Electrical Interventions in Cardiopulmonary Resuscitation: Defibrillation

In-Field Comparison between Fully Automatic and Semi-Automatic Defibrillators

The purpose of this clinical study was to compare the prehospital use of fully automatic defibrillators versus semi-automatic defibrillators.

Methods:

Fully and semi-automatic defibrillator use by EMTs in neighboring communities was compared.

Results:

Both programs had similar response times, age and gender distribution, proportion of witnessed arrests, and proportion of patients found initially with ventricular fibrillation (VF). The time-to-shock from proper lead placement was shorter when the fully automatic defibrillator was used (16.6 vs. 44.3 seconds; p<.001) and the survival to hospital discharge rate was greater (26% vs. 0%; p=.O4). The semi-automatic defibrillators were more sensitive in detecting VF than were the fully automatic devices.

Conclusions:

These data support the need for further comparison of the efficacy and effectiveness of semi- and fully automatic, external defibrillators.

Automatic external defibrillators

Early electrical therapy for patients with ventricular fibrillation and ventricular tachycardia can result in a significant increase of lives saved from sudden cardiac death. Rapid defibrillation has become a goal of prehospital and emergency department cardiac care, and the use of automatic external defibrillators can aid in reaching this objective. The history, mechanics, and implications of automatic external defibrillators are presented.

Prehospital countershock treatment of pediatric asystole

Prehospital care was retrospectively reviewed in 117 pulseless nonbreathing (PNB) pediatric patients (0 to 18 years of age) to determine the effects of immediate countershock treatment of asystole. Of 90 (77%) children with an initial rhythm of asystole, 49 (54%) received countershock treatment. Rhythm change occurred in ten (20%) of the asystolic children who received countershock treatment. Three of the countershocked asystolic children were successfully resuscitated, but none survived. Rhythm change occurred in nine (22%) of the asystolic children not countershocked. Six were successfully resuscitated, and one survived. The two groups (countershocked asystole v noncountershocked asystole) did not differ significantly in age, sex, witnessed arrest, witnessed arrest with bystander basic life support (BLS), prehospital endotracheal intubation, both intubation and vascular access success, or diagnosis. However, prehospital vascular access was successfully established in a significantly greater number of countershocked patients (P less than .05). The mean times to the scene, at the scene, and to the hospital for the countershocked v noncountershocked asystolic patients were 6.2, 23.8, and 6.1 v 5.9, 14.7 and 7.0 minutes. The mean time at the scene was significantly greater in the countershock group (P less than .001). The successful performance of prehospital endotracheal intubation was significantly associated with rhythm change (P less than .05). Patients age, witnessed arrest, witnessed arrest with bystander BLS, successful establishment of prehospital vascular access, diagnosis, and countershock treatment were not significantly associated with rhythm change. In conclusion, prehospital countershock treatment prolonged prehospital care time and was not associated with rhythm change in asystolic children. Therefore, prehospital countershock treatment of asystolic children is not recommended.

Cardiopulmonary resuscitation. A current perspective

Cardiopulmonary resuscitation is effective if established early and coupled with specific therapeutic interventions. Most cardiopulmonary arrest is due to ventricular fibrillation and early defibrillation offers the highest probability of success. External cardiac compression alone is inadequate to provide adequate perfusion to vital organs and, therefore, cannot sustain life unless coupled with advanced therapeutic interventions. Many new techniques for increasing flow have been developed, but have not been established clinically. The American Heart Association guidelines for CPR are still valid and are the basis for our current CPR. A practical perspective is presented whereby the therapeutic interventions are pursued systematically in an expeditious and coordinated fashion so that the key interventions are made within the first 10 to 15 minutes of the arrest.