Determinants of defibrillation: Prospective analysis of 183 patients

Kerber, Richard E.; Jensen, Susan R.; Gascho, Joseph; Grayzel, Joseph; Hoyt, Robert; Kennedy, J A

doi:10.1016/0002-9149(83)90408-3

Cited by 68 publications

(7 citation statements)

References 19 publications

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“…Evidence from 3 studies of monophasic defibrillation suggested equivalent outcomes with lower and higher starting energies (LOE 1 77 ; LOE 2 78,79 ).…”

Section: Monophasic Waveform (Damped Sinusoid or Truncated Exponential)mentioning

confidence: 99%

Part 6: Defibrillation

Sunde¹,

Deakin²,

Hazinski³

et al. 2010

Circulation

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“…Evidence from 3 studies of monophasic defibrillation suggested equivalent outcomes with lower and higher starting energies (LOE 1 77 ; LOE 2 78,79 ).…”

Section: Monophasic Waveform (Damped Sinusoid or Truncated Exponential)mentioning

confidence: 99%

Part 6: Defibrillation

Sunde¹,

Deakin²,

Hazinski³

et al. 2010

Circulation

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“…The typical patient impedance for external shock is 60 to 80 ⍀, 3,5,23 but the shock impedance in our study was Ϸ40 ⍀. Although the optimal phase-1 tilt value is 70% with a phase-1 pulse width of 3.0 ms in this study, this phase-1 pulse width will be longer in a clinical setting because of the higher impedance.…”

Section: Limitationsmentioning

confidence: 59%

Optimal Small-Capacitor Biphasic Waveform for External Defibrillation

et al. 1998

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Background-Biphasic waveforms have been reported to be more efficacious than monophasic waveforms for external defibrillation. This study examined the optimal phase-1 tilts and phase-2 leading-edge voltages with small capacitors (60 and 20 F) for external defibrillation. We also assessed the ability of the "charge-burping" model to predict the optimal waveforms. Methods and Results-Two groups of studies were performed. In group 1, 9 biphasic waveforms from a combination of 3 phase-1 tilt values (30%, 50%, and 70%) and 3 phase-2 leading-edge voltage values (0.5, 1.0, and 1.5 times the phase-1 leading-edge voltage, V 1 ) were tested. Phase-2 pulse width was held constant at 3 ms in all waveforms. Two separate 60-F capacitors were used in each phase. The energy value that would produce a 50% likelihood of successful defibrillation (E 50 ) decreased with increasing phase-1 tilt and increased with increasing phase-2 leading-edge voltage except for the 30% phase-1 tilt waveforms. In group 2, 9 waveforms were identical to the waveforms in group 1, except for a 20-F capacitor for phase 2. E 50 decreased with increasing phase-1 tilt. Phase-2 leading-edge voltage of 1.0 to 1.5 V 1 appeared to minimize E 50 for phase-1 tilt of 50% and 70% but worsened E 50 for phase-1 tilt of 30%. There was a significant correlation between E 50 and residual membrane voltage at the end of phase 2, as calculated by the charge-burping model in both groups (group 1, R 2 ϭ0.47, PϽ0.001; group 2, R 2 ϭ0.42, PϽ0.001). Conclusions-The waveforms with 70% phase-1 tilt were more efficacious than those with 30% and 50%. The relationship of phase-2 leading-edge voltage to defibrillation efficacy depended on phase-2 capacitance. The charge-burping model predicted the optimal external biphasic waveform. (Circulation. 1998;98:2487-2493.)

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“…The experiments reported here are in a porcine model where the transthoracic impedances were quite similar among the 10 pigs. These impedances are somewhat lower than average human transthoracic impedance 5 , 27 . Furthermore, because of the variation in size and other factors, the range of impedance seen in human external defibrillation is considerable and not at all comparable to the range seen in the experimental preparations.…”

Section: Discussionmentioning

confidence: 80%

“…These impedances are somewhat lower than average human transthoracic impedance. 5,27 Furthermore, because of the variation in size and other factors, the range of impedance seen in human external defibrillation is considerable and not at all comparable to the range seen in the experimental preparations. Similar to previous animal data, 28,29 our data for external defibrillation suggests a strength-duration relationship between average current and pulse duration with a rheobase current.…”

Section: Limitationmentioning

confidence: 99%

The Strength‐Duration Relationship of Monophasic Waveforms with Varying Capacitance Sizes in External Defibrillation

Yamanouchi

Brewer²,

Mowrey

et al. 2003

Pacing Clinical Electrophis

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The shape of the shock waveform influences defibrillation efficacy. However, the optimal combination between capacitance size and truncation/tilt which can determine monophasic waveform's shape, has not been determined for external defibrillation. The purpose of this study was to assess the effects of varying capacitance and tilt on external defibrillation using exponential monophasic waveforms. In a pig model of external defibrillation (n = 10, 30 +/- 6 kg), nine exponential monophasic waveforms combining three capacitance values (30 microF, 60 microF, and 120 microF) and three tilt values (55%, 75%, and 95%) were tested randomly. The energy and leading edge voltage at 50% defibrillation success (E50 and V50) were used to evaluate defibrillation efficacy. E50 and V50 were determined by the Bayesian technique. The lowest stored E50 for the 30microF, 60 microF, and 120 microF waveforms were 90 +/- 12 J (95% tilt), 106 +/- 45 J (55% tilt), and 107 +/- 52 J (75% tilt), respectively. The lowest V50 for the 30 microF, 60 microF, and 120 microF waveforms were 2,439 +/- 166 V (95% tilt), 1,849 +/- 375 V (55% tilt), and 1,301 +/- 322 V (75% tilt), respectively. The average current at external defibrillation threshold demonstrated a strength versus pulse duration relationship similar to that seen with pacing. Reducing capacitance has the same effect as truncating the waveform. The E50 is more sensitive to tilt values changes in larger capacitance waveforms. This study suggests that the optimal combination between capacitance and tilt may be 120 microF and 55%-75% for external defibrillation.

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Determinants of defibrillation: Prospective analysis of 183 patients

Cited by 68 publications

References 19 publications

Part 6: Defibrillation

Part 6: Defibrillation

Optimal Small-Capacitor Biphasic Waveform for External Defibrillation

The Strength‐Duration Relationship of Monophasic Waveforms with Varying Capacitance Sizes in External Defibrillation

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