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Pacemaker implant
AORN JOURNAL
J A N U A R Y 1989. VOL. 4Y. NO 1
Pacemaker Implant IMPLICATIONS FOR PERIOPERATIVE NURSES
Tony C. Welch, RN
P
acemakers are used to treat bradycardias and tachycardias caused by defects in the patient’s intrinsic cardiac conduction system (Fig 1). Perioperative nurses can significantly contribute to the patient’s perioperative care by knowing the implications of pacemaker therapy. This knowledge includes an understanding of pacemaker parameters, medications, and electrolyte imbalances that might affect the patient’s cardiac physiology. This article provides an overview of pacemaker implants and perioperative care of the patient receiving a permanent pacemaker for bradycardia.
Pathophysiology
P
ronounced bradycardia is a heart rate of less than 40 beats per minute in the adult patient. Conduction faults pertaining to bradycardias include the fo1lowing:l sick sinus syndrome-severe bradycardia,
sinus pauses, block, or arrest, atrioventricular (AV) junctional escape rhythms, bradycardia-tachycardia syndrome, second-degree AV blocks-Wenckebach, Mobitz I, or Mobitz I1 that leads to thirddegree heart block, symptomatic bifascicular or trifascicular blocks-left bundle branch block, right bundle branch block, left anterior heart block, or left posterior heart block, third-degree heart block or AV dissociation, and myocardial infarction (MI)-anterior MI with second-degree Mobitz I1 heart block, posterior MI with seconddegree AV block, or Mobitz I progressing to Mobitz 11. As a result of these defects in the conduction system, the heart is unable to respond appropriately to physiological demands. Patient symptoms associated with conduction abnormalities are
staff nurse at Olin E. Teague Veterans Administration Hospital, Temple, Tex. He received hD associate degree in nursing from Angelo State University, San Angelo, Tex, and hD bachelor of science degree in nursing from the University of M a y Hardin Baylor, Belton, Tex.
Tony C. Welch, RN, BSN, CNOR, is an OR
The opinions and assertions contained in this article are the private views of the author and are not to be construed as official or as reflecting the views of the Veterans Administration or the Department of Defense. 251
J A N U A R k 1989 VOL 49. ‘40 1
AORN J O U R N A L
vena cava
Fig I. The cardiac conduction system: sinus node (a), posterior internodal tract (b), left atrial extension of Bachmann’s bundle (c), Bachmann’s bundle (anterior internodal tract) (d), middle internodal tract (e), AV node 0,AV bundle (g), bundle of Kent (h), fibrous barrier (i), James fibers 0,Mahaim fibers (k), right bundle branch (I), left bundle branches (m), and Purkinje fibers (n). (Adapted from Cardiac Pacing: A Concise Guide to Clinical Practice (1979),P Varriale, E Naclerio, with permission from Lea & Febiger, Philadelphia)
vena cava
irregular pulse, clouding of memory, confusion, undue fatigue, dizziness, lightheadedness, and syncopy.?
Pacemaker L e a h and Generators
T
oday’s pacemakers are synchronous-their functions are tailored to compliment the patient’s intrinsic heart pattern. Pacemakers weigh 50 to 60 g (2 oz) and have a displacement of 30 to 40 mL. They are half the size of the original asynchronous pacemakers, which delivered an impulse irrespective of the intrinsic heart rate. Pacemakers consist of two components: the lead and the generator (Fig 2). Pacemaker leads may be either epicardial or endocardial; that is, they
are placed either outside or inside the patient’s heart. In the past, epicardial leads were implanted directly on the myocardium via a thoracotomy and either sutured or screwed in place. The most commonly used leads are endocardial. These are usually introduced transvenously. Endocardial leads are either an active or a passive fixation-type lead. Active leads positively attach to the endocardium when implanted, and passive leads usually intertwine in the heart’s trabeculae and fibrose into place. Postimplant, lead displacement may occur and result in loss of sensing or pacing. The patient, therefore, must be monitored with an electrocardiogram (ECG) for at least 24 to 48 hours after a passive lead implant. When an endocardial lead that has been in place for longer than two months is removed, endocardial or valvular avulsion may 259
JANUARY 1989, VOL. 49, NO 1
AORN JOURNAL
generator
Y
A- V node
stimulating& electrode
