Cardiac Emergencies

Left Ventricular Assist Device (LVAD)

Clinical Operation and

Patient Management

Review of Physiology

• Blood enters the right side of the heart via veins from the body. Blood is then pumped through the lungs where it is oxygenated.

• Blood then enters the left side of the heart. Finally, via the aorta, oxygenated blood is then delivered to the rest of the body.

The issue:

• Cardiomyopathy may be due to previous heart attack (ischemia), valvular heart disease, viruses, or other causes.

Idiopathic heart muscle disease or damage.

Patients who fail treatment with medical therapy may be candidates for mechanical circulatory support or Ventricular Assist Device (VAD).

Cannulation and Implantation

• The HM II is used to support only the left ventricle.

• Implantable VAD sits in a pre- or intra-peritoneal pocket.

• For LVAD support: cannulas are placed on the left side of the heart (apex of the left ventricle) and return blood to the aorta.

• Cannulas are then tunneled across the abdomen to minimize bending of cannula as the driveline exits the patient’s body.

Anatomical Placement

Key Design Features

• Relatively Simple Design

– Valveless

– Only one moving part, the

rotor

– Blood immersed bearings

designed for minimization

of blood damage

• Flow range: 3 – 10 L/min

Internal View

Outlet Housing Rotor Magnet Rotor

Bearings

Inlet Housing

Inlet Stator

Motor WindingOutlet Stator Motor Capsule

Pulsatility Index • The Pulsatility Index (PI) is a measurement of flow

pulse through the pump

• It is determined by the degree of native heart function and pump speed

– Pump speed determines the amount of LV

assistance

– As level of pump support ↑ (↑ speed), there is less

ventricular filling → leading to a ↓ in PI

– The higher the PI → the less support being

provided by the pump (more native heart function)

Equipment Overview

System Controller

Power Sources

Display Module

HM II System Controller

Microprocessor that:

• Delivers power to the

pump

• Controls pump speed

• Indicates alarms

• Provides complete

backup system

• Event recording

capability

This is a Data Cable and not a Battery Cable

HeartMate II Peripheral Equipment

• Power sources

– Power Base Unit

– Batteries & clips

– Emergency Power

Pack

• Display Module

Tethered Operation

Pt.’s connect

themselves to this

Power Base Unit

at night. This

device has to be a

stand alone in an

electrical socket.

It can be

unplugged and

taken into the

Amb. and plugged

into the vehicle’s

inverter for power.

Be sure you know

how to operate

the Ambulances

Inverter.

Battery Powered Operation

Power Base Unit (PBU)

• Serves as the electrical interface to the Display

Module

• Supplies mains power to LVAD

• Simultaneously test and charge up to six batteries

Batteries

• 12-volt, sealed Nicad

• 10 – 15 hours of support on a pair of batteries

• Batteries drain simultaneously.

• When alarm beeps q 4 sec. it is a Low Batt. Alarm

• When alarm has a steady Alarm Tone Batt. has approx. 15 min left

• When changing batteries be sure to only change One at a Time and have the pt. lay down when doing this to help prevent a syncopal episode.

Emergency Power Pack (EPP)

• Single use battery pack

• Provides approximately 12

hours of battery power in

event of extended power

outage

• Replace if used ≥ 3 hours

Display Module

• Parameters

– Pump Speed (RPM)

– PI (Pulsatility Index)

– Estimated Flow (lpm)

– Power (watts)

• Alarm conditions

– Highest priority alarm

message alternates

with flow and power

Fixed Speed 9600 PI 5.5 Flow 4.5 Power 8.2

Fixed Speed 9600 PI 5.5

LOW FLOW for < 1 min

ALARMS AND TROUBLESHOOTING

Advisory and

Hazard Alarms

Advisory Alarms

• Low acuity alarms

• Advisory Alarms

– Power Lead Disconnected • Alarm will sound 1 q second. If Green Light is still

On it is a cable issue, simply assure connection is secure.

– Replace System Controller • No Lights lit, sporadic Tones

– Low voltage • 1 Beep q 4 sec., Yellow Batt. Lit, less than 15 min

Batt. Life left

Hazard Alarms

• High acuity alarms

• Hazard Alarms

– Low Voltage

• Steady Tone, Red Battery Light, less than 5 min of

Batt. life

– Low Flow: pump may not be working

• Steady Tone, Red Heart Light,

– Loss of Power

Patient Management

Anticoagulation

Restrictions

Emergency

Procedures

Warnings & Restrictions

• Damage to the percutaneous lead, depending on the degree, may cause the pump to stop

• No excessive jumping or contact sports

• No swimming

• No exposure to MRI

• Must be a backseat passenger in car

Key Points • Check for Medic Alert Tags.

• There is No Age Limit for these devices, children can and do have them as well.

