Intra-Aortic Balloon Pump Flashcards
(10 cards)
What is meant by counterpulsation in the context of an intra-aortic balloon pump
Inflation of the balloon in diastole and deflation just before systole
What are the benefits of Intra-aortic balloon pump-generated counterpulsation to oxygen delivery to the left ventricle
Inflation of the balloon forces blood proximally, increasing the perfusion pressure of the coronary arteries and hence oxygen delivery to the myocardium
Deflation decreases afterload, reducing myocardial wall stress and oxygen demand in systole
Endothelially derived nitric oxide release due to vascular stretch may result in coronary arteriolar dilatation, resulting in increased blood flow and oxygen delivery
What is the effect of Intra-aortic balloon pump-generated counterpulsation on output from the left ventricle
Inflation forces blood Distally (as well as proximally) to, for example,e the cerebral vessels, therefore augmenting the apparent output of the left ventricle, along with deflation decreasing afterload during systole to promote ejection
What are the indications for the insertion of an Intra-Aortic Balloon Pump
Acute Heart Failure with Hypotension
Myocardial Infarction with acute left ventricular failure
Myocardial infarction with acute mechanical complication causing shock, e.g. acute mitral regurgitation due to papillary muscle rupture
Low Cardiac Output after CABG or failure to separate from cardiopulmonary bypass
As a bridge to definitive treatment in patient with intractable angina or myocardial ischemia, refractory heart failure or intractable ventricular arrhythmias
What are the contraindications to the insertion of an Intra-Aortic Balloon Pump
Aortic Aneurysm
Aortic Dissection
Moderate to severe aortic regurgitation
Chronic End Stage Heart Failure with no further treatment options
Uncontrolled sepsis
Uncontrolled Bleeding Diathesis
Severe, untreated peripheral artery or aortic disease
Previous reconstructive vascular surgery
Tachyarrhythmia at a rate that the IABP con not synchronise with
What is the anatomical location at which the cephalad and distal ends of the balloon of the Intra-Aortic Balloon Pump should be placed
The cephalad end should be 2 to 3 cm distal to the origin of the left subclavian artery
The distal end of the balloon should lie above the origin of the renal arteries
** Fluoroscopic guidance is used to site the IABP and the position can be checked with this or with X-ray on ultrasound, or with transesophageal echo**
What methods are there for timing balloon inflation while using an Intra-Aortic Balloon Pump
ECG triggered: The balloon inflates with the T wave and deflates at the peak of the R wave
Arterial pressure waveform triggered: The balloon inflates with the dicrotic notch (i.e., closure of the aortic valve) and deflates just before the upstroke of the arterial pressure waveform (i.e., just before the aortic valve opens).
** During a cardiac arrest, an IABP must be changed to pressure trigger mode as the ECG will no longer provide reliable triggering**
What are the physiological consequences of mistimed inflation of an Intra-Aortic Balloon Pump
Early inflation (Before the aortic valve closes)
Causes increased left ventricular afterload, aortic regurgitation, and increased myocardial oxygen demand
Late Inflation (after the dicrotic notch / aortic valve closes)
Suboptimal coronary artery perfusion due to inadequate counterpulsation
Early deflation (before the onset of systole)
Suboptimal reduction in afterload failing to improve myocardial oxygen demand
Late deflation (after onset of systole)
Causes an increase in afterload due to left ventricular ejection against an inflated balloon and consequent increased myocardial oxygen demand
List complications of insertion or use of an intra-aortic balloon pump
Related to vascular access:
Vascular injury causing: Bleeding, Haematoma, False Aneurysm, Arteriovenous Fistula
Infection
Poor Perfusion to the limb distally
Compartment syndrome
Related to device use:
Mistimed inflation
Limb, cerebral, spinal cord, mesenteric or renal ischaemia due to incorrect placement
Aortic dissection
Cardiac tamponade
Thromboembolism
Thrombocytopaenia / Haemolysis
Balloon rupture resulting in gas embolus (helium is used in the balloon and it is rapidly absorbed on account of it’s low density in the event of a balloon rupture)
Related to systemic anticoagulation:
Bleeding
What gas used to inflate the balloon of the intra-aortic balloon pump and why
Helium
It is used because:
It’s low density means that the flow will be laminar such that the gas is rapidly transferred from IABP machine to the balloon tip
It will also be rapidly absorbed into the blood in the event of a balloon rupture