Fig 2. Pacemakers consist of two components: the lead and the generator. (Adapted from Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980), with permission from Cardiac Pacemakers, Inc, St Paul) result and necessitate emergency open heart ~urgery.~ Pacemaker leads are made of a conductive platinum iridium alloy that is coated with silicone rubber tubing and attaches to the pacemaker via an in-line steel pin. This design helps prevent fracturing of the lead after implant, which also can result in loss of sensing or pacing. Leads may be either unipolar or bipolar (Fig 3). Bipolar leads are often preferred because they have a shorter electrical pathway, can serve as a unipolar lead, allow less electromagnetic interference, and are not as prone to oversensing. Another important feature of the bipolar lead is that it can be used with either a unipolar or bipolar type pacemaker, whereas a unipolar lead cannot. Current pacemakers provide circuitry features such as timing and output circuits that can deliver a set electrical output at a set time and can be matched with sensing circuit generators that initiate impulses or receive impulses via the leads. They also can include programming circuits that allow the pacemaker to be reset using a coded external transmitter and telemetry circuitry that monitors and reports the pacemaker and heart activities on demand. 260
Parameter Adjustments
T
he pacemaker must be set to recognize the patient’s intrinsic rate. This is accomplished by measuring the amplitude or height of the R wave (measured in milliamperes) and setting the pacemaker so that it recognizes the patient’s R wave. Pacemaker generators must also be set so that they achieve capture. This means that the voltage level from the generator must be strong enough to cause the heart to beat (measured in millivolts). Another measurement is the pulse width (measured in milliseconds), which allows the pacemaker to time the intrinsic rate of the heart or stimulate the heart if it surpasses a set time limit. The pacemaker must also be positioned in the heart so that resistance or impedance (measured in ohms) is minimized. Ideally, the pacemaker should have the lowest impedance with the lowest possible capture voltage, should recognize intrinsic R waves, and should limit voltage output to increase pacemaker longevity. The pacemaker must be set for upper and lower heart rates (eg, 110 beats per minute upper limit and 60 beats per minute lower limit).
AORN JOURNAL
J A N U A R Y 1989. VOL. 49, NO 1
return pathway
1
Fig 3. Leads may be either unipolar (top) or bipolar (bottom). (Adapted from Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980) with permksion from Cardiac Pacemakers, Inc, St Paul) Pacemaker generators have an identification code set up by the Association for the Advancement of Medical Instrumentation. The code identifies the parameters/functions of the pacemaker. The code began as a three-letter system, but will probably be expanded to at least a five-letter system to address the new generator capabilities? (See “Pacemaker Generator Identification Code.”) Pacemakers are sometimes referred to by parameters/functions. For example, a DDD pacemaker is capable of pacing both chambers, sensing both chambers, and responding in a triggered or inhibited mode. Pacemakers have become sophisticated, often expensive devices. Some pacemakers are responsive to or activated by blood temperature, respiratory rate, Q-T interval, body vibrations, and pH levels. The device that is responsive to body vibrations sells for about
$5,000.5 Pacemakers that are physiologically activated are still in relatively experimental or trial stages.
Perioperative Care
P
atient education and adjustment is a major concern for the pacemaker implant patient. The physician tells the patient that the pacemaker is implanted to augment the heart’s conduction system and that it is there to help the heart beat properly. The physician’s explanations may then be reinforced by the nurse. Every effort should be made to relate the pacemaker’s function in a fashion that is most comprehensive and comfortable for the patient. This could be in the form of an interview, a discussion, or a structured lesson plan. At this time the patient might be shown a pacemaker model and/or leads 261
JANUARY 1989. VOL 49. NO 1
Pacemaker Generator Identification Code Letter one-chamber paced A-atrium V-ventricle D-dual chamber Letter two-chamber sensed A-atrium V-ventricle D-dual chamber Letter three-response mode T-triggered response I-inhibited response 0-no response D-dual R-reverse Letter four-programmable functions P-programmable (rate and/or output only) M-multiprogrammable C-communicating (noninvasive program) 0-nonprogrammable Letter five-tachyarrhythmia function B-bursts N-normal rate competition (more thadless than drive pacing) S-scanning E-external of the type that will be used for his or her implant. After the procedure is thoroughly discussed with the patient, he or she signs an informed consent that authorizes the pacemaker implant procedure. The patient has the preliminary laboratory work completed, including a complete blood count, electrolytes, chemistry level, and electrocardiogram (ECG). The patient is usually admitted to the intensive care unit (ICU) preoperatively in case he or she requires an emergency temporary pacemaker. Zntraoperative care. Pacemakers are usually implanted in the OR using sterile technique and direct x-ray visualization. All personnel should wear radiation exposure monitor badges during the procedure. Instrumentation includes pacemaker test equipment, lead introducer sets, a minor instrument set. and vascular instruments.
