Biomedical subjects

Peter J Kudenchuk

Publications and source records attributed to Peter J Kudenchuk.

7 recordsLinked to original sources

PubMed2006

Transthoracic incremental monophasic versus biphasic defibrillation by emergency responders (TIMBER): a randomized comparison of monophasic with biphasic waveform ascending energy defibrillation for the resuscitation of out-of-hospital cardiac arrest due to ventricular fibrillation.

BACKGROUND: Although biphasic, as compared with monophasic, waveform defibrillation for cardiac arrest is increasing in use and popularity, whether it is truly a more lifesaving waveform is unproven. METHODS AND RESULTS: Consecutive adults with nontraumatic out-of-hospital ventricular fibrillation cardiac arrest were randomly allocated to defibrillation according to the waveform from automated external defibrillators administered by prehospital medical providers. The primary event of interest was admission alive to the hospital. Secondary events included return of rhythm and circulation, survival, and neurological outcome. Providers were blinded to automated defibrillator waveform. Of 168 randomized patients, 80 (48%) and 68 (40%) consistently received only monophasic or biphasic waveform shocks, respectively, throughout resuscitation. The prevalence of ventricular fibrillation, asystole, or organized rhythms at 5, 10, or 20 seconds after each shock did not differ significantly between treatment groups. The proportion of patients admitted alive to the hospital was relatively high: 73% in monophasic and 76% in biphasic treatment groups (P=0.58). Several favorable trends were consistently associated with receipt of biphasic waveform shock, none of which reached statistical significance. Notably, 27 of 80 monophasic shock recipients (34%), compared with 28 of 68 biphasic shock recipients (41%), survived (P=0.35). Neurological outcome was similar in both treatment groups (P=0.4). Earlier administration of shock did not significantly alter the performance of one waveform relative to the other, nor did shock waveform predict any clinical outcome after multivariate adjustment. CONCLUSIONS: No statistically significant differences in outcome could be ascribed to use of one waveform over another when out-of-hospital ventricular fibrillation was treated.

Adult↗

PubMed2006

Abnormal conduction increases risk of adverse outcomes from right ventricular pacing.

OBJECTIVES: The purpose of this study was to determine whether QRS duration or morphology increased the risk of adverse outcome in the DAVID (Dual Chamber and VVI Implantable Defibrillator) trial. BACKGROUND: The DAVID trial found an increased risk of the combined end point of death and new or worsening congestive heart failure (CHF) in defibrillator recipients who were paced DDDR-70 versus VVI-40. METHODS: We analyzed the combined end point in patients with abnormal QRS duration (AbQRS) (> or =110 ms) compared with those with normal QRS duration (NQRS) (<110 ms). RESULTS: The QRS data were available for 496 of the 506 patients enrolled in the trial, including 223 patients with NQRS (45%) and 273 patients with AbQRS (55%). In patients in whom defibrillators were programmed to pace infrequently (VVI-40), having an NQRS or AbQRS was not an indicator of increased risk of adverse outcome. However, among patients in whom defibrillators were programmed in a manner that promoted more frequent ventricular pacing (DDDR-70), there was a significant adverse interaction with AbQRS; this combination was independently associated with a higher risk for developing CHF or death (p = 0.017). CONCLUSIONS: Although patients with AbQRS tended to have other risk factors associated with poor outcome, the interaction of QRS duration with ventricular pacing (DDDR-70) independently contributed to a worse outcome and therefore, was a marker of patients in whom such treatment may be harmful. This should not imply that right ventricular pacing in NQRS patients is safe but rather that pacing in the context of an AbQRS is probably best avoided.

Cardiac Pacing, Artificial↗

PubMed2005

Automated external defibrillators: to what extent does the algorithm delay CPR?

STUDY OBJECTIVE: Maximizing cardiopulmonary resuscitation (CPR) during resuscitation may improve survival. Resuscitation protocols stack up to 3 shocks to achieve defibrillation, followed by an immediate postdefibrillation pulse check. The purpose of this study is to evaluate outcomes of rhythm reanalyses immediately after shock, stacked shocks, and initial postshock pulse checks in relation to achieving a pulse and initiating CPR. METHODS: We conducted an observational study of patients with ventricular fibrillation treated by first-tier emergency medical services (EMS). We collected data from EMS, dispatch, and hospital records. Additionally, we analyzed automatic external defibrillator recordings to determine the proportion of cardiac arrest victims who were defibrillated and achieved a pulse according to shock number (single versus stacked shock), proportion of victims with a pulse during the initial postdefibrillation pulse check, and interval from initial shock to CPR. RESULTS: The study included 481 cardiac arrest subjects. Automatic external defibrillators terminated ventricular fibrillation with the initial shock in 83.6% (n=402) of cases. A second shock terminated ventricular fibrillation in an additional 7.5% (n=36) of cases, and a third shock terminated ventricular fibrillation in 4.8% (n=23) of cases. The initial sequence of 3 shocks failed to terminate ventricular fibrillation in 4.1% (n=20) of cases. In total, automatic external defibrillators performed 560 rhythm reanalyses during the initial shock sequence and delivered 122 "stacked" shocks. Termination of ventricular fibrillation was not synonymous with return of a pulse. The initial shock produced a pulse that was eventually detected in 21.8% (105/481) of cases. Stacked shocks produced a pulse in 10.7% (13/122) of cases. For the 24.5 % (n=118) of cases in which a pulse returned, the pulse was detected during the initial postshock pulse check only 12 times, or 2.5% of all cases. The median interval from initial shock until CPR was 29 (23,41) seconds. CONCLUSION: Rhythm reanalyses, stacked shocks, and postshock pulse checks had low yield for achieving or detecting return of a pulse. CPR was not initiated until 29 seconds after the initial shock.

