• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1392-1398
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• 2022

This study was conducted for effective CPR by comparing the quality of chest compressions when using a new chest compression method during pediatric CPR. As an experimental study by Randomized Crossover Design, the depth, speed, compression-to-relaxation ratio, ease, and stability were measured when performing chest compressions for 28 Emergency Medical Technicians who completed the BLS Health Care-Provider qualification. The collected data were analyzed by using the SPSS Ver. 23.0 for Win statistical program. To summarize the results of this study, if the new chest compression method was used for chest compression in pediatric CPR, the qualitative indicators of chest compressions were improved. It is good to stick to the existing method, but through the new chest compression method, it will be necessary to confirm the possibility of clinical use based on additional research on various age groups and environmental factors.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.175-182
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• 2023

In this paper, we propose a study compared and analyzed the CPR results and muscle fatigue of the three groups. There is a group that counts loudly when compressing the mannequin's chest (Group A), a group that breathes autonomously without counting (Group B), and a group that breathes abdominally without counting (Group C). Twelve people were assigned to each group, and after performing chest compressions for 5 minutes, the results of CPR were analyzed using a program connected to the mannequin, and the muscle fatigue of the performers was analyzed using wireless electromyography. The most efficient method was found to be group B. If we only look at the speed and depth of compression within the normal range, Group C would be more efficient, but Group B showed significantly lower muscle fatigue, and Group A did not reach the normal range in depth of chest compression and muscle fatigue was the highest. Group B was also found to be the most accurate in hand positioning accuracy, and was also found to be the most efficient in maintaining concentration on chest compressions.

• Fire Science and Engineering
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• v.34 no.2
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• pp.103-109
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• 2020

This study aims to investigate the improvement in basic CPR quality on the basis of the hip joint angle of the rescuer among students in the Department of Emergency Medical Technology who completed a basic CPR curriculum. In this study, we carried out a comparative analysis using SimPad SkillReporter and Resusci Anne® QCPR® to measure the quality of CPR (depth of chest compressions, full relaxation, compression speed, and more) on the basis of the rescuer's hip joint angle in accordance with the 2015 AHA Guidelines and conducted chest compressions and CPR 5 times in a 30:2 ratio. It was found that maintenance of the rescuer's hip joint angle at 90 degrees while compressing and relaxing the chest made a statistically significant difference in both the experimental and control groups. Moreover, this indicated that the closer the hip joint angle was to 90 degrees, the better was the quality of basic CPR. However, there was no significant difference in the hip joint angle, degree of CPR, depth of chest compressions, chest compression speed, chest compression and relaxation percentages (%), accuracy of chest compressions, hands-off time during CPR, and percentage of chest compression time (p > 0.05). Maintaining the hip joint angle at 90 degrees for basic CPR was not significantly different from not maintaining this angle. Nonetheless, good results have been obtained at moderate depth and 100% recoil. Therefore, good outcome and high-quality CPR are expected.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.197-204
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• 2015

This study aims to identify the effects: quality of chest compressions, height and weight of pregnant women cardiac arrest while lying $30^{\circ}$ inclined to the left has on the quality of chest compressions administered by 119 EMT. For the purpose of this study, 62 members of 119 EMTs in M, N, S, Y cities and G cities of J province agreed to join in the test and the test was conducted from June 15 to 16 in 2015. Two mannequins (Resusci Anne$^{(R)}$) were used for the study and the chest compression process was recorded with the use of the Laerdal PC Skill Reporting System$^{(R)}$. As a result, it was discovered that for patients with a $30^{\circ}$ left inclination, who were below 170 cm in height and 65 kg in weight, the proper frequency and depth of compression were unsatisfactory. With this in mind, training programs and instruments that can improve the quality of chest compressions depending on a person's (patient's) height and weight should be developed.

• The Korean Journal of Emergency Medical Services
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• v.14 no.3
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• pp.71-81
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• 2010

