단기적 자율조절기능을 포함하는 심혈관계 혈류역학 모델링에 관한 수치적 연구

심은보,정찬일,최한고 대한의용생체공학회 2001 의공학회지 Vol.22 No.5

전체 심혈관계의 혈류역학적 특성을 분석할 수 있는 수치해석 방법을 개발하였다. 이는 12개의 요소들로 구성된 lumped parameter모델에 기초하고 있으며 인체의 신경계에 의한 자율조절기능을 모사하기 위해 주로 혈압의 단기적 조절을 위한.baroreflex system뿐 아니라 cardiopulmonary reflex 메커니즘가지도 구현하여 모델에 포함시켰다. 또한 교감 및 부교감 신경에 의한 자극-반응 전달을 구현함에 있어 생리학적 데이터에 기초한 방법을 사용하였다. 본 연구의 수치해석 코드를 검증하기 위하여 우선 보통 상태의 심혈관계에 대하여 혈류역학적 계산 결과를 기존의 참고문헌들에서의 값들과 비교 검토하였다. 심혈관계 모델의 혈류역학적 자극에 대한 반응 결과를 조사하기 위하여. 20% 출혈이 발생하는 경우와 LBNP(Lower Body Negative Pressure) 모사를 수행하였다. 두 경우 모두. 비교적 실험치와 잘 일cl하고 있음을 확인할 수 있었다. 특히 LBNP 수행 시, 외부압력의 크기가 커질수록 baroreflex만을 포함하고 있는 방법은 baroreflex와 cardiopulmonary reflex 모두를 포함하고 있는 방법에 비하여 다소 부정확한 결과를 보여주고 있는데. 이는 cardiopulmonary reflex 메커니즘의 중요성을 보여주고 있다. A computational model representative of cardiovascular circulation was built using 12 standard lumped compartments. Especially, both the baroreceptor reflex and the cardiopulmonary reflex control model were implemented to explain the auto-regulation of cardiovascular system. Another important aspect of this model is to utilize the impulse-response curve of the nerve system in transferring the impulse error signals to autonomous nerve system. For the verification of this model, we have computed the normal hemodynamic conditions and compared those with the clinical data. Then. hemodynamic shock of 20% hemorrhage to cardiovascular system was simulated to test the effects of the control system model. The results of these two simulations were well matched with the experimental ones. The steady state LBNP simulation was also performed. The transient changes of hemodynamic variables due to ramp increase of bias pressure of LBNP showed good agreement with the physiological experiments. Numerical solution using only the baroreflex model showed relatively a larger deviation from the experimental data. compared with the one using the control model haying both the baroreflex and the cardiopulmonary reflex systems, which shows an important role of the cardiopulmonary reflex system for the simulation of the hemodynamic behavior of the cardiovascular system .

PID 제어 모델을 이용한 심혈관시스템 시뮬레이션

최병철,김철한,남기곤,정동근,김윤진,김호종,이현철,예수영,정도운,전계록 대한의료정보학회 2004 Healthcare Informatics Research Vol.10 No.4

Objective: The electric analog circuit model can be used to analyse the various function of the cardio vascular system and the dynamic characteristics on each part of human body. According to the previous studies, viscous resistance, flow inertia, and vascular compliance in the cardiovascular system are analogous to resistance, inductance, and capacitance in electric circuit, so the cardiovascular system models have been represented by the electric circuit models. These approaches were to propose suitable models for the interested part of body and to simulate the various characteristics on the cardiovascular system. Methods: This paper tried to put the characteristics of morphologic structure into the suggested electric circuit model. After setting parameter values of the model the dynamic characteristics of the cardio vascular system is simulated using VisSim, which is one of the simulation tools. Results: The derived simulation results have represented major cardiovascular functions of normal adults. Also simulation results reflect the variation due to the pathophysiological state. Conclusion: The controller by baroreceptor, which is one of controllers to control the cardiovascular system, is appended in the model. The dynamic response characteristics and the procedure to restore blood pressure to normal state was observed by simulation lasted a certain period of bleeding.

