intra-aortic balloon counterpulsation
Also found in: Acronyms.
intra-aortic balloon counterpulsationAbbreviation: IABC
Patient preparation: If time permits, the health care provider explains to the patient that the cardiologist will place a special catheter into the aorta, usually via a femoral artery to help the heart pump more easily and to provide specific procedural and sensation information. The nurse explains that the catheter will be connected to a large console beside the bed that has an alarm system and that he or she will promptly answer any alarms. The nurse further explains that the console normally makes a pumping sound and assures the patient that this does not mean that the heart is not beating. The nurse also makes clear that because of the catheter, the patient will not be able to sit up, bend the knee, or flex the hip more than 30°. The patient will remain on the cardiac monitor and have a central line (pulmonary artery catheter), arterial line, and peripheral intravenous (IV) line in place. A thorough assessment of circulation of lower extremity pulses is conducted. Most insertions are performed under fluoroscopy. If the procedure is to be performed at the bedside, the nurse gathers the appropriate equipment, including a surgical tray for percutaneous catheter insertion, heparin solution, normal saline solution, the IABP catheter, and the pump console. The nurse prepares the femoral insertion site according to protocol, ascertains that a signed informed consent for the procedure has been obtained, and provides the patient with emotional support throughout the procedure. Sedation and analgesia are administered as prescribed.
Monitoring and aftercare: Following institutional protocol or physician orders, the nurse sets the console to regulate the rate of inflation and deflation of the balloon according to the electrocardiogram or the arterial waveform. The balloon rapidly inflates during the onset of diastole (the isometric or isovolumetric relaxation phase), as indicated by the dicrotic notch on the arterial waveform. Inflation forces blood into the coronary arteries and increases perfusion and blood flow to the kidneys, brain, and other organs and tissues. During the onset of ventricular systole, the balloon is rapidly deflated, causing a fall in aortic pressure that reduces myocardial oxygen consumption, decreases afterload, and increases stroke volume and cardiac output. (If the patient has no intrinsic heart rate, the pump may be set to its own intrinsic rate.) The nurse uses strict aseptic technique in caring for the catheter insertion site and connections and frequently inspects the site for bleeding or inflammation. If bleeding occurs at the insertion site, the nurse applies direct pressure over it and notifies the cardiologist. The nurse maintains the catheterized leg in correct body alignment and prevents hip flexion. The nurse maintains elevation of the head at no more than 30° to prevent upward migration of the catheter and occlusion of the left subclavian artery. If the balloon occludes the artery, the nurse can expect to note a diminished left radial pulse and the patient's report of dizziness. (Incorrect balloon placement may also occlude the renal artery, causing flank pain or a sudden drop in urine output.) Hemodynamic parameters are monitored according to agency protocols; urine output is monitored hourly. The nurse also periodically assesses distal pulses and documents the color, temperature, and capillary refill of the patient's extremities. The nurse also evaluates the warmth of the affected leg, color, pulses, and the patient's ability to move the toes at 30-min intervals for the first 4 hr after balloon insertion, then hourly for the duration of IABP. (Often, arterial flow to the involved extremity diminishes during insertion, but the pulse should strengthen once pumping begins.)
Even if the patient is receiving anticoagulants to inhibit thrombosis, the nurse keeps in mind that the patient may still be at risk for formation of thrombi and observes for such indications such as a sudden weakening of pedal pulses, pain in the limb, and motor or sensory loss. The nurse applies antithrombotic stockings (or pneumatic pulsatile stockings) as prescribed and encourages active range-of-motion exercises every 2 hr for the arms, the unaffected leg, and the affected ankle. The patient is also assisted with pulmonary hygiene. Meticulous skin care is provided.
An alarm on the console may detect gas leaks from a damaged or ruptured balloon. If the alarm sounds, or if the nurse observes blood in the catheter, he or she should shut down the pump console and immediately place the patient in the Trendelenburg position to prevent an air (gas) embolus from reaching the brain and then notify the cardiologist.
Once the signs and symptoms of left ventricular failure have diminished and the patient requires only minimal pharmacological support, the patient will be gradually weaned from IABP by decreasing the balloon volume, the frequency of balloon inflation and deflation, or both over a period of hours or days. To discontinue IABP, the cardiologist or a designate will deflate the balloon, clip the sutures, and remove the catheter, allowing the site to bleed for 5 seconds to expel clots. Because of the potential for blood splattering, involved personnel should wear protective coverings and eye-shields. The nurse then applies direct pressure to the site for at least 15 min (longer if anticoagulant therapy has been administered), followed by a pressure dressing with a sandbag on top. The nurse evaluates the site for bleeding and hematoma formation hourly for the next 4 hr and reports frank bleeding, local swelling, and increased patient pain. Usually the patient will be transferred to a telemetry unit for follow-up care until ready for discharge.