Cardiovascular Therapeutic Management 2013 MS II

Objectives Describe the functions of a temporary pacemaker and an implantable cardioverter-defibrillator. (continued)

Temporary Pacemakers Electronic devices used to initiate the heartbeat when the heart’s intrinsic rhythm cannot effectively generate a rate adequate to support cardiac output Uses Temporarily Supportively Prophylactically Permanently Duration – until the condition responsible for the rate or conduction disturbance resolves.

Indications Bradydysrhythmias Tachydysrhythmias Causes Drug toxicity Acute MI Acute Coronary Syndromes Following cardiac surgery

Pacemaker System Simple electrical circuit consisting of a pulse generator and a pacing lead with one, two or three electrodes. Pulse generator is designed to generate an electrical current that travels through the pacing lead and exits through an electrode (exposed portion of the wire) that is in direct contact with the heart. The electrical current initiates a myocardial depolarization. The current returns to the pulse generator to complete the circuit. Power source is a 9-volt alkaline battery

Pacing Lead Systems FIGURE 13-1 The Components of a Temporary Bipolar Transvenous Catheter. A, Singlechamber temporary (external) pulse generator. B, Bridging cable. C, Pacing lead. D, Enlarged view of the pacing lead tip. (A, Courtesy Medtronic Inc., Minneapolis, Minn.)

Pacing Routes Transcutaneous use of two large skin electrodes One placed on the anterior chest the other on the posterior chest These are connected to an external pulse generator Rapid, noninvasive procedure First line intervention that nurses can initiate in the ACLS algorithm – for the treatment of symptomatic bradycardia Used as an emergency short-term therapy until the situation resolves or another route of pacing can be established

Epicardial Pacing Insertion of temporary epicardial pacing wires is a routine procedure during most cardiac surgical cases Ventricular and in some case atrial pacing wires are loosely sewn to the epicardium. The terminal wires are pulled through the skin before the chest is closed. These are removed several days after surgery by gentle traction at the skin surface with minimal bleeding risk

Transvenous Pacing http://rnbob.tripod.com/transven.htm Temporary – transvenous endocardial pacing is accomplished by advancing a pacing electrode wire through the subclavian or internal jugular and into the right atrium or right ventricle. Insertion Fluoroscopy Through a pacing swan Through a central line cordis

Pacing Modes Synchronous – pacemaker only delivers a stimulus when the heart’s intrinsic pacemaker fails to function at a predetermined rate. Atrial/Ventricular Pacing Most physiologic Mimics the sequential relationship between the atrium and the ventricle Increases cardiac output

Pacing Modes Asynchronous pacing Fixed rate Ignores the patient’s intrinsic rate Used in emergencies when the patient is in asystole as a life saving measure Sometimes used in the operating room when electromagnetic interference from electrocautery and other electrical equipment can interferer with normal pacemaker function.

Nursing Care of the patient with an emergent pacemaker Continuous ECG monitoring – patent IV access (two sites at least) Set monitor on pacing to sense pacer energy or spikes Assess vitals regularly depending on patient status Assess perfusion – check a radial pulse while watching the monitor. Does the pacer spike generate a pulse Reassure the patient Provide pain medication/sedation for a patient with transcutaneous pacing Prepare for transfer or for transvenous pacing/permanent pacer insertion depending on the setting.

Permanent Implanted pacemaker Paces the atrium and the ventricle

Nursing Care of the patient with a pacemaker Prevention of pacemaker malfunction Assessment – ECG monitoring Secure pacing leads and bridging cable to the body Secure the external pulse generator Have extra batteries available Securing pacing leads and bridging cable to the body, reassess this with position changes, ambulation. The external pulse generator can be placed on the patient’s waist or placed in a telemetry bag. For the patient on bedrest the pulse generator can be suspended with twill tape from an Iv pole mounted overhead on the ceiling

Stray electricity Protecting against micro-shock Even a small amount of stray electrical current from other equipment can precipitate ventricular fibrillation a lethal arrhythmia Nurses should wear rubber gloves – non-latex variety when caring for the patient Cover terminal pacing pins with caps or gloves as well Use a non-electric grounded bed Keep all electrical equipment away from the bed Only rechargeable electric razors

Pacemaker Problems Failure to Capture Failure to Pace Undersensing See page 222 Failure to Pace Undersensing Oversensing

Risk for infection Assess site for s/s of infection – manifested by _____________________________________________________________________________________________________________________________________________ Endocarditis is a risk for a patient with epicardial pacing wires in place

Myocardial Perforation Very rare but can occur Symptoms Rhythmic hiccoughs Cardiac Tamponade Review symptoms of cardiac tamponade – falling arterial pressures, narrowing pulse pressure, muffled heart sounds, shock.

Patient education temporary pacemakers Instruct the patient to not handle the exposed portion of the lead wire. Notify the nurse if the dressing over the insertions site becomes soiled, wet, or dislodged. Done use any electrical devices brought in from home that could interfere with pacemaker function. Restrict movement of the affected extremity to avoid displacement. I-Pods are big culprits for pacemaker malfunction, electric appliances need to be disconnected and used with the battery on.

http://missinglink.ucsf.edu/lm/pacemaker_module/index.htm