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Qi Q, Yu M, Ge J, Li C, Zhang G, Chen F. A combined impedance compensation strategy applied to external automatic defibrillators. BIOMED ENG-BIOMED TE 2023; 68:651-665. [PMID: 37350466 DOI: 10.1515/bmt-2022-0185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/07/2023] [Indexed: 06/24/2023]
Abstract
Transthoracic impedance is one of the key factors affecting the success of defibrillation. Impedance compensation technique is used to adjust defibrillation parameters according to the transthoracic impedance of the defibrillator. In this paper, a combined impedance compensation strategy is proposed to address the shortcomings of existing compensation strategies. In order to evaluate the performance of the combined compensation strategy, this paper uses the prototype as the experimental machine, and uses two AED with representative impedance compensation strategies as the control machine, and the simulated defibrillation method is used for comparative testing. The results show that the combined impedance compensation has a more steadier distribution over the defibrillation energy and current: compared with the energy-based impedance compensation strategy, this strategy can significantly reduce the peak current (25 Ω: 27.8 vs. 54.7 A; 50 Ω: 20.7 vs. 32.3 A) and average current (25 Ω: 24.8 vs. 37.5 A) of defibrillation at low impedance, and compared with the current impedance compensation strategy, it can significantly reduce the defibrillation energy (150 Ω: 8.6 vs. 1.7 %, 175 Ω: 15.6 vs. 4.9 %, 200 Ω: 21.9 vs. 8.5 %) at high impedance. Impedance compensation is more precise and the current passing during defibrillation is steadier.
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Affiliation(s)
- Qi Qi
- Unit for Drug and Instrument Supervision and Inspection of Wuxi Joint Logistic Support Center, PLA, Nanjing, China
| | - Ming Yu
- Medical Support Technology Research Department,Systems Engineering Institute, Academy of Military Sciences, PLA, Tianjin, China
| | - Jianhui Ge
- Unit for Drug and Instrument Supervision and Inspection of Wuxi Joint Logistic Support Center, PLA, Nanjing, China
| | - Chuanjun Li
- Unit for Drug and Instrument Supervision and Inspection of Wuxi Joint Logistic Support Center, PLA, Nanjing, China
| | - Guang Zhang
- Medical Support Technology Research Department,Systems Engineering Institute, Academy of Military Sciences, PLA, Tianjin, China
| | - Feng Chen
- Medical Support Technology Research Department,Systems Engineering Institute, Academy of Military Sciences, PLA, Tianjin, China
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Neumann T, Finke SR, Henninger M, Lemke S, Hoepfner B, Steven D, Maul AC, Schroeder DC, Annecke T. First-time evaluation of ascending compared to rectangular transthoracic defibrillation waveforms in modelled out-of-hospital cardiac arrest. Resusc Plus 2020; 1-2:100006. [PMID: 34223293 PMCID: PMC8244241 DOI: 10.1016/j.resplu.2020.100006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 11/04/2022] Open
Abstract
Aim of the study Prognosis in out-of-hospital cardiac arrest (OHCA) depends on cardiopulmonary resuscitation (CPR) duration. Therefore, the optimal biphasic defibrillation waveform shows high conversion rates besides low energy. Matthew Fishler theoretically predicted it to be truncated ascending exponential. We realised a prototypic defibrillator and compared ascending with conventional rectangular waveforms in modelled OHCA and CPR. Methods Approved by the authorities, 57 healthy swine (Landrace × Piétrain) were randomised to ASCDefib (n 26) or CONVDefib (n 26). Five swine served as sham control. We induced ventricular fibrillation (VF) electrically in anaesthetised swine randomised to ASCDefib or CONVDefib and discontinued mechanical ventilation. After 5 min of untreated cardiac arrest, we started CPR with mechanical chest compressions and ventilation. We performed transthoracic biphasic defibrillations after 2, 4, 6 and 8 min CPR targeting 4 J/kg in either group. Depending on the randomised group, the defibrillation protocol was either three ascending followed by one rectangular waveform (ASCDefib) or three rectangular followed by one ascending waveform (CONVDefib). Results Under our model-specific conditions, VF was initially terminated by 13/80 ascending waveforms and 13/79 rectangular waveforms and persistent return of spontaneous circulation was achieved in 8/26 (ASCDefib) vs. 10/26 (CONVDefib) animals. Mean current rather than waveform design was predictive for defibrillation success in a generalised linear model. Conclusion Contrary to theoretical assumptions, transthoracic biphasic defibrillation with ascending waveforms is not superior to rectangular waveforms in modelled OHCA. We advocate defibrillation dosage to be guided by current, that has proven its predictive value again. Institutional protocol number 84–02.04.2017.A176.
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Affiliation(s)
- Tobias Neumann
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Simon-Richard Finke
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Maja Henninger
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Sebastian Lemke
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Ben Hoepfner
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Daniel Steven
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Electrophysiology, Kerpener Str. 62, 50937 Cologne, Germany
| | - Alexandra C Maul
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Center for Experimental Medicine, Kerpener Str. 62, 50937 Cologne, Germany
| | - Daniel C Schroeder
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
| | - Thorsten Annecke
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, Research Group "Clinical Research and Teaching", Kerpener Str. 62, 50937 Cologne, Germany
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Deale OC, Ng KT, Lerman BB. Calibrated current divider network for precision current delivery during high-voltage transthoracic defibrillation. IEEE Trans Biomed Eng 2005; 52:1970-3. [PMID: 16285402 DOI: 10.1109/tbme.2005.856299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The design of a calibrated resistive-network current divider for precision current delivery during transthoracic defibrillation shocks is presented together with test results. The current divider presents a constant 50-ohm load to the defibrillator and thus maintains a constant pulse shape. Current is selected before the shock by setting three rheostats using a computer-generated calibration table. Following each shock, the data acquisition and display software updates the calibration table based on the measured value of transthoracic resistance. Over a range of 15-27 A, the root-mean-square (rms) error for delivered versus selected current was 0.48% for a 45-ohm resistive load, and 0.71% for a 100-ohm load. These test results were confirmed by animal experiments. Over 3 dogs, the rms error was 0.49% from 15-27 A and not greater than 1.5% over the entire 8-44 A range.
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Affiliation(s)
- O Carlton Deale
- Cardiology Division, Department of Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA.
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