The pulse-less can now talk!.......adapted from Partyka and Taylor 2014 - EMA review article: Ventricular assist devices in the Emergency department (PMID:24707998)
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)