动物造模,心搏骤停模型 z-bio 2023-10-16 788

　　1. Healthy mice, weighing 30-50g, regardless of gender.

　　2. Intraperitoneal injection of urethane (1g/kg) for general anesthesia, tracheotomy, and insertion of 18G cannula to connect the small animal ventilator. Separate and cut open the left common carotid artery, insert a 24G intravenous catheter pre filled with heparin sodium, and monitor arterial pressure through a pressure transducer. At the same time, standard limb lead electrocardiogram was recorded through subcutaneous needle electrodes in the limbs.

　　3. Transesophageal cardiac pacing induces ventricular fibrillation. The 4-pole 5F pacing electrode is inserted into the esophagus through the mouth for about 4cm, and the proximal end of the electrode is connected to the output end of the electrophysiological stimulation. Firstly, measure the ventricular pacing threshold (usually with a pacing voltage of 15-18V and a pulse width of 5-8 milliseconds), and the induced ventricular fibrillation voltage should be 3-5 V higher than the pacing threshold. Using continuous rapid pacing to induce ventricular fibrillation, the parameters are set to: voltage 20V, pulse width 10 milliseconds, and frequency 20Hz. After pacing for 90 seconds, pause and observe for 1-2 seconds. If the electrocardiogram shows that the ventricular fibrillation induced by pacing automatically reverts, immediately resume pacing for 30 seconds until the induced ventricular fibrillation persists, or there is no pulse electrical activity or a straight line (cardiac arrest), usually lasting for 90 to 180 seconds. Cardiopulmonary resuscitation was performed 4 minutes after the start of pacing stimulation. Mechanical ventilation was performed using a constant volume small animal ventilator with a ventilation frequency of 70 times/minute and a tidal volume of 4ml/kg. Extrathoracic cardiac compression was performed manually with a frequency of 200 times/minute. The pressing depth is 1/3 of the anterior and posterior diameter of the mouse chest. Continuous monitoring of electrocardiogram and blood pressure throughout the experiment. The criteria for inducing cardiac arrest are invasive blood pressure monitoring showing a mean arterial pressure of<10mmhg accompanied="" by="" the="" disappearance="" of="" normal="" arterial="" pulsatile="" and="" electrocardiogram="" showing="" ventricular="" fibrillation="" or="" no="" pulse="" electrical="" a="" straight="" standard="" for="" judging="" recovery="" autonomic="" circulation="" is="" presence="" supraventricular="" rhythms="" including="" junctional="" mean="" pressure="">20mmHg, lasting for more than 1 minute.