Intra-aortic Balloon Pump	101
Khusrav Bajan

A 55-year-old male patient was admitted to hospital with a history of chest pain for about 3 h. He was drowsy, extremities were cold, and his blood pressure was 84/60 mmHg. He was started on inotropic and vasopressor support, but he remained hypotensive.

Intra-aortic balloon pump (IABP) is a mechanical support device to support cardiac pump function by increasing coronary perfusion and decreasing afterload and used as a salvage therapy in cardiogenic shock. IABP therapy should only be considered for use in patients who have the potential for left ventricular recovery or to support those awaiting cardiac transplantation.

Step 1: Assess the need for IABP—indications

Since the balloon counterpulsation helps to improve myocardial oxygen supply and decrease oxygen demand, the IABP is indicated for conditions with decreased myocardial oxygen supply–demand ratio:

•Cardiogenic shock

•Acute myocardial infarction with pulmonary edema

•Mechanical complications of myocardial infarction (ventricular septal defect, acute mitral regurgitation)

•High-risk angioplasty

•Unstable angina refractory to medical treatment

•In conjunction with thrombolysis in myocardial infarction

•Bridge to cardiac transplant

K. Bajan, M.D. (*)

Emergency Department, P.D. Hinduja Hospital and Medical Research Centre, Mumbai, India

e-mail: [e-mail]

R. Chawla and S. Todi (eds.), ICU Protocols: A stepwise approach,	815
DOI 10.1007/978-81-322-0535-7_101, © Springer India 2012

816	K. Bajan

•Ventricular arrhythmias secondary to ischemia

•High-risk cardiac surgeries

•Patients undergoing noncardiac surgery with high cardiac risk

•Postoperative low cardiac output syndrome

•Weaning from bypass open heart surgery

•Stunned myocardium

•Drug-induced cardiac failure

•Myocardial contusion

•Aortic stenosis

Step 2: Check for any contraindications

•Absolute

–Irreversible brain damage

–Chronic end-stage heart disease without the possibility of heart transplant

–Dissecting aortic aneurysms

•Relative

–Aortic incompetence

–Severe peripheral vascular disease where the decision is based on patient risk–benefit ratio

Step 3: Understand principles of IABP

•The IABP is positioned in the descending thoracic aorta just distal to the left subclavian artery.

•It is connected to an IABP console, which shuttles helium in and out of the balloon, and is timed to inflate and deflate in synchronization with the mechanical cardiac cycle; i.e. the balloon inflates during cardiac diastole and deflates during cardiac systole.

•Inflation at the onset of diastole results in proximal and distal displacement of blood volume in the aorta. This displacement creates elevated pressures by which the coronary artery and systemic perfusion is increased.

•Deflation occurs just prior to the onset of systole. This leads to reduction in the systolic pressure thus decreasing the afterload. Myocardial oxygen demand is decreased as a result of the reduction in systolic pressure and thus improving cardiac output.

Step 4: Techniques and sites of insertion

•It consists of two principal parts:

–The first part is a catheter with two lumens, one for flushing and pressure monitoring and another for delivery of helium gas in a closed balloon (20–50 cm3).

–The second part is a mobile console for delivering helium, controlling balloon inflation and deflation cycling, and displaying pressure waveform and alarms.

•The balloon is inserted from the femoral artery using a Seldinger technique.

•In rare cases, it may be inserted through the axillary artery in patients with severe peripheral arterial disease with bilateral femoral artery occlusion or graft.

101 Intra-aortic Balloon Pump	817

Augmented diastolic pressure

Non-augmented systolic

pressure Reduced systolic pressure

Dicrotic notch

Unassisted aortic enddiastolic pressure

Reduced aortic enddiastolic pressure

Fig. 101.1 IABP waveform (From www.aic.cuhk.edu.hk)

Step 5: Position the balloon

•The tip of the balloon should lie 2–3 cm below the left subclavian artery so that the entire length of the balloon lies in the descending thoracic aorta.

•The tip of the balloon catheter is radiopaque, and hence, a check X-ray should always be taken after insertion to ensure correct balloon placement.

•The balloon should not be too high, so as to avoid blocking the branches of the arch of aorta, especially the left subclavian artery, and should not be too low, so as to avoid blocking the renal arteries.

Step 6: Set cycling time for IABP (Fig. 101.1)

•The mechanical cardiac cycle represented by the arterial pressure waveform is observed to assess appropriate timing.

•Electrocardiographic synchronization may also be done for cycling.

•Inflation of the intra-aortic balloon occurs at the onset of diastole noted by the dicrotic notch on the arterial waveform.

•A sharp deep “V” should be observed when the balloon inflates. As balloon inflates, aortic diastolic pressure is augmented and a second peak is observed. This peak is referred to as diastolic augmentation.

•Diastolic augmentation (30%) is ideally higher than the patient’s systolic pressure and is generated by the displacement of blood volume within the aorta.

818	K. Bajan

•Deflation occurs at end-diastole prior to the next systole. The precise timing of deflation is found by observing the arterial pressure tracing. The optimal deflation point is selected to achieve the greatest reduction (20%) in the next unassisted systole.

•An effective IABP cycling will result in increase of mean arterial pressure, decrease in heart rate, decrease in pulmonary capillary wedge pressure, and increase in cardiac output.

Step 7: Beware of complications

•Trauma to the arterial wall incurred while inserting and advancing the guidewire or balloon (laceration, dissection, subadventitial hematoma) (1–5%)

•Limb ischemia associated with the position of the balloon catheter, which disappears with catheter removal (5–11%)

•Dislodged thrombus created during balloon removal, resulting in distal embolization (peripheral, renal) (1–5%)

•Hematologic (thrombocytopenia, red blood cell hemolysis, hemorrhage) (1–5%)

•Balloon leak/rupture (1–4%)

•Infection (2–4%)

•Cholesterol embolization—presents with fever, thrombocytopenia, livedo reticularis

Step 8: Know the factors affecting IABP complications

•The following factors increase IABP complications:

–Peripheral artery disease

–Old age

–Female sex

–Diabetes mellitus

–Hypertension

–Prolonged support

–Large catheter size (>9.5 Fr)

–Low cardiac index

–Low body surface area

•The following factors are associated with less IABP complications:

–Decrease in balloon size

–Sheathless technique

Step 9: Take routine care of IABP

•Specialized nursing care with 1:1 nursing every shift is needed to take care of patients.

•The chest X-ray to document position of the catheter tip, which should be at the bifurcation of the left and right main bronchi.

•Three times daily documentation of peripheral pulses.

•Daily measurement of hematocrit, platelet count, and creatinine.

•Anticoagulation parameters.