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Watanabe H, Yagi SI. Why the natural frequency and the damping coefficient do not evaluate the dynamic response of clinically used pressure monitoring circuits correctly. J Anesth 2020; 34:898-903. [PMID: 32860541 DOI: 10.1007/s00540-020-02843-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 08/13/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE The dynamic response of pressure monitoring circuits must be evaluated to obtain true invasive blood pressure values. Since Gardner's recommendations in 1981, the natural frequency and the damping coefficient have become standard parameters for anesthesiologists. In 2006, we published a new dynamic response evaluation method (step response analysis) that can plot frequency spectrum curves instantly in clinical situations. We also described the possibility of the defect of the standard parameters. However, the natural frequency and the damping coefficient are considered the gold standard and are even included in a major anesthesiology textbook. Therefore, we attempted to clarify the issues of these parameters with easy-to-understand pressure waves and basic numerical formulae. METHODS A blood pressure wave calibrator, a single two-channel pressure amplifier, and personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using our step response analysis program. RESULTS We compared two different circuits with almost the same natural frequency and damping coefficients. However, their amplitude spectrum curves and input/output pressure values were significantly different. CONCLUSIONS The natural frequency and the damping coefficient are inadequate for the dynamic response evaluation. These parameters are primarily obtained from the phase spectrum curve and not from the amplitude spectrum curve. We strongly recommend an evaluation using the amplitude spectrum curve with our step response analysis method. It is crucial to maintain an amplitude gain of 1 (input amplitude = output amplitude) in the pressure wave frequency range of 0-20 Hz.
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Affiliation(s)
- Hiroaki Watanabe
- Department of Anesthesiology, School of Medicine, Sapporo Medical University, South-1, West-16, Chuo-ku, Sapporo, 060-8543, Japan.
| | - Shin-Ichi Yagi
- School of Information Science, Ultrasonic Engineering in Medicine, Meisei University, Tokyo, Japan
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Fujiwara SJL, Tachihara K, Mori S, Ouchi K, Itakura S, Yasuda M, Hitosugi T, Imaizumi U, Miki Y, Toyoguchi I, Yoshida KI, Yokoyama T. Influence of the marvelous™ three-way stopcock on the natural frequency and damping coefficient in blood pressure transducer kits. J Clin Monit Comput 2017; 32:63-72. [PMID: 28074417 DOI: 10.1007/s10877-017-9979-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 01/04/2017] [Indexed: 11/25/2022]
Abstract
Two types of Planecta™ ports are commonly used as sampling ports in blood pressure transducer kits: a flat-type port (FTP) and a port with a three-way stopcock (PTS). Recently, a new type of three-way stopcock (Marvelous™) has been released as a Planecta™ counterpart, but its effects on the frequency characteristics and reliability of blood pressure monitoring have not been investigated. We assessed the influence of the Marvelous™ stopcock on the frequency characteristics of the pressure transducer kit. The basic pressure transducer kit, DT4812J, was modified by replacing one or two of the original three-way stopcocks with Marvelous™ stopcocks. The frequency characteristics (i.e., natural frequency and damping coefficient) of each kit were determined using wave parameter analysis software, and subsequently evaluated on a Gardner chart. Replacement of the original blood pressure transducer kit stopcocks with Marvelous™ stopcocks decreased the natural frequency (48.3 Hz) to 46.3 Hz or 44.8 Hz, respectively; the damping coefficient was not significantly changed. Plotting the data on a Gardner chart revealed that the changes fell within the adequate dynamic response region, indicating they were within the allowable range. Insertion of Marvelous™ stopcocks slightly affects the natural frequency of the pressure transducer kit, similar to inserting a PTS. The results indicate that the Marvelous™ stopcock is useful for accurate monitoring of arterial blood pressure, and may be recommended when insertion of two or more closed-loop blood sampling systems is necessary.
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Affiliation(s)
- Shigeki Joseph Luke Fujiwara
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa, 238-0003, Japan.
