#bivad

VAD Basics

Left ventricular assist devices (LVAD) most common but Right (RVAD) and Bi-Ventricular assist devices (BIVAD) exist

Older devices = pulsatile / New devices = continuous flow (much simpler & found to significantly improve survival free from stroke & device failure)

All devices currently require an external power source and new devices have no ‘fail-safe’ handheld pump if failure occurs

Continuous flow LADs increased diastolic pressures without significantly increasing systolic pressures. Pulse pressure is therefore low (5-10 mmHg average).

Patients are generally treated with BOTH anti-coagulant and anti-platelet therapy

VAD Tips and Tricks

Patients will generally be pulseless BUT their MAP will be 70-90 (low pulse pressure variation of 5-10mmHg means a pulse will not be felt) if the VAD is working properly

Oxygen saturation readings are often erroneous (due to lack of pulse pressure variation)

NIBP (automatic or manual) are often of no use  

Patients can be in an ‘arrest rhythm’ (VF / VT) while sitting up and talking….ECGs are essential!

BP can be taken non-invasively with a manual sphygmomanometer and Doppler probe

Unwell patients NEED an arterial line (placed via USS guidance as a pulse won’t be felt!) - MAP will be accurate and oxygenation on an ABG can be assessed

..........For ALL cases presenting

CALL local VAD team ASAP where possible

Family / patient may be good source of immediate information re: the pump

Approach to the hypotensive / peri-arrest patient with a VAD

Usual ABCDE approach

Specifics:

Fluid resuscitation is key

pumps are pre-load dependent (pumps need blood volume at the intake otherwise a ‘suction event’ will occur where the ventricular all is sucked into the pump preventing flow and after load sensitive

Get an ECG (the patient may be in a shockable rhythm while still ‘awake’)

Arterial line is essential

Bedside echo is invaluable

GET the local VAD team involved ASAP

Causes………divide into VAD and non-VAD related:

VAD related (individual pumps have alarms and suggested actions)

Pump failure

Pump / cannula obstruction (conduit compression / kink OR thrombus (common!))

Pump speed set too high

Non-VAD related …..VADs all require preload to pump so largely caused by ‘suction event’ where no blood is getting to pump

Hypovolaemia - bleeding is common! (anticoagulants / anti-platelets)

Ventricular arrhythmia

Right ventricular failure

Cardiac tamponade

Aortic valve regurgitation

Approach to the arrested patient with a VAD

Usual ABCDE approach

Specifics as above where appropriate for the peri-arrest patient

Specifics:

Most companies suggest CPR ‘ONLY’ if absolutely necessary (CPR can move the VAD) - I’d say arrest would be a ‘necessitate’ CPR!

BUT....just remember to get the VAD checked (position / function) after CPR / defibrillation etc...

Defibrillation / cardioversion is OK........AP pad position is preferred

Use usual ALS drugs

Remember fluid resuscitation! (VADs are pre-load dependent)

Think of reversible causes (see above)

Thrombolysis for pump / cannula thrombus may be indicated

Allocate a team member to dealing with the pump (connect to power etc) / assessing faults etc