AORN JOURNAL
After the patient is transferred from the ICU to the OR, the circulating nurse verifies the consent and checks the chart for completion. The nurse reassures the patient and reviews the procedures that will be done for him or her in the OR. This will help minimize the patient’s anxiety and discomfort. Because most implants are done under local anesthesia, the patient is often cognizant of his or her surroundings. This is an opportunity for the nurse to establish a rapport that will enhance the patient’s surgical experience. The nurse assists the patient onto the OR bed, and the anesthesiologist attaches the ECG monitoring pads and inserts an intravenous line. Often a light sedative agent such as diazapam or fentanyl is administered to decrease patient anxiety. The circulating nurse pads and tucks the arms and places a headrest under the patient’s head. The circulating nurse preps the patient from mandible to nipple line with povidone-iodine or other suitable antimicrobial agents, and the surgeon places an iodophor-impregnated drape along with other sterile drapes over the prepped area. The surgeon then administers a local anesthetic such as 1%lidocaine and implants the pacing leads via the subclavian vein. He or she verifies lead placement radiologically and functionally by testing sensing, capture, and impedance with the pacemaker representative as a technical advisor. The surgeon then secures the lead with either a suture ligature or a tie at the entry site and attaches it to the generator. After testing the pacemaker generator functions, the surgeon makes a subcutaneous pocket to place it in. Pocket sites may be in any of several locations. The most frequently used location is the pectoral pocket site (Fig 4). The parameters are checked by the surgeon and pacemaker representative, and a printout record is made. The surgeon then closes the wound, and the nurse applies a dressing over the operative site. The nurse documents the implant procedure on the OR record and assists in transferring the patient back to the ICU, where the patient is observed for 24 to 48 hours. This is the critical time for possible lead displacement. Postoperative care. The patient will need to 263
JANUARY 1989, VOL. 49, NO I
AORN JOURNAL
right deltopectoral groove
w
- --
deltopectoral groove
pocket site
Fig 4. Pacemaker implant pocket sites may be in any of several locations. The most frequently used l a tion is the pectoral pocket site. (Adaptedfrom Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980), with permissionfrom Cardiec Pacemakers, Inc, St Paul) know how, when, and why the pacemaker must be checked after it is implanted. The nurse must teach the patient how to check his or her pulse. The patient should do this daily or have it done by a significant other in the event the patient is physiologically or psychologically unable to do so. Patients also need to know about the possibility of pacemaker pocket infection and the signs they should look for (eg, swelling, redness, soreness, or drainage at the incision site). In addition, the nurse should alert the patient to symptoms that could indicate a pacemaker dysfunction (ie, dizziness, weakness, syncope) and when to seek immediate help. Before discharge, the nurse also tells the patient about local pacemaker clubs where he or she can interact with others with similar experiences. Patients are usually in the hospital for two to five days depending on their condition. Within a lO-day period, patients are reevaluated by their cardiologist. Follow-up is often on a weekly basis for a month, then biweekly for a month, and monthly thereafter. Evaluation may include a physical examination, review of history and symptoms, chest x-ray, and an ECG. Another form of evaluation used today is telephonic monitoring. Using a bracelet monitor 264
or a Holter-type device, the activity of the heart and pacemaker are picked up and transmitted in the form of a single-lead ECG. This is another instance in which the patient needs instructions and education. As the patient’s pacemaker nears the end of its projected life span, the patient will again need to be closely monitored (ie, weekly). The telephonic device greatly facilitates patient monitoring.
Complications
P
acemaker insertion complications are usually in one of the following categories: thrombosis and/or embolism, infection, pacemaker-induced arrhythmias, myocardial perforation, or cardiac tamponade. Inclusive of these complications are those associated with permanent pacemakers. Early complications include: hematoma, infection, electrode displacement (perforation), cardiac tamponade, loss of sensing or pacing (without electrode displacement), improper lead-generator connection,
AORN J O U R N A L
generator malfunction, and/or inappropriate response to programming. Late complications of pacemaker insertions include: a recurrent symptoms, a electrode fracture (wire or insulation), a electrode displacement (perforation), a infection, 8 deep venous thrombosis, a extrusion (Twiddler’s syndrome), a runaways, a premature generator failure, 0 pacemaker-related tachycardias (endless loop), a myoinhibition, a chest-wall or diaphragmatic pacing, and a external interference. A possible complication in pacemaker implant procedures can result from the use of the electrocautery unit. Many surgeons will not use an electrocautery unit during implantation, or they will use it only to effect hemostasis before implementation. For those patients coming to the OR that already have a pacemaker implanted, the following guidelines are recommended? The dispersive pad should be located as far from the generator as possible and should not be located between the active electrode and the generator. Current settings should be set as low as possible, and short bursts should be used to cauterize bleeding. The cautery tip should not be used within 15 cm (6 inches) of the pacemaker, especially with an unipolar unit, because of possible ventricular fibrillation. In addition, the dispersive pad draws current away from the pacemaker if the intersection of the current to the lead is perpendicular (ie, meets at right angles).