Purpose: To minimize an interruption in chest compression, reduce the hands-off time, the American Heart Association has recommended the ratio of chest compression to ventilation ratio to 30:2 from 2005 CPR guideline to 2010 CPR guideline. However, current studies have shown that the hands-off time was > 10 seconds with that method. For this reason, we devised new CPR method that a ventilation to chest compression ratio of 2:30 to reduce pt assessment time and skipped the assessment step of carotid artery pulse would be a more effective way to reduce the hands-off time & the time to set the CPR. According to the more detailed purpose are listed below. 1) We would like to confirm efficiency of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 to reduce the hands-off time & the time to set the CPR. 2) We would like to evaluate possibility of increasing for chest compression accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 3) We would like to evaluate possibility of increasing for ventilation accuracy of a ventilation to chest compression ratio of 2:30 than a chest compression to ventilation ratio of 30:2 Methods: According to 2005 American Heart Association Guidelines, 60 paramedic students(20 students X freshmen, sophomore, junior) performed 5 cycles of 3~ chest compressions : 2 ventilations after A, B, C evaluation with Laerdal Resusci R Anne SkillReporters. After 5 minutes rest, the 60 students performed 5 cycles of 2 ventilations : 30 chest compressions after A, B evaluation with the manikins between 13 and 17 September 2010. The short reports including speed & accuracy of chest compression, respiratory, CPR cycle were gained from the manikins. Hands-off times were measured by assistants. Results: Recently, the importance of high quality CPR was emphasized in order to perform the CPR faster and more accurate. To find out improving the conventional CPR method, we switch the procedure of the compression and the ventilation. By switching the procedure back and forth, we are able to compare the effectiveness of CPR between two type of CPR method which are 2:30 and 30:2 methods. 2:30 is that the breaths is delivered twice, first and perform 30 compressions while 30:2 perform 30 compressions first and give 2 breaths followed by the ABC method. Also, we verify the effectiveness of the hands off time, compression accuracy of the compression through the comparison of the two procedure as mentioned earlier. Consequently research verified that 2:30 is the efficient by providing faster set up delivering more accurate chest compression. Conclusion: 2:30 can minimize a time delay from cardiac standstill until starting the chest compression. In addition, hands-off time which is an interruption in chest compression can be shortened by 2:30 method, which result to effective oxygenation of coronary artery & maintenance of the bloodstream. Once again, performing the 2:30 method provide lessen hands off time and increase the accuracy of the chest compression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.381-388
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• 2017

The CPR guidelines emphasize the delivery of effective chest compressions but do not address the effects of chest compressions on CPR providers. This study determined the effects of chest compressions on healthy adult firefighters' symptoms, hemodynamics, and electrocardiography after performing multiple cycles of CPR. Healthy adult firefighters were trained in CPR and performed CPR on mannequins. The provider vital signs, electrocardiography, and fatigue scores were determined immediately before CPR, after 5cycles of CPR, and after 10 cycles of CPR. In addition, the presence of clinical symptoms among the providers was determined after CPR; 39 firefighters participated in the study. Their mean age was $35.54{\pm}10.26years$. Many providers developed fatigue, shortness of breath, and dizziness. Significant changes in heart rate (p=0.000), respiratory rate (p=0.010), end-tidal CO2(p=0.000), O2 saturation(p=0.000), and pulse pressure (p=0.000) were observed after both 5 and 10 cycles of CPR. One participant developed sinus dysrhythmia and premature ventricular contractions after 10 cycles of CPR. The delivery of chest compression results in fatigue and hemodynamic alterations in many young healthy adults after performing 5 or 10 cycles of CPR. The CPR guidelines and education should take into consideration the effects of chest compressions on CPR providers.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.151-157
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• 2020

This study is to find out the effectiveness by Infant CPR method of a single rescuer. It was conducted for 51 general public. And typical infant CPR method by a single rescuer and a new method, CPR with two thumb chest compressions wrapped in both hands over the head were compared. SPSS 22.0 was used as an analysis method and to compare the both CPR methods, Paired t-test was used. As a result of the study, the average chest compression depth(39.38±1.07 mm) by CPR with two thumb chest compressions wrapped in both hands over the head was significantly high(p<0.001). Ease of mouth-to-mouth resuscitation(p<0.001), convenience of CPR method(p<0.001), and finger pain level(p<0.001) had a significant difference. As for the preference of the CPR method, 80.4%(41 people) preferred CPR with two thumb chest compressions wrapped in both hands over the head. In this study, CPR with two thumb chest compressions wrapped in both hands over the head showed more effective results than typical CPR method. However, as a virtual study using mannequins, further research is needed to apply high-quality CPR methods to field.

• Communications of the Korean Mathematical Society
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• v.10 no.4
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• pp.899-906
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• 1995

We discuss certain structure theorems in the class A which is closely related to the study of the problems of solving systems concerning the predual of a dual operator algebra generated by a contraction on a separable infinite dimensional complex Hilbert space.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.187-200
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• 2019

Truncated Hankel operators are compressions of classical Hankel operators to model spaces. In this paper we describe matrix representations of truncated Hankel operators on finite-dimensional model spaces. We then show that the obtained descriptions hold also for some infinite-dimensional cases.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.118-125
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• 2009

Bumper is designed to protect the automotive frame without damage at low velocity. Expanded polypropylene (EPP) foam is used in the bumper as an energy absorbing material. In order to exactly predict the energy absorbing performance of the foam material under impact loading condition, it is important to use high strain rate material properties. In this study, a new apparatus for dynamic compression tests was developed to investigate the high strain rate behavior of EPP foams. Three kinds of EPP foams which have different expansion ratios were tested to investigate the quasi-static and dynamic compression behavior. Quasi-static compressions were performed at low strain rates of 0.001/s, 0.1/s and 1/s. The dynamic compressions were carried out at high strain rates of 50/s and 100/s with the developed apparatus. It was observed that the EPP foam has significant strain rate effect as compared to quasi-static behavior.