INTRODUCTION:

The ‘Impella’ is the device which is known as ‘world’s smallest heart pump’, this is used to support the heart when it’s failing for 4 to 14-days or longer than that. This is catheter like device and works on the principle of submersible water pump. It is approximately 6 inches long and thick as a pencil. Other device needs a surgical procedure to implant and those are large in size. The Impella device can be inserted into the heart without any surgery. It will be inserted through the femoral artery percutaneously in the Cath Labs. It provides blood flows of 2.5 – 5.5 litters/min. It is used to maintain stable heart function and to ensure blood flow maintained to vital organs such as the brain and kidneys in cases of cardiogenic shock or during high risk surgical procedures. When once Impella inserted in position, the Impella heart pump withdraws blood from the left ventricle/right ventricle and expels it in to the ascending aorta/pulmonary arteries, the same effect that happens with the pumping motion of heart.

It has been proven the Impella device is support the heart, improve safety during the procedure and improve outcomes. After procedure or the heart recovery occurs, the device will be removed like a catheter. It is approved and has been used in USA and Europe for the last few years and also introduced into India now. Cost of Impella device in India is 20 to 35 lacks approximately.

The Impella device was used for the first time on 26th June 2018 in India at Fortis Escorts Heart Institute Delhi in case of 86-year old male who was admitted with the severe recurrent chest pains over a week and impending myocardial infractions angiogram showed that three arteries were blocked more than 90% with calcium deposited life threatening blockages. He had prohibitive risk for cardiac surgery so angioplasty was performed as a lifesaving procedure with the support of Impella. The patient was Rot ablator drilling performed on all three arteries to remove the calcium and five stents was implanted, this procedure lasting for 2½ hours. The heart was supported by the Impella pump to maintain stable pressure and perfusion to vital organs throughout procedure. The patient remained conscious, stable and complication free during the procedure. The patient shifted to CCU (coronary care unit) after 05hours patient weaned off from the pump.

History of Impella device:

The Greek mathematician Archimedes (282–212 BC) while he was living in Alexandria, Egypt, he developed one water pump machine which is known as Archimedes’ screw this was used for raising water up from leaking ships also used to water fields of crops by using the screw to pull water from lakes and rivers. The machine was powered by hand or cattle. Dr. Richard Wampler, American physician was visited to Egypt on medical mission he was interested in irrigation pump he realized that these pump were based on Archimedes’ screw, Dr. Wampler involved in designing artificial heart s and left ventricular assist devices so he set out to design a system, based on the Archimedes’ screw, to pump blood from the LV to the aorta. While working with Nimbus Corporation in Rancho Cordova, California, in 1985, Dr. Wampler achieved this goal with the invention of the Hemopump (Medtronic, Minneapolis, MN). It was catheter-based and introduced via the femoral artery, The screw was powered by an external rotating motor that connected to the screw via a long metal shaft running through the centre of the catheter a rotating screw within a covered housing pulled blood from a port positioned in the LV and pumped it through the housing to an outlet port positioned in the proximal aorta. It provided 03 to 04 L/min extra cardiac output. Finally in 1988 Hemopump was implanted in patient by Dr. O.H. Frazier at the Texas Heart Institute in Houston.

Siess and colleagues in Aachen, Germany began working on Modifications of the Hemopump design to make a more effective assist device in 1991, they were included short rotating impeller, and long screw and miniature motor on catheter itself. In 2000 and 2003 Meyns and colleagues at the University of Leuven in Belgium conducted experimental studies to evaluate the ability of this newly designed device to attenuate the effects of acute myocardial ischemia. They found that the Impella device may help to reduce myocardial oxygen consumption during ischemia and reperfusion and led to a reduction in infarct size. These experimental findings helped lead to the approval in 2005 for clinical use of the Impella system in Europe.

In the U.S., the first Impella models (the Impella 2.5) received Food and Drug Administration (FDA) approval in 2008 and the Impella Cardiac Power (CP) model (known as cVAD (central venous access devices) in Europe) received approval in 2012. Since its introduction, there has been enthusiastic adoption of the Impella with > 50, 000 Impella devices having been to date implanted in the U.S. Currently, Impella devices are implanted at > 1, 000 sites in the U.S. The cost of an Impella 2.5 device is $22, 000 (vs. $800 to 1, 000 for an IABP).

