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Wolf J, Buckley GJ, Rozanski EA, Fletcher DJ, Boller M, Burkitt-Creedon JM, Weigand KA, Crews M, Fausak ED. 2024 RECOVER Guidelines: Advanced Life Support. Evidence and knowledge gap analysis with treatment recommendations for small animal CPR. J Vet Emerg Crit Care (San Antonio) 2024; 34 Suppl 1:44-75. [PMID: 38924633 DOI: 10.1111/vec.13389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 04/25/2024] [Indexed: 06/28/2024]
Abstract
OBJECTIVE To systematically review the evidence and devise clinical recommendations on advanced life support (ALS) in dogs and cats and to identify critical knowledge gaps. DESIGN Standardized, systematic evaluation of literature pertinent to ALS following Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Prioritized questions were each reviewed by Evidence Evaluators, and findings were reconciled by ALS Domain Chairs and Reassessment Campaign on Veterinary Resuscitation (RECOVER) Co-Chairs to arrive at treatment recommendations commensurate to quality of evidence, risk:benefit relationship, and clinical feasibility. This process was implemented using an Evidence Profile Worksheet for each question that included an introduction, consensus on science, treatment recommendations, justification for these recommendations, and important knowledge gaps. A draft of these worksheets was distributed to veterinary professionals for comment for 4 weeks prior to finalization. SETTING Transdisciplinary, international collaboration in university, specialty, and emergency practice. RESULTS Seventeen questions pertaining to vascular access, vasopressors in shockable and nonshockable rhythms, anticholinergics, defibrillation, antiarrhythmics, and adjunct drug therapy as well as open-chest CPR were reviewed. Of the 33 treatment recommendations formulated, 6 recommendations addressed the management of patients with nonshockable arrest rhythms, 10 addressed shockable rhythms, and 6 provided guidance on open-chest CPR. We recommend against high-dose epinephrine even after prolonged CPR and suggest that atropine, when indicated, is used only once. In animals with a shockable rhythm in which initial defibrillation was unsuccessful, we recommend doubling the defibrillator dose once and suggest vasopressin (or epinephrine if vasopressin is not available), esmolol, lidocaine in dogs, and/or amiodarone in cats. CONCLUSIONS These updated RECOVER ALS guidelines clarify the approach to refractory shockable rhythms and prolonged CPR. Very low quality of evidence due to absence of clinical data in dogs and cats continues to compromise the certainty with which recommendations can be made.
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Affiliation(s)
- Jacob Wolf
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | | | - Elizabeth A Rozanski
- Department of Clinical Sciences, Tufts University School of Veterinary Medicine, North Grafton, Massachusetts, USA
| | - Daniel J Fletcher
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Manuel Boller
- VCA Canada Central Victoria Veterinary Hospital, Victoria, British Columbia, Canada
- Faculty of Veterinary Medicine, Department of Veterinary Clinical and Diagnostic Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Jamie M Burkitt-Creedon
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Kelly A Weigand
- Cary Veterinary Medical Library, Auburn University, Auburn, Alabama, USA
- Flower-Sprecher Veterinary Library, Cornell University, Ithaca, New York, USA
| | - Molly Crews
- Department of Small Animal Clinical Sciences, Texas A&M University College of Veterinary Medicine & Biomedical Sciences, College Station, Texas, USA
| | - Erik D Fausak
- University Library, University of California, Davis, Davis, California, USA
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McCartney B, Harvey A, Kernaghan A, Morais S, McAlister O, Crawford P, Biglarbeigi P, Bond R, Finlay D, McEneaney D. Pediatric defibrillation shocks alone do not cause heart damage in a porcine model. Resusc Plus 2022; 9:100203. [PMID: 35146463 PMCID: PMC8816722 DOI: 10.1016/j.resplu.2022.100203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/03/2021] [Accepted: 01/06/2022] [Indexed: 11/24/2022] Open
Abstract
AEDs utilize specific low energy pediatric modes to reduce myocardial damage. This study applied various shocks in sinus rhythm without cardiac instrumentation. Isolated clinically relevant shock sequences do not result in myocardial damage. Typical variations in pediatric shocks did not affect safety and efficacy. These results may inform future pediatric resuscitation guidelines.
Aim Automated external defibrillators (AEDs) use various shock protocols with different characteristics when deployed in pediatric mode. The aim of this study is to assess and compare the safety and efficacy of different AED pediatric protocols using novel experimental approaches. Methods Two defibrillation protocols (A and B) were assessed across two studies: Protocol A: escalating (50–75–90 J) defibrillation waveform with higher voltage, shorter duration and equal phase durations. Protocol B; non-escalating (50–50–50 J) defibrillation waveform with lower voltage, longer duration and unequal phase durations. Experiment 1: Isolated shock damage was assessed following shocks to 12 anesthetized pigs. Animals were randomized into two groups, receiving three shocks from Protocol A (50–75–90 J) or B (50–50–50 J). Cardiac function, cardiac troponin I (cTnI), creatine phosphokinase (CPK) and histopathology were analyzed. Experiment 2: Defibrillation safety and efficacy were assessed through shock success, ROSC, ST-segment deviation and contractility following 16 randomized shocks from protocol A or B delivered to 10 anesthetized pigs in VF. Results Experiment 1: No clinically meaningful difference in cTnI, CPK, ST-segment deviation, ejection fraction or histopathological damage was observed following defibrillation with either protocol. No difference was observed between protocols at any timepoint. Experiment 2: all defibrillation types demonstrated shock success and ROSC ≥ 97.5%. Post-ROSC contractility was similar between protocols. Conclusions There is no evidence that administration of clinically relevant shock sequences, without experimental confounders, result in significant myocardial damage in this model of pediatric resuscitation. Typical variations in AED pediatric mode settings do not affect defibrillation safety and efficacy.
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Roh SY, Ahn J, Lee KN, Baek YS, Kim DH, Lee DI, Shim J, Choi JI, Kim YH. The Impact of Personal Thoracic Impedance on Electrical Cardioversion in Patients with Atrial Arrhythmias. ACTA ACUST UNITED AC 2021; 57:medicina57060618. [PMID: 34199329 PMCID: PMC8231855 DOI: 10.3390/medicina57060618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/31/2021] [Accepted: 06/11/2021] [Indexed: 11/30/2022]
Abstract
Background and Objectives: Direct current cardioversion (DCCV) is a safe and useful treatment for atrial tachyarrhythmias. In the past, the energy delivered in DCCV was decided upon empirically, based only on the type of tachyarrhythmia. This conventional method does not consider individual factors and may lead to unnecessary electrical damage. Materials and Methods: We performed DCCV in patients with atrial tachyarrhythmias. The impedance and electrical current at the moment of shock were measured. The human thoracic impedance between both defibrillator patches and the electric current that was used were measured. Results: A total of 683 DCCVs were performed on 466 atrial tachyarrhythmia patients. The average impedance was 64 ± 11 Ω and the average successful current was 23 ± 6 mA. The magnitude of the electrical current that was successful depended upon the human impedance (linear regression, B = −0.266, p < 0.001) and the left atrial diameter (B = 0.092, p < 0.001). Impedance was directly proportional to body mass index (BMI) (B = 1.598, p < 0.001) and was higher in females than in males (77 ± 15 Ω vs. 63 ± 11 Ω, p < 0.001). Notably, the high-impedance (>70 Ω) group had a higher BMI (27 ± 4 kg/m2 vs. 25 ± 3 kg/m2, p < 0.001) and a higher proportion of females (37% vs. 9%, p < 0.001) than the low-impedance group (<70 Ω). However, thoracic impedance was not an independent predictor for successful DCCV. Conclusions: Human thoracic impedance was one of the factors that impacted the level of electrical current required for successful DCCV in patients with atrial arrhythmias. In the future, it will be helpful to consider individual predictors, such as BMI and gender, to minimize electrical damage during DCCV.
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Affiliation(s)
- Seung-Young Roh
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul 02841, Korea; (S.-Y.R.); (J.S.); (J.-I.C.)
| | - Jinhee Ahn
- Division of Cardiology, Department of Internal Medicine, Pusan National University Hsopital, Busan 49241, Korea;
| | - Kwang-No Lee
- Division of Cardiology, Department of Internal Medicine, Ajou University Hospital, Suwon 16499, Korea;
| | - Yong-Soo Baek
- Division of Cardiology, Department of Internal Medicine, Inha University hospital, Incheon 22332, Korea;
| | - Dong-Hyeok Kim
- Division of Cardiology, Department of Internal Medicine, Ewha University Hospital, Seoul 07804, Korea;
| | - Dae-In Lee
- Division of Cardiology, Department of Internal Medicine, Chungbuk National University Hospital, Chungju-si 28644, Korea;
| | - Jaemin Shim
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul 02841, Korea; (S.-Y.R.); (J.S.); (J.-I.C.)
| | - Jong-Il Choi
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul 02841, Korea; (S.-Y.R.); (J.S.); (J.-I.C.)
| | - Young-Hoon Kim
- Division of Cardiology, Department of Internal Medicine, Korea University College of Medicine and Korea University Medical Center, Seoul 02841, Korea; (S.-Y.R.); (J.S.); (J.-I.C.)