Effects of Medication and Electro&tes
P
erioperatively, the nurse should review the patient record for medications that may affect the patient’s physiology and make appropriate interventions. The nurse should also be alert for laboratory values that might affect the cardiac response. There are several medications that can have 266
JANUARY 1989, VOL. 49, NO 1
a deleterious effect on the function of the heart, especially when they exceed therapeutic levels.’ These medications may either mask or cause signs or symptoms that represent a deterioration in the patient’s condition. Examples are: narcotics that lower blood pressure and depress cardiovascular functions (eg, meperidine, morphine sulfate), beta blockers that reduce beta-receptor activity (eg, propranolol, atenolol), calcium-channel blockers that compete for calcium (eg, Procardias, verapamil), glycosides and antiarrhythmics that may block or prolong conduction when given in excess (eg, digoxin, quinidine, Isuprels, procainamide), diuretics that reduce or concentrate serum electrolytes (eg, furosemide, Aldactones), and psychotropic drugs that mask symptoms, potentiate narcotics, or lower blood pressure (eg, phenothiazines, chlorpromazines). Medical therapy for the cardiac patient can be very interdependent, depending on the medication and on the patient’s physiological responses to the medications. In addition, serum electrolytes, especially potassium, calcium, or magnesium, in excess of or less than accepted normals may cause slowing or speeding of the patient’s heart rate.8 This information is meant as a guidepost for medical therapy in the cardiac patient. A simple rule of thumb is that the more medication the patient takes, the greater the possibility that the patient will have a detrimental chemistry or dosage 0 alteration if not carefully monitored. Notes 1. P Varriale, E Naclerio, eds, Cardiac Pacing: A Concke Guide to Clinical F’ractice (Philadelphia: Lea and Febiger, 1979) 83-96; P Kowery, D Mullan, L Wetstein, “Pacemaker therapy,” in Surgical Clinics of North America 65 (June 1985) 596; R Medina, E Michelson, “Update on cardiac pacemakers: Description, complications, indications, and follow up,” Cardiovascular Clinics 16 (1985) 199; J Zaidan, “Pacemakers,” Anesthesiofogy 60 (April 1984) 3 19334; M ONeill, D Davis, “Pacemakers in noncardiac surgery,” in Surgical Clinics of North America 63 (October 1983) 1103.
J A N U A R Y 1989. VOL 49, NO 1
2. O’Neill, Davis, “Pacemakers in noncardiac surgery,” 1 108; Varriale, Naclerio, eds, Cardiac Pacing: A Concde Guide to Clinical Practice, 135; Cardiac Pacemakers, Inc, TroubleshootingPacing Problems: A ComprehensiveReferencefor Medical Professionals (St Paul Cardiac Pacemakers, Inc, 1980) 1; C Hudak, B Gallo, T Lohr, Critical Care Nursing: A HolLvtic Approach, fourth ed (Philadelphia: J B Lippincott Co, 1986) 85. 3. Kowery, Mullan, Wetstein, “Pacemaker therapy,” 603; Medina, Michelson, “Update on cardiac pacemakers: Description, complications, indications, and followup,” 194, 198; B Phibbs, H Marriott, “Complications of permanent transvenouspacing,” New England Journal of Medicine 312 (May 1985) 1428-1432; Cardiac Pacemakers, Inc, Troubleshooting Pacing Problems, 8. 4. P Ludmer, N Goldschlager, “Cardiac pacing in the 198Os,” New England Journal of Medicine 31 1 (December 1984) 1674. 5. N Fearnot, H Smith, “Trends in pacemakers which physiologically increase rate: DDD and rate respon-
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sive,” Pacing and Clinical Electrophysiologv (PACE) 9 (November 1986) 939-947; D Bolthaus, “Pacemaker adjusts heart rate for exercise,” Hospitals 61 (Sept 20, 1987) 78. 6. Zaidan, “Pacemakers,” 325; Ludmer, Goldschlager, “Cardiac pacing in the 1980s,” 1673; ONeill, Davis, “Pacemakers in noncardiac surgery,” 1105-1107; A Simon, “Perioperative management of the pacemaker patient,” Anesthesiologv 46 (February 1977) 127-131. 7. Kowery, Mullan, Wetstein, “Pacemaker therapy,” 599; Hudak, Gallo, Lohr, Critical Care Nursing, 161167; L Weeks, Advanced Cardiovascular Nursing (Boston: Blackwell Scientific Publications, 1986) 91103, 743-767; Phibbs, Marriot, “Complications of permanent transvenous pacing,” 1431; M Goldin, Intensive Care of the Surgical Patient, second ed (Chicago: Year Book Medical Publishers, Inc, 1981) 326-347; Varriale, Naclerio, Cardiac Pacing, 67, 80. 8. Varriale, Naclerio, Cardiac Pacing, 67; Kowery, Mullan, Wetstein, “Pacemaker therapy,” 599; Weeks, Advanced Cardiovascular Nursing 43, 87-91,475.
