPP less than 15 will not allow return of spontaneous rhythm

35. TRIGGER MODES: ECG In most instances this is the trigger of choice.
The computer analyzes the SLOPE and HEIGHT of a positively or negatively deflected QRS complex.
Rejects pacer spikes on the basis of sharp rising edge.
Automatically initiates ARRHYTHMIA TIMING when at least 8 out of 16 beats are detected as irregular.

36. TRIGGER MODES: ECG
In AUTOPILOT mode, if no QRS or AP trigger is found, it will trigger on the V SPIKE of an AV paced rhythm.
In OPERATOR mode, the ECG trigger key can be used to toggle between triggering on the R WAVE and the V SPIKE of a V or AV paced rhythm.

37. TRIGGER MODES: ARTERIAL PRESSURE (AP)
The computer uses the SYSTOLIC UPSTROKE of an arterial pressure waveform as the trigger signal.
A 14mmHg minimum pulse pressure is required to initially recognize the trigger.
Once pumping begins the subsequent pulse pressure requirement is reduced to 7mmHg.
Every 64th beat is unassisted and reassessed.
This mode is available as an option for clinical situations where an ECG is unavailable or distorted.
Not recommended for irregular rhythms or irregular pulse pressures.

38. Gas Alarms/Balloon Pressure Waveform
During a cycle of inflation/deflation, helium is rapidly moved in and out of the balloon.
The environment within the balloon and the surrounding forces that affect balloon behavior all contribute to a predictable pattern of gas flow and pressure.
The gas pressure characteristics are converted into a waveform that is reflective of the behavior of the gas.

39. This transduced waveform tells much about the interaction of the balloon within the patient's aorta.
Understanding the balloon pressure waveform is important for troubleshooting of the console as most alarms are based on the gas surveillance system.

40. IABP Waveform Zero baseline (on console) Balloon pressure baseline
Rapid inflation
Peak inflation artifact
Balloon pressure plateau (IAB fully inflated)
Rapid deflation
Balloon deflation artifact
Return to baseline (IAB fully deflated)
Duration of balloon cycle

41. Normal Waveform Variations
Tachycardia
Bradycardia
Hypertension
Hypotension

42. Abnormal Waveform Variation: Wide Inflation and/or Deflation Artifact
Check for kinks, as they may trap gas in the IAB.
If water is present in the gas tubing, remove the condensation.
Pushing the helium through the water during inflation and deflation slows down gas transition.
If gas transition is prolonged too much, it can create alarms.

43. Abnormal Waveform Variation: Helium Loss / Gas Loss / Gas Leakage Alarms
Observe for blood in the gas tubing. If even a slight amount is present, it may indicate a balloon rupture.
Do not resume pumping.
Notify physician immediately and prepare for IAB removal.
Check connections where gas tubing connects to IAB and to pump.
Secure if loose.

44. Abnormal Waveform Variation: High Pressure / Kinked Line Alarm
Note that the plateau pressure is still greater than 250mmHg when it is time to deflate.
This indicates that not all of the gas could enter the balloon.
It is generally due to a kink in the catheter, either internal to the patient or external.

45. Reposition patient. Keep affected leg straight.
Use rolled towel under hip to hyperextend hip.
Apply slight traction to the catheter if kinking at the insertion site or in the artery is suspected.
The distal portion of the IAB may be in the sheath if a long introducer sheath was used. Pull sheath back until IAB bladder has exited the sheath.
Introducer sheath may be kinked which in turn is kinking the balloon. Suspect this particularly if placement of the sheath was difficult. Pull sheath back or rotate sheath a partial turn.

46. Check placement of the balloon; it may be too high or too low.
IAB may be partially wrapped if alarm occurs shortly after insertion. Take steps to facilitate unwrapping (consult IAB manufacturer).
The balloon may be too large for the patient. Reduce the helium volume the balloon is inflated with. (It is recommended to not reduce the volume below 2/3 of maximum. For example, do not decrease volume in a 40cc IAB below 27cc)

47. Abnormal Waveform Variation: High Baseline / Fill Pressure
Check for intermittent obstruction of gas lumen.
Check for overfill of system.
This condition may occur during ascent in air transport since gas expands as you go up in altitude. Reset the alarm and restart pumping. The volume will be adjusted automatically for current barometric pressure.
In AutoCAT® or TransAct® the vent valve may be malfunctioning.
In the AutoCAT, ensure that the tubing to the condensation bottle (located behind the helium tank) is not kinked.

48. Complications of IABP
The following patients are at the greatest risk of developing complications associated with IABP:
Females, diabetics, smokers, obese patients
Patients with PVD, HTN, high SVR, shock

49. Complications of IABP
Aortic wall dissection, rupture or local vascular injury
Care as indicated
Emboli: thrombus, plaque or air
Treatment of an air embolism is as follows: 100% oxygen, intubate, Trendelenberg in left lateral decubitus position, fluid resuscitation, etc.
Administer 100% oxygen and intubate for significant respiratory distress or refractory hypoxemia. Oxygen may reduce bubble size by increasing the gradient for nitrogen to move out.
Promptly place patient in Trendelenburg (head down) position and rotate toward the left lateral decubitus position. This maneuver helps trap air in the apex of the ventricle, prevents its ejection into the pulmonary arterial system, and maintains right ventricular output.
Maintain systemic arterial pressure with fluid resuscitation and vasopressors/beta-adrenergic agents if necessary.
Consider transfer to a hyperbaric chamber. Potential benefits of this therapy include (1) compression of existing air bubbles, (2) establishment of a high diffusion gradient to speed dissolution of existing bubbles, and (3) improved oxygenation of ischemic tissues and lowered intracranial pressure.
Circulatory collapse should be addressed with CPR and consideration of more invasive procedures as described above.

50. Complications of IABP IABP Rupture:
COFFEE GROUNDS seen in the drive line is a precursor to a rupture (make sure they are on the inside and not the outside of the tubing)
NOTIFY PHYSICIAN!!!!!
IF THERE IS A FLAGRANT RUPURE OF THE IABP CLAMP THE GAS LINE!!!!!

51. Complications of IABP Infection Check catheter insertion site often
STRICT ASEPTIC TECHNIQUE
Restrict movement while IABP in place

52. Complications of IABP Obstruction Malposition
Too high – obstruction of left subclavian and carotids
CHECK LEFT RADIAL ARTERY PULSE
Too low – obstruction of renal and mesenteric arteries
MONITOR URINE OUTPUT

53. Complications of IABP Compromised circulation due to catheter Ischemia
Routine nursing care and monitoring
Compartment syndrome
Rare complication seen in the LE, usually related to infection
Monitor calf circumference

54. Complications of IABP Hematologic ALL PATIENTS typed & crossmatched!!!
Bleeding
REMOVE THE DRESSING!!!
PUT ON STERILE GLOVES!!!
HOLD PRESSURE!!!
Thrombocytopenia
Routine monitoring

55. Weaning of IABP Timing of weaning Decreasing inotropic support
Patient should be stable for hours
Decreasing inotropic support
Decreasing pump ratio
From 1:1 to 1:2 or 1:3
Decrease augmentation
Monitor patient closely
If patient becomes unstable, weaning should be immediately discontinued
Weaning should only be attempted on order of a physician.

56. IAB Removal Discontinue heparin six hours prior
Check platelets and coagulation factors
Deflate the balloon
Apply manual pressure above and below IABP insertion site
Remove and alternate pressure to expel any clots
Apply constant pressure to the insertion site for a minimum of 30 minutes
Check distal pulses frequently
IAB should only be pulled by a physician or the cardiac P.A.

57. Thank you for your attention