• Pts can and will be dressed in various styles to accommodate their wearing these batteries, often wearing fishing style vests.

• Pts will also always have with them camera style ‘go bags’ all the time as well.

• The VAD will continue to pump in VT and VF.

• Even if you suspect Cardiac Arrest, Never do external chest compressions/CPR on VAD patients!

– BVM and Defib are appropriate

Defibrillation / Cardioversion

• If patient not tolerating arrhythmias, defibrillation may be performed.

– Do not stop or disconnect the pump for any reason

– There is NO handpump for the HM II

– In the event of device failure, switch to backup system controller ASAP

• If the LVAD stops operating, retrograde flow may occur

• If blood is stagnant in the pump for more than a few minutes, there is a risk of stroke or thromboembolism if the device is restarted

Important Points • Patients often will not have a palpable pulse with

the LVAD; Pulse Ox will also not register

• Assess for other signs of perfusion:

– mentation

– skin color

– Extremities Temperature (warm/dry)

– Cap Refill

• BP may also not be palpable or auscultated

– Use Doppler if available

These conditions are Normal for this device – go by

your “pt. assessment” for treatments

Emergency Procedures

• Patients must have their backup system controller and extra batteries with them at all times. Always collect and bring all their batteries and equipment with you.

• Their family/support system has been trained in changing to the backup controller.

• If possible, transport trained family members/ significant others with the patient during an emergency to help support the patient and device.

• Pt/family will also carry a Binder with them at all times with Hx. and device info, bring it with you.

Emergency Procedures

• Patients will call EMS for device failure, or any medical condition that requires urgent transport.

• Patients with specific VAD/Heart related issues must be transported to Hartford or Yale VAD Centers ONLY! Other local hospitals are not VAD centers and have no access to backup equipment and staff who can appropriately manage the patient. Be sure to contact Med Control though for guidance/concurrence.

• If reason for call is other than Heart/VAD related, any Hosp. is fine to transport to.

Emergency Patient Transport • Patients are sent home with contact numbers.

This is to be carried with them at all times. You

can call Hartford Hosp.(860.545.1212 x1)

anytime for assistance/guidance yourself. The

Call Center however Cannot act as your Med

Control.

• HM II LVAD is approved for all modes of

emergency transportation: including fixed wing

aircraft, helicopter and ambulance transport.

• The use of Life Star however should Only be

considered for extreme circumstances and not

routine or automatic use.

Emergency Patient Transport

• Remember that most likely you are not going to be called to the pt. unless there is a significant event going on with them. Family members are well Versed on how to assist and operate the pumps and batteries.

• Be confident in your assessment skills and treatment capabilities and don’t focus solely on the equipment.

Replacing System Controller

1. Obtain backup system controller

and power source

2. Explain procedure to patient &

have patient sit or lie down

3. Rotate perc lock on replacement

controller & current controller to

unlocked position

4. Connect backup controller to

power

– Silence Red Heart hazard alarm

LOCKED

UNLOCKED

Replacing System Controller

5. Disconnect percutaneous lead from current controller and attach to replacement controller

– Pump will automatically restart if speed set ≥ 8,000 rpm

– Speed set < 8,000 rpm, press test select or silence alarm button to restart pump

6. Rotate perc lock into

locked position

7. Disconnect old controller

from power

8. Notify on-call VAD staff

Replacing System Controller

• If controller does not restart:

– Press silence alarm or test select button

– Ensure percutaneous lead is fully inserted into socket

– Check power sources

– Attempt to restart using controller back up system

• Simultaneously press silence alarm & test select buttons

• Notify VAD staff & be prepared to switch to another controller

Additional Cardiac Devices

AICD/Pacemaker Combo device

99% of all LVAD pt.s will also have an AICD as well.

Sudden Cardiac Arrests (SCA)

• 1000 events occur every day

– 95% are unsuccessful

– 80% are at home unwitnessed

Most Risk of SCA is within 30 days post AMI

– AICD’s are 98% effective in preventing SCA

Life Vests

• This New Device is designed to sustain a brittle cardiac pt. post MI who is awaiting an AICD implant

• Ins. Co.’s typically won’t pay within 90 days post MI for an AICD

• The Life Vest therefore is a temporary, sustaining device until AICD is implanted.

Battery Pack

Anterior/Posterior

Pad placements

Life Vest

• Has pre-action alarm / vibration and voice prompts – can be turned off

• Delivers up to 6 shocks, 150 joules each, every 20 seconds

• Anterior/posterior pad placements emit a gel just prior to electrical discharge

• Can be used for up to approx. 2-1/2 to 3 mos. post AMI

• Can be removed for showering etc. per pt’s needs.

Life Vest

• As long as it is shocking let it shock.

• No harm will come by touching a pt. while

it is discharging

• Do Not cut away any straps. Either leave

in tact or simply remove, but bring all

equipment with you.