Sr. No	Impella device	Introducing diameter	Pump motor	Access	Flow rate	Duration of support	Indication
1.	Impella RP	23fr	22fr	Femoral vein.	4.4L/min	14day’s	Right Sided heart failure, Acute MI, STEMI, Pulmonary hypertension.
2.	Impella CP	14fr.	14fr.	Femoral, axillary	3.7L/min	4days	Cardiogenic shock, high risk percutaneous intervention, patients at high bleeding risk, left ventricular failure. Hemodynamic Support during ablation of ventricular tachycardia (VT), Cardiomyopathy, Myocarditis.
3.	Impella LD	21fr.	-	Direct inserted in AA	5.3L/min	14days
4.	Impella 2.5	13fr.	12fr.	Femoral, axillary	2.5L/min	4days
5.	Impella 5.5	23fr.	19fr.	Axillary, Direct inserted in AA	5.5L/min	14days
6.	Impella 5.0	23fr.	21fr.	Femoral, axillary	5L/min	14days

AA-Ascending aorta, STEMI-ST segment elevation myocardial infarction, MI (myocardial infarction),

Contraindication:

· Left Ventricular Thrombus.

· Ventricular Septal Defect.

· Severe Peripheral Arterial Disease.

· Aortic Stenosis and Regurgitation.

· Mechanical Haemolysis.

· Peripheral Vascular Ischemia.

Nursing care of patient with Impella device:

1. Device monitoring:

Maintain saline pressurized flush bag to red pressure side arm. Change the tubing every 96 hrs and change the normal saline bag every 24hrs.

· Maintain purge pressure between 300-1100mmhg. Purge infusion rate 2-30ml/hr if glucose concentration is changed purge rate and pressure will be affected. Heparinized purge solution as per order. It will be 12.5units/ml and 50units /ml. Purge system monitoring should be done

· The machine will be operating for 1 hr after batteries have been fully charged after unplugged. Ensure the patient is on complete bed rest. Do not raise bed more than 30 degree. Position of Impella should be checked.

· Trace tubing from the patient to its points of origin to make sure that the system is set up properly and all tubing is attached to its proper port. Label the tubing at the distal and proximal ends to reduce risk of misconnection.

2. Patient monitoring:

Vital signs monitoring, document arterial line or non-invasive cuff for blood pressure.

Circulation: Check colour, temperature, capillary refilling and distal pulses of the cannulated limb.

hemodynamic values:

Monitor pulmonary artery pressure and central venous pressure assess cite of catheter for bleeding, hematoma.

Assess the following upon initiation and a minimum of every hour:

Catheter centre centimetre marking at insertion site. Urine output and colour of urine purge pressure and flow. Hemodynamic should be checked eg. CVP, O2. Check wound and mobility of the patient, sheath should be removed in cath lab, avoid unnecessary movements of patient, use leg immobilizer to reduce trauma to access site.

· Assess vital signs every 15 min first hour, every 30min second hr. and hourly if patient is stable. Check distal pulses and placement of device.

3. Monitor pump placement using the placement screen a minimum of every hour:

· The placement screen displays both placement signal waveform and motor current waveform.

· The placement signal is used to verify whether the Impella catheter is in the aorta or in the ventricle by evaluating the current pressure waveform as an aortic or ventricular waveform.

· The motor current provides information about the catheter position relative to the aortic valve .when catheter is positioned correctly, with inlet ventricle and outlet area in aorta the motor current is pulsatile because of the pressure difference between the inlet and outlet areas changes with the cardiac cycle.

· Motor current is dampened or flat when there is no pressure difference between the inlet and outlet area indicating mal positioning.

4. Monitor activated clotting time (ACT) in cath lab partial thromboplastic time in CCU as ordered:

· Cardiac cath lab /operating room: ACT goal prior to device insertion is greater than 250 and ACT post procedure goal is 160 -180

· ICU: Maintain anti Xa (Assays Low Molecular Weight Heparins) level per pharmacy protocol.

