Biomaterial Database

Influence of ventilation phase on transthoracic impedance and defibrillation effectiveness. 1980

G A Ewy, and D A Hellman, and S McClung, and D Taren

The influence of the phase of ventilation on the transthoracic impedance and defibrillation success was studied in 6 mongrel dogs. Ventricular fibrillation was induced by a transvenous bipolar catheter electrode. Defibrillation was attempted after 1 min of ventricular fibrillation. The initial stored energy levels were 20 watt-sec for the 1st two shocks, one delivered in inspiration and one in expiration. If the shock at the initial energy level was not successful, the energy level was increased by 10 watt-sec before the next energy level shock. Initial discharge was given at inspiration in half of the animals and at expiration in the other half. The transthoracic impedance to defibrillator discharge was measured with each shock. The study revealed a significantly higher transthoracic impedance with inspiration (76.3 +/- 13 ohms versus 68.4 +/- 12 ohms expiration, p less than 0.01), and a significant decrease in defibrillation success rate when shocks were delivered in inspiration (10%) compared to expiration (50%). The phase of ventilation is an important determinant of transthoracic impedance to defibrillator discharge and has a significant influence on defibrillation effectiveness.

UI	MeSH Term	Description	Entries
D010992	Plethysmography, Impedance	Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)	Rheography,Impedance Plethysmography,Impedance Plethysmographies,Plethysmographies, Impedance,Rheographies
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D002307	Cardiography, Impedance	A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.	Impedance, Transthoracic,Plethysmography, Impedance, Transthoracic,Impedance Cardiography,Impedance Plethysmography, Transthoracic,Plethysmography, Transthoracic Impedance,Transthoracic Impedance Plethysmography,Cardiographies, Impedance,Impedance Cardiographies,Impedance Plethysmographies, Transthoracic,Impedances, Transthoracic,Plethysmographies, Transthoracic Impedance,Transthoracic Impedance,Transthoracic Impedance Plethysmographies,Transthoracic Impedances
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004554	Electric Countershock	An electrical current applied to the HEART to terminate a CARDIAC ARRHYTHMIA.	Cardiac Electroversion,Cardioversion,Defibrillation, Electric,Electroversion, Cardiac,Electrical Cardioversion,Electroversion Therapy,Therapy, Electroversion,Cardiac Electroversions,Cardioversion, Electrical,Cardioversions,Cardioversions, Electrical,Countershock, Electric,Countershocks, Electric,Defibrillations, Electric,Electric Countershocks,Electric Defibrillation,Electric Defibrillations,Electrical Cardioversions,Electroversion Therapies,Electroversions, Cardiac,Therapies, Electroversion
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D006323	Heart Arrest	Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.	Asystole,Cardiac Arrest,Cardiopulmonary Arrest,Arrest, Cardiac,Arrest, Cardiopulmonary,Arrest, Heart,Asystoles
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia