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Discussion: There were no statistically significant differences between biphasic andmono-phasic AED waveform defibrillation on the patients neurologic outcome and ROSC.

Conclusion: Our results suggest that, regardless waveform type of the AED, It is impor-tant to increase the number of AED installed and increase number of bystander CPR.

doi:10.1016/j.resuscitation.2010.09.073

Abstracts / Resuscita

eferences

1. Berger RD, Palazzolo J, Halperin H. Rhythm discrimination during uninterrupted CPRusing motion artefact reduction system. Resuscitation 2007;75:145–52.

2. Wik L, Kramer-Johansen J, Myklebust H, et al. Quality of cardiopulmonary resuscitationduring out-of-hospital cardiac arrest. JAMA 2005;293:299–304.

3. Worksheetfor Evidence-Based Review of Science for Emergency Cardiac Care BLS-039.http://www.americanheart.org/presenter.jhtml?identifier=3070881.

oi:10.1016/j.resuscitation.2010.09.070

S055

ands-on defibrillation: How well would medical examination gloves protect res-uers from defibrillation voltages?

ullivan J.L., Chapman F.W.

Physio-Control, Redmond, WA, USA

Purpose: Hands-on defibrillation can reduce pauses in chest compressions during CPR,ut how safe is it? Common biphasic defibrillation shocks range from 1400 to 2800 V;onophasic defibrillators can go to 5000 V. Safety of a rescuer contacting the patient

uring these shocks is determined by (1) the fraction of the shock voltage presentedo the rescuer, and (2) the breakdown voltage of the rescuer’s gloves. Neither has beendequately investigated. We determined the electrical breakdown voltage for medicalxamination gloves.

Methods: We used a dielectric analyzer to apply an increasing voltage ramp to eachlove until an electrical arc occurred, current flow exceeded a pre-defined limit, or 5000 Vas reached. Four glove polymers were tested in single-layer and double-layer config-rations with current limits of 0.1 mA (based on existing leakage current standards) or0 mA (threshold for glove breakdown and significant injury potential) for a total of 320easurements.

Results:

Glove breakdown voltages minimum, median, n

Polymer Single layer Double layer0.1mA 10mA 0.1 mA

Latex 3000 V, 5000 V, 40 2502 V, 4252 V, 20 –Chloroprene 2250 V, 2986 V, 40 2998 V, 3321 V, 20 –Nitrile 811 V, 1575 V, 40 1745 V, 3221 V, 20 2092 V, 2453 V, 40Vinyl 604 V, 972 V, 40 1873 V, 3995 V, 20 789 V, 965 V, 40

Of the single gloves tested, 0% latex, 29% chloroprene, 100% nitrile and 100% vinylloves exceeded leakage current standards at or below 2800 V. In addition, 10% latex,% chloroprene, 8% nitrile, and 8% vinyl gloves permitted current levels that could allowignificant rescuer injury.

Conclusions: The voltages at which leakage current standards were exceeded or elec-rical breakdown occurred varied considerably between glove types. The other factorffecting safety, the fraction of shock voltage presented to the rescuer, may be difficult tossess. Until this fraction is firmly established it may be prudent to use gloves designedo withstand the maximum defibrillator output voltage.

oi:10.1016/j.resuscitation.2010.09.071

S056

an waveform analysis-guided treatment (shock-first versus CPR first) improve sur-ival among patients with low quality VF? Results of an international prospectiveouble-blinded randomised controlled trial

reese J.P. 1,2, Jorgenson D.B. 3, Liu P. 4, Innes J. 5, Matallana L. 1, Nammi K. 3, Donohoe.T. 5, Whitbread M. 5, Silverman R.A. 1,6, Kaufman B.J. 1,6, Isaacs D.A. 1,6, Prezant D.J. 1

Office of Medical Affairs, Fire Department of New York (FDNY), New York, NY USADepartment of Emergency Medicine, Emergency Medical Associates LLC / Hudson Valleyospital, Cortlandt Manor, NY USAPhilips Healthcare, Seattle, WA USAFred Hutchinson Cancer Research Center, Seattle, WA USALondon Ambulance Service, London, England UKDepartment of Emergency Medicine, North Shore – Long Island Jewish Medical Center, Newyde Park, NY USA

Purpose: The 2005 American Heart Association Guidelines noted the potential usef ventricular fibrillation (VF) waveform analysis to “include prediction of success ofardioversion. . . and optimization of timing of defibrillation relative to CPR and med-cation delivery.”1 This prospective double-blinded randomized controlled trial wasesigned to assess the use of a VF waveform analysis algorithm to improve survival.

