See also: [[Cardioversion]], [[ALS algorithm|ALS]], [[ICD]] See: [Hayes’ - Defibrillation](x-devonthink-item://97457CFF-6D8F-48B6-AB4E-5DF07F0A34C8) #incomplete Factoids: - optimal current is 30–40 amps (A).  - The current delivered at a fixed energy is ==inversely related to the transthoracic impedance==, so a standard energy dose of 200 J delivers about 30 A to the average patient. - Biphasic (bidirectional) truncated transthoracic shock defibrillators are effective at lower energies and result in fewer post-defibrillation ECG abnormalities ***Circmstances that may make pt refractory to defibrillation:*** - [[Hypothermia]] - prolonged resus or long no-flow time (no CPR) - volatile solvent toxicity - chronic amiodarone therapy (↑ energy requirement of AICD by ~60%) - phenytoin therapy