Effects of Active Compression-Decompression Cardiopulmonary Resuscitation with the Inspiratory Threshold Valve in a Young Porcine Model of Cardiac Arrest

Abstract

Active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with the inspiratory threshold valve (ITV) has been recently recommended by the American Heart Association for treatment of adults in cardiac arrest (class IIb: alternative, useful intervention), but this new technique has never been used in a pediatric population. Thus, this study was designed to evaluate ACD ϩ ITV CPR in a young porcine model of cardiac arrest. After 10 min of ventricular fibrillation, and 8 min of standard CPR, ACD ϩ ITV CPR was performed in seven 4-to 6-wk-old pigs (8 -12 kg); defibrillation was attempted 8 min later. Within 2 min after initiation of ACD ϩ ITV CPR, mean (Ϯ SEM) coronary perfusion pressure increased from 18 Ϯ 2 to 24 Ϯ 3 mm Hg (p ϭ 0.018). During standard versus ACD ϩ ITV CPR, mean left ventricular myocardial and total cerebral blood flow was 59 Ϯ 21 versus 126 Ϯ 32 mL·min Ϫ1 ·100 g Ϫ1 , and 36 Ϯ 7 versus 60 Ϯ 15 mL· min Ϫ1 ·100 g Ϫ1 , respectively (p ϭ 0.028). Six of seven animals were successfully defibrillated, and survived Ͼ15 min. In conclusion, the combination of ACD ϩ ITV CPR significantly increased both coronary perfusion pressure and vital organ blood flow after prolonged standard CPR in this young porcine model of ventricular fibrillation. Pediatric cardiopulmonary arrest has a very poor prognosis, and survival rates range only from 2 to 17% (1, 2). Moreover, survivors often remain neurologically disabled (1). Inasmuch as current basic and ACLS methods often fail to restore cardiac function and preserve brain function, new alternative circulation methods merit evaluation in children. In this regard, the American Heart Association and European Resuscitation Council Guidelines emphasize the need for better data regarding epidemiology and treatment of pediatric cardiopulmonary arrest (3, 4).Intermittent impedance to the inflow of respiratory gases during the decompression phase of CPR has recently been shown to enhance CPR efficacy (5). As such, using an ITV improved coronary perfusion pressure and myocardial blood flow in both standard (6) and ACD CPR in adult animal models (7). Furthermore, coronary perfusion pressure was significantly higher in patients receiving ACD CPR with the ITV when compared with ACD CPR alone (8). However, neither ACD CPR alone nor ACD ϩ ITV CPR has been studied in a pediatric population yet, and a suitable ACD device for infants is not currently available. Moreover, in infants undergoing CPR, acquisition of rapid vascular access is not a simple task, even for an experienced emergency physician, and i.v. administration of vasopressor drugs may therefore be delayed, or even impossible. Whereas standard chest compressions alone are often ineffective to ensure adequate vital organ blood flow, ABSTRACT523

Comparison of Standard Cardiopulmonary Resuscitation Versus the Combination of Active Compression-Decompression Cardiopulmonary Resuscitation and an Inspiratory Impedance Threshold Device for Out-of-Hospital Cardiac Arrest

“…Consistent with earlier animal and human studies, [1][2][3][4][5]11,12 the results from this first clinical comparison of S-CPR versus ACDϩITD CPR demonstrated that there was a significant improvement in ROSC and 1-and 24-hour survival rates for all patients in the new treatment group. The improvement in short-term survival was notable in patients with a witnessed arrest; however, the short-term impact on survival with ACDϩITD CPR was most striking in patients with VF who were not resuscitated by 3 sequential DC shocks before randomization.…”

“…This vacuum draws more venous blood back into the heart, resulting in increased cardiac preload, followed by improved cardiac output and vital organ perfusion. Building on recent animal and clinical studies, [1][2][3][4][5] this study compared survival rates after treatment with manual S-CPR versus ACDϩITD CPR in patients with out-ofhospital cardiac arrest.…”

Inspiratory resistance delays the reporting of symptoms with central hypovolemia: association with cerebral blood flow

“…The ITD was designed to create a greater reduction in intrathoracic pressure during inspiration, enhancing the natural vacuum within the chest (26,37). This vacuum promotes an increase in venous return, thereby increasing ventricular preload and subsequent cardiac output (Q) and arterial blood pressure (9,26).…”

Vital organ blood flow with the impedance threshold device

“…Voelckel et al (32) further demonstrated substantial benefit of the combination of the ITD and ACD CPR when compared with standard CPR in a pediatric model of cardiac arrest. Ventricular fibrillation (VF) was induced in 10-kg piglets.…”