Methods: Out-of-hospital cardiac arrest (OOHCA) patients from two large metropoli-an EMS systems were treated with automated external defibrillators (AEDs) randomizedo a universal shock-first or VF waveform analysis protocol. Study inclusion was limitedo presenting VF of primary cardiac aetiology. VF waveform characteristics were used to

alculate a novel score representing VF quality. Patients whose score was below a prede-ned threshold received either immediate defibrillation or a 2-min period of CPR prior toefibrillation based on AED randomization. The primary outcome was survival to hospitalischarge.

Results: Between May 5, 2006 and June 30, 2009, a total of 6738 OOHCA patients werenrolled. 5751 patients were excluded, the majority (85%) due to a non-VF presentinghythm. Of the 987 included cases, 540 (54.7%) presented below threshold and comprised

1S (2010) S1–S114 S15

the primary analysis group. Based on the AED randomization, 262/540 patients were giventwo minutes of CPR prior to defibrillation and 278/540 patients were treated with a shock-first protocol. The initial VF score was highly predictive (p < 0.001) for survival to hospitaldischarge overall. For subjects below threshold, no significant differences were identifiedbetween the shock-first and CPR-first protocols for ROSC (27% vs. 29%, p = 0.57), sustainedROSC (20% vs. 22%, p = 0.75), and survival to admission (23% vs. 22%, p = 1.00) or discharge(7% vs. 7%, p = 1.00).

Conclusions: Initial VF score is highly predictive for subsequent survival to hospitaldischarge. However, its use to guide initial CPR treatment for patients with low qualityVF did not alter survival.

doi:10.1016/j.resuscitation.2010.09.072

AS057

Biphasic AED or mono-phasic AED? Which is effective on OHCA patients outcome: Annationwide population-based, observational study

Takahashi H. 1, Tanaka H. 1, Takyu H. 2, Kaneko H. 3

1 Graduate school of Emergency Medical System, Kokushikan University, Tama, Japan2 Department of Rehabilitation, Chubu Gakuin University, Seki, Japan3 Nagoya City Fire Department, Nagoya, Japan

Background: Biphasic automated external defibrillator (AED) has been reported to bebetter defibrillation waveform than mono-phasic AED. However, those two AEDs are stillequally used for out-of-hospital cardiac arrest (OHCA) patients in Japan. Thus, it remainsunclear whether biphasic AED improves outcomes or not.

Objective: To compare the effectiveness of a biphasic AED with a mono-phasic AEDon witnessed OHCA due to ventricular fibrillation.

Materials and methods: From January 1, 2007 through December 31, 2008, a total of14,950 OHCA patients were extracted from nationwide Utstein style database.

Exclusion criteria: Patients younger than 18 and older than 120 of age.Endpoint: The primary outcome measure was 1-month survival with good neuro-

logic outcome (CPC 1 or 2) and secondary outcome was return of spontaneous circulation(ROSC) before arriving at hospital.

Statistical analysis: Propensity score and conditional logistic regression modelingtechnique were used to calculate the relative risk (RR) of biphasic waveform over mono-phasic waveform, adjusting for potential confounders including witness status of thearrest, bystander cardiopulmonary resuscitation, initial ECG rhythm, and call-responseinterval.

Results: 14,950 VF OHCA patients extracted from over all data. Termination of VFwith first shock in 2246/6022 patients (37.3%) in the biphasic AED and 469/1251 patients(37.5%) in the mono-phasic AED. The propensity score matching yielded 682 matchedpairs. A RR (95%CI) of biphasic waveform for the CPC score at 1-month post-arrest was1.22 (0.91–1.63) and a RR (95%CI) of biphasic waveform for the ROSC was 1.25 (0.98–1.59).