Contents
When Is Mechanical Support Used?
- Cardiogenic shock refractory to fluids and inotropes/pressors
- Bridge to recovery, decision, transplant, or durable device
- Goal: augment cardiac output and/or unload the failing ventricle
- Used in massive MI, decompensated heart failure, post-cardiotomy shock
Intra-Aortic Balloon Pump (IABP) — How It Works
- Balloon sits in the descending aorta just distal to the left subclavian
- Inflates in diastole → augments coronary/diastolic perfusion
- Deflates just before systole → reduces afterload, eases LV ejection
- Net effect: better coronary perfusion + reduced myocardial Oâ‚‚ demand
IABP Timing & Triggers
- Timed to the ECG (R wave) or the arterial waveform (dicrotic notch)
- Inflation at the dicrotic notch; deflation right before the next systole
- Early/late inflation or deflation reduces benefit or harms the patient — a tested concept
- Common ratios: 1:1 (every beat) down to 1:2/1:3 during weaning
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Start Free Practice →IABP Contraindications & Cautions
- Aortic regurgitation (augmentation worsens regurgitation)
- Aortic dissection / aortic aneurysm
- Severe peripheral arterial disease (insertion/limb ischemia risk)
- Keep affected leg straight; HOB usually ≤30–45° to prevent catheter migration/kinking
Impella
- A percutaneous axial-flow pump that sits across the aortic valve
- Pulls blood from the LV and ejects it into the aorta — directly unloads the LV
- Provides more flow than IABP in many cases
- Monitor for hemolysis, position alarms, and limb ischemia
Ventricular Assist Devices (VADs)
- LVAD: mechanically pumps blood from the LV to the aorta
- Often continuous-flow — patients may have a weak/absent palpable pulse (assess MAP via Doppler)
- Bridge to transplant or destination therapy
- Driveline infection and pump thrombosis are key complications
ECMO: VA vs VV
- VA ECMO: supports BOTH heart and lungs (cardiac + respiratory failure / cardiogenic shock)
- VV ECMO: supports lungs only (severe respiratory failure, e.g., ARDS) — needs an adequate native heart
- Requires systemic anticoagulation; high bleeding and clotting risk
- Monitor circuit, oxygenator function, and distal limb perfusion
Complications Across Devices
- Limb ischemia distal to a large arterial cannula
- Bleeding (anticoagulation) and thrombus/embolism
- Hemolysis, infection, and device malfunction
- Hemodynamic instability if the device fails — have a plan
Hemodynamic Monitoring
- Continuous arterial pressure, MAP, and device parameters
- Watch perfusion: urine output, lactate, mentation, distal pulses
- Recognize alarms and waveform abnormalities promptly
- Coordinate closely with perfusion/cardiac teams
Nursing Priorities
- Protect and assess the insertion site and distal limb every hour
- Maintain correct positioning (leg straight, HOB limit for IABP)
- Monitor anticoagulation labs and bleeding
- Never abruptly stop support; recognize and escalate device failure
Can you answer these 3 CCRN questions?
Here are 3 questions in the style of our premium bank. The full rationale explains exactly why the right answer is right — and why the distractors trap most test-takers.
Premium Practice Question
The intra-aortic balloon pump inflates during which part of the cardiac cycle, and what is the benefit?
- Systole, to increase afterload
- Diastole, to augment coronary perfusion
- Systole, to augment coronary perfusion
- Diastole, to increase afterload
Rationale: The IABP inflates during diastole at the dicrotic notch, augmenting coronary and systemic diastolic perfusion, and deflates before systole to reduce afterload....
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Premium Practice Question
Which condition is an absolute contraindication to an intra-aortic balloon pump?
- Cardiogenic shock
- Aortic regurgitation
- Acute MI
- Atrial fibrillation
Rationale: Aortic regurgitation is a contraindication because diastolic balloon inflation worsens regurgitant flow back into the left ventricle; aortic dissection is also contraindicated....
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Premium Practice Question
A patient on continuous-flow LVAD has no palpable peripheral pulse. The nurse should:
- Begin CPR immediately
- Assess MAP with a Doppler
- Defibrillate
- Disconnect the device
Rationale: Continuous-flow LVADs often produce little or no palpable pulse; perfusion is assessed by mean arterial pressure (often via Doppler), not a palpable pulse....
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Frequently Asked Questions
How does an intra-aortic balloon pump work?
The balloon inflates during diastole to augment coronary and systemic perfusion and deflates just before systole to reduce afterload, improving coronary blood flow while lowering the heart's oxygen demand. Timing is set to the ECG R wave or the arterial dicrotic notch.
What are the contraindications to an IABP?
Aortic regurgitation and aortic dissection or aneurysm are contraindications, and severe peripheral arterial disease is a major caution because of limb-ischemia and insertion risks.
What is the difference between VA and VV ECMO?
VA (veno-arterial) ECMO supports both the heart and lungs and is used for cardiogenic shock or combined failure. VV (veno-venous) ECMO supports only the lungs and requires an adequately functioning native heart, typically for severe respiratory failure like ARDS.
Why might an LVAD patient have no palpable pulse?
Many LVADs provide continuous (non-pulsatile) flow, so a peripheral pulse may be weak or absent. Perfusion is assessed using the mean arterial pressure, often obtained with a Doppler, rather than a palpable pulse.
What is a major complication of large arterial cannulas and balloon pumps?
Limb ischemia distal to the insertion site is a key complication, so distal pulses and perfusion must be assessed frequently, along with bleeding from required anticoagulation.
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