J A N U A R Y 1989. VOL. 4Y. NO 1
Pacemaker Implant IMPLICATIONS FOR PERIOPERATIVE NURSES
Tony C. Welch, RN
P
acemakers are used to treat bradycardias and tachycardias caused by defects in the patient’s intrinsic cardiac conduction system (Fig 1). Perioperative nurses can significantly contribute to the patient’s perioperative care by knowing the implications of pacemaker therapy. This knowledge includes an understanding of pacemaker parameters, medications, and electrolyte imbalances that might affect the patient’s cardiac physiology. This article provides an overview of pacemaker implants and perioperative care of the patient receiving a permanent pacemaker for bradycardia.
Pathophysiology
P
ronounced bradycardia is a heart rate of less than 40 beats per minute in the adult patient. Conduction faults pertaining to bradycardias include the fo1lowing:l sick sinus syndrome-severe bradycardia,
sinus pauses, block, or arrest, atrioventricular (AV) junctional escape rhythms, bradycardia-tachycardia syndrome, second-degree AV blocks-Wenckebach, Mobitz I, or Mobitz I1 that leads to thirddegree heart block, symptomatic bifascicular or trifascicular blocks-left bundle branch block, right bundle branch block, left anterior heart block, or left posterior heart block, third-degree heart block or AV dissociation, and myocardial infarction (MI)-anterior MI with second-degree Mobitz I1 heart block, posterior MI with seconddegree AV block, or Mobitz I progressing to Mobitz 11. As a result of these defects in the conduction system, the heart is unable to respond appropriately to physiological demands. Patient symptoms associated with conduction abnormalities are
staff nurse at Olin E. Teague Veterans Administration Hospital, Temple, Tex. He received hD associate degree in nursing from Angelo State University, San Angelo, Tex, and hD bachelor of science degree in nursing from the University of M a y Hardin Baylor, Belton, Tex.
Tony C. Welch, RN, BSN, CNOR, is an OR
The opinions and assertions contained in this article are the private views of the author and are not to be construed as official or as reflecting the views of the Veterans Administration or the Department of Defense. 251
J A N U A R k 1989 VOL 49. ‘40 1
AORN J O U R N A L
vena cava
Fig I. The cardiac conduction system: sinus node (a), posterior internodal tract (b), left atrial extension of Bachmann’s bundle (c), Bachmann’s bundle (anterior internodal tract) (d), middle internodal tract (e), AV node 0,AV bundle (g), bundle of Kent (h), fibrous barrier (i), James fibers 0,Mahaim fibers (k), right bundle branch (I), left bundle branches (m), and Purkinje fibers (n). (Adapted from Cardiac Pacing: A Concise Guide to Clinical Practice (1979),P Varriale, E Naclerio, with permission from Lea & Febiger, Philadelphia)
vena cava
irregular pulse, clouding of memory, confusion, undue fatigue, dizziness, lightheadedness, and syncopy.?
Pacemaker L e a h and Generators
T
oday’s pacemakers are synchronous-their functions are tailored to compliment the patient’s intrinsic heart pattern. Pacemakers weigh 50 to 60 g (2 oz) and have a displacement of 30 to 40 mL. They are half the size of the original asynchronous pacemakers, which delivered an impulse irrespective of the intrinsic heart rate. Pacemakers consist of two components: the lead and the generator (Fig 2). Pacemaker leads may be either epicardial or endocardial; that is, they
are placed either outside or inside the patient’s heart. In the past, epicardial leads were implanted directly on the myocardium via a thoracotomy and either sutured or screwed in place. The most commonly used leads are endocardial. These are usually introduced transvenously. Endocardial leads are either an active or a passive fixation-type lead. Active leads positively attach to the endocardium when implanted, and passive leads usually intertwine in the heart’s trabeculae and fibrose into place. Postimplant, lead displacement may occur and result in loss of sensing or pacing. The patient, therefore, must be monitored with an electrocardiogram (ECG) for at least 24 to 48 hours after a passive lead implant. When an endocardial lead that has been in place for longer than two months is removed, endocardial or valvular avulsion may 259
JANUARY 1989, VOL. 49, NO 1
AORN JOURNAL
generator
Y
A- V node
stimulating& electrode