맥진연구를 위한 심혈관계 시뮬레이터의 개발

이주연 ( Ju-yeon Lee ),신상훈 ( Sang-hoon Shin ) 대한한의진단학회 2012 大韓韓醫診斷學會誌 Vol.16 No.1

Objectives The aim of this study is to develop a cardiovascular simulator that can reproduce blood pressure pulse and blood flow similar to those of the human body. Methods In order to design a system similar to the human cardiovascular system, the required performances were determined by investigating the hemodynamic characteristics of the heart and the arterial system. Main organ to be imitated is heart in simulator. The rest of the system was minimally designed. Also, a blood pressure and blood flow measurement system was developed for measuring the results. Results The developed system showed blood pressure pulse at similar range of the human aorta. The result waveform include primary wave caused by ventricular systole except reflected wave. Conclusions The blood pressure and blow flow patterns were replicated by the simulator. These patterns were similar to those of the human body. The system will play an important role in studying pulse diagnostics.

Automatic Extraction of Aortic Aneurysm from Thoracic CTA based on Fuzzy-based 3-D Region Growing Method

Tatsushi Tokuyasu,Takashi Shuto,Kenji Yufu,Shotaro Kanao,Akira Marui,Masashi Komeda 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

Computer-Aided Diagnosis (CAD) system that helps medical staffs to diagnose patient"s disease conditions has been used in a variety fields of medicine. For cardiovascular surgery, radiologists manually construct 3-D volume model of patient organ and provide this information to cardiovascular surgeons, therefore automation technique for image processing of building patient 3-D volume model is highly requested from clinical site. The 3-D volume model is used in not only diagnosing patient disease condition, but also making a surgical plan before an operation. In the case of using CAD system for a cardiovascular disease patient, computed tomography angiography (CTA) has been used as the source data that clearly indicates the region of blood flow on the image due to contrast agent. However, sufficient information for the diagnosis is not obtained from CTA, because the regions of aneurysm and aortic wall tissue can not distinguished correctly even using the latest CAD system. Then, this study proposes Fuzzy-based region growing method that enables a computer to have the ability of reading radiogram. We focused on the skill of reading radiogram of experienced doctors, because they know the boundary line between aneurysm and aortic wall tissue on CTA image. Hence, Fuzzy inference has been employed to express doctor"s skill of reading radiogram and used as the growing criteria. The proposed method is applied to one patient CTA data and its result is shown and discussed in this paper.

호흡 제어에 따른 임피던스 심장도와 지첨용적맥파에 관한 연구

고영일 ( Young-il Ko ),박영배 ( Young-bae Park ),박영재 ( Young-jae Park ),이현수 ( Hyon-soo Lee ) 대한한의진단학회 2007 大韓韓醫診斷學會誌 Vol.11 No.1

Purpose: We performed this study to examine the effect of controlled respiration on cardiovascular system in healthy adult subjects using impedance cardiography and photo-plethysmography. Materials and Methods: This study had performed on 74 subjects, which were healthy men and women without a experience of respiration practice. Using the instruments for impedance cardiography and photoplethysmography, parameters of each subject had been measured after each controlled respirations which were natural respiration, controlled natural respiration (I:E=1.1.6), longer inspiration(I:E=3:3), and longer expiration(I:E=2:4). The measured parameters of impedance cardiography and photoplethysmography were processed statistically by one-way repeated ANOVA. Results: 1. HR and CI of impedance cardiography were decreased significantly during controlled respiration comparing with the result of basal state(the state of enough break). There was no significant difference among the results of controlled respiration. 2. PEP of impedance cardiography had no significant difference among the result of basal state and the results of controlled respiration(p=0.059). 3. VI of impedance cardiography had significant differences among the result of basal state and the results of controlled respiration, and decreased continuously through the controlled respiration. 4. b/a of photoplethysmography had no significant difference among the result of basal state and the results of controlled respiration(p=0.554). 5. c/a of photoplethysmography were decreased significantly during controlled respiration comparing with the result of basal state. There was no significant difference among the results of controlled respiration. 6. d/a of photoplethysmography had significant differences among the results of the controlled respiration decreasing continuously through the controlled respiration and had no significant difference between the result of basal state and the result of natural respiration. 7. AGI of photoplethysmography had significant differences among the result of basal state and the results of the controlled respiration increasing continuously through the controlled respiration. Conclusion: We had examined the effects of controlled respirations on cardiovascular system in multiple points of view. The effects of controlled respirations on cardiovascular system can`t be explained in a simple way, as the cardiovascular system is controlled by many factors. Therefore, more physiological parameters must be measured in the future study on the effect of the controlled respiration on human cardiovascular system.