- Correspondence:
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Granfeldt A. Resuscitation Plus: The right journal for a new dawn for experimental resuscitation science research. Resusc Plus 2020; 3:100019. [PMID: 34223302 PMCID: PMC8244456 DOI: 10.1016/j.resplu.2020.100019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 07/14/2020] [Indexed: 01/01/2023] Open
Affiliation(s)
- Asger Granfeldt
- Corresponding author. Department of Intensive Care, Aarhus University hospital, Palle Juul Jensens Blvd. 99 G304, 8200, Aarhus N, Denmark.
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Chiou YA, Cheng LK, Lin SF. Effects of high-frequency biphasic shocks on ventricular vulnerability and defibrillation outcomes through synchronized virtual electrode responses. PLoS One 2020; 15:e0232529. [PMID: 32357163 PMCID: PMC7194403 DOI: 10.1371/journal.pone.0232529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/16/2020] [Indexed: 11/19/2022] Open
Abstract
Electrical defibrillation is a well-established treatment for cardiac dysrhythmias. Studies have suggested that shock-induced spatial sawtooth patterns and virtual electrodes are responsible for defibrillation efficacy. We hypothesize that high-frequency shocks enhance defibrillation efficacy by generating temporal sawtooth patterns and using rapid virtual electrodes synchronized with shock frequency. High-speed optical mapping was performed on isolated rat hearts at 2000 frames/s. Two defibrillation electrodes were placed on opposite sides of the ventricles. An S1-S2 pacing protocol was used to induce ventricular tachyarrhythmia (VTA). High-frequency shocks of equal energy but varying frequencies of 125–1000 Hz were used to evaluate VTA vulnerability and defibrillation success rate. The 1000-Hz shock had the highest VTA induction rate in the shorter S1-S2 intervals (50 and 100 ms) and the highest VTA defibrillation rate (70%) among all frequencies. Temporal sawtooth patterns and synchronous shock-induced virtual electrode responses could be observed with frequencies of up to 1000 Hz. The improved defibrillation outcome with high-frequency shocks suggests a lower energy requirement than that of low-frequency shocks for successful ventricular defibrillation.
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Affiliation(s)
- Yu-An Chiou
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Li-Kuan Cheng
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Shien-Fong Lin
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- * E-mail:
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Plancke AM, Connolly A, Gemmell PM, Neic A, McSpadden LC, Whitaker J, O'Neill M, Rinaldi CA, Rajani R, Niederer SA, Plank G, Bishop MJ. Generation of a cohort of whole-torso cardiac models for assessing the utility of a novel computed shock vector efficiency metric for ICD optimisation. Comput Biol Med 2019; 112:103368. [PMID: 31352217 PMCID: PMC6873640 DOI: 10.1016/j.compbiomed.2019.103368] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/22/2019] [Accepted: 07/22/2019] [Indexed: 11/29/2022]
Abstract
Implanted cardiac defibrillators (ICDs) seek to automatically detect and terminate potentially lethal ventricular arrhythmias by applying strong internal electric shocks across the heart. However, the optimisation of the specific electrode design and configurations represents an intensive area of research in the pursuit of reduced shock strengths and fewer device complications and risks. Computational whole-torso simulations play an important role in this endeavour, although knowing which specific metric should be used to assess configuration efficacy and assessing the impact of different patient anatomies and pathologies, and the corresponding effect this may have on different metrics has not been investigated. We constructed a cohort of CT-derived high-resolution whole torso-cardiac computational models, including variants of cardiomyopathies and patients with differing torso dimensions. Simulations of electric shock application between electrode configurations corresponding to transveneous (TV-ICD) and subcutaneous (S-ICD) ICDs were modelled and conventional metrics such as defibrillation threshold (DFT) and impedance computed. In addition, we computed a novel metric termed the shock vector efficiency (η), which quantifies the fraction of electrical energy dissipated in the heart relative to the rest of the torso. Across the cohort, S-ICD configurations showed higher DFTs and impedances than TV-ICDs, as expected, although little consistent difference was seen between healthy and cardiomyopathy variants. η was consistently <2% for S-ICD configurations, becoming as high as 13% for TV-ICD setups. Simulations also suggested that a total torso height of approximately 20 cm is required for convergence in η. Overall, η was seen to be approximately negatively correlated with both DFT and impedance. However, important scenarios were identified in which certain values of DFT (or impedance) were associated with a range of η values, and vice-versa, highlighting the heterogeneity introduced by the different torsos and pathologies modelled. In conclusion, the shock vector efficiency represents a useful additional metric to be considered alongside DFT and impedance in the optimisation of ICD electrode configurations, particularly in the context of differing torso anatomies and cardiac pathologies, which can induce significant heterogeneity in conventional metrics of ICD efficacy.
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Affiliation(s)
- Anne-Marie Plancke
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Adam Connolly
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Philip M Gemmell
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Aurel Neic
- Institute of Biophysics, Medical University of Graz, Austria
| | | | - John Whitaker
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Mark O'Neill
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Christopher A Rinaldi
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Ronak Rajani
- Cardiovascular Imaging Department, St Thomas' Hospital, London, UK
| | - Steven A Niederer
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Austria
| | - Martin J Bishop
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK.
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Connolly A, Williams S, Rhode K, Rinaldi CA, Bishop MJ. Conceptual Intra-Cardiac Electrode Configurations That Facilitate Directional Cardiac Stimulation for Optimal Electrotherapy. IEEE Trans Biomed Eng 2019; 66:1259-1268. [PMID: 31021745 PMCID: PMC7054045 DOI: 10.1109/tbme.2018.2871863] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Electrotherapy remains the most effective direct therapy against lethal cardiac arrhythmias. When an arrhythmic event is sensed, either strong electric shocks or controlled rapid pacing is automatically applied directly to the heart via an implanted cardioverter defibrillator (ICDs). Despite their success, ICDs remain a highly non-optimal therapy: the strong shocks required for defibrillation cause significant extra-cardiac stimulation, resulting in pain and long-term tissue damage, and can also limit battery life. When used in anti-tachycardia pacing mode, ICDs are also often ineffective, as the pacing electrode can be far away from the centre of the arrhythmia, making it hard for the paced wave to interrupt and terminate it. METHODS In this paper, we present two conceptual intra-cardiac directional electrode configurations in silico based on novel arrangements of pairs of positive-negative electrodes. Both configurations have the potential to cause preferential excitation on specific regions of the heart. RESULTS We demonstrate how the properties of the induced field varies spatially around the electrodes and how it depends upon the specific arrangements of dipole electrode pairs. The results show that when tested within anatomically-realistic rabbit ventricular models, both electrode configurations produce strong virtual electrodes on the targeted endocardial surfaces, with weaker virtual electrodes produced elsewhere. CONCLUSIONS The proposed electrode configurations may facilitate targeted far-field anti-tachycardia pacing and/or defibrillation, which may be useful in cases where conventional anti-tachycardia pacing fails. In addition, the conceptual electrode designs intrinsically confine the electric field to the immediate vicinity of the electrodes, and may, thus, minimize pain due to unnecessary extra-cardiac stimulation.
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Semenov I, Grigoryev S, Neuber JU, Zemlin CW, Pakhomova ON, Casciola M, Pakhomov AG. Excitation and injury of adult ventricular cardiomyocytes by nano- to millisecond electric shocks. Sci Rep 2018; 8:8233. [PMID: 29844431 PMCID: PMC5974370 DOI: 10.1038/s41598-018-26521-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Intense electric shocks of nanosecond (ns) duration can become a new modality for more efficient but safer defibrillation. We extended strength-duration curves for excitation of cardiomyocytes down to 200 ns, and compared electroporative damage by proportionally more intense shocks of different duration. Enzymatically isolated murine, rabbit, and swine adult ventricular cardiomyocytes (VCM) were loaded with a Ca2+ indicator Fluo-4 or Fluo-5N and subjected to shocks of increasing amplitude until a Ca2+ transient was optically detected. Then, the voltage was increased 5-fold, and the electric cell injury was quantified by the uptake of a membrane permeability marker dye, propidium iodide. We established that: (1) Stimuli down to 200-ns duration can elicit Ca2+ transients, although repeated ns shocks often evoke abnormal responses, (2) Stimulation thresholds expectedly increase as the shock duration decreases, similarly for VCMs from different species, (3) Stimulation threshold energy is minimal for the shortest shocks, (4) VCM orientation with respect to the electric field does not affect the threshold for ns shocks, and (5) The shortest shocks cause the least electroporation injury. These findings support further exploration of ns defibrillation, although abnormal response patterns to repetitive ns stimuli are of a concern and require mechanistic analysis.