Fig 2. Pacemakers consist of two components: the lead and the generator. (Adapted from Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980), with permission from Cardiac Pacemakers, Inc, St Paul) result and necessitate emergency open heart ~urgery.~ Pacemaker leads are made of a conductive platinum iridium alloy that is coated with silicone rubber tubing and attaches to the pacemaker via an in-line steel pin. This design helps prevent fracturing of the lead after implant, which also can result in loss of sensing or pacing. Leads may be either unipolar or bipolar (Fig 3). Bipolar leads are often preferred because they have a shorter electrical pathway, can serve as a unipolar lead, allow less electromagnetic interference, and are not as prone to oversensing. Another important feature of the bipolar lead is that it can be used with either a unipolar or bipolar type pacemaker, whereas a unipolar lead cannot. Current pacemakers provide circuitry features such as timing and output circuits that can deliver a set electrical output at a set time and can be matched with sensing circuit generators that initiate impulses or receive impulses via the leads. They also can include programming circuits that allow the pacemaker to be reset using a coded external transmitter and telemetry circuitry that monitors and reports the pacemaker and heart activities on demand. 260
Parameter Adjustments
T
he pacemaker must be set to recognize the patient’s intrinsic rate. This is accomplished by measuring the amplitude or height of the R wave (measured in milliamperes) and setting the pacemaker so that it recognizes the patient’s R wave. Pacemaker generators must also be set so that they achieve capture. This means that the voltage level from the generator must be strong enough to cause the heart to beat (measured in millivolts). Another measurement is the pulse width (measured in milliseconds), which allows the pacemaker to time the intrinsic rate of the heart or stimulate the heart if it surpasses a set time limit. The pacemaker must also be positioned in the heart so that resistance or impedance (measured in ohms) is minimized. Ideally, the pacemaker should have the lowest impedance with the lowest possible capture voltage, should recognize intrinsic R waves, and should limit voltage output to increase pacemaker longevity. The pacemaker must be set for upper and lower heart rates (eg, 110 beats per minute upper limit and 60 beats per minute lower limit).
AORN JOURNAL
J A N U A R Y 1989. VOL. 49, NO 1
return pathway
1
Fig 3. Leads may be either unipolar (top) or bipolar (bottom). (Adapted from Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980) with permksion from Cardiac Pacemakers, Inc, St Paul) Pacemaker generators have an identification code set up by the Association for the Advancement of Medical Instrumentation. The code identifies the parameters/functions of the pacemaker. The code began as a three-letter system, but will probably be expanded to at least a five-letter system to address the new generator capabilities? (See “Pacemaker Generator Identification Code.”) Pacemakers are sometimes referred to by parameters/functions. For example, a DDD pacemaker is capable of pacing both chambers, sensing both chambers, and responding in a triggered or inhibited mode. Pacemakers have become sophisticated, often expensive devices. Some pacemakers are responsive to or activated by blood temperature, respiratory rate, Q-T interval, body vibrations, and pH levels. The device that is responsive to body vibrations sells for about
$5,000.5 Pacemakers that are physiologically activated are still in relatively experimental or trial stages.
Perioperative Care
P
atient education and adjustment is a major concern for the pacemaker implant patient. The physician tells the patient that the pacemaker is implanted to augment the heart’s conduction system and that it is there to help the heart beat properly. The physician’s explanations may then be reinforced by the nurse. Every effort should be made to relate the pacemaker’s function in a fashion that is most comprehensive and comfortable for the patient. This could be in the form of an interview, a discussion, or a structured lesson plan. At this time the patient might be shown a pacemaker model and/or leads 261
JANUARY 1989. VOL 49. NO 1
Pacemaker Generator Identification Code Letter one-chamber paced A-atrium V-ventricle D-dual chamber Letter two-chamber sensed A-atrium V-ventricle D-dual chamber Letter three-response mode T-triggered response I-inhibited response 0-no response D-dual R-reverse Letter four-programmable functions P-programmable (rate and/or output only) M-multiprogrammable C-communicating (noninvasive program) 0-nonprogrammable Letter five-tachyarrhythmia function B-bursts N-normal rate competition (more thadless than drive pacing) S-scanning E-external of the type that will be used for his or her implant. After the procedure is thoroughly discussed with the patient, he or she signs an informed consent that authorizes the pacemaker implant procedure. The patient has the preliminary laboratory work completed, including a complete blood count, electrolytes, chemistry level, and electrocardiogram (ECG). The patient is usually admitted to the intensive care unit (ICU) preoperatively in case he or she requires an emergency temporary pacemaker. Zntraoperative care. Pacemakers are usually implanted in the OR using sterile technique and direct x-ray visualization. All personnel should wear radiation exposure monitor badges during the procedure. Instrumentation includes pacemaker test equipment, lead introducer sets, a minor instrument set. and vascular instruments.
