1. Intra-aortic Balloon Pump (IABP)
By David Kloda

2. History
Realization that coronary perfusion mainly occurs during diastole -1950s
Aspiration of arterial blood during systole with reinfusion during diastole decreased cardiac work without compromising coronary perfusion – Harkin-1960s
Intravascular volume displacement with latex balloons - early 1960s

3. Background Preload Afterload Coronary flow
Myocardial oxygen consumption in the heart is determined by:
Pulse rate
Transmural wall stress
Intrinsic contractile properties

5. Myocardial Oxygen Consumption
Has a linear relationship to:
Systolic wall stress
Intraventricular pressure
Afterload
End diastolic volume
Wall thickness

7. Indications for IABP
Cardiac failure after a cardiac surgical procedure
Refractory angina despite maximal medical management
Perioperative treatment of complications due to myocardial infarction
Failed PTCA
As a bridge to cardiac transplantation

9. IABP in Myocardial Infarction and Cardiogenic Shock
Improves diastolic flow velocities after angioplasty
Allows for additional intervention to be done more safely

10. IABP During or After Cardiac Surgery
Patients who have sustained ventricular damage preoperatively and experience harmful additional ischemia during surgery
Some patients begin with relatively normal cardiac function an experienced severe, but reversible, myocardial stunning during the operation

12. IABP As a Bridge to Cardiac Transplantation
15 to 30 % of endstage cardiomyopathy patients awaiting transplantation need mechanical support
May decrease the need for more invasive LVAD support

13. Other Indications for IABP
Prophylactic use prior to cardiac surgery in patients with:
Left main disease
Unstable angina
Poor left ventricular function
Severe aortic stenosis

14. Contraindications to IABP
Severe aortic insufficiency
Aortic aneurysm

15. Insertion Techniques
Percutaneous
sheath less
Surgical insertion

16. 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

18. Timing of Counterpulsation
Electrocardiographic
Arterial pressure tracing

20. Weaning of IABP
Decreasing inotropic support
Decreasing pump ratio

21. Complications Limb ischemia Bleeding and insertion site
Thrombosis
Emboli
Bleeding and insertion site
Groin hematomas
Aortic perforation and/or dissection
Renal failure and bowel ischemia
Neurologic complications including paraplegia
Heparin induced thrombocytopenia
Infection

22. IABP 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

23. Cardiopulmonary Bypass
The heart lung machine
The pump
The bypass machine

24. History
Concept of diverting the circulation to an extracorporeal oxygenator – 1885
Mechanical pump oxygenators – 1953
Controlled cross circulation – 1954
First series of intracardiac operations using a pump oxygenator – 1955

25. The Apparatus Pumps Venous reservoir Oxygenator Heat exchanger Other
Simple roller pump
Centrifugal pump
Venous reservoir
Oxygenator
Heat exchanger
Other

26. Venous Reservoir Siphons blood by gravity
Provide storage of excess volume
Allows escape of any air bubbles returning with the venous blood

27. Oxygenator Provides oxygen to the blood Removes carbon dioxide
Several types
Bubble oxygenator
Membrane oxygenator
Microporous hollow-fiber oxygenators

28. Heat Exchanger Also called the heater / cooler
Controls perfusate temperature
Warm and cold

29. Cardiopulmonary Bypass
Heparinization
Total bypass
Partial bypass
Flowrates l/min. per square meter
Flowrates depend on body size
Flowrates depend on cannula sizes
Hypothermia

30. Shed Blood
Is aspirated with a suctioning apparatus, filtered and return to the oxygenator
A cell saving device may also be utilized during and after bypass

31. Blood Pressure Decreases sharply with onset of bypass (vasodilatation)
Mean arterial pressure needs to the above mm Hg.
After 30 minutes perfusion pressure usually increases (vasoconstriction)

32. Oxygen and Carbon Dioxide Tensions
Concentrations are periodically measured in both arterial and venous lines
Arterial oxygen tension should be above 100 mm Hg
Arterial carbon dioxide tensions should be mm Hg
A drop in venous oxygen saturation suggests underperfusion

33. Myocardial Protection
Cold hyperkalemic solutions
Produces myocardial quiescence
Decreases metabolic rate
Provides protection for 2-3 hours
Blood vs. crystalloid

34. Termination of Perfusion
Systemic rewarming
Flowrates are decreased
Hemodynamic parameters
Venous line clamping
Pharmacologic support
Neutralization of heparin

35. Complications of Cardio- Pulmonary Bypass
Post perfusion syndrome
Duration of bypass
Age
Anemia
Other