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Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
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Anantharaman V, Wan PW, Tay SY, Manning PG, Lim SH, Chua SJT, Mohan T, Rabind AC, Vidya S, Hao Y. Role of peak current in conversion of patients with ventricular fibrillation. Singapore Med J 2017; 58:432-437. [PMID: 28741007 DOI: 10.11622/smedj.2017070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Peak currents are the final arbiter of defibrillation in patients with ventricular fibrillation (VF). However, biphasic defibrillators continue to use energy in joules for electrical conversion in hopes that their impedance compensation properties will address transthoracic impedance (TTI), which must be overcome when a fixed amount of energy is delivered. However, optimal peak currents for conversion of VF remain unclear. We aimed to determine the role of peak current and optimal peak levels for conversion in collapsed VF patients. METHODS Adult, non-pregnant patients presenting with non-traumatic VF were included in the study. All defibrillations that occurred were included. Impedance values during defibrillation were used to calculate peak current values. The endpoint was return of spontaneous circulation (ROSC). RESULTS Of the 197 patients analysed, 105 had ROSC. Characteristics of patients with and without ROSC were comparable. Short duration of collapse < 10 minutes correlated positively with ROSC. Generally, patients with average or high TTI converted at lower peak currents. 25% of patients with high TTI converted at 13.3 ± 2.3 A, 22.7% with average TTI at 18.2 ± 2.5 A and 18.6% with low TTI at 27.0 ± 4.7 A (p = 0.729). Highest peak current conversions were at < 15 A and 15-20 A. Of the 44 patients who achieved first-shock ROSC, 33 (75.0%) received < 20 A peak current vs. > 20 A for the remaining 11 (25%) patients (p = 0.002). CONCLUSION For best effect, priming biphasic defibrillators to deliver specific peak currents should be considered.
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Affiliation(s)
| | - Paul Weng Wan
- Department of Emergency Medicine, Singapore General Hospital, Singapore
| | - Seow Yian Tay
- Emergency Department, Tan Tock Seng Hospital, Singapore
| | | | - Swee Han Lim
- Department of Emergency Medicine, Singapore General Hospital, Singapore
| | | | - Tiru Mohan
- Accident and Emergency Department, Changi General Hospital, Singapore
| | | | - Sudarshan Vidya
- Department of Emergency Medicine, Singapore General Hospital, Singapore
| | - Ying Hao
- Health Services Research Unit, Singapore General Hospital, Singapore
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Remote Postconditioning Alone and Combined with Hypothermia Improved Postresuscitation Cardiac and Neurological Outcomes in Swine. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6743648. [PMID: 28097144 PMCID: PMC5206419 DOI: 10.1155/2016/6743648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 11/20/2016] [Accepted: 11/29/2016] [Indexed: 11/18/2022]
Abstract
Objective. Previously, we demonstrated that remote ischemic postconditioning (RIpostC) improved postresuscitation myocardial and cerebral functions in rat. Here, we investigated the effects of RIpostC alone and combined with therapeutic hypothermia (TH) on cardiac and neurological outcomes after CPR in swine. Methods. Twenty-one pigs were subjected to 10 mins of VF and then 5 mins of CPR. The animals were randomized to receive RIpostC alone, or its combination with TH, or sham control. RIpostC was induced by 4 cycles of limb ischemia followed by reperfusion. TH was implemented by surface cooling to reach a temperature of 32–34°C. Results. During 72 hrs after resuscitation, lower level of cardiac troponin I and greater stroke volume and global ejection fraction were observed in animals that received RIpostC when compared to the control. RIpostC also decreased serum levels of neuron-specific enolase and S100B and increased neurologic alertness score after resuscitation. The combination of RIpostC and TH resulted in greater improvement in cardiac and neurological outcomes than RIpostC alone. Conclusion. RIpostC was conducive to improving postresuscitation myocardial and cerebral functions and reducing their organ injuries. Its combination with TH further enhanced its protective effects.
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Bougouin W, Cariou A. Dysfonction myocardique post-arrêt cardiaque. MEDECINE INTENSIVE REANIMATION 2014. [DOI: 10.1007/s13546-014-0849-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Postresuscitation Treatment With Argon Improves Early Neurological Recovery in a Porcine Model of Cardiac Arrest. Shock 2014; 41:72-8. [DOI: 10.1097/shk.0000000000000049] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Fluid Resuscitation Guided by Sublingual Partial Pressure of Carbon Dioxide During Hemorrhagic Shock in a Porcine Model. Shock 2013; 39:361-5. [DOI: 10.1097/shk.0b013e31828936aa] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The effects of a newly developed miniaturized mechanical chest compressor on outcomes of cardiopulmonary resuscitation in a porcine model*. Crit Care Med 2013; 40:3007-12. [PMID: 23080437 DOI: 10.1097/ccm.0b013e31825d924d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE When the duration of cardiac arrest is prolonged, reperfusion of the vital organs by effective chest compression is the most important intervention for successful resuscitation. We investigated the effects of a newly developed miniaturized chest compressor on the outcomes of cardiopulmonary resuscitation. DESIGN Prospective, randomized, controlled experimental study. SETTING University-affiliated animal research laboratory. SUBJECTS Thirty male domestic pigs. INTERVENTIONS Ventricular fibrillation was induced in 30 male domestic pigs weighing 35 ± 2 kg. Cardiopulmonary resuscitation was initiated after 7 mins of untreated ventricular fibrillation. The animals were randomized to receive mechanical chest compression with a miniaturized chest compressor, a LUCAS device or a Thumper device. After 5 mins of cardiopulmonary resuscitation, a 150-J defibrillation was delivered. If resuscitation was not successful, cardiopulmonary resuscitation was continued for 2 mins before the next defibrillation. The protocol was continued until successful resuscitation or for a total of 15 mins of cardiopulmonary resuscitation. The animals were observed for 72 hrs after resuscitation. MEASUREMENTS AND MAIN RESULTS The miniaturized chest compressor generated significantly greater coronary perfusion pressure, end-tidal PCO2, carotid blood flow, and intrathoracic negative pressure, with significantly lower compression depth and fewer rib fractures when compared with both the LUCAS and Thumper devices. Both the miniaturized chest compressor and LUCAS devices required lower numbers of defibrillation for successful resuscitation when compared with the Thumper device. This was associated with lower prevalence of recurrent ventricular fibrillation and better postresuscitation myocardial and neurological function when compared with the Thumper device. CONCLUSIONS The miniaturized chest compressor improves hemodynamic efficacy and the success of cardiopulmonary resuscitation with significantly less injury, which is as effective as the LUCAS device. It may provide a new option for cardiopulmonary resuscitation.
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Rozanski EA, Rush JE, Buckley GJ, Fletcher DJ, Boller M. RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 4: Advanced life support. J Vet Emerg Crit Care (San Antonio) 2012; 22 Suppl 1:S44-64. [DOI: 10.1111/j.1476-4431.2012.00755.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - John E. Rush
- Cummings School of Veterinary Medicine; Tufts University; North Grafton; MA
| | - Gareth J. Buckley
- College of Veterinary Medicine, University of Florida; Gainesville; FL
| | - Daniel J. Fletcher
- College of Veterinary Medicine, Department of Clinical Sciences; Cornell University; Ithaca; NY
| | - Manuel Boller
- Department of Clinical Studies, School of Veterinary Medicine and the Department of Emergency Medicine, School of Medicine; Center for Resuscitation Science University of Pennsylvania; Philadelphia; PA
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High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics. Crit Care Med 2010; 36:S422-7. [PMID: 20449905 DOI: 10.1097/ccm.0b013e31818a84c5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES We examined the effects of energy delivered with electrical defibrillation on myocyte contractility and intracellular Ca2+ dynamics. We hypothesized that increasing the defibrillation energy would produce correspondent reduction in myocyte contractility and intracellular Ca2+ dynamics. DESIGN Randomized prospective study. SETTING University-affiliated research laboratory. SUBJECTS Ventricular myocytes from male Sprague-Dawley rat hearts. MATERIALS AND METHODS Ventricular cardiomyocytes loaded with Fura-2/AM were placed in a chamber mounted on an inverted microscope and superfused with a buffer solution at 37 degrees C. The cells were field stimulated to contract and mechanical properties were assessed using a video-based edge-detection system. Intracellular Ca2+ dynamics were evaluated with a dual-excitation fluorescence photomultiplier system. Myocytes were then randomized to receive 1) a single 0.5-J biphasic shock; 2) a single 1-J biphasic shock; 3) a single 2-J biphasic shock; and 4) a control group without shock. After the shock, myocytes were paced for an additional 4 mins. RESULTS A single 0.5-J shock did not have effects on contractility and intracellular Ca2+ dynamics. Higher energy shocks, i.e., 1- or 2-J shocks, significantly impaired contractility and intracellular Ca2+ dynamics. The adverse effects were greater after a 2-J shock compared with a 1-J shock. CONCLUSIONS Higher defibrillation energy significantly impairs ventricular contractility at the myocyte level. Reductions in cardiomyocyte shortening and intracellular Ca2+ dynamics abnormalities were greater when higher energy shock was used.
