Use of an Inspiratory Impedance Valve Improves Neurologically Intact Survival in a Porcine Model of Ventricular Fibrillation

Lurie, Keith G.; Zielinski, Todd; McKnite, Scott; Aufderheide, Tom P.; Voelckel, Wolfgang G.

doi:10.1161/hc0102.101391

Cited by 136 publications

(74 citation statements)

References 14 publications

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“…Nevertheless, 25-to 35-kg swine are the animal model of choice for cardiac arrest and CPR studies because of their similarity to adults in terms of chest wall size and configuration and coronary artery anatomy. 11,14,20,21,[27][28][29] In conclusion, this study demonstrates that both RV and LV volumes increase substantially during the first minutes of untreated VF in swine with closed chest and closed pericardium. The implications of these findings for resuscitation from VF deserve further investigation.…”

Section: Discussionmentioning

confidence: 59%

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

et al. 2005

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Section: Discussionmentioning

confidence: 59%

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

et al. 2005

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“…The ITD is a small, light-weight, disposable plastic valve that was recently developed for treatment of a number of different clinical conditions associated with significant life-threatening hypotension (24,26,32,33,38). The ITD includes a specially designed valve that closes when the pressure within the thorax is less than atmospheric pressure and a second valve (termed the safety check valve) that opens at a preset negative intrathoracic pressure.…”

Section: Methodsmentioning

confidence: 99%

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

Rickards

Ryan

Cooke

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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Rickards CA, Ryan KL, Cooke WH, Lurie KG, Convertino VA. Inspiratory resistance delays the reporting of symptoms with central hypovolemia: association with cerebral blood flow. Am J Physiol Regul Integr Comp Physiol 293: R243-R250, 2007. First published May 16, 2007; doi:10.1152/ajpregu.00087.2007.-We tested the hypothesis that breathing through an inspiratory threshold device (ITD) during progressive central hypovolemia would protect cerebral perfusion and attenuate the reporting of presyncopal symptoms. Eight human subjects were exposed to lower-body negative pressure (LBNP) until the presence of symptoms while breathing through either an active ITD (Ϫ7 cmH2O impedance) or a sham ITD (0 cmH2O). Cerebral blood flow velocity (CBFV) was measured continuously via transcranial Doppler and analyzed in both time and frequency domains. Subjects were asked to report any subjective presyncopal symptoms (e.g., dizziness, nausea) at the conclusion of each LBNP exposure. Symptoms were coincident with physiological evidence of cardiovascular collapse (e.g., hypotension, bradycardia). Breathing on the active ITD increased LBNP tolerance time (mean Ϯ SE) from 2,014 Ϯ 106 s to 2,259 Ϯ 138 s (P ϭ 0.006). We compared CBFV responses at the time of symptoms during the sham ITD trial with those at the same absolute time during the active ITD trial (when there were no symptoms). While there was no difference in mean CBFV at these time points (sham, 44 Ϯ 4 cm/s vs. active, 47 Ϯ 4; P ϭ 0.587), total oscillations (sum of high-and low-frequency spectral power) of CBFV were higher (P ϭ 0.004) with the active ITD (45.6 Ϯ 10.2 cm/s 2 ) than the sham ITD (22.1 Ϯ 5.4 cm/s 2 ). We conclude that greater oscillations around the same absolute level of mean CBFV are induced by inspiratory resistance and may contribute to the delay in symptoms and cardiovascular collapse that accompany progressive central hypovolemia.inspiratory threshold device; cerebral blood flow regulation; lowerbody negative pressure THE PRESERVATION OF CEREBRAL blood flow during hypotensive stress is integral in delaying the onset of presyncopal symptoms and maintaining consciousness. Recent data reported from several investigations have demonstrated the benefits of an inspiratory impedance threshold device (ITD) in elevating cerebral perfusion pressure in animals (39, 40) and reducing the reporting of presyncopal symptoms in humans (8, 27) with reductions in central blood volume.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). Breathing on the ITD also increases cerebral blood flow velocity (CBFV) in resting, supine humans (12) and in the hemorrhaging porcine model, application of negative intrathoracic pressure reduces intracranial pressure (ICP) and subsequently elevates cerebral perfusion pressure (40, 41). Th...

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“…11,12 Hyperventilation should be avoided because it may increase intrathoracic pressure, which decreases venous return and consequently cardiac preload and output or cause gastric distension leading to pulmonary aspiration. 11,13 The two consecutive ventilations currently recommended in CPR guidelines might adversely affect resuscitation of the cardiac arrest patient. When two ventilations in a CPR cycle are performed, the rescuer needs to wait for exhalation after the first ventilation, which results in over 4 seconds prolongation of hands-off time 14 and associated risk of decreased chest compression fraction (CCF), which in turn affects the rate of return of spontaneous circulation (ROSC).…”

mentioning

confidence: 99%

Comparison Between 30:1 and 30:2 Compression‐to‐ventilation Ratios for Cardiopulmonary Resuscitation: Are Two Ventilations Necessary?

Cha

Kim

et al. 2015

Academic Emergency Medicine

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Objectives: Controversy is continuing over the need for ventilation and the optimal compressionventilation (CV) ratio during cardiopulmonary resuscitation (CPR). The aim of this study was to comparatively elucidate the effect on hemodynamics and arterial oxygen saturation of a single ventilation relative to two consecutive ventilations during CPR in a dog model of cardiac arrest.Methods: Twenty mongrel dogs were divided into two groups. After 3 minutes of ventricular fibrillation (VF), the single-ventilation group received CPR with a 30:1 CV ratio, and the two-ventilation group received CPR with a 30:2 CV ratio, all with room air for 7 minutes. Thereafter, continuous chest compressions and intermittent ventilation at rate of 10 per minute were followed for both groups for 10 minutes. Hemodynamic parameters, arterial blood gas profiles, and variables from CPR were compared at baseline and at 5, 10, 15, and 20 minutes after induction of VF.

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Use of an Inspiratory Impedance Valve Improves Neurologically Intact Survival in a Porcine Model of Ventricular Fibrillation

Abstract: Background-This study evaluated the potential for an inspiratory impedance threshold valve (ITV)

Cited by 136 publications

References 14 publications

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

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

Comparison Between 30:1 and 30:2 Compression‐to‐ventilation Ratios for Cardiopulmonary Resuscitation: Are Two Ventilations Necessary?

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