Aged↗

PubMed2003

Defibrillation waveform and post-shock rhythm in out-of-hospital ventricular fibrillation cardiac arrest.

BACKGROUND: The importance of the defibrillation waveform on the evolving post-shock cardiac rhythm is uncertain. The primary objective of this study was to evaluate cardiac rhythms following the first defibrillation shock, comparing biphasic truncated exponential (BTE), monophasic damped sinusoidal (MDS), and monophasic truncated exponential (MTE) waveforms in patients experiencing out-of-hospital ventricular fibrillation cardiac arrest (OHCA). METHODS: We reviewed the automated external defibrillator (AED) and emergency medical services (EMS) records of 366 patients who suffered OHCA and were treated with defibrillation shocks by first-tier emergency responders between 1 January 1999 and 31 August 2002 in King County, Washington. The post first shock rhythms were determined at 5, 10, 20, 30, and 60 s and compared according to defibrillation waveform. RESULTS: The MDS and BTE waveforms were associated with significantly higher frequency of defibrillation than the MTE waveform, though only the BTE association persisted to 30 and 60 s. No difference in defibrillation rates was detected between MDS and BTE waveforms. By 60 s, an organized rhythm was present in a greater proportion for BTE (40.0%) compared with MDS (25.4%, P=0.01) or MTE (26.5%, P=0.07). CONCLUSION: In this retrospective cohort investigation, MDS and BTE waveforms had higher first shock defibrillation rates than the MTE waveform, while patients treated with the BTE waveform were more likely to develop an organized rhythm within 60 s of the initial shock. The results of this investigation, however, do not provide evidence that these surrogate advantages are important for improving survival. Additional investigation is needed to improve the understanding of the role of waveform and its potential interaction with other clinical factors in order to optimize survival in OHCA.

Aged↗

PubMed2002

Advanced cardiac life support antiarrhythmic drugs.

As exemplified in this discussion of ACLS antiarrhythmic drugs, the evidence-based evaluation process has created a high standard for the acceptance and ranking of therapies for cardiac arrest. This process also has identified critical areas needing further investigation, fostered a healthy sense of discomfort with the adequacy of our present interventions for cardiac arrest, and hopefully will continue to spur the science while sifting the dogma out of CPR.

Amiodarone↗

PubMedDate not supplied

Prehospital management of cardiac arrest: how useful are vasopressor and antiarrhythmic drugs?

Out-of-hospital resuscitation protocols for patients suffering cardiac arrest have historically included cardiopulmonary resuscitation, defibrillation, and rapid transport to a hospital. For many years, use of drugs to improve myocardial perfusion or to correct arrhythmias that occur during cardiac arrest has been part of prehospital efforts to revive patients in ventricular tachycardia or ventricular fibrillation. Use of some of these drugs, however, may be based more on tradition than on well-documented evidence of efficacy. The authors reviewed pertinent data on the vasopressors epinephrine and vasopressin and the antiarrhythmics amiodarone and lidocaine to evaluate the usefulness of these drugs in cardiac arrest. They found little clinical data supporting the prehospital use of lidocaine in cardiac arrest, and despite a great deal of laboratory and clinical data addressing the efficacy of epinephrine, there is no large, randomized, controlled clinical trial supporting its use. Data on amiodarone and vasopressin support the use of these drugs in out-of-hospital resuscitation efforts.

Amiodarone↗

PubMedDate not supplied

Prehospital management of acute tachyarrhythmias.

Arrhythmias are commonly encountered by emergency medical services (EMS) personnel. The potential seriousness of acute symptomatic arrhythmias necessitates thorough up-to-date training of EMS personnel. The three most common acute tachyarrhythmias, not linked to cardiac arrest, that are observed outside the hospital are paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation with rapid ventricular response (RAF), and perfusing ventricular tachycardia (VT). Ideally, these tachyarrhythmias should be operationally defined in a manner that simplifies, particularly for EMS providers, their diagnosis and treatment. The authors recommend referring to these rhythms as regular narrow-complex tachycardia (presumed PSVT), irregularly irregular narrow-complex tachycardia (presumed RAF), or regular wide-complex tachycardia (presumed VT or aberrantly conducted PSVT). Although the value of treatments such as cardioversion is widely understood, the benefit from others, such as lidocaine, is unclear. Current preferences, recommendations, and concerns regarding the treatment of most arrhythmias outside the hospital reflect the dichotomy that sometimes exists between available evidence and actual practice.

Acute Disease↗