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Intra-arrest rapid head cooling improves postresuscitation myocardial function in comparison with delayed postresuscitation surface cooling. Crit Care Med 2010; 36:S434-9. [PMID: 20449907 DOI: 10.1097/ccm.0b013e31818a88b6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare resuscitation outcomes and myocardial function among intra-arrest head cooling, delayed surface cooling, and uncooled controls. DESIGN Prospective animal study. SETTING University-affiliated animal research laboratory. SUBJECTS Twenty-four male domestic pigs. INTERVENTIONS Ventricular fibrillation remained untreated for 10 mins after which animals were assigned into three groups: 1) intra-arrest head cooling, 2) postresuscitation surface cooling, and 3) uncooled controls. Head cooling by evaporative perfluorochemical began coincident with the start of cardiopulmonary resuscitation and continued for a total of 4 hrs. Surface cooling using a cooling blanket began at 2 hrs after return of spontaneous circulation and continued for 8 hrs. Control animals were treated identically with the exception for cooling. MEASUREMENTS AND MAIN RESULTS Return of spontaneous circulation was achieved in eight of eight head-cooled animals, in seven of eight surface-cooled animals, and in seven of eight of controls. Myocardial functions measured by transthoracic echocardiography were significantly better in the head-cooled animals than in surface-cooled and controls. All head-cooled animals survived for more than 96 hrs. This contrasted with six of eight survivors after surface cooling, and only two of eight among controls. CONCLUSIONS Both intra-arrest head cooling and delayed surface cooling improved postresuscitation myocardial dysfunction. The beneficial effects were greatest with head cooling initiated with cardiopulmonary resuscitation.
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Walcott GP, Melnick SB, Killingsworth CR, Ideker RE. Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation. PREHOSP EMERG CARE 2010; 14:62-70. [PMID: 19947869 DOI: 10.3109/10903120903349838] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Since the initial development of the defibrillator, there has been concern that, while delivery of a large electric shock would stop fibrillation, it would also cause damage to the heart. This concern has been raised again with the development of the biphasic defibrillator. OBJECTIVE To compare defibrillation efficacy, postshock cardiac function, and troponin I levels following 150-J and 360-J shocks. METHODS Nineteen swine were anesthetized with isoflurane and instrumented with pressure catheters in the left ventricle, aorta, and right atrium. The animals were fibrillated for 6 minutes, followed by defibrillation with either low-energy (n = 8) or high-energy (n = 11) shocks. After defibrillation, chest compressions were initiated and continued until return of spontaneous circulation (ROSC). Epinephrine, 0.01 mg/kg every 3 minutes, was given for arterial blood pressure < 50 mmHg. Hemodynamic parameters were recorded for four hours. Transthoracic echocardiography was performed and troponin I levels were measured at baseline and four hours following ventricular fibrillation (VF). RESULTS Survival rates at four hours were not different between the two groups (low-energy, 5 of 8; high-energy, 7 of 11). Results for arterial blood pressure, positive dP/dt (first derivative of pressure measured over time, a measure of left ventricular contractility), and negative dP/dt at the time of lowest arterial blood pressure (ABP) following ROSC were not different between the two groups (p = not significant [NS]), but were lower than at baseline. All hemodynamic measures returned to baseline by four hours. Ejection fractions, stroke volumes, and cardiac outputs were not different between the two groups at four hours. Troponin I levels at four hours were not different between the two groups (12 +/- 11 ng/mL versus 21 +/- 26 ng/mL, p = NS) but were higher at four hours than at baseline (19 +/- 19 ng/mL versus 0.8 +/- 0.5 ng/mL, p < 0.05, groups combined). CONCLUSION Biphasic 360-J shocks do not cause more cardiac damage than biphasic 150-J shocks in this animal model of prolonged VF and resuscitation.
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Affiliation(s)
- Gregory P Walcott
- Department of Medicine-Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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Wang H, Barbut D, Tsai MS, Sun S, Weil MH, Tang W. Intra-arrest selective brain cooling improves success of resuscitation in a porcine model of prolonged cardiac arrest. Resuscitation 2010; 81:617-21. [PMID: 20207471 DOI: 10.1016/j.resuscitation.2010.01.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 12/09/2009] [Accepted: 01/17/2010] [Indexed: 11/26/2022]
Abstract
AIMS OF STUDY We have previously demonstrated that early intra-nasal cooling improved post-resuscitation neurological outcomes. The present study utilizing a porcine model of prolonged cardiac arrest investigated the effects of intra-nasal cooling initiated at the start of cardiopulmonary resuscitation (CPR) on resuscitation success. Our hypothesis was that rapid nasal cooling initiated during "low-flow" improves return of spontaneous resuscitation (ROSC). METHODS In 16 domestic male pigs weighing 40+/-3 kg, VF was electrically induced and untreated for 15 min. Animals were randomized to either head cooling or control. CPR was initiated and continued for 5 min before defibrillation was attempted. Coincident with starting CPR, the hypothermic group was cooled with a RhinoChill device which produces evaporative cooling in the nasal cavity of pigs. No cooling was administrated to control animals. If ROSC was not achieved after defibrillation, CPR was resumed for 1 min prior to the next defibrillation attempt until either successful resuscitation or for a total of 15 min. MAIN RESULTS Seven of eight animals in the hypothermic group (87.5%) and two of eight animals in control group (25%) (p=0.04) were successfully resuscitated. At ROSC, brain temperature was increased from baseline by 0.3 degrees C in the control group, and decreased by 0.1 degrees C in the hypothermic animals. Pulmonary artery temperature was above baseline in both groups. CONCLUSION Intra-nasal cooling initiated at the start of CPR significantly improves the success of resuscitation in a porcine model of prolonged cardiac arrest. This may have occurred by preventing brain hyperthermia.
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Affiliation(s)
- Hao Wang
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA, USA
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The effects of phase duration on defibrillation success of dual time constant biphasic waveforms. Resuscitation 2009; 81:236-41. [PMID: 19945206 DOI: 10.1016/j.resuscitation.2009.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/30/2009] [Accepted: 10/21/2009] [Indexed: 11/24/2022]
Abstract
AIM OF STUDY The effects of first and second phase duration of biphasic waveforms on defibrillation success were evaluated in a guinea pig model of ventricular fibrillation (VF). We hypothesized that waveform duration, and especially the first phase duration, played a main role on defibrillation efficacy in comparison to energy, current and voltage, when a dual time constant biphasic shock was employed. METHODS VF was induced and untreated for 5s in 30 male guinea pigs, prior to attempting a single defibrillatory shock with one of 5 defibrillation waveforms which had different durations of the first and second phase. A five step up-down protocol was utilized for determining the defibrillation efficacy. After a 3-min interval, the procedure was repeated. A total of 25 cardiac arrest events and defibrillations were investigated for each animal. RESULTS The defibrillation waveforms with an intermediate first phase of 5 ms, yielded the highest defibrillation success (p<0.05). These waveforms also presented significantly lower energy, current and voltage in comparison to waveforms with shorter or longer first phase durations (p<0.001). However, no differences on defibrillation success were observed among waveforms with different second phase durations varying from 1.5 ms to 3.5 ms. CONCLUSIONS For dual time constant biphasic waveforms, the first phase duration played a main role on defibrillation success. The intermediate first phase duration of 5 ms, yielded the best defibrillation efficacy compared with shorter or longer first phase durations. While the second phase duration did not affect defibrillation outcomes.
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Li Y, Wang H, Cho JH, Didon JP, Bisera J, Weil MH, Tang W. Comparison of efficacy of pulsed biphasic waveform and rectilinear biphasic waveform in a short ventricular fibrillation pig model. Resuscitation 2009; 80:1047-51. [DOI: 10.1016/j.resuscitation.2009.05.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 05/12/2009] [Accepted: 05/15/2009] [Indexed: 11/15/2022]
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Individual effect of components of defibrillation waveform on the contractile function and intracellular calcium dynamics of cardiomyocytes. Crit Care Med 2009; 37:2394-401. [PMID: 19531953 DOI: 10.1097/ccm.0b013e3181a02ea1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Although electrical shock is a unique and effective treatment for fatal arrhythmia, it produces myocardial dysfunction closely related to the intensity of shock delivered. The isolated contribution of defibrillator components to postshock contractile impairment is not yet securely established. We sought to evaluate contractile function in cardiomyocytes following electrical shocks with different peak currents, energies, and durations. We hypothesized that peak current may play a more important role than energy in determining postshock dysfunction. Prolongation of the duration may reduce contractile impairment. DESIGN Prospective, randomized, controlled study. SETTING University-affiliated research institute. SUBJECTS Male albino Sprague-Dawley rats. INTERVENTIONS We assigned 324 cardiomyocytes isolated from adult male rats to 11 groups having different waveforms (triangular and square), peak currents (derived from peak voltage gradients of 25 V/cm, 35.4 V/cm, 50 V/cm, 70.7 V/cm, and 100 V/cm), and durations (10 and 20 msecs) of shocks delivered. One single shock was given to each cardiomyocyte, and length shortening and Ca transients were recorded optically with fura-2 loading. MEASUREMENTS AND MAIN RESULTS Increase of peak current and corresponding energy caused more cells to have irregular beating (p < .001) and reduced length shortening (p < .001). This was associated with increased Ca abnormality (p < .05). Increasing peak current independent of energy significantly impaired postshock contractile function (p < .05), whereas the change of energy alone did not. Prolongation of duration independent of energy and peak current reduced postshock contractile impairment (p < .05). CONCLUSIONS Peak current may play a more determinative role in producing postshock contractile dysfunction than does energy.