AORN JOURNAL
After the patient is transferred from the ICU to the OR, the circulating nurse verifies the consent and checks the chart for completion. The nurse reassures the patient and reviews the procedures that will be done for him or her in the OR. This will help minimize the patient’s anxiety and discomfort. Because most implants are done under local anesthesia, the patient is often cognizant of his or her surroundings. This is an opportunity for the nurse to establish a rapport that will enhance the patient’s surgical experience. The nurse assists the patient onto the OR bed, and the anesthesiologist attaches the ECG monitoring pads and inserts an intravenous line. Often a light sedative agent such as diazapam or fentanyl is administered to decrease patient anxiety. The circulating nurse pads and tucks the arms and places a headrest under the patient’s head. The circulating nurse preps the patient from mandible to nipple line with povidone-iodine or other suitable antimicrobial agents, and the surgeon places an iodophor-impregnated drape along with other sterile drapes over the prepped area. The surgeon then administers a local anesthetic such as 1%lidocaine and implants the pacing leads via the subclavian vein. He or she verifies lead placement radiologically and functionally by testing sensing, capture, and impedance with the pacemaker representative as a technical advisor. The surgeon then secures the lead with either a suture ligature or a tie at the entry site and attaches it to the generator. After testing the pacemaker generator functions, the surgeon makes a subcutaneous pocket to place it in. Pocket sites may be in any of several locations. The most frequently used location is the pectoral pocket site (Fig 4). The parameters are checked by the surgeon and pacemaker representative, and a printout record is made. The surgeon then closes the wound, and the nurse applies a dressing over the operative site. The nurse documents the implant procedure on the OR record and assists in transferring the patient back to the ICU, where the patient is observed for 24 to 48 hours. This is the critical time for possible lead displacement. Postoperative care. The patient will need to 263
JANUARY 1989, VOL. 49, NO I
AORN JOURNAL
right deltopectoral groove
w
- --
deltopectoral groove
pocket site
Fig 4. Pacemaker implant pocket sites may be in any of several locations. The most frequently used l a tion is the pectoral pocket site. (Adaptedfrom Troubleshooting Pacing Problems: A Comprehensive Reference for Medical Professionals (1980), with permissionfrom Cardiec Pacemakers, Inc, St Paul) know how, when, and why the pacemaker must be checked after it is implanted. The nurse must teach the patient how to check his or her pulse. The patient should do this daily or have it done by a significant other in the event the patient is physiologically or psychologically unable to do so. Patients also need to know about the possibility of pacemaker pocket infection and the signs they should look for (eg, swelling, redness, soreness, or drainage at the incision site). In addition, the nurse should alert the patient to symptoms that could indicate a pacemaker dysfunction (ie, dizziness, weakness, syncope) and when to seek immediate help. Before discharge, the nurse also tells the patient about local pacemaker clubs where he or she can interact with others with similar experiences. Patients are usually in the hospital for two to five days depending on their condition. Within a lO-day period, patients are reevaluated by their cardiologist. Follow-up is often on a weekly basis for a month, then biweekly for a month, and monthly thereafter. Evaluation may include a physical examination, review of history and symptoms, chest x-ray, and an ECG. Another form of evaluation used today is telephonic monitoring. Using a bracelet monitor 264
or a Holter-type device, the activity of the heart and pacemaker are picked up and transmitted in the form of a single-lead ECG. This is another instance in which the patient needs instructions and education. As the patient’s pacemaker nears the end of its projected life span, the patient will again need to be closely monitored (ie, weekly). The telephonic device greatly facilitates patient monitoring.
Complications
P
acemaker insertion complications are usually in one of the following categories: thrombosis and/or embolism, infection, pacemaker-induced arrhythmias, myocardial perforation, or cardiac tamponade. Inclusive of these complications are those associated with permanent pacemakers. Early complications include: hematoma, infection, electrode displacement (perforation), cardiac tamponade, loss of sensing or pacing (without electrode displacement), improper lead-generator connection,
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generator malfunction, and/or inappropriate response to programming. Late complications of pacemaker insertions include: a recurrent symptoms, a electrode fracture (wire or insulation), a electrode displacement (perforation), a infection, 8 deep venous thrombosis, a extrusion (Twiddler’s syndrome), a runaways, a premature generator failure, 0 pacemaker-related tachycardias (endless loop), a myoinhibition, a chest-wall or diaphragmatic pacing, and a external interference. A possible complication in pacemaker implant procedures can result from the use of the electrocautery unit. Many surgeons will not use an electrocautery unit during implantation, or they will use it only to effect hemostasis before implementation. For those patients coming to the OR that already have a pacemaker implanted, the following guidelines are recommended? The dispersive pad should be located as far from the generator as possible and should not be located between the active electrode and the generator. Current settings should be set as low as possible, and short bursts should be used to cauterize bleeding. The cautery tip should not be used within 15 cm (6 inches) of the pacemaker, especially with an unipolar unit, because of possible ventricular fibrillation. In addition, the dispersive pad draws current away from the pacemaker if the intersection of the current to the lead is perpendicular (ie, meets at right angles).
