Pre-brief (the abcde of evaluating an LVAD)
Taking care of an LVAD patient in extremis can be nerve-wracking. Call their VAD coordinator immediately. Then, just as you would in a code situation, take your own pulse first (because the patient may not have one), take a deep breath, and remember your ABCs.
Appearance
What does the patient look like? Are they altered, is their skin mottled? Signs of poor perfusion are a red flag for LVAD dysfunction.
Auscultation
What does the LVAD sound like? Is it humming (normal)? Is it knocking (abnormal)? Is there NO sound (very BAD)?
Blood pressure
LVAD patients are preload dependent and afterload sensitive, with a narrow range for appropriate MAP: 65-90 mmHg.
Battery
Check the battery charge. Switch the patient to the back-up power system to ensure definitive power source and save battery life.
Controller
All alarms will be logged by the device, and will guide further differential diagnosis and evaluation. For example, “low flow” alarms indicate there has been decreased flow across the pump and can be due to arrhythmias, inflow tract obstruction/thrombosis, or anything that decreases LV filling.
Connections
Make sure everything is plugged in and connected well.
Driveline
Is the driveline fractured? Are there signs of infection?
Echo
- In a low flow state, a bedside echo will help determine the issue and next steps.
- A small LV is either due to underfilling (hypovolemia, RV failure, tamponade) or over-emptying (excessive pump speed), and can result in a suckdown event.
- A distended LV is due to either pump issue (malfunction, thrombus) or elevated afterload (hypertension, aortic valve dysfunction).
- A small RV is likely due to underfilling (hypovolemia, tamponade).
- A distended RV is either due to RV failure, volume overload, pulmonary hypertension/PE, or tricuspid regurgitation.
So:
- A small LV and small RV = underfilling, tamponade, excessive pump speed
- A small LV and large RV = pulmonary HTN/PE, RV failure
- A large LV and large RV = pump malfunction/thrombosis, volume overload, hypertension, aortic valve dysfunction
The Debrief
- Call the patient’s VAD coordinator immediately.
- Assess the patient’s global perfusion & MAP.
- Ensure the LVAD is powered and working.
- Use echo to determine the potential cause of poor perfusion states.
References
Long B, Robertson J, Koyfman A, Brady W. Left ventricular assist devices and their complications: A review for emergency clinicians. Am J Emerg Med. 2019;37(8):1562-70. doi:10.1016/j.ajem.2019.04.05
Trinquero P, Pirotte A, Gallagher LP, et al. Left Ventricular Assist Device Management in the Emergency Department. West J Emerg Med. 2018;19(5):834-41. doi:10.5811/westjem.2018.5.37023
