Mechanical circulatory support Flashcards
(53 cards)
What are the 4 mains types of mechanical circulatory support
Intra aortic baloon pump
Impella device
Tandem heart
ECMO
IABP how does it work? CO?
Essentially a balloon on a stick in the aorta
Inserted into femoral artery -> tip in descending aorta
Inflates in diastole
Deflates in systole
-> reduces vascular resistance and increase CO (up to 0.5L/min)
What is the impella device? CO?
Small pump -> inserted transfemorally into LV
Has external pump outside body
Sucks blood from LV -> external pump -> Aorta
Increases CO by 1-5L/min
What is the tandem heart? CO?
2 catheters
1st removes blood from LA
- Femoral vein -> Right atrium -> septal puncture -> Left atrium
- 2nd pumps blood into common iliac artery
- Femoral artery puncture
Increase CO by 2.5-5L/min
VAECMO vs VVECMO
Venous - arterial ECMO
- Catheter in vein removes blood -> gets oxygenated and put back in artery eg descending aorta
Venous venous ECMO
Blood taken from femoral vein
-> returned into superior vena cava
Which ECMO might worsen LV failure?
VA ECMO
As blood pumped retrograde into Aorta
-> Increases afterload
Key contraindication to all MCS
Unable to tolerate anticoagulation eg Haemorrhagic stroke
Severe peripheral arterial disease
IABP contraindications
significant AR (as will worsen)
Aortic aneurysm / dissection
Main indications for IABP
Increase coronary blood flow in patients awaiting revascularisation
Reduce afterload in acute heart failure / papillary muscle rupture + MR
[no data to say it improves outcomes in pure cardiogenic shock]
Contraindications for impella
Mechanical AVR
LV thrombus
VSD
Severe preipheral arterial disease
[Has to pass through AV]
AS / AR and the impella
AS - may be harder to place and may cause calcium embolism
AR - Less effective as blood pumped to ascending aorta
How does balloon pump increase coronary blood flow
‘Diastolic augmentation’
Coronary blood flow mainly in diastole
Balloon inflates in diastole -> increased blood in proximal aorta -> increased to coronaries
What does the dicrotic notch on ABP trace represent?
Aortic valve closure
What do aortic pressures look like in relation to ECG timings? What happens with a IABP?
Increase in systole then slow decrease in diastole
With pump pressures high in diastole
How does IABP affect systole
Deflates in presystole
-> creates a vacuum effect which helps pull blood out LV
How does IABP know when to inflate / deflate?
Uses ECG
Inflates in middle of T wave (start of diastole)
What does each part of this correspond to with IABP? What setting is this one
1:1 - inflates with each cardiac cycle
Where is the systolic and diastolic pressures on this IABP
Systolic lower
Augmented diastolic - higher and broader
What does an augmented pressure of 116mmHg mean?
Pressure inside balloon + early diastolic pressure
What does this IABP pressure tracing show?
1:2 - inflates on every second cardiac cycle
What happens to peak systolic pressure with ballon pump?What does this mean
Assisted peak systolic pressure is lower
-Because unassisted end diastolic pressure is lower [due to deflation and vacuum effect]
-> Reduces Afterload
What does the diastolic reporting on the console represent with the IABP
end diastolic pressure
[NOT the augmented pressure]
Common complications of IABP
Thrombocytopenia
Bleeding
Vascular injury including aortic dissection
Femoral arery occlusion -> limb ischemia
Why might someone develop acute kidney failure after insertion of IABP?
Balloon too big and occludes renal arteries
