Comparison of rectilinear biphasic waveform with biphasic truncated exponential waveform in a pediatric defibrillation model.

Objective: To compare the rectilinear biphasic waveform with a biphasic truncated exponential waveform for pediatric defibrillation.

Design: Prospective, randomized study.

Setting: Experimental laboratory of a university-affiliated research institute.

Spontaneous gasping produces carotid blood flow during untreated cardiac arrest.

Objectives: Coincident with "agonal" gasping during cardiac arrest, there are prominent increases in stroke volumes even in the absence of chest compression. In the present study, we tested the hypothesis that gasps also increase carotid blood flow (CBF) during untreated cardiac arrest.

Materials And Methods: The tracheas of nine domestic male pigs, weighing 39+/-2kg, were intubated and animals were ventilated mechanically.

Outcomes of CPR in the presence of partial occlusion of left anterior descending coronary artery.

Objectives: To develop a clinically relevant experimental model of cardiac arrest and CPR in which a partial occlusion of the left anterior descending coronary artery (LAD) is maintained during the resuscitation procedure and the initial post-resuscitation interval.

Materials And Methods: Ventricular fibrillation (VF) was induced by LAD occlusion with a balloon tipped catheter in 16 domestic male pigs weighing 41+/-2kg. After a 7min interval of untreated VF, the LAD balloon occlusion was deflated and the catheter withdrawn in eight animals.

The quality of chest compressions during cardiopulmonary resuscitation overrides importance of timing of defibrillation.

Background: We address the quality of chest compressions and the impact on initial defibrillation or initial chest compressions after sudden death.

Methods: Ventricular fibrillation was induced by occlusion of the left anterior descending coronary artery in 24 domestic pigs with a mean (+/- SD) weight of 40 +/- 2 kg. Cardiac arrest was left untreated for 5 min.

A comparison of electrically induced cardiac arrest with cardiac arrest produced by coronary occlusion.

Objective: The present study was undertaken to compare an animal model of electrically induced VF with ischemically induced VF. In a preponderance of models of cardiac arrest and resuscitation in intact animals, ventricular fibrillation (VF) is induced by an alternating current delivered directly to the epicardium or endocardium. Yet, the applicability of such animal models has been challenged for it is not an electrical current alone but rather a current generated in the ischemic myocardium that triggers VF.

delta-Opioid-induced pharmacologic myocardial hibernation during cardiopulmonary resuscitation.

Objectives: Cardiac arrest and cardiopulmonary resuscitation is an event of global myocardial ischemia and reperfusion, which is associated with severe postresuscitation myocardial dysfunction and fatal outcome. Evidence has demonstrated that mammalian hibernation is triggered by cyclic variation of a delta-opiate-like compound in endogenous serum, during which the myocardial metabolism is dramatically reduced and the myocardium tolerates the stress of ischemia and reperfusion without overt ischemic and reperfusion injury. Previous investigations also proved that the delta-opioid agonist elicited the cardioprotection in a model of regional ischemic intact heart or myocyte.

Simultaneous blockade of alpha1- and beta-actions of epinephrine during cardiopulmonary resuscitation.

Objective: Experimental and clinical studies have implicated that alpha1- and beta-adrenergic effects of epinephrine significantly increased the severity of postresuscitation myocardial dysfunction by increasing myocardial oxygen consumption during ventricular fibrillation. This prompted experimental studies to investigate the effect of simultaneous blockade of alpha1- and beta-actions of epinephrine during cardiopulmonary resuscitation.

Design: Literature review.

Microcirculation during cardiac arrest and resuscitation.

Objective: Direct observations of the microcirculation using orthogonal polarization spectral imaging have attracted attention and revealed that, especially in cardiogenic and distributive shock, there is discordance between the macrocirculation and the microcirculation. We evaluated serial changes and the effects of epinephrine on microcirculatory blood flow in the most severe form of circulatory failure, namely, cardiac arrest.

Design And Setting: : Controlled laboratory animal study.

Comparison of buccal microcirculation between septic and hemorrhagic shock.

Objective: Microcirculatory perfusion is disturbed in sepsis, and global hemodynamics does not necessarily reflect microcirculatory blood flow. In this study, we investigated the effect of the same level of mean arterial pressure (MAP) or cardiac index on the changes in buccal microcirculation between septic and hemorrhagic shock.

Design: Prospective, controlled laboratory study.

Role of buccal PCO2 in the management of fluid resuscitation during hemorrhagic shock.

Arterial pressure is a widely used measurement for estimating the severity of hemorrhagic shock and to guide its management. However, this capability is reduced when very low arterial pressure values cannot be reliably measured by noninvasive methods. Moreover, hypoperfusion may be masked by compensatory hemodynamic changes, and therefore, in the presence of near normal blood pressure, tissue hypoperfusion may progress undetected.

Effects of biphasic waveforms on outcomes of cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest.

Objectives: The effects of two clinically available biphasic waveforms on the success of defibrillation and postresuscitation myocardial dysfunction after prolonged ventricular fibrillation were compared with two newly designed dual-path sequential and simultaneous rectilinear biphasic waveforms. Defibrillation via sequential pulses and encircling, overlapping multiple pathway may depolarize a larger myocardial mass and facilitate transthoracic defibrillation.

Design: Animal study.

Microvascular blood flow during cardiopulmonary resuscitation is predictive of outcome.