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Freeman K, Hendey GW, Shalit M, Stroh G. Biphasic Defibrillation Does not Improve Outcomes Compared to Monophasic Defibrillation in Out-of-Hospital Cardiac Arrest. PREHOSP EMERG CARE 2009; 12:152-6. [DOI: 10.1080/10903120801907240] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Minimal interruption of cardiopulmonary resuscitation for a single shock as mandated by automated external defibrillations does not compromise outcomes in a porcine model of cardiac arrest and resuscitation. Crit Care Med 2008; 36:3048-53. [PMID: 18824916 DOI: 10.1097/ccm.0b013e318186f612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Current automated external defibrillations require interruptions in chest compressions to avoid artifacts during electrocardiographic analyses and to minimize the risk of accidental delivery of an electric shock to the rescuer. The earlier three-shock algorithm, with prolonged interruptions of chest compressions, compromised outcomes and increased severity of postresuscitation myocardial dysfunction. In the present study, we investigated the effect of timing of minimal automated external defibrillation-mandated interruptions of chest compressions on cardiopulmonary resuscitation outcomes, using a single-shock algorithm. We hypothesized that an 8-sec interruption of chest compressions for a single shock, as mandated by automated external defibrillations, would not impair initial resuscitation and outcomes of cardiopulmonary resuscitation. DESIGN Randomized prospective animal study. SETTING University affiliated research laboratory. SUBJECTS Domestic pigs. MEASUREMENTS AND MAIN RESULTS In 24 domestic male pigs weighing 41 +/- 2 kg, ventricular fibrillation was induced by left anterior descending coronary artery occlusion and untreated for 7 min. Cardiopulmonary resuscitation, including chest compressions and ventilation with oxygen, was then performed for an interval of 2 min before attempted defibrillation. Animals were randomized into three groups: A) interruption immediately before defibrillation; B) interruption after 1 min of cardiopulmonary resuscitation; or C) no interruption. Chest compressions were delivered with the aid of a mechanical chest compressor at a rate of 100 compressions/min and compression/ventilation ratio of 30:2. Defibrillation was attempted with a single biphasic 150-J shock. Each animal was successfully resuscitated and survived for >72 hr. No differences in the number of shocks before return of spontaneous circulation, frequency of recurrent ventricular fibrillation, duration of cardiopulmonary resuscitation, and severity of postresuscitation myocardial dysfunction were observed. CONCLUSIONS In this experimental model of cardiac arrest and cardiopulmonary resuscitation, minimal automated external defibrillation-mandated interruption of chest compressions for a single-shock algorithm did not have adverse effects on postresuscitation myocardial or neurologic function. All animals, whether subjected to cardiopulmonary resuscitation interruptions or not, survived.
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Abstract
Although cardiac arrhythmias less commonly cause hemodynamic compromise in children than in adults, prompt recognition and treatment of arrhythmias remain an important part of pediatric resuscitation because of the availability of specific, effective therapies. This article summarizes the 2005 American Heart Association Guidelines for Pediatric Advanced Life Support regarding tachyarrhythmias, including treatment with antiarrhythmics and direct current countershock therapy, and provides an update of recent literature since the guidelines were published.
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Cardiac Arrest and Cardiopulmonary Resuscitation. Crit Care Med 2008. [DOI: 10.1016/b978-032304841-5.50003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ristagno G, Sun S, Tang W, Castillo C, Weil MH. Effects of epinephrine and vasopressin on cerebral microcirculatory flows during and after cardiopulmonary resuscitation. Crit Care Med 2007; 35:2145-9. [PMID: 17855828 DOI: 10.1097/01.ccm.0000280427.76175.d2] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Both epinephrine and vasopressin increase aortic and carotid arterial pressure when administered during cardiopulmonary resuscitation. However, we recently demonstrated that epinephrine reduces cerebral cortical microcirculatory blood flow. Accordingly, we compared the effects of nonadrenergic vasopressin with those of epinephrine on cerebral cortical microvascular flow together with cortical tissue Po2 and Pco2 as indicators of cortical tissue ischemia. DESIGN Randomized, prospective animal study. SETTING University-affiliated research laboratory. SUBJECTS Domestic pigs. MEASUREMENTS AND MAIN RESULTS The tracheae of ten domestic male pigs, weighing 40 +/- 2 kg, were noninvasively intubated, and the animals were mechanically ventilated. A frontoparietal bilateral craniotomy was created. Microcirculatory blood flow was quantitated with orthogonal polarization spectral imaging. Blood flow velocity in pial and cortical penetrating vessels measuring <20 microm was graded from 0 (no flow) to 3 (normal). Cerebral cortical tissue carbon dioxide and oxygen tensions (Pbco2 and Pbo2) were measured concurrently using miniature optical sensors. Ventricular fibrillation, induced with an alternating current delivered to the right ventricular endocardium, was untreated for 3 mins. Animals were then randomized to receive central venous injections of equipressor doses of epinephrine (30 microg/kg) or vasopressin (0.4 units/kg) at 1 min after the start of cardiopulmonary resuscitation. After 4 mins of cardiopulmonary resuscitation, defibrillation was attempted. Spontaneous circulation was restored in each animal. However, postresuscitation microvascular flows and Pbo2 were greater and Pbco2 less after vasopressin when compared with epinephrine. We observed that a significantly greater number of cortical microvessels were perfused after vasopressin. CONCLUSIONS Cortical microcirculatory blood flow was markedly reduced after epinephrine, resulting in a greater severity of brain ischemia after the restoration of spontaneous circulation in contrast to the more benign effects of vasopressin.
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Chang YT, Tang W, Russell JK, Ristagno G, Sun S, Weil MH. Exclusion of a patient assessment interval and extension of the CPR interval both mitigate post-resuscitation myocardial dysfunction in a swine model of cardiac arrest. Resuscitation 2007; 76:285-90. [PMID: 17728041 DOI: 10.1016/j.resuscitation.2007.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 06/29/2007] [Accepted: 07/02/2007] [Indexed: 11/16/2022]
Abstract
AIM OF STUDY Interruptions in cardiopulmonary resuscitation (CPR), particularly as guided by automated external defibrillators, have been implicated in poor survival from cardiac arrest. Interruptions of CPR may be reduced by eliminating repetition of shocks between periods of CPR, elimination of the interval for patient assessment before CPR, and extension of the periods of CPR. MATERIALS AND METHODS The effects of exclusion of a 30s post-shock assessment interval prior to CPR and use of a longer interval (180s versus 90s) of CPR on resuscitation and post-resuscitation function were assessed in a factorial design using an established swine model of cardiac arrest. Repetitive shocks were excluded. Ventricular fibrillation was induced ischemically and maintained untreated for 5min. RESULTS All subjects were resuscitated, 95% survived 3 days, and 97% of survivors had full neurological recovery. Exclusion of the assessment interval reduced the delay to first return of spontaneous circulation by 33.1s (P=0.004) and the delay to sustained resuscitation by 99.2s (P=0.004), reduced post-resuscitation ECG ST elevation by 0.12mV (P=0.03), and alleviated transient post-resuscitation ejection fraction reduction (P<0.0001). Extension of the CPR interval reduced transient post-resuscitation fractional area change impairment (P=0.003). CONCLUSIONS Exclusion of an interval for assessment of airway, breathing and signs of circulation mitigates post-resuscitation dysfunction in a swine model of cardiac arrest. Extension of the period of CPR independently provides measurable, though less comprehensive, mitigation as well.
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Affiliation(s)
- Yun-Te Chang
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA 92270-1761, USA
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Ristagno G, Castillo C, Tang W, Sun S, Bisera J, Weil MH. Miniaturized mechanical chest compressor: a new option for cardiopulmonary resuscitation. Resuscitation 2007; 76:191-7. [PMID: 17728044 DOI: 10.1016/j.resuscitation.2007.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 06/27/2007] [Accepted: 07/02/2007] [Indexed: 11/25/2022]
Abstract
AIM OF STUDY After cardiac arrest, uninterrupted chest compressions with restoration of myocardial blood flow facilitates restoration of spontaneous circulation. We recognized that this may best be accomplished with a mechanical device and especially so during transport. We therefore sought to develop a lightweight, portable chest compressor which may be carried on the belt or attached to the oxygen tank typically carried on the back of the first response rescuer. A miniaturized pneumatic chest compressor (MCC) weighing less than 2 kg was developed and compared with a currently marketed "Michigan Thumper", which weighed 19 kg. We hypothesized that the 2 kg, low profile, portable device will be as effective as the standard pneumatic Thumper for restoring circulation during CPR. MATERIAL AND METHODS Ventricular fibrillation was electrically induced in 10 domestic male pigs weighing 39+/-2 kg, and untreated for 5 min. Animals were then randomized to receive chest compressions with either the MCC or the Thumper. After 5 min of mechanical chest compression, defibrillation was attempted with a 150 J biphasic shock. Coronary perfusion pressure (CPP) and end tidal PCO(2) (EtPCO(2)) were measured by conventional techniques together with right carotid artery blood flow (CBF). RESULTS Four of five animals compressed with the Thumper and each animal compressed with the MCC were successfully resuscitated. No significant differences in CPP, EtPCO(2), CBF and post-resuscitation myocardial function were observed between groups. Resuscitated animals survived for more than 72 h without neurological impairment. CONCLUSION The low profile, 2 kg miniaturized chest compressor is as effective as the conventional Thumper in an experimental model of CPR.
