Apr 25, 2007

Effects of an impedance threshold device on hemodynamics and restoration of spontaneous circulation in prolonged porcine ventricular fibrillation

Prehospital Emergency Care : Official Journal of the National Association of EMS Physicians and the National Association of State EMS Directors
James J MenegazziTimothy J Mader


An impedance threshold device (ITD) has been designed to enhance circulation during CPR by creating a negative intrathoracic pressure during the relaxation phase of chest compression. We sought to determine the effects of the ITD on coronary perfusion pressure (CPP), return of spontaneous circulation (ROSC), and short-term survival (20 minutes after ROSC). We hypothesized that the ITD would improve all 3 variables when compared to standard CPR. Using a case-control design nested within a randomized primary study, we compared CPR with the ITD (ITD-CPR) to standard CPR without the device (S-CPR). We systematically assigned 36 domestic swine, weighing 23-29 kg, (18 per group) to resuscitation with either ITD-CPR or S-CPR after 8 minutes of untreated ventricular fibrillation (VF). At minute 8, mechanical chest compression and ventilation began, and drugs (0.1 mg/kg epinephrine, 40U vasopressin, 1.0 mg propranolol, 1 mEq/kg sodium bicarbonate) were given. The first rescue shock (150J biphasic) was delivered at minute 11 of VF. We recorded CPP, ROSC (systolic pressure > 80 mmHg sustained for 60 s continuously), and survival. Data were analyzed with Fisher's exact test and generalized estimating equations (GEE), with alpha = 0.05. We ...Continue Reading

Mentioned in this Paper

Coronary Circulation
Ventricular Fibrillation
Electric Impedance
Antidiuretic Hormone Measurement
Weighing Patient
Circulatory Process
Basic Cardiac Life Support
Regional Blood Flow
Sodium Bicarbonate
Anterior Thoracic Region

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