|
...atrioventricular the setting of inferior wall myocardial infarction, or when transvenous pacing is not immediately available or carries a high risk of complications. Most patients with minimal hemodynamic compromise require a current of 40 to 80 mA; pacing thresholds tend to be higher in patients who have emphysema or pericardial effusion and in those who receive positive pressure ventilation. On electrocardiography, successful capture usually is characterized by a widened ORS complex, followed by a distinct ST segment and broad T wave. The hemodynamic response to pacing also must be confirmed by assessing the patient's arterial pulse. Proper skin preparation and electrode positioning ensure successful capture in most si tuations. Adequate sedation and analgesia are essential in ensuring patient comfort. (J Crit Illness. 2003; 18(5):219-225)
**********
Transcutaneous pacing was first introduced by Zoll and associatses (1) in 1956 as a novel method of treating asystole and significant bradyarrhythmias. However, the high current densities that the skin electrodes required to pace the cardiac tissue in those early devices caused painful stimulation of the cutaneous nerves and underlying skeletal muscles.
With the development of transvenous pacing leads later in the 1950s, interest in external pacing waned. Transvenous pacing has served as the mainstay of urgent temporary pacing since then, although the significant time and operator skill needed to implement the technique are less than ideal. As a result, noninvasive pacing reemerged, in the 1980s, as a therapy for bradycardia and asystole. (2,3) Technical advances, including large adhesive electrodes and EGG filtering, have largely overcome the early problems of extreme discomfort and interpretation of capture on the ECG.
External noninvasive pacing offers several advantages over invasive pacing. It is widely available on most crash carts, along with defibrillator units. It is easy to perform and requires minimal training and, therefore, may be instituted by physicians, nurses, and paramedics. Because it can be performed quickly, noninvasive pacing can be initiated almost immediately, eliminating the setup and the insertion time of invasive techniques (transvenous and epicardial pacing). Noninvasive pacing carries a much smaller risk of serious complications compared with invasive techniques, and it is more cost-effective.
In this article, we will review the indications and techniques for transcutaneous pacing and how to avoid complications.
INDICATIONS
Transcutaneous cardiac pacing is a temporary method of pacing indicated in various clinical settings, including some cardiac emergencies. In general, external pacing is indicated as a temporary method of pacing in patients with severe symptomatic or hemodynamically unstable bradyarrhythmias, particularly in those who do not respond to pharmacologic therapy (such as atropine).
It is particularly helpful in reversible or transient conditions (such as digoxin toxicity and atrioventricular [AV] block in the setting of inferior wall myocardial infarction [MI]) or when transvenous pacing is not immediately available or carries a high risk of complications. (4-8) It is often used as a bridge to temporary transvenous pacing or to a permanent pacemaker, and it should not be relied on if temporary pacing is required for a prolonged period.
The hemodynamically significant bradyarrhythmias that often require temporary pacing include various types of acquired AV block, sinus node dysfunction, and symptomatic bifascicular block (Table 1). In addition, transcutaneous pacing has been used in patients with asystolic cardiac arrest (asystole). (9-12)
However, in randomized clinical trials, patients with out-of-hospital asystolic cardiac arrest in whom early external pacing was established by paramedics had no significant improvement in survival, compared with controls, despite modest initial success in achieving pacing. (13-17)
Similar results were found using transcutaneous pacing in patients with in-hospital asystolic cardiac arrest, (18) as well as in patients arriving at the emergency department with asystolic arrest. (19) Pacing is not routinely recommended in such patients, in view...
NOTE: All illustrations and photos
have been removed from this article.
More articles from The Journal of Critical Illness
Finding the key lung function parameters in primary pulmonary hyperten..., May 01, 2003
Comparing percutaneous and surgical tracheotomies. (Pulmonary Corner)...., May 01, 2003
Evaluating and managing GI bleeding in the elderly: atypical presentat..., May 01, 2003
Looking for additional articles?
Search our database of over 3 million articles.
Looking for more in-depth information on this industry?
Search our complete database of Industry & Market reports by text, subject, publication
name or publication date.
About Goliath
Whether you're looking for sales prospects, competitive information, company
analysis or best practices in managing your organization,
Goliath can help you meet your business needs.
Our extensive business information databases empower business
professionals with both the breadth and depth of credible,
authoritative information they need to support their business
goals. Whether it be strategic planning, sales prospecting,
company research or defining management best practices -
Goliath is your leading source for accurate information.
|