Effects of Medication and Electro&tes
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erioperatively, the nurse should review the patient record for medications that may affect the patient’s physiology and make appropriate interventions. The nurse should also be alert for laboratory values that might affect the cardiac response. There are several medications that can have 266
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a deleterious effect on the function of the heart, especially when they exceed therapeutic levels.’ These medications may either mask or cause signs or symptoms that represent a deterioration in the patient’s condition. Examples are: narcotics that lower blood pressure and depress cardiovascular functions (eg, meperidine, morphine sulfate), beta blockers that reduce beta-receptor activity (eg, propranolol, atenolol), calcium-channel blockers that compete for calcium (eg, Procardias, verapamil), glycosides and antiarrhythmics that may block or prolong conduction when given in excess (eg, digoxin, quinidine, Isuprels, procainamide), diuretics that reduce or concentrate serum electrolytes (eg, furosemide, Aldactones), and psychotropic drugs that mask symptoms, potentiate narcotics, or lower blood pressure (eg, phenothiazines, chlorpromazines). Medical therapy for the cardiac patient can be very interdependent, depending on the medication and on the patient’s physiological responses to the medications. In addition, serum electrolytes, especially potassium, calcium, or magnesium, in excess of or less than accepted normals may cause slowing or speeding of the patient’s heart rate.8 This information is meant as a guidepost for medical therapy in the cardiac patient. A simple rule of thumb is that the more medication the patient takes, the greater the possibility that the patient will have a detrimental chemistry or dosage 0 alteration if not carefully monitored. Notes 1. P Varriale, E Naclerio, eds, Cardiac Pacing: A Concke Guide to Clinical F’ractice (Philadelphia: Lea and Febiger, 1979) 83-96; P Kowery, D Mullan, L Wetstein, “Pacemaker therapy,” in Surgical Clinics of North America 65 (June 1985) 596; R Medina, E Michelson, “Update on cardiac pacemakers: Description, complications, indications, and follow up,” Cardiovascular Clinics 16 (1985) 199; J Zaidan, “Pacemakers,” Anesthesiofogy 60 (April 1984) 3 19334; M ONeill, D Davis, “Pacemakers in noncardiac surgery,” in Surgical Clinics of North America 63 (October 1983) 1103.
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2. O’Neill, Davis, “Pacemakers in noncardiac surgery,” 1 108; Varriale, Naclerio, eds, Cardiac Pacing: A Concde Guide to Clinical Practice, 135; Cardiac Pacemakers, Inc, TroubleshootingPacing Problems: A ComprehensiveReferencefor Medical Professionals (St Paul Cardiac Pacemakers, Inc, 1980) 1; C Hudak, B Gallo, T Lohr, Critical Care Nursing: A HolLvtic Approach, fourth ed (Philadelphia: J B Lippincott Co, 1986) 85. 3. Kowery, Mullan, Wetstein, “Pacemaker therapy,” 603; Medina, Michelson, “Update on cardiac pacemakers: Description, complications, indications, and followup,” 194, 198; B Phibbs, H Marriott, “Complications of permanent transvenouspacing,” New England Journal of Medicine 312 (May 1985) 1428-1432; Cardiac Pacemakers, Inc, Troubleshooting Pacing Problems, 8. 4. P Ludmer, N Goldschlager, “Cardiac pacing in the 198Os,” New England Journal of Medicine 31 1 (December 1984) 1674. 5. N Fearnot, H Smith, “Trends in pacemakers which physiologically increase rate: DDD and rate respon-
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sive,” Pacing and Clinical Electrophysiologv (PACE) 9 (November 1986) 939-947; D Bolthaus, “Pacemaker adjusts heart rate for exercise,” Hospitals 61 (Sept 20, 1987) 78. 6. Zaidan, “Pacemakers,” 325; Ludmer, Goldschlager, “Cardiac pacing in the 1980s,” 1673; ONeill, Davis, “Pacemakers in noncardiac surgery,” 1105-1107; A Simon, “Perioperative management of the pacemaker patient,” Anesthesiologv 46 (February 1977) 127-131. 7. Kowery, Mullan, Wetstein, “Pacemaker therapy,” 599; Hudak, Gallo, Lohr, Critical Care Nursing, 161167; L Weeks, Advanced Cardiovascular Nursing (Boston: Blackwell Scientific Publications, 1986) 91103, 743-767; Phibbs, Marriot, “Complications of permanent transvenous pacing,” 1431; M Goldin, Intensive Care of the Surgical Patient, second ed (Chicago: Year Book Medical Publishers, Inc, 1981) 326-347; Varriale, Naclerio, Cardiac Pacing, 67, 80. 8. Varriale, Naclerio, Cardiac Pacing, 67; Kowery, Mullan, Wetstein, “Pacemaker therapy,” 599; Weeks, Advanced Cardiovascular Nursing 43, 87-91,475.