Effect of hypothermia on transthoracic defibrillation in a swine model

Rhee, Benjamin; Zhang, Yi; Boddicker, Kimberly A.; Davies, Loyd R.; Kerber, Richard E.

doi:10.1016/j.resuscitation.2004.10.013

Cited by 35 publications

(20 citation statements)

References 17 publications

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“…In a porcine cardiac arrest model, Wang et al 18,29 showed that nasal cooling initiated at the same time as CPR eases resuscitation and improves ROSC rates. Others have also shown a reduction in the electric threshold for successful defibrillation during hypothermic resuscitation 30,31 and an improvement in the ROSC rate. 32 A possible explanation for the failure in the present study to see an improvement in ROSC may be the fact that in our study design, we did not specify exactly when cooling needed to be initiated, for fear of interfering with the resuscitation routine.…”

Section: Castrén Et Al Prehospital Intra-arrest Transnasal Coolingmentioning

confidence: 99%

Intra-Arrest Transnasal Evaporative Cooling

et al. 2010

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Background-Transnasal evaporative cooling has sufficient heat transfer capacity for effective intra-arrest cooling and improves survival in swine. The aim of this study was to determine the safety, feasibility, and cooling efficacy of prehospital transnasal cooling in humans and to explore its effects on neurologically intact survival to hospital discharge. Methods and Results-Witnessed cardiac arrest patients with a treatment interval Յ20 minutes were randomized to intra-arrest cooling with a RhinoChill device (treatment group, nϭ96) versus standard care (control group, nϭ104). The final analysis included 93 versus 101 patients, respectively. Both groups were cooled after hospital arrival. The patients had similar demographics, initial rhythms, rates of bystander cardiopulmonary resuscitation, and intervals to cardiopulmonary resuscitation and arrival of advanced life support personnel. Eighteen device-related adverse events (1 periorbital emphysema, 3 epistaxis, 1 perioral bleed, and 13 nasal discolorations) were reported. Time to target temperature of 34°C was shorter in the treatment group for both tympanic (102 versus 282 minutes, Pϭ0.03) and core (155 versus 284 minutes, Pϭ0.13) temperature. There were no significant differences in rates of return of spontaneous circulation between the groups (38% in treated subjects versus 43% in control subjects, Pϭ0.48), in overall survival of those admitted alive (44% versus 31%, respectively, Pϭ0.26), or in neurologically intact survival to discharge (Pittsburgh cerebral performance category scale 1 to 2, 34% versus 21%, Pϭ0.21), although the study was not adequately powered to detect changes in these outcomes. Conclusions-Prehospital

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Section: Castrén Et Al Prehospital Intra-arrest Transnasal Coolingmentioning

confidence: 99%

Intra-Arrest Transnasal Evaporative Cooling

et al. 2010

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“…It has been shown in animals that early application of hypothermia results in a larger benefit [15][16][17] and that mild to moderate hypothermia facilitates transthoracic defibrillation. 18 In addition, the therapeutic value of postresuscitation mild to moderate hypothermia for enhancing neurologically intact survival in comatose survivors of cardiac arrest has been established with 2 randomized, controlled trials. 19,20 The earliest that hypothermia can be applied clinically is with the initiation of cardiopulmonary resuscitation (CPR).…”

Section: Clinical Perspective On P 1435mentioning

confidence: 99%

Intra–Cardiopulmonary Resuscitation Hypothermia With and Without Volume Loading in an Ischemic Model of Cardiac Arrest

