• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.501-504
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• 2006

The estimation of the work of heart can be treated as one of the most important parameters for determining the amount of circulating blood needed for harmonious metabolism in the human body. By monitoring the work of heart, one can detect increased work load of heart and start the treatment at the early stage of CHF. Thus it is necessary to estimate the work of heart. The contractility of the left ventricle, the second important parameter for representing the motion of heart, can be estimated through information on the work of heart. In this study, the modified Windkessel model, which has been used for a measure of vascular hemodynamic impedance parameters, was adapted to estimate the work of heart.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.1
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• pp.39-43
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• 2023

Nasotracheal intubation is commonly performed under general anesthesia in oral and maxillofacial surgery. For the convenience of surgery, nasal Ring-Adair-Elwyn (RAE) tubes are mainly used. Because the nasal RAE tubes were bent in an "L" shape, the insertion depth was limited. Particularly, it is necessary to accurately determine the appropriate depth of the RAE tubes in children. Several types of nasal RAE tubes are used in the medical market, which vary in material and length. We performed endotracheal intubation using a nasal RAE tube for double-jaw surgery, but air leakage persisted even when the air pressure in the cuff was increased. When checked with a laryngoscope, it was confirmed that the tube was pushed out, and the cuff was caught on the vocal cords, causing air leakage. Since inserting the tube deeply did not solve the problem, replacing it with a nasal RAE tube (Polar^TM, Preformed Tracheal Tube, Smith Medical, Inc., USA) did not cause air leakage; thus, we reported this case.

• Quality Improvement in Health Care
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• v.3 no.1
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• pp.94-103
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• 1996

Background : Blood pressure is an important indicator in diagnosis and assessing treatment of a patient. Clinical staffs use blood pressure on the assumption that measured value is accurate and reliable. However, whether measured blood pressure is accurate has been rarely investigated in Korea. Objectives : The aims of this study are to evaluate clinical staffs' knowledge and technique as well as accuracy of sphygmomanometer. Also the program to improve the measurement is developed. Methods : Seventy-three registered nurses were asked nine multiple choice questions including Korotkoff sound, cuff size, and deflation rate. Simultaneously characteristics of nurses were examined, age, working place, duration of employment and academic degree. A testing videotape(Standardizing Measurement Video-Tutored Course) was used for evaluating the accuracy of measurement. Testees were to read and record the 12 cases of blood pressure measurement, watching a falling mercury column and hearing Korotkoff sounds. After 10 minutes' education, they were again tested with the same cases. Additionally, 83 mercury sphygmomanometers were checked to find defects such as inaccurate calibration and zero setting, leaky bladder, etc. Results: For the knowledge testing correct response rate was 41.1%. They were the lowest in selecting the proper cuff size and Korotkoff sound. In examining accuracy of blood pressure with videotape, nurses had 67.7% correct response rate. The correct response rate was significantly improved by a session of education. About 23% of sphygmomanometers was without discernable defects. Conclusion : The knowledge and skill of clinical staffs along with the accuracy of equipment have to be improved. A properly designed education program would contribute to the accuracy improvement of blood pressure measurement. Also, more concerns should be given to the precision and maintenance of equipment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.9
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• pp.822-829
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• 2013

Hypertension is one of the most common clinical diseases, with an increasing prevalence globally. Hypertension triggers various harmful consequences and affects multiple organs. Life-long care may be required in some cases. According to the Korea Center for Disease Control and Prevention, the prevalence of hypertension is gradually increasing. A 2011 survey revealed that 28.9% of Korean adults had hypertension. The prevalence rates were slightly higher among men than women. Accurate measurement of blood pressure(BP) is crucial to classify patients, to identify BP-related risks, and to inform correct treatment. For accurate blood pressure measurement, the use of a cuff bladder size appropriate for the mid-upper arm circumference(MUAC) is essential. Incorrect sized cuff bladder is one of the main causes of equipment error affecting sphygmomanometer accuracy. When commercial sphygmomanometers were examined, the cuff bladders differed from the dimensions specified in the ISO 81060-1:2007 standards. Undercuffing is responsible for a spurious overestimation of BP in patients with large arms leading to overdiagnosis of hypertension, whereas overcuffing (that is, use of relatively large cuffs with small arms), may be responsible for an opposite problem, leading to erroneous underestimation of BP levels. The cuff bladder sizes recommended by the American Heart Association(AHA) are an arm circumference(AC) of 17-25 cm for small-sized adults, AC of 24-32 cm for adults, AC of 32-42 cm for normal-sized adults, and AC of 42-50 cm for obese adults. In contrast, the AC of Korean adults ranges from 23-31 cm, belonging to a single type of adult bladder. Three types of bladders are necessary for Korean adults with an AC of 23-31cm. Hospitals often use one or two differently-sized Western cuffs for adult patients, which can yield inaccurate BP determinations. Cuff bladders with dimensions based on anthropometric reference data obtained from Koreans will aid hospitals to measure BP more accurately.