A Wrist Watch-type Cardiovascular Monitoring System using Concurrent ECG and APW Measurement

Kwonjoon Lee,Kiseok Song,Taehwan Roh,Hoi-jun Yoo 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.5

A wrist watch type wearable cardiovascular monitoring device is proposed for continuous and convenient monitoring of the patient’s cardiovascular system. For comprehensive monitoring of the patient’s cardiovascular system, the concurrent electrocardiogram (ECG) and arterial pulse wave (APW) sensor front-end are fabricated in 0.18 mm CMOS technology. The ECG sensor front-end achieves 84.6-dB CMRR and 2.3-mVrms-input referred noise with 30-mW power consumption. The APW sensor front-end achieves 3.2-V/W sensitivity with accurate bio-impedance measurement lesser than 1% error, consuming only 984-mW. The ECG and APW sensor front-end is combined with power management unit, micro controller unit (MCU), display and Bluetooth transceiver so that concurrently measured ECG and APW can be transmitted into smartphone, showing patient’s cardiovascular state in real time. In order to verify operation of the cardiovascular monitoring system, cardiovascular indicator is extracted from the healthy volunteer. As a result, 5.74 m/second-pulse wave velocity (PWV), 79.1 beats/minute-heart rate (HR) and positive slope of b-d peak-accelerated arterial pulse wave (AAPW) are achieved, showing the volunteer’s healthy cardiovascular state.

A Wrist Watch-type Cardiovascular Monitoring System using Concurrent ECG and APW Measurement

Lee, Kwonjoon,Song, Kiseok,Roh, Taehwan,Yoo, Hoi-jun The Institute of Electronics and Information Engin 2016 Journal of semiconductor technology and science Vol.16 No.5

A wrist watch type wearable cardiovascular monitoring device is proposed for continuous and convenient monitoring of the patient's cardiovascular system. For comprehensive monitoring of the patient's cardiovascular system, the concurrent electrocardiogram (ECG) and arterial pulse wave (APW) sensor front-end are fabricated in $0.18{\mu}m$ CMOS technology. The ECG sensor frontend achieves 84.6-dB CMRR and $2.3-{\mu}Vrms$-input referred noise with $30-{\mu}W$ power consumption. The APW sensor front-end achieves $3.2-V/{\Omega}$ sensitivity with accurate bio-impedance measurement lesser than 1% error, consuming only $984-{\mu}W$. The ECG and APW sensor front-end is combined with power management unit, micro controller unit (MCU), display and Bluetooth transceiver so that concurrently measured ECG and APW can be transmitted into smartphone, showing patient's cardiovascular state in real time. In order to verify operation of the cardiovascular monitoring system, cardiovascular indicator is extracted from the healthy volunteer. As a result, 5.74 m/second-pulse wave velocity (PWV), 79.1 beats/minute-heart rate (HR) and positive slope of b-d peak-accelerated arterial pulse wave (AAPW) are achieved, showing the volunteer's healthy cardiovascular state.

심활성도 압반사 제어 모델을 이용한 심혈관시스템 모델링 및 시뮬레이션

최병철,정도운,손정만,예수영,김호종,이현철,김윤진,정동근,이상훈,전계록,Choi Byeong Cheol,Jeong Do Un,Shon Jung Man,Yae Su Yung,Kim Ho Jong,Lee Hyun Cheol,Kim Yun Jin,Jung Dong keun,Yi Sang Hun,Jeon Gye Rok 대한의용생체공학회 2004 의공학회지 Vol.25 No.6