et al. 2009

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Background-We investigated the effects of intra-cardiopulmonary resuscitation (CPR) hypothermia with and without volume loading on return to spontaneous circulation and infarction size in an ischemic model of cardiac arrest. Methods and Results-Using a distal left anterior descending artery occlusion model of cardiac arrest followed by resuscitation with a total of 120 minutes of occlusion and 90 minutes of reperfusion, we randomized 46 pigs into 5 groups and used myocardial staining to define area at risk and myocardial necrosis. Group A had no intervention. Immediately after return of spontaneous circulation, group B received surface cooling with cooling blankets and ice. Group C received intra-CPR 680Ϯ23 mL of 28°C 0.9% normal saline via a central venous catheter. Group D received intra-CPR 673Ϯ26 mL of 4°C normal saline followed by surface cooling after return of spontaneous circulation. Group E received intra-CPR and hypothermia after return of spontaneous circulation with an endovascular therapeutic hypothermia system placed in the right atrium and set at a target of 32°C. Intra-CPR volume loading with room temperature (group C) or iced saline (group D) significantly (PϽ0.05) decreased coronary perfusion pressure (group C, 12.8Ϯ4.78 mm Hg; group D, 14.6Ϯ9.9 mm Hg) compared with groups A, B, and E (20.6Ϯ8.2, 20.1Ϯ7.8, and 21.3Ϯ12.4 mm Hg). Return of spontaneous circulation was significantly improved in group E (9 of 9) compared with groups A plus B and C (10 of 18 and 1 of 8). The percent infarction to the area at risk was significantly reduced with intra-CPR hypothermia in groups D (24.3Ϯ4.2%) and E (4Ϯ3.4%) compared with groups A (72Ϯ5.1%) and B (67.3Ϯ4.2%). Conclusions-Intra-CPR hypothermia significantly reduces myocardial infarction size.

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“…We have previously found that severe induced hypothermia (30°C) facilitates transthoracic defibrillation in short-duration (30 seconds) VF, with less postdefibrillation ventricular asystole. 17 In the present study, we investigated the effects of preexisting induced hypothermia on defibrillation success and resuscitation outcome in a swine model undergoing prolonged VF.…”

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confidence: 99%

Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

et al. 2005

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Background-Induced hypothermia is recommended to improve neurological outcomes in unconscious survivors of out-of-hospital ventricular fibrillation (VF) cardiac arrest. Patients resuscitated from a VF arrest are at risk of refibrillation, but there are few data on the effects of already existing hypothermia on defibrillation and resuscitation. Methods and Results-Thirty-two swine (meanϮSE weight, 23.0Ϯ0.6 kg) were divided into 4 groups: normothermia (nϭ8), mild hypothermia (35°C) (nϭ8), moderate hypothermia (33°C) (nϭ8), and severe hypothermia (30°C) (nϭ8). Hypothermia was induced by surrounding the animal with ice, and VF was electrically induced. After 8 minutes of unsupported VF (no CPR), the swine were defibrillated (biphasic waveform) with successive shocks as needed and underwent CPR until resumption of spontaneous circulation or no response (Ն10 minutes). First-shock defibrillation success was higher in the moderate hypothermia group (6 of 8 hypothermia versus 1 of 8 normothermia; Pϭ0.04). The number of shocks needed for late defibrillation (Ն1 minute after initial shock) was less in all 3 hypothermia groups compared with normothermia (all PϽ0.05). None of the 8 animals in the normothermia group achieved resumption of spontaneous circulation compared with 3 of 8 mild hypothermia (PϭNS), 7 of 8 moderate hypothermia (Pϭ0.001), and 5 of 8 severe hypothermia (Pϭ0.03) animals. Coronary perfusion pressure during CPR was not different between the groups. Conclusions-When VF was induced in the setting of moderate or severe hypothermia, resuscitative measures were facilitated with significantly improved defibrillation success and resuscitation outcome. The beneficial effect of hypothermia was not due to alteration of coronary perfusion pressure, which suggests that changes in the mechanical, metabolic, or electrophysiological properties of the myocardium may be responsible.

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Effect of hypothermia on transthoracic defibrillation in a swine model

Cited by 35 publications

References 17 publications

Intra-Arrest Transnasal Evaporative Cooling

Intra-Arrest Transnasal Evaporative Cooling

Intra–Cardiopulmonary Resuscitation Hypothermia With and Without Volume Loading in an Ischemic Model of Cardiac Arrest

Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

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