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Affiliation(s)
- Giuseppe Ristagno
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA 92270, United States
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Ristagno G, Tang W, Xu TY, Sun S, Weil MH. Outcomes of CPR in the presence of partial occlusion of left anterior descending coronary artery. Resuscitation 2007; 75:357-65. [PMID: 17574322 DOI: 10.1016/j.resuscitation.2007.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 04/04/2007] [Accepted: 04/04/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES To develop a clinically relevant experimental model of cardiac arrest and CPR in which a partial occlusion of the left anterior descending coronary artery (LAD) is maintained during the resuscitation procedure and the initial post-resuscitation interval. MATERIALS AND METHODS Ventricular fibrillation (VF) was induced by LAD occlusion with a balloon tipped catheter in 16 domestic male pigs weighing 41+/-2kg. After a 7min interval of untreated VF, the LAD balloon occlusion was deflated and the catheter withdrawn in eight animals. The LAD balloon was deflated in the remaining eight animals but the catheter was kept in place in order to maintain a partial occlusion of the LAD, which was approximately 75% of the internal lumen. CPR, including chest compressions and ventilations with oxygen, was then performed for 2min before a defibrillation attempt. Thirty minutes following successful resuscitation the LAD catheter was withdrawn in the animals with partial occlusion of the LAD. RESULTS In the animals that had the LAD totally unoccluded before to starting CPR, each animal was resuscitated successfully and survived for more than 72h with better neurological recovery during the initial 24h post-resuscitation than did the partially occluded group. When a partial occlusion of the LAD was maintained during CPR, six of eight animals were resuscitated and only four of these survived for 72h. A significantly greater number of electrical shocks prior to ROSC were required when a partial occlusion of the LAD was maintained during CPR. Significantly greater severity of post-resuscitation myocardial dysfunction was observed in animals resuscitated with a partial occlusion of the LAD. CONCLUSIONS In this model of prolonged untreated cardiac arrest, maintaining a partial occlusion of the LAD during CPR and the initial post-resuscitation interval required a greater number of shocks before ROSC, increased severity of post-resuscitation myocardial dysfunction significantly and yielded less favourable outcomes.
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Affiliation(s)
- Giuseppe Ristagno
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA, United States
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Ristagno G, Tang W, Chang YT, Jorgenson DB, Russell JK, Huang L, Wang T, Sun S, Weil MH. The quality of chest compressions during cardiopulmonary resuscitation overrides importance of timing of defibrillation. Chest 2007; 132:70-5. [PMID: 17550931 DOI: 10.1378/chest.06-3065] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND We address the quality of chest compressions and the impact on initial defibrillation or initial chest compressions after sudden death. METHODS Ventricular fibrillation was induced by occlusion of the left anterior descending coronary artery in 24 domestic pigs with a mean (+/- SD) weight of 40 +/- 2 kg. Cardiac arrest was left untreated for 5 min. Animals were then randomized to receive chest compressions-first or defibrillation-first and were further randomized to "optimal" or "conventional" chest compressions. A total of four groups of animals were investigated using a factorial design. For optimal chest compressions, the anterior posterior diameter of the chest was reduced by 25%, representing approximately 6 cm. Only 70% of this depth, or approximately 4.2 cm, represented conventional chest compressions. Chest compressions were delivered with a mechanical chest compressor. Defibrillation was attempted with a single biphasic 150-J shock. Postresuscitation myocardial function was echocardiographically assessed. RESULTS Coronary perfusion pressures and end-tidal Pco(2) were significantly lower with conventional chest compressions. With optimal chest compressions, either as an initial intervention or after defibrillation, each animal was successfully resuscitated. Fewer shocks were required prior to the return of spontaneous circulation after initial optimal chest compressions. No animals were resuscitated when conventional chest compressions preceded the defibrillation attempt. When defibrillation was attempted as the initial intervention followed by conventional chest compressions, two of six animals were resuscitated. CONCLUSIONS In this animal model of cardiac arrest, it was the quality of the chest compressions, rather then the priority of either initial defibrillation or initial chest compressions, that was the predominant determinant of successful resuscitation.
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Affiliation(s)
- Giuseppe Ristagno
- Weil Institute of Critical Care Medicine, 35100 Bob Hope Dr, Rancho Mirage, CA 92270, USA
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Chang YT, Tang W, Wang J, Brewer JE, Freeman G, Sun S, Weil MH. Effects of biphasic waveforms on outcomes of cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest. Crit Care Med 2006; 34:3024-8. [PMID: 17075369 DOI: 10.1097/01.ccm.0000248881.15376.b4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The effects of two clinically available biphasic waveforms on the success of defibrillation and postresuscitation myocardial dysfunction after prolonged ventricular fibrillation were compared with two newly designed dual-path sequential and simultaneous rectilinear biphasic waveforms. Defibrillation via sequential pulses and encircling, overlapping multiple pathway may depolarize a larger myocardial mass and facilitate transthoracic defibrillation. DESIGN Animal study. SETTING Experimental laboratory. SUBJECTS Thirty-two 40 +/- 3 kg pigs. INTERVENTIONS Ventricular fibrillation was ischemically induced in 32 pigs. After 7 mins of untreated ventricular fibrillation, cardiopulmonary resuscitation was initiated and continued for 5 mins. Animals were then randomized to receive up to three shocks with a) single-path rectilinear biphasic waveform; b) single-path biphasic truncated exponential waveform; c) dual-path rectilinear biphasic sequential defibrillation; or d) dual-path rectilinear biphasic simultaneous defibrillation. MEASUREMENTS AND MAIN RESULTS Rectilinear biphasic, dual-path sequential defibrillation, and simultaneous defibrillation had significantly fewer shocks (1.1 +/- 0.4, 1.4 +/- 0.5, 1.3 +/- 0.7, respectively) before restoration of spontaneous circulation than biphasic truncated exponential waveform (2.6 +/- 1.4, p < .005) and less postresuscitation myocardial dysfunction (p < .05). Also, dual-path sequential defibrillation had higher postresuscitation ejection fraction than rectilinear biphasic and dual-path simultaneous defibrillation (p < .005). CONCLUSIONS The energy requirements for terminating ischemically induced ventricular fibrillation were significantly lower and minimized early postresuscitation myocardial dysfunction in the rectilinear biphasic, dual-path sequential defibrillation, and simultaneous defibrillation than the biphasic truncated exponential waveform. Dual-path sequential defibrillation had less postresuscitation myocardial dysfunction than rectilinear biphasic and dual-path simultaneous defibrillation, but at 72 hrs these differences were no longer significant.
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Affiliation(s)
- Yun-Te Chang
- Weil Institute of Critical Care Medicine, Rancho Mirage, CA, USA
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Samson RA, Berg MD, Berg RA. Cardiopulmonary resuscitation algorithms, defibrillation and optimized ventilation during resuscitation. Curr Opin Anaesthesiol 2006; 19:146-56. [PMID: 16552221 DOI: 10.1097/01.aco.0000192799.87548.d3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW In 2005, the American Heart Association released its Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. This article reviews the treatment algorithms for Advanced Cardiac Life Support, citing the evidence on which the Guidelines are based. Additional focus is placed on defibrillation and optimized ventilation. RECENT FINDINGS Major changes include a reorganization of the algorithms for cardiac arrest. Emphasis on effective cardiopulmonary resuscitation is placed as the key to improved survival. Single defibrillation shocks are recommended (compared with three 'stacked' shocks) with immediate provision of cardiopulmonary resuscitation and minimal interruptions in chest compressions. The recommended chest compression : ventilation rate for single rescuers has been changed to 30:2. SUMMARY Despite advances in resuscitation science, basic life support remains the key to improving survival outcomes. Ultimately, as new knowledge is gained, we believe resuscitation therapies will be more individualized, on the basis of pathophysiology and etiology of the initial cardiac arrest.