본 연구에서는 심혈관시스템 내의 압력 변화를 감지하는 압수용체 중 가장 대표적인 대동맥 압수용체의 시뮬레이션을 위한 심활성도 압반사 제어모델을 제안하였다. 그리고 제안된 모델은 압반사 조절, 시간지연을 포함한 전기회로 모델들로 구성하였으며, 대동맥동의 압반사 조절시 시간지연이 심주기와 일회 심박출량에 주는 영향을 관찰할 수 있도록 하였다. 심활성도 압수용체 제어 모델에서 시간지연의 기전은 대동맥동 압수용체에서 감지된 압력 정보가 구심성 신경으로 전달되고, 이 정보는 중추신경을 거쳐 원심성 신경으로 전달되어 제어 기능을 수행한다. 제안된 모델의 시뮬레이션 결과 시간지연에 따라 심혈관시스템 변이성의 세가지 패턴을 관찰할 수 있었다. 먼저 시간지연이 2.5초 이상일 경우에는 대동맥압, 일회심박출량, 심박동수가 비주기적으로 발생하고 불규칙인 것을 관찰할 수 있었고, 시간지연이 0.1초에서 2.5초 사이일 경우에는 주기적인 진동이 발생함을 관찰할 수 있었다. 그리고 시간지연이 0.1초 이하인 경우에는 심박동수와 동맥압-심박동수의 궤적은 안정상태를 유지함을 관찰할 수 있었다. In this paper, we proposed a heart activity control model for simulation of the aortic sinus baroreceptor, which was the most representative baroreceptor sensing the variance of pressure in the cardiovascular system. And then, the heart activity control model composed electric circuit model of the cardiovascular system with baroreflex control and time delay sub-model to observe the effect of time delay in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The mechanism of time delay in the heart activity baroreflex control model is as follows. A control function is conduct sensing pressure information in the aortic sinus baroreceptor to transmit the efferent nerve through central nervous system. As simulation results of the proposed model, we observed three patterns of the cardiovascular system variability by the time delay. First of all, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate was observed non-periodically and irregularly. However, if the time delay from 0.1 second to 0.25 second, the regular oscillation was observed. And then, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory were maintained in stable state.

평압저산소에서 60분간 운동부하가 심혈관호흡기계 및 면역기계의 급성영향

이동준(Lee Dong-Jun) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.4

The purpose of this study was to investigate the acute influences of cardiovascular, respiratory, and immune system on 60min-prolonged exercise test of HR at 5O%VO₂max intensity in an exposed normobaric hypoxic environment. The subjects were 15 male college students(19.1±1.0yr, BMI 22.3±2.1, fat mass 10.9±3.1㎏, %fat 15.5±3.2%, LBM 55.3±5.8㎏, VO₂max 39.0±3.3㎖/㎏/min). Items of measurement after 60min-prolonged exercise on sea level and 3000m altitude were HR, SV, CO, SVR, SBP, DBP, MAP, TVC of cardiovascular system, VO₂, VO₂max, RR, RQ, VE, Mets, VT, VCO₂ of respiratory system, and ACTH, HGH, cortisol, epinephrine, norepinephrine, RBC, WBC, HCT, Hb, NKcell, Tcell, Bcell et al of immune system and hormone. As the result of the verifying hypothesis, the results may suggest new findings: first, VO₂, RR, VE, in respiratory system increased significantly at 3000m altitude better than sea level(p<.01). Second, HR, SV, CO, SVR in respiratory system increased significantly at 3000m altitude better than sea level(p<.01). Third, Cortisol, norepinephrine, WBC, NKcell in immune system and hormone increased significantly at 3000m altitude better than sea level(p<.01). In conclusion, 60min-prolonged exercise on normobaric hypoxic environment may affect cardiovascular, respiratory, and immune system.

장기적인 TSH 억제가 심혈관계에 미치는 영향

송종민 대한갑상선학회 2012 International Journal of Thyroidology Vol.5 No.1

Prolonged thyroid-stimulating hormone (TSH) suppression caused by exogenous subclinical thyrotoxicosis has been reported to impose harmful effects on cardiovascular system. Those effects involve increase in heart rate and myocardial mass, impaired ventricular diastolic and systolic function, decreased exercise capacity,decreased arterial elasticity, development of atrial tachyarrhythmia, and increase in cardiovascular adverse events. Tailored dose adjustment of thyroid hormone under the guidance of TSH level for obviating oversuppression of TSH, and use of beta blockers can reduce cardiovascular adverse effects in patients who undergo thyroid hormone therapy.