· Initiate purge heparin per provider, Systemic low dose heparin infusion per pharmacy protocol does not administer heparin boluses.

5. Obtain labs according to orders:

· Complete blood count (CBC)

· Basic metabolic panel

· Troponin.

· Creatine phosphokinase (CPK)

· Arterial or venous blood gas.

· Prothrombin time

· PTT and INR (for the patient with argatroban drip)

· Baseline and serial anti-Xa

· Plasma free haemoglobin

6. Obtain and assess value of anti -Xa as follows:

· Heparinized purge solution: as per provider order

· Systemic low dose heparin infusion: as per pharmacy protocol.

· Obtain daily chest x-ray and ECG.

· Confirm the device’s performance level setting determines the number of times the pump rotates per minute and the rate of blood flow.

· Assess pressure bag over the flush solution every 1-3 hours to make sure the pressure is maintained at 300-350mmhg.

· Assess vasoactive medications as needed and prescribed.

7. Document parameters hourly:

flow rate, mean motor current, purge flow rate, purge pressure, purge volume, heparin dosing, purge dextrose dose.

Document location of catheter at insertion site, cardiopulmonary assessment every 2 hourly.

· Vascular assessment via Doppler of palpable pulse.

Turn patient at least every 2 hrs, to reduce risk of pressure sore.

· -Provide nutritional support orally, etrally or parentrally.

8. Dressing changes at the site:

sterile dressing changes immediately if damp or soiled.

· Use chlorexhidie and transparent no gauze dressing.

· Use additional staff to stabilize catheter during changes.

9. Post catheter removal care:

Although manual pressure is applied to the arteriotomy site for least 40min monitor for re-bleeding, hematoma, pseudo aneurysm. Follow up per individual hospital protocol.

· Document site, cardiovascular status of affected limb, vital signs, and patient tolerance to procedure.

10. Emergency management:

Give chest compressions and defibrillation during pump operation. If suction alarm occurs ensure that patient has adequate volume, check the catheter positioning. If catheter is displaced report cardiologist or cardiothoracic surgeon, do echocardiogram and prepare for repositioning of catheter.

· Give health education to the patient or family explain about purposes functions, management and monitoring of Impella. Inform immediate if patient having leg pain, bleeding or dislocation of cannula.

Nurse should report immediately if:

Loss of distal pulses or change in neurovascular assessment, displacement of catheter, dark urine, bleeding from insertion site, suction alarm, and abnormal lab values.

REFERENCE:

1. A tiny pump – an Impella device – can save the lives of patients struggling with heart diseases, and does not show any mortality concerns, the United States Food and Drugs Administration has said in its post-approval study recently. The Hindu, ET Health world.

2. María Monteagudo, Vela, Andre Simon, Fernando Riesgo, Gil, Alex Rosenberg, Miles Dalby, Tito Kabir, Diana García, Saez, Vasileios Panoulas, Clinical Indications of Impella Short-Term Mechanical Circulatory Support in a Tertiary Centre. https://doi.org/10.1016/j.carrev.2019.12.010.

3. James J. Glazier, Amir Kaki. The Impella Device: Historical Background, Clinical Applications and Future Directions. International Journal of Angiology. 2019; 28(2): 118–123. DOI https://doi.org/10.1055/s-0038-1676369.

4. Rami Zein, Chirdeep Patel, Adrian Mercado-Alamo, Theodore Schreiber and Amir Kaki. A Review of the Impella Devices. Interventional Cardiology: Reviews, Research, Resources, Interventional Cardiology. 2022; 17: 05. DOI: https://doi.org/10.15420/icr.2021.11

5. Abiomed. Impella 2.5 with the automated Impella controller: circulatory support system instruction for use. 2016

6. Lippincott, Williams and Wilkins. Ventricular assisted device (Impella) percutaneous management. Nursing procedure and skill. 2016.

7. Mc Culloch, B. Use of the Impella 2.5in high risk percutaneous coronary intervention. Critical Care Nurse. 2011; 31(1): e1-e16.

Received on 06.10.2023 Modified on 30.12.2023

A and V Pub Int. J. of Nursing and Medical Res. 2024; 3(1):33-36.

DOI: 10.52711/ijnmr.2024.07