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Affiliation(s)
- Ricardo A Samson
- Department of Pediatrics, Steele Children's Research Center, The University of Arizona, Tucson, Arizona, USA
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Deakin CD, Ambler JJS. Post-shock myocardial stunning: A prospective randomised double-blind comparison of monophasic and biphasic waveforms. Resuscitation 2006; 68:329-33. [PMID: 16378672 DOI: 10.1016/j.resuscitation.2005.07.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 07/13/2005] [Accepted: 07/26/2005] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Compared with monophasic defibrillation, biphasic defibrillation is associated with less myocardial stunning and earlier activation of sodium channels. We therefore hypothesised that earlier sodium channel activation would result in earlier restoration of the first sinus beat following elective DC cardioversion. METHODS Adults undergoing elective DC cardioversion were randomised to receive either monophasic or biphasic escalating transthoracic shocks. The ECG was recorded electronically during defibrillation and the time from delivery of the shock to restoration of the first sinus beat, measured from the beginning of the 'P' wave, was calculated. RESULTS Seventy four patients were studied. Data were unavailable from 18 patients. There was no demographic difference between groups. Median time to the first sinus beat following monophasic defibrillation (n=25) was 3.66 s (95% CI 2.55-4.61 s) and following biphasic defibrillation (n=33) was 2.21s (95% CI 1.76-2.56 s; P<or=0.0001). Linear regression confirmed that the waveform was an independent predictor of time to restoration of sinus rhythm; P<0.0001. The final defibrillation energy level used to achieve cardioversion was not an independent predictor of time to restoration of sinus rhythm; P=0.49. CONCLUSION Biphasic defibrillation for elective DC cardioversion achieved more rapid restoration of the first sinus beat compared with a monophasic waveform. Waveform, but not energy level that achieved defibrillation, was an independent predictor of time to restoration of the first sinus beat. The mechanism for this may be related to the earlier reactivation of sodium channels associated with the biphasic waveform.
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Affiliation(s)
- Charles D Deakin
- Shackleton Department of Anaesthetics, Southampton University Hospital NHS Trust, Tremona Road, Southampton SO16 6YD, UK.
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Fang X, Tang W, Sun S, Wang J, Huang L, Weil MH. The characteristics of postcountershock pulseless electrical activity may indicate the outcome of CPR. Resuscitation 2006; 69:303-9. [PMID: 16459008 DOI: 10.1016/j.resuscitation.2005.07.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 07/17/2005] [Accepted: 07/17/2005] [Indexed: 11/17/2022]
Abstract
OBJECTIVES When ventricular fibrillation is cardioverted to pulseless electrical activity (PEA), PEA has been regarded as a non-resuscitatable rhythm. Yet, recent reports and our earlier observations suggested otherwise. We therefore investigated outcomes after postcountershock PEA, and aimed to develop a scoring system for outcome classification at the onset of initial postcountershock PEA. METHODS Data from 215 domestic pigs were retrospectively reviewed. VF was induced and untreated for 7 min. Defibrillation was attempted with up to three 150 J biphasic shocks. Failing to restore spontaneous circulation (ROSC), 1 min of CPR preceded subsequent sequences of shocks until animals were resuscitated or for a total of 15 min. Fifty-nine instances of PEA followed defibrillation, including 29 animals that attained ROSC. RESULTS ROSC animals required a shorter interval between the first shock and the initial postcountershock PEA, fewer shocks prior to onset of initial postcountershock PEA, demonstrated a greater VF wavelet amplitude prior to onset of initial PEA, smaller QRS intervals, and higher heart rates. Using Fisher's linear discriminant analysis, 79.3% of the ROSC and 63.3% of non-ROSC cases were predicted correctly. A total of 71.2% of all cases were classified correctly. CONCLUSIONS Animals in which postcountershock PEA was converted to ROSC required shorter intervals from first shock to initial postcountershock PEA, fewer shocks prior to onset of initial postcountershock PEA, had greater VF wavelet amplitude prior to initial postcountershock PEA, small QRS intervals, and higher heart rates. Fisher's discriminant analysis is helpful in predicting the likelihood of ROSC for an individual animal presenting with postcountershock PEA.
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Affiliation(s)
- Xiangshao Fang
- Weil Institute of Critical Care Medicine, 35100 Bob Hope Drive, Rancho Mirage, CA, USA
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Atkins DL, Kenney MA. Automated external defibrillators: safety and efficacy in children and adolescents. Pediatr Clin North Am 2004; 51:1443-62. [PMID: 15331293 DOI: 10.1016/j.pcl.2004.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although children do not suffer from ventricular fibrillation (VF) as frequently as adults, it does occur in 10% to 20% of pediatric cardiac arrests. The technology is available to recognize and treat ventricular fibrillation in children as quickly as we can for adults. This article discusses the evidence to support automated external defibrillator use in young children. As this technology gains increased acceptance, resuscitation rates and outcomes for VF in children should approach those that are seen in adults.
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Affiliation(s)
- Dianne L Atkins
- Division of Pediatric Cardiology, Roy J. and Lucille A. Carver College of Medicine, 200 Hawkins Drive, University of Iowa, Iowa City, IA 52242, USA.
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Weil MH, Sun S. Clinical review: Devices and drugs for cardiopulmonary resuscitation -- opportunities and restraints. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2004; 9:287-90. [PMID: 15987382 PMCID: PMC1175861 DOI: 10.1186/cc2960] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The science and technology of CPR is only just emerging from its infancy. However, substantial improvements are anticipated, including the ability of lay rescuers to identify cardiac arrest promptly, the availability of additional measurements, and expanded intelligence provided by expanded AEDs with which to more effectively prompt the rescuer through the resuscitation procedure. Most important in our view is the ability to maintain uninterrupted precordial compression. Better timing and better waveforms for defibrillation are emerging. The recognition of the importance of postresuscitation myocardial dysfunction and the selection of better vasopressor agents to minimize the adverse inotropic and chronotropic actions of adrenergic drugs are also likely to improve outcomes of CPR.
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Affiliation(s)
- Max Harry Weil
- Institute of Critical Care Medicine, Palm Springs, California, USA.
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Tang W, Weil MH, Sun S, Jorgenson D, Morgan C, Klouche K, Snyder D. The effects of biphasic waveform design on post-resuscitation myocardial function. J Am Coll Cardiol 2004; 43:1228-35. [PMID: 15063435 DOI: 10.1016/j.jacc.2003.10.055] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 10/14/2003] [Accepted: 10/20/2003] [Indexed: 11/18/2022]
Abstract
OBJECTIVES This study examined the effects of biphasic truncated exponential waveform design on survival and post-resuscitation myocardial function after prolonged ventricular fibrillation (VF). BACKGROUND Biphasic waveforms are more effective than monophasic waveforms for successful defibrillation, but optimization of energy and current levels to minimize post-resuscitation myocardial dysfunction has been largely unexplored. We examined a low-capacitance waveform typical of low-energy application (low-energy biphasic truncated exponential [BTEL]; 100 microF, < or =200 J) and a high-capacitance waveform typical of high-energy application (high-energy biphasic truncated exponential [BTEH]; 200 microF, > or =200 J). METHODS Four groups of anesthetized 40- to 45-kg pigs were investigated. After 7 min of electrically induced VF, a 15-min resuscitation attempt was made using sequences of up to three defibrillation shocks followed by 1 min of cardiopulmonary resuscitation. Animals were randomized to BTEL at 150 J or 200 J or to BTEH at 200 J or 360 J. RESULTS Resuscitation was unsuccessful in three of the five animals treated with BTEH at 200 J. All other attempts were successful. Significant therapy effects were observed for survival (p = 0.035), left ventricular ejection fraction (p < 0.001), stroke volume (p < 0.001), fractional area change (p < 0.001), cardiac output (p = 0.044), and mean aortic pressure (p < 0.001). Hemodynamic outcomes were negatively associated with energy and average current but positively associated with peak current. Peak current was the only significant predictor of survival (p < 0.001). CONCLUSIONS Maximum survival and minimum myocardial dysfunction were observed with the low-capacitance 150-J waveform, which delivered higher peak current while minimizing energy and average current.
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Affiliation(s)
- Wanchun Tang
- Insitute of Critical Care Medicine, Palm Springs, California 92262-5309, USA.
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Weil MH, Tang W. Time-dependent interventions. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2004; 8:11-2. [PMID: 14975039 PMCID: PMC420057 DOI: 10.1186/cc2395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The contribution by Pepe and colleagues provides additional evidence that initial defibrillation is not necessarily the optimal intervention for victims of cardiac arrest and especially when cardiac arrest has been untreated for more than 3 min. Precordial compression therefore remains the mainstay of basic life support cardiopulmonary resuscitation after sudden death. It is increasingly apparent that neither epinephrine whether in conventional or high doses nor vasopressin improve ultimate survival. To the contrary, there is evidence favoring beta1-adrenergic blockade.
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Affiliation(s)
- Max Harry Weil
- Institute of Critical Care Medicine, Palm Springs, California, USA.
