Abstract 2225: A Blinded, Randomized Controlled Evaluation Of An Impedance Threshold Device During Cardiopulmonary Resuscitation In Swine
Background: An impedance threshold device (ITD) has been designed to enhance circulation during CPR. A recent study suggests that the ITD does not improve hemodynamics and that it may worsen outcomes. We sought to determine, in a blinded fashion, the effect of the ITD on coronary perfusion pressure (CPP), passive ventilation (paO2 & paCO2), and return of spontaneous circulation (ROSC), in a porcine model of prolonged ventricular fibrillation (VF). We hypothesized that, when compared to sham, the active device would have no significant impact on these variables.
Methods: Thirty devices (15 active/15 sham) were purchased from the Resuscitation Outcomes Consortium. Thirty male Yorkshire swine were instrumented under anesthesia. VF was electrically induced. After 8” of untreated VF, baseline characteristics were documented and CPR was begun (chest compressions rate 100/minute and ventilations at a ratio of 30:2). The device used on a given animal (active or sham) was randomly assigned. After 3 cycles of basic CPR, a second ABG was drawn and a drug cocktail was given followed by 6 CPR cycles. We recorded CPP continuously. The first 150J rescue shock (RS) was delivered after 9 complete cycles (3 minutes) of CPR. A third ABG was drawn just prior to the first RS. ROSC was defined as systolic blood pressure >80 mmHg for >60s continuously. The randomization code was revealed once preliminary data analysis was completed. Group comparisons were assessed using descriptive statistics, Student’s t-test for continuous variables and Fisher’s Exact Test for dichotomous variables. Proportions with 95% confidence intervals were calculated for the rate of ROSC.
Results: Baseline characteristics between the two groups were the same. ROSC occurred in 14/15 animals in both active and sham. The table⇓ summarizes the results (mean) by group after each event/intervention (CPP in mmHg, paO2 & paCO2 in torr).
Conclusions: Use of the active device had no impact on CPP, paO2 & paCO2 or ROSC compared to sham.