Dataset Information

Increasing CPR duration prior to first defibrillation does not improve return of spontaneous circulation or survival in a swine model of prolonged ventricular fibrillation.

ABSTRACT:

Introduction

The optimum duration of cardiopulmonary resuscitation (CPR) prior to first rescue shock is unknown. Clinical trials have used 90 and 180 s. Neither of these durations may be optimal. We sought to determine the optimum duration of CPR prior to first defibrillation attempt and whether this varied depending on the duration of ventricular fibrillation (VF). In this porcine model of basic life support, our outcomes were rates of return of spontaneous circulation (ROSC), survival, and coronary perfusion pressure (CPP).

Methods

We anesthetized and instrumented 45 swine and then induced VF. After 5 or 8 min of untreated VF, we randomized the swine to mechanical CPR for 90, 180, or 300 s. A single rescue shock (150 J biphasic) was then administered. If this shock failed, 2 min of mechanical CPR were completed prior to the next rescue shock. CPP was calculated for each 30s epoch. ROSC was defined as a blood pressure >80 mmHg sustained for 60s. Survival was defined as sustained ROSC for 20 min. Data were analyzed with descriptive statistics, Fisher's exact test, and ANOVA.

Results

In the 5 min VF cohort, the rate of ROSC did not differ between the three groups (90 s: 25%; 180 s: 38%; 300 s: 38%, p>.05). Survival rates did not differ (90 s: 25%; 180 s: 25%; 300 s: 25%, p>0.05). In the 8 min VF cohort, no animals experienced ROSC or survival. CPP were calculated by 30s epoch and did not differ between the three groups (p>0.05). CPPs decline after 180 s of CPR.

Conclusions

ROSC and survival were equivalent regardless of VF duration and CPR duration. When CPR begins late, CPPs are low, stressing the importance of early CPR. We do not recommend 300 s of CPR unless a defibrillator is unavailable.

SUBMITTER: Rittenberger JC

PROVIDER: S-EPMC2582345 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

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Publications

Increasing CPR duration prior to first defibrillation does not improve return of spontaneous circulation or survival in a swine model of prolonged ventricular fibrillation.

Rittenberger Jon C JC Suffoletto Brian B Salcido David D Logue Eric E Menegazzi James J JJ

Resuscitation 20080711 1

<h4>Introduction</h4>The optimum duration of cardiopulmonary resuscitation (CPR) prior to first rescue shock is unknown. Clinical trials have used 90 and 180 s. Neither of these durations may be optimal. We sought to determine the optimum duration of CPR prior to first defibrillation attempt and whether this varied depending on the duration of ventricular fibrillation (VF). In this porcine model of basic life support, our outcomes were rates of return of spontaneous circulation (ROSC), survival, ...[more]

PMID: 18620793

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Project description:BackgroundExternal defibrillators are used for arrhythmia cardioversion and for defibrillating during cardiac arrest. During defibrillation, short-duration biphasic pulses cause intense motion due to rapid chest-wall muscle contraction. A reduced motion external defibrillator (RMD) was constructed by integrating a commercial defibrillator with a Tetanizing-waveform generator. A long-duration, low-amplitude, tetanizing waveform slowly stimulated the chest musculature before the biphasic pulse, reducing muscle contraction during the shock.ObjectiveThe purpose of this study was to evaluate RMD defibrillation in swine for subject motion during defibrillation pulses and for defibrillation effectiveness. RMD defibrillation can reduce the duration of arrhythmia ablation therapy or simplify cardioversion procedures.MethodsThe tetanizing unit delivered a triangular 1-kHz pulse of 0.25- to 2.0-second duration and 10- to 100-V peak amplitude, subsequently triggering the conventional defibrillator to output standard 1- to 200-J energy biphasic pulses at the next R wave. Forward limb motion was evaluated by measuring peak acceleration and limb work during RMD (tetanizing + biphasic) or biphasic pulse-only waveforms at 10-3-second sampling rate. Seven swine were arrested electrically and subsequently defibrillated. Biphasic pulse-only and RMD defibrillations were repeated 25-35 times per swine, varying tetanizing parameters and biphasic pulse energy. Defibrillation thresholds (DFTs) were established by measuring the minimum energy required to restore sinus rhythm with biphasic pulse-only or RMD defibrillations.ResultsTwo forward-limb acceleration peaks occurred during both the tetanizing waveform and biphasic pulse, indicating rapid and slower nociceptic (pain sensation) nerve fiber activation. Optimal RMD tetanizing parameters (25-35 V, 0.25- to 0.75-second duration), relative to biphasic pulse-only defibrillations, resulted in 74% ± 10% smaller peak accelerations and 85% ± 10% reduced limb work. DFT energies were identical when comparing RMD to biphasic pulse-only defibrillations.ConclusionRelative to conventional defibrillations, RMD defibrillations maintain rhythm restoration efficiency with drastically reduced subject motion.

Project description:Background Treatment with an automated external defibrillator (AED) improves outcome in out-of-hospital cardiac arrest (OHCA). Audiovisual feedback from an AED may assist bystanders achieve higher quality cardiopulmonary resuscitation. However, the association between audiovisual feedback and clinical outcomes is not well assessed in real-life OHCA. The aim of this study was to assess the association between audiovisual feedback from an AED used in bystander resuscitation with rates of return of spontaneous circulation (ROSC) and 30-day survival in a real-life cohort of patients with OHCA. Methods and Results We included 325 patients treated with bystander AED use before arrival of emergency medical services during 2016 to 2019 from the Capital Region of Denmark. Patients were divided into a "feedback" and a "nonfeedback" group, depending on presence of audiovisual feedback from the AED. Audiovisual feedback was defined as voice prompts with continuous feedback to ongoing resuscitation. Rates of ROSC upon hospital admission and 30-day survival were assessed, and univariate and multivariable models were applied to decide the association to audiovisual feedback. Multivariable models were adjusted for sex, age, primary heart rhythm, and location of OHCA. A total of 155 (48%) patients had a bystander AED applied with audiovisual feedback and 170 (52%) without audiovisual feedback. A lower rate of ROSC was found in the feedback group compared with the nonfeedback group (33% [n=51] versus 45% [n=76]; P=0.03). No association was observed between AV feedback and 30-day survival (feedback=27% [n=42] and nonfeedback=31% [n=53]; P=0.49). In the unadjusted logistic regression model, audiovisual feedback was associated with a decreased chance of ROSC (odds ratio, 0.61; 95% CI, 0.38-0.95; P=0.03), which remained significant after adjusted analysis (odds ratio, 0.53; 95% CI, 0.29-0.97; P=0.04), whereas we found no significant association between audiovisual feedback and 30-day survival in the unadjusted and adjusted analyses. Conclusions Audiovisual feedback from an AED used by bystanders was associated with a lower chance of ROSC at hospital admission, but we found no significant difference in 30-day survival. Focus on early and correct bystander cardiopulmonary resuscitation and AED use remain key for OHCA survival.

Dataset Information

Increasing CPR duration prior to first defibrillation does not improve return of spontaneous circulation or survival in a swine model of prolonged ventricular fibrillation.

Introduction

Methods

Results

Conclusions

Publications

Increasing CPR duration prior to first defibrillation does not improve return of spontaneous circulation or survival in a swine model of prolonged ventricular fibrillation.

Similar Datasets

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