Intra-Aortic Balloon Pump (IABP) — Rapid Summary

Concept & Components

  • Mechanism: Inflate in diastole → ↑diastolic & mean arterial pressure (MAP), ↑coronary/systemic perfusion; deflate at systolic onset → vacuum effect, ↓afterload.

  • Hardware: Catheter with distal pressure lumen + helium inflation lumen (fast laminar flow) and a mobile console.

  • Sizes (adult): 35 cc (<≈162 cm) and 40 cc (≈162–183 cm).

Triggers & “Auto”

  • Triggers: ECG (default), Pressure (during CPR), Pacer V/AV or A, Internal (brief pauses in compressions/OR).

  • Auto mode: Uses ECG + pressure algorithm; correct timing ~“most of the time.”

Indications (lecture framing)

  • Cardiogenic shock refractory to ≥2 inotropes/pressors (evidence largely negative).

  • Low CO post-CPB (weaning aid).

  • Mechanical complications of AMI: Acute MR (papillary rupture) and post-MI VSD — strong benefit(afterload reduction → favors forward flow; ↓shunt).

  • Intractable ischemia / left main pending CABG / adjunct to high-risk PCI: weak evidence.

  • LV unloading on VA-ECMO.

Hemodynamic Effects & Bedside Assessment

  • Effects: ↓SBP (~afterload drop), ↑DBP (augmentation), ↑MAP, ~20% CO rise (≈0.5–1.0 L/min), possible ↓HR.

    1. Augmented diastolic > native systolic (check at 1:1).

    2. Assisted aortic end-diastolic < native diastolic (set 1:2).

    3. Assisted systolic < native systolic (set 1:2).

      Augmentation criteria (prove it works):

Timing Errors (recognize & impact)

  • Too early inflation / late deflation (long inflation time): harm—↑afterload, impedes ejection (“step on systole”).

  • Late inflation / early deflation (short inflation time): loss of benefit—suboptimal augmentation/afterload reduction.

Contraindications

  • Absolute: >mild aortic regurgitation; aortic dissection/major aneurysm.

  • Relative: Uncontrolled sepsis/bleeding, severe PAD (access issues).

Insertion & Positioning

  • Approaches: Femoral (common femoral); central (surgical, descending aorta); axillary (facilitates ambulation).

  • Confirm: CXR tip ~2 cm above left main bronchus / distal to subclavian on TEE.

Complications

  • Vascular: Limb/visceral ischemia, emboli, vascular injury, pseudoaneurysm, major bleed.

  • Non-vascular: Sepsis, thrombocytopenia, stroke (rare, malposition/air).

Anticoagulation (context-dependent)

  • No firm consensus; weigh thrombosis vs bleeding. Often avoided early post-cardiac surgery; commonly used in CCU AMI settings.

Weaning

  • Preferred: Ratio wean (1:1 → 1:2 → 1:3), observe 4–6 h at each step.

  • Alternative: Volume wean (reduce augmentation).

  • Remove only when on minimal/off inotropes/pressors and hemodynamics/organ perfusion stable; keep 1:1 while awaiting removal, set standby during extraction.

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