Use of an inspiratory impedance valve improves neurologically intact survival in a porcine model of ventricular fibrillation.

Cardiac Arrhythmia Center, Department of Medicine, University of Minnesota, Minneapolis 55455, USA.
Circulation (Impact Factor: 14.95). 01/2002; 105(1):124-9.
Source: PubMed

ABSTRACT This study evaluated the potential for an inspiratory impedance threshold valve (ITV) to improve 24-hour survival and neurological function in a pig model of cardiac arrest.
Using a randomized, prospective, and blinded design, we compared the effects of a sham versus active ITV on 24-hour survival and neurological function. After 6 minutes of ventricular fibrillation (VF), followed by 6 minutes of cardiopulmonary resuscitation (CPR) with either a sham or an active valve, anesthetized pigs received 3 sequential 200-J shocks. If VF persisted, they received epinephrine (0.045 mg/kg), 90 seconds of CPR, and 3 more 200-J shocks. A total of 11 of 20 pigs (55%) in the sham versus 17 of 20 (85%) in the active valve group survived for 24 hours (P<0.05). Neurological scores were significantly higher with the active valve; the cerebral performance score (1=normal, 5=brain death) was 2.2+/-0.2 with the sham ITV versus 1.4+/-0.2 with the active valve (P<0.05). A total of 1 of 11 in the sham versus 12 of 17 in the active valve group had completely normal neurological function (P<0.05). Peak end-tidal CO2 (PETCO2) values were significantly higher with the active valve (20.4+/-1.0) than the sham (16.8+/-1.5) (P<0.05). PETCO2 >18 mm Hg correlated with increased survival (P<0.05).
Use of a functional ITV during standard CPR significantly improved 24-hour survival rates and neurological recovery. PETCO2 and systolic blood pressure were also significantly higher in the active valve group. These data support further evaluation of ITV during standard CPR.

  • Source
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: The purpose of this pilot clinical study was to determine if a novel chest compression device would improve hemodynamics when compared to manual chest compression during cardiopulmonary resuscitation (CPR) in humans. The device is an automated self-adjusting electromechanical chest compressor based on AutoPulse™ technology (Revivant Corporation) that uses a load distributing compression band (A-CPR) to compress the anterior chest. Methods: A total of 31 sequential subjects with in-hospital sudden cardiac arrest were screened with institutional review board approval. All subjects had received prior treatment for cardiac disease and most had co-morbidities. Subjects were included following 10 min of failed standard advanced life support (ALS) protocol. Fluid-filled catheters were advanced into the thoracic aorta and the right atrium and placement was confirmed by pressure waveforms and chest radiograph. The coronary perfusion pressure (CPP) was measured as the difference between the aortic and right atrial pressure during the chest compression’s decompressed state. Following 10 min of failed ALS and catheter placement, subjects received alternating manual and A-CPR chest compressions for 90 s each. Chest compressions were administered without ventilation pauses at 100 compressions/min for manual CPR and 60 compressions/min for A-CPR. All subjects were intubated and ventilated by bag-valve at 12 breaths/min between compressions. Epinephrine (adrenaline) (1 mg i.v. bolus) was given at the request of the attending physician at 3–5 min intervals. Usable pressure signals were present in 16 patients (68±6 years, 5 female), and data are reported from those patients only. A-CPR chest compressions increased peak aortic pressure when compared to manual chest compression (153±28 mmHg versus 115±42 mmHg, P<0.0001, mean±S.D.). Similarly, A-CPR increased peak right atrial pressure when compared to manual chest compression (129±32 mmHg versus 83±40 mmHg, P<0.0001). Furthermore, A-CPR increased CPP over manual chest compression (20±12 mmHg versus 15±11 mmHg, P<0.015). Manual chest compressions were of consistent high quality (51±20 kg) and in all cases met or exceeded American Heart Association guidelines for depth of compression. Conclusion: Previous research has shown that increased CPP is correlated to increased coronary blood flow and increased rates of restored native circulation from sudden cardiac arrest. The A-CPR system using AutoPulse technology demonstrated increased coronary perfusion pressure over manual chest compression during CPR in this terminally ill patient population.
    Resuscitation 05/2004; DOI:10.1016/S0300-9572(04)00048-6 · 3.96 Impact Factor

Full-text (2 Sources)

Available from
May 26, 2014