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van Alem AP, Post J, Koster RW. VF recurrence: characteristics and patient outcome in out-of-hospital cardiac arrest. Resuscitation 2003; 59:181-8. [PMID: 14625108 DOI: 10.1016/s0300-9572(03)00208-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Refibrillation after successful defibrillation in out-of-hospital cardiac arrest is a frequent event. Little is known of factors that predispose to the occurrence of refibrillation. The effect of recurrence of ventricular fibrillation (VF) on survival is not known. METHODS Data of patients in out-of-hospital cardiac arrest were collected in a combined first responder and paramedic programme in Amsterdam, the Netherlands. Continuous recorded rhythm data of 322 patients covering the entire out-of-hospital resuscitation attempt was included in the analysis. Recurrence of VF was recorded, the patient and process characteristics were analysed in relation to the occurrence of refibrillation. The number of refibrillations was related to survival. RESULTS AND CONCLUSION Of the studied patients 79% had at least one recurrence of VF, and a median number of two times 25-75%; one to four times). The median time from successful first shock to VF recurrence was 45 s (25-75%: 23-115 s). A significant inverse relation was found between the number of refibrillations and survival of out-of-hospital cardiac arrest. The recurrence of VF was independent of the underlying cardiac disorder, the time to defibrillation, the defibrillation waveform and other characteristics of the patient and the process. Anti-arrhythmics should be considered in all patients found in VF to reduce the number of recurrences.
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Affiliation(s)
- Anouk P van Alem
- Department of Cardiology, Academic Medical Centre, room B2-239, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands.
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van Alem AP, Chapman FW, Lank P, Hart AAM, Koster RW. A prospective, randomised and blinded comparison of first shock success of monophasic and biphasic waveforms in out-of-hospital cardiac arrest. Resuscitation 2003; 58:17-24. [PMID: 12867305 DOI: 10.1016/s0300-9572(03)00106-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Evidence suggests that biphasic waveforms are more effective than monophasic waveforms for defibrillation in out-of-hospital cardiac arrest (OHCA), yet their performance has only been compared in un-blinded studies. METHODS AND RESULTS We compared the success of biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks for defibrillation in OHCA in a prospective, randomised, double blind clinical trial. First responders were equipped with MDS and BTE automated external defibrillators (AEDs) in a random fashion. Patients in ventricular fibrillation (VF) received BTE or MDS first shocks of 200 J. The ECG was recorded for subsequent analysis continuously. The success of the first shock as a primary endpoint was removal of VF and required a return of an organized rhythm for at least two QRS complexes, with an interval of <5 s, within 1 min after the first shock. The secondary endpoint was termination of VF at 5 s. VF was the initial recorded rhythm in 120 patients in OHCA, 51 patients received BTE and 69 received MDS shocks. The success rate of 200 J first shocks was significantly higher for BTE than for MDS shocks, 35/51 (69%) and 31/69 (45%), P=0.01. In a logistic regression model the odds ratio of success for a BTE shock was 4.01 (95% CI 1.01-10.0), adjusted for baseline cardiopulmonary resuscitation, VF-amplitude and time between collapse and first shock. No difference was found with respect to the secondary endpoint, termination of VF at 5 s (RR 1.07 95% CI: 0.99-1.11) and with respect to survival to hospital discharge (RR 0.73 95% CI: 0.31-1.70). CONCLUSION BTE-waveform AEDs provide significantly higher rates of successful defibrillation with return of an organized rhythm in OHCA than MDS waveform AEDs.
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Affiliation(s)
- Anouk P van Alem
- Department of Cardiology, Academic Medical Center, Room B2-238, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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Abstract
PURPOSE OF REVIEW Successful treatment of cardiac arrest requires that an electrically stable and mechanically competent cardiac activity be promptly reestablished. However, many interventions used to attempt to reestablish cardiac activity may also inflict additional myocardial injury and, in turn, compromise resuscitability. In this review, we examine mechanisms of such myocardial injury and discuss potential new strategies for myocardial protection during resuscitation from cardiac arrest. RECENT FINDINGS Efforts are currently directed at understanding underlying mechanisms of myocardial injury associated with current resuscitation methods, with the purpose of developing alternative approaches that are safer and more effective. These new approaches include, among others, the development of alternative low-energy defibrillation waveforms, methods for optimizing the timing for attempting defibrillation, and the use of vasopressor agents devoid of beta-agonist effects. There is also interest in understanding the role that activation of pathways of ischemic and reperfusion injury could play during resuscitation from cardiac arrest. To this end, activation of the sarcolemmal sodium-hydrogen exchanger isoform 1 seems to play an important role. Other potentially important pathways involve adenosine metabolism, activation of potassium ATP channels, and generation of oxygen radical species. These pathways may become novel pharmacologic targets for cardiac resuscitation. SUMMARY The growing body of research in these areas is bringing hope that in a not so distant future new approaches and interventions for cardiac resuscitation could be available for resuscitation of humans in various clinical settings.
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Affiliation(s)
- Raúl J Gazmuri
- Department of Medicine, Finch University of Health Sciences/The Chicago Medical School, North Chicago, Illinois, USA.
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Niemann JT, Garner D, Lewis RJ. Transthoracic impedance does not decrease with rapidly repeated countershocks in a swine cardiac arrest model. Resuscitation 2003; 56:91-5. [PMID: 12505744 DOI: 10.1016/s0300-9572(02)00292-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
STUDY PURPOSE Successful defibrillation is dependent upon the delivery of adequate electrical current to the myocardium. One of the major determinant of current flow is transthoracic impedance. Prior work has suggested that impedance falls with repeated shocks during sinus rhythm. The purpose of this study was to evaluate changes in transthoracic impedance with repeated defibrillation shocks in an animal model of cardiac arrest due to ventricular fibrillation (VF). METHODS VF was electrically induced in anesthetized swine. After 5 min of untreated VF, monophasic or biphasic waveform defibrillation was attempted using a standard sequence of 'stacked shocks' (200, 300, then 360 J, if necessary) administered via adhesive electrodes. If one of the first three shocks failed to convert VF, conventional CPR was initiated and defibrillation (360 J) attempted 1 min later. Strength-duration curves for delivered voltage and current were measured during each shock and transthoracic impedance calculated. Animals requiring a minimum of four shocks were selected for study inclusion. Impedance data from sequential shocks were analyzed using mixed linear models to account for the repeated-measures design and the variability of the initial impedance of individual animals. RESULTS Thirteen animals (monophasic waveform, n=7, biphasic waveform, n=6) required at least four shocks to terminate VF (range 4-6). Transthoracic impedance did not change from the first shock in the 13 animals (46+/-8 Omega) to the fourth shock (46+/-9 Omega). In animals receiving more than four shocks, transthoracic impedance likewise did not change significantly from the first to the last shock, which terminated VF. The lack of a significant change in impedance was also observed when animals were analyzed according to defibrillation waveform. CONCLUSION Transthoracic impedance does not change significantly with repeated shocks in a VF cardiac arrest model. This is likely due to the lack of reactive skin and soft tissue hyperemia and edema observed in non-arrest models.
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Affiliation(s)
- James T Niemann
- Department of Emergency Medicine, UCLA School of Medicine, Harbor-UCLA Medical Center, Box 21, 1000 West Carson Street, Torrance, CA 90509, USA.
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Capucci A, Aschieri D, Piepoli MF, Bardy GH, Iconomu E, Arvedi M. Tripling survival from sudden cardiac arrest via early defibrillation without traditional education in cardiopulmonary resuscitation. Circulation 2002; 106:1065-70. [PMID: 12196330 DOI: 10.1161/01.cir.0000028148.62305.69] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Early defibrillation is the most important intervention affecting survival from sudden cardiac arrest (SCA). To improve public access to early defibrillation, we established Piacenza Progetto Vita (PPV), the first system of out-of-hospital early defibrillation by first-responder volunteers. METHODS AND RESULTS The system serves a population of 173 114 residents in the Piacenza region of Italy. Equipment for the system comprises 39 semiautomatic external biphasic defibrillators (AEDs): 12 placed in high-risk locations, 12 in lay-staffed ambulances, and 15 in police cars; 1285 lay volunteers trained in use of the AED, without traditional education in cardiac pulmonary resuscitation, responded to all cases of suspected SCA, in coordination with the Emergency Medical System (EMS). During the first 22 months, 354 SCA occurred (72+/-12 years, 73% witnessed). The PPV volunteers treated 143 SCA cases (40.4%), with an EMS call-to-arrival time of 4.8+/-1.2 minutes (versus 6.2+/-2.3 minutes for EMS, P=0.05). Overall survival rate to hospital discharge was tripled from 3.3% (7 of 211) for EMS intervention to 10.5% (15 of 143) for PPV intervention (P=0.006). The survival rate for witnessed SCA was tripled by PPV: 15.5% versus 4.3% in the EMS-treated group (P=0.002). A "shockable" rhythm was present in 23.8% (34 of 143) of the PPV patients versus 15.6% (33 of 211) of the EMS patients (P=0.055). The survival rate from shockable dysrhythmias was higher for PPV versus EMS: 44.1% (15 of 34) versus 21.2% (7 of 33), P=0.046. The neurologically intact survival rate was higher in PPV-treated versus EMS-treated patients: 8.4% (12 of 143) versus 2.4% (5 of 211), P=0.009. CONCLUSIONS Broad dissemination of AEDs for use by nonmedical volunteers enabled early defibrillation and tripled the survival rate for out-of-hospital SCA.
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Weil MH, Tang W. Cardiopulmonary resuscitation for pulseless rhythms and asystole. Crit Care Med 2002; 30:245. [PMID: 11902271 DOI: 10.1097/00003246-200201000-00036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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