Defibrillator works as follows
Cardiac defibrillation reset when the role of the heart is a transient high-energy pulse is generally 4 ~ 10ms in duration, the electrical energy in the 40 ~ 400J (Joule). The device used to defibrillate the heart is called a defibrillator, which can complete the electrical shock resuscitation, i.e. defibrillation. It is used when a patient has a severe tachyarrhythmia, such as atrial flutter, atrial fibrillation, supraventricular or ventricular tachycardia.
These often result in varying degrees of hemodynamic impairment. Especially when the patient has ventricular fibrillation, due to the ventricle has no overall contraction ability, the heart ejection and blood circulation termination, if not timely rescue, often cause the patient due to the brain hypoxia time is too long and death. If a defibrillator is used, it can eliminate certain arrhythmias by controlling a certain amount of energy current through the heart.
Can restore the heart rhythm to normal, thus enabling patients with the above heart diseases to be rescued and treated . The original defibrillator was a direct defibrillator utilizing industrial alternating current (AC), which often resulted in death or injury due to electrocution, so now, in addition to AC defibrillation (ventricular defibrillation) during cardiac surgery, direct current defibrillation is generally used.
The defibrillator is mainly composed of a monitoring part, an electrical cardioversion machine, electrode plates, batteries and other parts. Electric cardioversion machine, also known as defibrillator, is the main equipment for the implementation of electric cardioversion. Equipped with electrode plates, most of them have two pairs of size, large for adults, small for children.
Extended information:
Cautions
Energy is required for defibrillation, and the appropriate energy is selected to generate sufficient current through the myocardium during defibrillation. If the energy and current are too low, the shock will not terminate the arrhythmia. If the energy and current are too high, functional and morphological damage can result. In adults there is no clear relationship between body size and the energy required for defibrillation, and transthoracic impedance does not play an important role.
The recommended energy for the first defibrillation is 200 J, and the energy level for the second shock should be 200-300 J. Any energy given is likely to achieve defibrillation, so an energy range of 50-360 J can be specified, and because transthoracic impedance decreases with repeated shocks, subsequent shocks, even if they are of the same energy, will produce a higher current.
For this reason, if the first shock fails to terminate ventricular fibrillation, it is best to repeat the second shock with the same energy as the first. If the first two shocks fail to defibrillate, a third shock of 360 J should be given immediately. If VF is terminated by the shock but recurs thereafter, the shock should be repeated with the same level of energy as was given for the previous successful defibrillation.
Baidu Encyclopedia-Defibrillator