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Basics of Intraaortic balloon pumps (IABPs)Inflate during early diastole augmenting diastolic pressureDeflate during systole reducing aortic volume and decreasing afterloadImproves coronary diastolic flow, decreases myocardial systolic O2 demand. Polyurethane bladder mounted on flexible shaft, tip just distal to left subclavian arteryInflated w/helium (fast inflation and deflation)Triggered by ECG,
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1. Intro to intra-aortic balloon counterpulsation(IABP)
2. Basics of Intraaortic balloon pumps (IABPs)
Inflate during early diastole augmenting diastolic pressure
Deflate during systole reducing aortic volume and decreasing afterload
Improves coronary diastolic flow, decreases myocardial systolic O2 demand
3. Polyurethane bladder mounted on flexible shaft, tip just distal to left subclavian artery
Inflated w/helium (fast inflation and deflation)
Triggered by ECG, optimized by arterial waveform
4. Indications:
Cardiogenic shock due to complicated MI or reversible cause such as ischemia, myocarditis, sepsis, drug toxicity
Inability to wean off bypass after cardiac surgery
Refractory arrhythmia
Bridge to transplantation
Refractory ischemia from failed PTCA, UA, complex PTCA/stent
Prophylaxis after high risk angioplasty (data-free zone)
5. Contraindications:
Significant AI
Abdominal aortic aneurysm
Aortic dissection
Severe aorto-iliac or femoral disease
Uncontrolled septicemia
Uncontrolled bleeding diathesis
6. Counterpulsation timing
Coordinated with central aortic pressure tracing from balloon guidewire lumen using 1:2 setting
Inflation should initiate at aortic valve closure upstroke should fuse w/central aortic dicrotic notch to form U
Deflation should initiate when distole ends just before opening of aortic valve, set early then delay until maximal decrease in systolic pressure of subsequent beat, ~10-15 mm Hg
Early balloon inflation or late deflation-> increases afterload
Late inflation or early deflation->submaximal augmentation
7. Management of IABP patient
Check position daily w/CXR to confirm radioaque tip 2cm below top of aortic knob
Anticoagulate w/heparin, PTT goal 50-70, +/- when inserted w/o a sheath
ABX prophylaxis: ancef if no PCN allergy while IABP in place
Platelet monitoring daily, mild to moderate thrombocytopenia common but rarely drop to <50-100K, if occurs much look for other causes such as HIT
Check DP/DT pulses q8 to monitor for thromboembolic events
8. Weaning
Heparin off ~4hrs prior to balloon removal (verify PTT)
Always at 1:1 when off heparin
Check EKG and PA line hemodynamics with each change to ensure maintenance of appropriate timing
Weaning protocols:
Fast: (UA, MI, s/p PTCA and EF<40%)
1:2 x 1h -> 1:4 x 1h -> 1:8 x 1h -> 1:1 x 4h -> IABP out
Medium: (UA, MI, or s/p PTCA and EF<40%)
1:2 x 2h -> 1:4 x 2h ->1:8 x 2h -> 1:1 x 4h -> IABP out
Slow: (cardiogenic shock)
1:2 x 4h -> 1:4 x 4h -> 1:8 x 4h -> 1:1 O/N -> in am 1:2 x 1h -> 1:4 x 1h -> 1:8 x 1h ->1:1 x 4h -> IABP out
9. Complications
Limb ischemia: within hours of insertion often secondary to mechanical obstruction of vessel by balloon (reversible), late ischemia often caused by formation of local thrombus; options are to remove IABP, change IABP insertion site to contralateral femoral artery, or cross-femoral grafting
Arterial dissection: aortic rupture can occur if balloon inserted into false lumen
Balloon rupture: helium embolization may cause prolonged ischemia or CVA, Rx includes hyperbaric oxygen
CVA: often caused by excessively proximal placement of IABP or vigorous flushing of the cetnral lumen of the balloon to correct dampened readings of the aortic pressure
Sepsis: onset most prominent after 1 wk of IABP use