FUNCTION TESTS FOR DEFIBRILLATORS, POWER MEASUREMENT AND SYNCHRONIZATION CHECKING
Due to advances in medical science at the turn of the 19th to the 20th century resulting in longer life expectancies, heart diseases became a serious health problem and the leading cause of death. Previously, people usually died of infectious diseases before they reached an age at which heart problems posed a real health threat. Around this time, Swiss researchers Jean-Louis Prévost and Frédéric Batelli made the paradoxical discovery that electric current could cause fibrillation of the ventricles and, more importantly, defibrillation when they experimented with a dog’s heart.
Figure 1: Defibrillator Training with a Manikin
A defibrillator is a medical device used for defibrillation and, under some circumstances, cardioversion. It’s capable of stopping cardiac arrhythmias such as ventricular fibrillation and ventricular flutter, as well as ventricular tachycardia, atrial fibrillation and atrial flutter by applying targeted electric shocks (cardioversion). Defibrillators are kept available in intensive care units, operating rooms, emergency rooms and ambulances. To an ever greater extent since the 1990s, automated external defibrillators have been made available in buildings open to the public such as train stations, airports, and other locations for use by laypersons.
A defibrillator improves the chances of successful cardiopulmonary resuscitation, but can’t replace it.
Today’s modern external defibrillators are rugged, portable and comprehensive medical devices used by emergency medical service personnel, which provide a complete life-saving solution. Defibrillator technologies provide essential emergency care for adults, children and infants. Higher-end, top-of-the-line defibrillators are available on the market with AED (automated external defibrillation), manual defibrillation, non-invasive transcutaneous stimulation and synchronized electrical cardioversion. Other optional enhancements include functions for monitoring vital signs.
TYPES OF DEFIBRILLATORS
- Automated External Defibrillators
- Implantable Cardioverter Defibrillators
- Defibrillator Vest
- Manual Defibrillators
Defibrillators play an important role in implementing the measures necessary for successful CPR (cardiopulmonary resuscitation). Thanks to technological advances, emergency responders are now able to provide solutions which reduce the number of potentially fatal cases. AEDs also improve recovery results for out-of-hospital cardiac arrest (OHCA), and can be found in many public places all over the world for use by laypersons.
High performance GOSSEN METRAWATT defibrillator test sets can accurately analyze energy levels ranging from 0 to 360 J for all monophasic, biphasic, standard and pulsating waveforms via a non-inductive, fixed 50 Ω load and can accommodate external variable loads if required.
E (energy in J), Vp (peak voltage in V), Ip (peak current in I), and t (pulse duration in ms) can all be indicated at the displays. No oscilloscope is required to view the captured waveforms.
Defibrillator cardiac synchronization timing can be measured in ms with the analyzers. The defibrillator synchronizes itself to the ECG’s R wave. Heart rate can be varied; timing of the synchronized R wave and the delivered energy pulse is measured.
Battery recovery recording is required by IEC 60601-2-4. The SECULIFE DF PRO is equipped with a stopwatch function for the determination of charging time duration, which is typically set to maximum charging. Charging time is measured from triggering of the charging cycle at the defibrillator through discharging of the energy via the analyzer’s load.
The instruments are capable of simulating cardiac arrhythmias via the test loads, thus making it possible for an AED to analyze and distinguish a shockable ECG from a nonshockable ECG; the AED discharges its energy accordingly via the test load.