There is growing evidence that microcirculatory blood flow is the ultimate determinant of the outcome in circulatory shock states. We therefore examined changes in the microcirculation accompanying the most severe form of circulatory failure, namely cardiac arrest and the effects of subsequent cardiopulmonary resuscitation. Ventricular fibrillation was electrically induced in nine pigs and untreated for 5min prior to beginning closed chest cardiac compression and attempting electrical defibrillation.

New cardiopulmonary resuscitation guidelines 2005: importance of uninterrupted chest compression.

The evidence supports quality controlled chest compression as the initial intervention after "sudden death" before attempted defibrillation, if the duration of cardiac arrest is more than 5 minutes. The new guidelines mandate lesser interruptions for ventilation, before and following electrical shocks, and single rather than multiple electrical shocks before resuming chest compression. The new guidelines refocus on uninterrupted chest compression after cardiac arrest of nonasphyxial cause and modifications in practices that reduce the need for interruptions.

Cardiopulmonary resuscitation in a rat model of chronic myocardial ischemia.

Our group has developed a rat model of cardiac arrest and cardiopulmonary resuscitation (CPR). However, the current rat model uses healthy adult animals. In an effort to more closely reproduce the event of cardiac arrest and CPR in humans with chronic coronary disease, a rat model of coronary artery constriction was investigated during cardiac arrest and CPR.

Mechanism by which activation of delta-opioid receptor reduces the severity of postresuscitation myocardial dysfunction.

Objective: Postresuscitation myocardial dysfunction has been recognized as a leading cause of early death after initially successful cardiopulmonary resuscitation. We have previously demonstrated that opening adenosine triphosphate (ATP)-sensitive K (KATP) channels or activation of delta-opioid receptors minimized the severity of postresuscitation myocardial dysfunction and increased the duration of postresuscitation survival. In the present study, we investigated the potential mechanism of myocardial protection following delta-opioid receptor activation in a rat model of cardiac arrest and cardiopulmonary resuscitation.

One-shock versus three-shock defibrillation protocol significantly improves outcome in a porcine model of prolonged ventricular fibrillation cardiac arrest.

Background: The success of resuscitation with a 1-shock versus the conventional 3-shock defibrillation protocol was investigated subject to the range of treatment variation imposed by automated external defibrillators (AEDs).

Methods And Results: Ventricular fibrillation was induced in 44 domestic pigs. After 7 minutes of untreated VF, animals were randomized among 4 groups representing all combinations of the 1- versus 3-shock protocol and 2 different AED regimens (AED1, AED2).

Challenging the rationale of three sequential shocks for defibrillation.

The 2000 guidelines for cardiopulmonary resuscitation (CPR) recommend up to three sequential shocks for persistent ventricular fibrillation (VF). We hypothesized that the time consumed for repetitive rhythm analyses and recharging of the capacitor compromises the success of the second and third shock of each sequence. In 60 domestic pigs, VF was electrically induced and untreated for 7 min.

The characteristics of postcountershock pulseless electrical activity may indicate the outcome of CPR.

Objectives: When ventricular fibrillation is cardioverted to pulseless electrical activity (PEA), PEA has been regarded as a non-resuscitatable rhythm. Yet, recent reports and our earlier observations suggested otherwise. We therefore investigated outcomes after postcountershock PEA, and aimed to develop a scoring system for outcome classification at the onset of initial postcountershock PEA.

Increases in tissue Pco2 during circulatory shock reflect selective decreases in capillary blood flow.

Objectives: Tissue Pco2 reflects metabolic alterations due to circulatory failure during circulatory shock. This study addresses simultaneous changes in gastric and buccal tissue Pco2 with changes in microcirculatory blood flow in a rat model of circulatory shock induced by cecal ligation and puncture.

Design: Prospective controlled laboratory study.

In-hospital cardiac arrest.

To review the current management of in-hospital cardiac arrest and to identify variables that influence outcomes, OLDMEDLINE from 1950 to 1966 and MEDLINE from 1966 to March 2005 were searched using the keywords cardiopulmonary resuscitation, cardiac arrest, in hospital, and adult. Secondary sources were derived from review publications and personal communications by one of the authors. There is no secure evidence that the ultimate outcomes after cardiopulmonary resuscitation in settings of in-hospital cardiac arrest have improved in the >40 yrs that followed the landmark report by Kouwenhoven, Jude, and Knickerbocker, which launched the modern era of cardiopulmonary resuscitation.

Levosimendan improves postresuscitation outcomes in a rat model of CPR.

In this study we sought to determine whether a calcium sensitizer, levosimendan, would have a more favorable effect on postresuscitation myocardial function and, consequently, postresuscitation survival than beta-adrenergic dobutamine. The extreme decrease in survival before hospital discharge of resuscitated victims is attributed, in part, to postresuscitation myocardial failure, and dobutamine has been recommended for the management of postresuscitation myocardial failure. We studied a total of 15 animals.

Buccal capnometry to guide management of massive blood loss.

In both clinical and experimental settings, tissue P(CO2) measured in the oral mucosa is a practical and reliable measurement of the severity of hypoperfusion. We hypothesized that a threshold level of buccal tissue P(CO2) (P(CO2) BU)) would prognosticate the effects of volume repletion on survival. Twenty pentobarbital-anesthetized Sprague-Dawley male breeder rats, each weighing approximately 0.