Swine Model Of Ventricular Fibrillation Research Articles

A comparison of etanercept vs. infliximab for the treatment of post-arrest myocardial dysfunction in a swine model of ventricular fibrillation

AimsTo compare the effects of two TNF-α antagonists, etanercept and infliximab, on post-cardiac arrest hemodynamics and global left ventricular function (LV) in a swine model following ventricular fibrillation (VF). MethodsDomestic swine (n=30) were placed under general anesthesia and instrumented before VF was induced electrically. After 7min of VF, standard ACLS resuscitation was performed. Animals achieving return of spontaneous circulation (ROSC) were randomized to immediately receive infliximab (5mg/kg, n=10) or etanercept (0.3mg/kg [4mg/m2], n=10) or vehicle (250mL normal saline [NS], n=10) and LV function and hemodynamics were monitored for 3h. ResultsFollowing ROSC, mean arterial pressure (MAP), stroke work (SW), and LV dP/dt fell from pre-arrest values in all groups. However, at the 30min nadir, infliximab-treated animals had higher MAP than either the NS group (difference 14.4mmHg, 95% confidence interval [CI] 4.2–24.7) or the etanercept group (19.2mmHg, 95% CI 9.0–29.5), higher SW than the NS group (10.3 gm-m, 95% CI 5.1–15.5) or the etanercept group (8.9gm-m, 95% CI 4.0–14.4) and greater LV dP/dt than the NS group (282.9mmHg/s, 95% CI 169.6–386.1 higher with infliximab) or the etanercep group (228.9mmHg/s, 95% CI 115.6–342.2 higher with infliximab). ConclusionsOnly infliximab demonstrated a beneficial effect on post cardiac arrest hemodynamics and LV function in this swine model. Etanercept was no better in this regard than saline.

Abstract 80: Infliximab Is Superior to Etanercept for the Treatment of Postresuscitation Myocardial Dysfunction in a Swine Model of Ventricular Fibrillation

Introduction: Infliximab, a monoclonal antibody directed against the inflammatory cytokine TNF-α, has been shown to attenuate the myocardial dysfunction and hemodynamic decompensation associated with post-cardiac arrest syndrome. The aim of this study was to compare the effects of etanercept, a TNF-α receptor antagonist, to infliximab in a swine model of ventricular fibrillation (VF). Methods: Under general anesthesia, VF was induced electrically in domestic swine (n=30). After 7 minutes of VF, standard ACLS resuscitation was performed. Animals achieving return of spontaneous circulation (ROSC) were randomized to immediately receive infliximab (5 mg/kg, n=10) or etanercept (0.3 mg/kg [4 mg/m2], n=10) or vehicle (250 mL normal saline [NS], n=10) and LV function and hemodynamics were monitored for 3 hours. Results: Following ROSC, mean arterial pressure (MAP), stroke work (SW), and LV dP/dt fell from prearrest values in all groups. However, at the 30 minute nadir, infliximab-treated animals had higher MAP than either the NS group (difference 14.4 mm Hg, 95% confidence interval [CI] 4.2-24.7) or the etanercept group (19.2 mm Hg, 95% CI 9.0-29.5), higher SW than the NS group (10.3 gm-m, 95% CI 5.1-15.5, Figure) or the etanercept group (8.9 gm-m, 95% CI 4.0-14.4) and greater LV dP/dt than the NS group (282.9 mm Hg/sec, 95% CI 169.6-386.1) or the etanercep group (228.9 mm Hg/sec, 95% CI 115.6-342.2). Conclusions: In conclusion, only infliximab demonstrated a beneficial effect on post cardiac arrest hemodynamics and LV function in this swine model. Etanercept was no better in this regard than saline.

The effects of 3 different compression methods on intrathoracic pressure in a swine model of ventricular fibrillation

ObjectiveThe aim of this study was to provide a realistic comparison of 3 different extracorporeal compression methods during cardiopulmonary resuscitation on intrathoracic pressure (ITP), hemodynamics, and oxygen metabolism in a swine model of ventricular fibrillation (VF). MethodsEight minutes after the development of VF, pigs were subjected to 3 different extracorporeal compression methods: traditional artificial manual compression, mechanical compression using an AutoPulse apparatus, or manual sucker. Heart rhythm was assessed by electrocardiography after 5 cycles of extracorporeal compression. If VF still occurred, electrical defibrillation was performed. After defibrillation, an additional 5 cycles of extracorporeal compression were performed. Resuscitation was considered to have failed if the above procedure was continued for 30 minutes without return of spontaneous circulation. Hemodynamics and ITP waveforms were monitored continuously. Oxygen metabolism indices were measured, and success rates were compared among the groups. ResultsManual compression showed advantages over both of the other methods in terms of maximal ITP and fluctuation amplitude, hemodynamic and oxygen dynamic changes, convenience of administration, and duration of treatment. Survival rates and cerebral performance category scores for the manual compression group were significantly higher than that for the other groups. ConclusionsMechanical compression cannot replace traditional artificial manual compression, which remains the preferred method for cardiopulmonary resuscitation.

