Ewy G A, Hellman D A, McClung S, Taren D
Crit Care Med. 1980 Mar;8(3):164-6. doi: 10.1097/00003246-198003000-00015.
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.
在6只杂种犬中研究了通气阶段对经胸阻抗和除颤成功率的影响。通过经静脉双极导管电极诱发心室颤动。心室颤动1分钟后尝试除颤。前两次电击的初始储能水平为20瓦秒，一次在吸气时发放，一次在呼气时发放。如果初始能量水平的电击未成功，则在下一次能量水平电击前将能量水平增加10瓦秒。一半动物在吸气时进行初始放电，另一半在呼气时进行初始放电。每次电击时测量经胸对除颤器放电的阻抗。该研究显示，吸气时经胸阻抗显著更高（吸气时为76.3±13欧姆，呼气时为68.4±12欧姆，p<0.01），与呼气时（50%）相比，吸气时发放电击的除颤成功率显著降低（10%）。通气阶段是经胸对除颤器放电阻抗的重要决定因素，对除颤效果有显著影响。