• Science of Emotion and Sensibility
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• v.11 no.2
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• pp.235-244
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• 2008

This study is to develop automatic extraction system of continuous blood pressure using ECG (Electrocardiogram) and PPG(Photoplethysmography) for u-health care technology. PTT (Pulse Transit Time) was determined from peak difference between ECG and PPG and its inverse made to get blood pressure. Since the peaks were vulnerable to be contaminated from noise and variation of amplitude, this study developed the adaptive algorithm for peak calculation in any noise condition. The developed method of the adaptive peak calculation was proven to make the standard deviations of PPT decrease to 28% and the detection of noise increase to 18%. Also, the correlation model such as blood pressure = -0.044 $\cdot$ PTT + 133.592 has successfully been determined for predicting the continuous pressure measured without using cuff but with using PPG and ECG, only.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1257-1264
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• 2019

The traditional cuff-based method for BP(Blood Pressure) measurement is not suitable for continuous real-time BP measurement techniques. For this reason, the previous studies estimated various blood pressures by fusion with the electrocardiography (ECG) and photoplethysmogram (PPG) sensor signals. However, conventional techniques based on PPG bio-sensing measurement face many challenging issues such as noisy supply fluctuation, small pulsation, and drifting non-pulsatile. This paper proposed a novel BP estimation methods using PPG and ECG sensors, which can be derived from the relationship between PPG and ECG using PTT(Pulse Transit Time) and PWV(Pulse Wave Velocity). Unlike conventional height ratio features, which are extracted on the basis of the peaks in the PPG and ECG waveform. The proposed method can be reliably obtained even if there are missing peaks among the sensed PPG signal. The increased reliability comes from periodical estimation of the peak-to-peak interval time using ECG and PPG. After 250,000 times trials of the blood pressure measurement, the proposed estimation technique was verified with the accuracy of ±28.5% error, compared to a commercialized BP device.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.1
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• pp.3-7
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• 2010

In this study, we developed a circuit device detecting korotkoff sounds of forearm electronic blood pressure monitor by digital signal. In order to test a circuit detecting signal from korotkoff sounds, systolic and diastolic pressure were compared our developed circuit device with the existing forearm electronic blood pressure monitor (Model: SE-7000, Korea). Devices for an experiment composed of a forearm cuff, a stethoscope, an amplifier, a PC with A/D board, etc. Results of korotkoff sounds was similar to a pattern of oscilometric signals from the existing forearm electronic blood pressure monitor. We thought it is possible to measure blood pressures, if blood pressures were detected precisely using signals of korotkoff sounds.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.335-343
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• 2022

Objective: This study aimed to investigate the effects of ischemic compression treatment (ICT) or low-level laser therapy (LLLT) applied to the trigger points of the infraspinatus muscle on shoulder pain and function in patients with shoulder pain. Design: A randomized clinical trial Methods: Thirty patients with shoulder pain were randomly allocated into the ICT group (n=15) or LLLT groups (n=15). ICT was performed on three myofascial trigger points (MTrPs) of the infraspinatus muscle twice a week for 4 weeks (eight sessions), with 5 minutes of treatment per trigger point. LLLT was performed similarly. Shoulder pain was assessed using the visual analogue scale (VAS) and pain pressure threshold (PPT), and shoulder function was assessed using the Korean Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, rotator cuff strength, and range of motion (ROM) of shoulder flexion and abduction. Results: Significant changes in VAS score and PPT were found after the intervention in both groups (p<0.05). Significant changes were observed in the Korean DASH score, rotator cuff strength, and ROM of shoulder flexion (p<0.05) but not in the ROM of shoulder abduction (p<0.05). There were no significant differences between the two groups. Conclusions: This study showed that both ICT and LLLT applied on the MTrPs of the infraspinatus muscle were effective for relieving shoulder pain and improving shoulder functions in patients with shoulder pain.

• Journal of the Optical Society of Korea
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• v.10 no.2
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• pp.91-95
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• 2006

Blood pressure was predicted from photoplethysmography (PPG). To obtain PPG, backscattered light from a fingertip was measured and its waveform was analyzed. Systolic upstroke time and diastolic time in the pulse waveform were used as parameters to predict blood pressure. The experiment was carried out with five subjects on five different days. The systolic upstroke time had a correlation coefficient of -0.605 with respect to systolic blood pressure and the diastolic time had a correlation coefficients of -0.764 for diastolic pressure. This PPG method does not require an air-cuff installation on the arm and can predict blood pressure continuously. This simple LED/photo detector setup can be a good candidate for nonconstrained monitoring of blood pressure variations.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.82-82
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• 1993

Tracheostomy was done to form temporary opening in the trachea, to remove secretion, to maintain ventilation and to protect against aspiration. In recent times, with the development of care methods such as low pressure cuff, endotracheal intubation is being combined with tracheostomy in the treatment of patients who are treated long period in the intensive care units and the duration from endotracheal intabation to tracheostomy is like to prolong. To determine the proper time of tracheostomy in the patient in the intensive care units, authors reviewed retrospectively the 96 patients who received the tracheostomy procedure among the 8776 patients who were admitted in the intensive care units of Asan medical center form March 1990 to March 1993, and analyzed the complications of tracheostomy, decannulation and the cause of decannulation failure according to disease, age indication of endotracheal intubation and duration of endotracheal intubation.