Analysis of amplitude spectral area and slope to predict defibrillation in out of hospital cardiac arrest due to ventricular fibrillation (VF) according to VF type: recurrent versus shock-resistant.

BACKGROUND: In out-of-hospital cardiac arrest (OHCA) due to ventricular fibrillation (VF), VF may recur during resuscitation (recurrent VF) or fail to defibrillate (shock-resistant VF). While retrospective studies have suggested that amplitude spectral area (AMSA) and slope predict defibrillation, it is unknown whether the predictive power is influenced by VF type. We hypothesized that in witnessed OHCA with initial rhythm of VF that the utility for AMSA and slope to predict defibrillation would differ between shock-resistant and recurrent VF. METHODS: AMSA and slope were measured immediately prior to each shock. For second or later shocks, VF was classified as recurrent or shock-resistant. Cardiac arrest was classified according to whether the majority of shocks were for recurrent VF or shock-resistant VF. RESULTS: 44 patients received 98 shocks for recurrent VF and 96 shocks for shock-resistant VF; 24 patients achieved ROSC in the field. AMSA and slope were higher in recurrent VF compared to shock-resistant VF (AMSA: 28.8±13.1 vs 15.2±8.6 mVHz, P<0.001, and slope: 2.9±1.4 vs 1.4±1.0 mVs(-1), P=0.001). Recurrent VF was more likely to defibrillate than shock-resistant VF (P<0.001). AMSA and slope predicted defibrillation in shock-resistant VF (P<0.001 for both AMSA and slope) but not in recurrent VF. Recurrent VF predominated in 79% of patients that achieved ROSC compared to 55% that did not (P=0.10). CONCLUSIONS: In witnessed OHCA with VF as initial rhythm, recurrent VF is associated with higher values of AMSA and slope and is likely to re-defibrillate. However, when VF is shock-resistant, AMSA and slope are highly predictive of defibrillation.

Improving performance of emergency medical services personnel during resuscitation of cardiac arrest patients: the McMAID approach.

PURPOSE OF REVIEW: The article presents the method we developed to improve emergency medical service personnel training. RECENT FINDINGS: Following the introduction of new prehospital protocol for emergency medical services that initially dramatically improved survival of patients with witnessed out-of-hospital cardiac arrest, we found that without an adequate training and retraining program, survival rates decreased. A new training methodology called McMAID was developed to improve the quality of the resuscitation effort. SUMMARY: It is possible to train personnel to routinely execute an organized resuscitation if the approach to training is modified.

Cardiocerebral resuscitation.

Cardiocerebral resuscitation (CCR) is a new approach to patients with out-of-hospital cardiac arrest that has been shown to improve rates of neurologically intact survival by 250%-300% over the approach advocated by the 2000 American Heart Association guidelines. And EMS systems can realize these improvements without having to buy a single new gadget or device.

Cardiocerebral resuscitation improves neurologically intact survival of patients with out-of-hospital cardiac arrest.

STUDY OBJECTIVE: In an effort to improve neurologically normal survival of victims of cardiac arrest, a new out-of-hospital protocol was implemented by the emergency medical system medical directors in 2 south-central rural Wisconsin counties. The project was undertaken because the existing guidelines for care of such patients, despite their international scope and periodic updates, had not substantially improved survival rates for such patients during nearly 4 decades. METHODS: The neurologic status at or shortly after discharge was documented for adult patients with a witnessed collapse and an initially shockable rhythm. Patients during two 3-year periods were compared. During the 2001 through 2003 period, in which the 2000 American Heart Association guidelines were used, data were collected retrospectively. During the mid-2004 through mid-2007 period, patients were treated according to the principles of cardiocerebral resuscitation. Data for these patients were collected prospectively. Cerebral performance category scores were used to define the neurologic status of survivors, and a score of 1 was considered as "intact" survival. RESULTS: In the 3 years preceding the change in protocol, there were 92 witnessed arrests with an initially shockable rhythm. Eighteen patients survived (20%) and 14 (15%) were neurologically intact. During the 3 years after implementation of the new protocol, there were 89 such patients. Forty-two (47%) survived and 35 (39%) were neurologically intact. CONCLUSION: In adult patients with a witnessed cardiac arrest and an initially shockable rhythm, implementation of an out-of-hospital treatment protocol based on the principles of cardiocerebral resuscitation was associated with a dramatic improvement in neurologically intact survival.

Compression-only cardiopulmonary resuscitation for bystanders and first responders.

PURPOSE OF REVIEW: The current resuscitation guidelines consider ventilation and chest compression essential components of resuscitation and therefore only one methodology, standard cardiopulmonary resuscitation, is explicitly recommended for the treatment of both respiratory and cardiac arrests. Pathophysiological and experimental observations argue that this generalization results in suboptimal treatment for victims of cardiac arrest. RECENT FINDINGS: For more than a decade animal studies have demonstrated that assisted ventilation is not essential during the initial treatment of a fibrillatory arrest; but only in the last year have these results been confirmed in humans. These new observations come from a handful of systems utilizing cardiocerebral resuscitation in their prehospital resuscitation of adult victims of presumed cardiac arrest. They have all demonstrated a dramatic increase in survival. Recent data also indicate that survival is significantly increased when laypersons perform chest-compression-only cardiopulmonary resuscitation. SUMMARY: The current resuscitation guidelines regarding the prehospital treatment of victims of adult cardiac arrest should be modified to explicitly permit the use of continuous-chest-compression cardiopulmonary resuscitation.

Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest.

PURPOSE: The guidelines for cardiopulmonary resuscitation (CPR) have been in place for decades; but despite their international scope and periodic updates, there has been little improvement in survival rates in out-of-hospital cardiac arrest for patients who did not receive early defibrillation. The Emergency Medical Service directors in 2 rural Wisconsin counties initiated a new protocol for the pre-hospital management of adult cardiac arrest victims in an attempt to improve survival rates. The results observed after implementation of this protocol are presented and compared with those observed during a three-year period that preceded initiation of the project. METHODS: The protocol, based upon the principles of cardiocerebral resuscitation, was significantly different from the standard CPR protocol. A major objective was to minimize interruptions of chest compressions. Each defibrillation, including the first, was preceded by 200 uninterrupted chest compressions. Single shocks, rather than stacked shocks, were utilized. Post shock rhythm and pulse checks were eliminated, and chest compressions were resumed immediately after a shock was delivered. Initial airway management was limited to an oral pharyngeal device and supplemental oxygen. If the arrest was witnessed, assisted ventilations and intubation were delayed until either a return of spontaneous circulation or until three series of "compressions + analysis +/- shock" were completed. RESULTS: In the 3 years preceding the change in protocol, where standard CPR was utilized, there were 92 witnessed out-of-hospital adult cardiac arrests with an initially shockable rhythm. Eighteen patients survived, and 14 of 92 (15%) were neurologically intact. After implementing the new protocol in early 2004, there were 33 witnessed out-of-hospital adult cardiac arrests with an initially shockable rhythm. Nineteen survived, and 16 of 33 (48%) were neurologically normal. Differences in both total and neurologically normal survival are significant (chi-squared = 0.001). CONCLUSION: Instituting the new cardiocerebral resuscitation protocol for managing prehospital cardiac arrest improved survival of adult patients with witnessed cardiac arrest and an initially shockable rhythm.