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
- Department of Health and Medical Engineering School of Science and Engineering, Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo, 154-8515, Japan.
| | - Keiichi Tachihara
- Department of Clinical Engineering, Teikyo Junior College, 6-31-1 Honmachi, Shibuya-ku, Tokyo, 151-0071, Japan
| | - Satoshi Mori
- Clinical Engineering, Almeida Memorial Hospital, 1509-2 Miyazaki, Oita-shi, Oita, 870-1133, Japan
| | - Kentaro Ouchi
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Shoko Itakura
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa, 238-0003, Japan
| | - Michiko Yasuda
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa, 238-0003, Japan
| | - Takashi Hitosugi
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Uno Imaizumi
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa, 238-0003, Japan
| | - Yoichiro Miki
- Section of Dental Education, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Izumi Toyoguchi
- Argon Medical Devices Japan, Davinchi-Ningyocho 6F, 2-13-9 Nihonbashi-ningyochou, Chuo-ku, Tokyo, 103-0013, Japan
| | - Kazu-Ichi Yoshida
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa, 238-0003, Japan
| | - Takeshi Yokoyama
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Saugel B, Bendjelid K, Critchley LA, Rex S, Scheeren TWL. Journal of Clinical Monitoring and Computing 2016 end of year summary: cardiovascular and hemodynamic monitoring. J Clin Monit Comput 2017; 31:5-17. [PMID: 28064413 DOI: 10.1007/s10877-017-9976-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 01/02/2017] [Indexed: 12/29/2022]
Abstract
The assessment and optimization of cardiovascular and hemodynamic variables is a mainstay of patient management in the care for critically ill patients in the intensive care unit (ICU) or the operating room (OR). It is, therefore, of outstanding importance to meticulously validate technologies for hemodynamic monitoring and to study their applicability in clinical practice and, finally, their impact on treatment decisions and on patient outcome. In this regard, the Journal of Clinical Monitoring and Computing (JCMC) is an ideal platform for publishing research in the field of cardiovascular and hemodynamic monitoring. In this review, we highlight papers published last year in the JCMC in order to summarize and discuss recent developments in this research area.
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Affiliation(s)
- Bernd Saugel
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
| | - Karim Bendjelid
- Department of Anesthesiology and Intensive Care, Geneva University Hospitals, Geneva, Switzerland
| | - Lester A Critchley
- Department of Anesthesia and Intensive Care, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Steffen Rex
- Department of Anesthesiology and Department of Cardiovascular Sciences, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Thomas W L Scheeren
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Fujiwara S, Mori S, Tachihara K, Yamamoto T, Yokoe C, Imaizumi U, Morimoto Y, Miki Y, Toyoguchi I, Yoshida KI, Yokoyama T. Frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes. J Clin Monit Comput 2016; 31:371-380. [PMID: 26946147 DOI: 10.1007/s10877-016-9854-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/29/2016] [Indexed: 10/22/2022]
Abstract
The accurate monitoring of arterial blood pressure is important for cardiovascular management. However, the frequency characteristics of pressure transducer kits are influenced by the length of the pressure-resistant tube. To date, there have been few studies addressing the frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes (pressure-resistant extension tube (ET) circuits). In this study, we examine ET circuits from the viewpoint of the frequency characteristics of pressure transducer kits. DT4812J transducer kits (length 150 cm; Argon Medical Devices, TX, USA) were used. Three original ET circuits were prepared, with the pressure-resistant tube of the DT4812J being extended with a 30-cm length of pressure-resistant tube (180ET circuit), a 60-cm length of pressure-resistant tube (210ET circuit), and a 90-cm length of pressure-resistant tube (240ET circuit). Each of these circuits was evaluated as part of this study. The natural frequency of the original DT4812J circuit was 45.90 Hz while the damping coefficient was 0.160. For the 180 ET circuit, the natural frequency and damping coefficient were 36.4 Hz and 0.162, respectively. For the ET210 circuit, the natural frequency and damping coefficient were 30.3 Hz and 0.175, respectively. For the ET210 circuit, the natural frequency and damping coefficient were 25.3 Hz and 0.180, respectively. As a result of extending the circuit, it was found that the natural frequency decreased drastically, while the damping coefficient increased slightly. When the extension of a pressure transducer kit is required, we should pay careful attention to the major decrease in the natural frequency, which may influence the pressure monitoring.
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Affiliation(s)
- Shigeki Fujiwara
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa, 238-8580, Japan.
| | - Satoshi Mori
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Keiichi Tachihara
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takeshi Yamamoto
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Chizuko Yokoe
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa, 238-8580, Japan
| | - Uno Imaizumi
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa, 238-8580, Japan
| | - Yoshinari Morimoto
- Department of Oral Science, Graduate School of Dentistry, Kanagawa Dental University, Inaoka-cho 82, Yokosuka, Kanagawa, 238-8580, Japan
| | - Yoichiro Miki
- Section of Dental Education, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Izumi Toyoguchi
- Argon Medical Devices Japan, DaVinci-Ningyocho 6F, 2-13-9 Nihonbashi-Ningyocho, Chuo-ku, Tokyo, 103-0013, Japan
| | - Kazu-Ichi Yoshida
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa, 238-8580, Japan
| | - Takeshi Yokoyama
- Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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