The hemodynamic influence of rhythmic abdominal lifting and compression during cardiopulmonary resuscitation in a swine model of ventricular fibrillation

ObjectiveThis study was designed to compare the hemodynamic influences of standard external cardiopulmonary resuscitation (STD-CPR) and rhythmic abdominal lifting and compression during cardiopulmonary resuscitation (CPR) in a swine model of...

A comparison of autopsy detected injuries in a porcine model of cardiac arrest treated with either manual or mechanical chest compressions

The objective of this study was to evaluate and compare the complications of cardiopulmonary resuscitation after manual or mechanical chest compressions in a swine model of ventricular fibrillation. In this retrospective study, 106 swine were treated with either manual (n=53) or mechanical chest compressions with the LUCAS device (n=53). All swine cadavers underwent necropsy. The animals with no autopsy findings were significantly fewer in the LUCAS group (P=0.004). Sternal fractures were identified in 18 animals in the manual and only two in the LUCAS group (P=0.003). Rib fractures were present in 16 animals in the manual and only four in the LUCAS group (P=0.001). Nine animals in the manual, and two in the LUCAS group had liver hematomas (P=0.026%). In the manual group, eight animals were detected with spleen hematomas whereas no such injury was identified in the LUCAS group (P=0.003). LUCAS devise minimized the resuscitation-related trauma compared with manual chest compressions in a swine model of cardiac arrest.

Atenolol in combination with epinephrine improves the initial outcome of cardiopulmonary resuscitation in a swine model of ventricular fibrillation

Study Objectives The aim of the present study was to assess whether a β-adrenergic blocking agent such as atenolol, administered during cardiopulmonary resuscitation, would improve initial resuscitation success. Methods Ventricular fibrillation was induced in 20 Landrace/Large White piglets, which were left untreated for 8 minutes before attempted resuscitation with precordial compression, mechanical ventilation, and electrical defibrillation. Animals were randomized into 2 groups (10 animals each) to receive saline as placebo (20 mL dilution, bolus) + epinephrine (0.02 mg/kg) (group A) or atenolol (0.05 mg/kg per 20 mL dilution, bolus) + epinephrine (0.02 mg/kg) (group B) during cardiopulmonary resuscitation. Electrical defibrillation was attempted after 10 minutes of ventricular fibrillation. Results Nine animals in group B restored spontaneous circulation in comparison to only 4 in group A. Aortic systolic and diastolic pressures as well as coronary perfusion pressure were significantly increased during cardiopulmonary resuscitation in group B. Furthermore, postresuscitation heart rate of the atenolol-treated group was significantly decreased. Conclusions A β-adrenergic blocking agent, when administered during cardiopulmonary resuscitation, significantly improves initial resuscitation success and increases blood and coronary perfusion pressures during cardiopulmonary resuscitation.

Abstract 41: Early Post-Resuscitation Levels of Cytochrome- c and Interleukin-6 after Prolonged Porcine Cardiac Arrest

Background: The identification of serum biomarkers of ischemic injury could provide a means of assessing interventions designed to limit reperfusion injury after return of spontaneous circulation (ROSC). We sought to characterize the early post-ROSC timecourse of two candidate biomarkers of ischemic injury (cytochrome- c and IL-6) in a swine model of ventricular fibrillation (VF). We hypothesized that these two biomarkers would be elevated immediately after ROSC. Methods: Twenty-five mixed breed domestic swine were anesthetized and instrumented with ECG, temperature probe, and aortic and right atrial pressure transducers. VF was induced with a transthoracic shock and untreated for 8 minutes. Then mechanical CPR was done for 2 minutes, before drugs were given (epinephrine, vasopressin, and propranolol) with 3 additional minutes of CPR (first defibrillation attempt at 13 minutes of VF). Blood samples were drawn at the end of instrumentation (i.e. just prior to VF), and at 20, 40, and 60 minutes after ROSC. Samples were centrifuged and serum extracted. Cytochrome- c was analyzed via Western immunoblotting. IL-6 was analyzed with ELISA. Results: No cytochrome- c was detected in any animal, at any timepoint through 60 min. IL-6 was similar to baseline levels through 40 min, but was 121% of baseline at 60. Conclusions: Neither biomarker was elevated immediately after ROSC. Mitochondrial damage (as indicated by the absence of cytochrome- c ) may be delayed by as much as an hour after ROSC, hinting at a possible therapeutic window for interventions like hypothermia. Likewise, inflammatory cascades (as indicated by IL-6) may not begin immediately post-ROSC, but might by one hour.

Pressure-synchronized cineangiography during experimental cardiopulmonary resuscitation.

Pressure-synchronized cineangiography during experimental cardiopulmonary resuscitation.