• Journal of Chest Surgery
• /
• v.30 no.5
• /
• pp.471-478
• /
• 1997

Introduction: The use of rabbits as a cardiopulmonary bypass(CPB) animal model is extremely dif%cult mainly due to technical problems. On the other hand, deep hypothermic circulatory arrest(CA) is used to facilitate surgical repair in a variety of cardiac diseases. Although steroids are generally known to be effective in the treatment of cerebral edema, the protective effects of steroids on the brain during CA are not conclusively established. Objectives of this study are twofold: the establishment of CPB technique in rabbits and the evaluation of preventive effect of steroid on the development of brain edema during CA. Material '||'&'||' Methods: Fifteen New Zealan white rabbits(average body weight 3.5kg) were divided into three experimental groups; control CA group(n=5), CA with Trendelenberg position group(n=5), and CA with Trendelenberg position + steroid(methylprednisolone 30 mglkg) administration group(n=5). After anesthetic induction and tracheostomy, a median sternotomy was performed. An aortic cannula(3.3mm) and a venous ncannula(14 Fr) were inserted, respectively in the ascending aorta and the right atrium. The CPB circuit consisted of a roller pump and a bubble oxygenator. Priming volume of the circuit was approximately 450m1 with 120" 150ml of blood. CPB was initiated at a flow rate of 80~85ml/kg/min, Ten min after the start of CPB, CA was established with duration of 40min at $20^{\circ}C$ of rectal temperature. After CA, CPB was restarted with 20min period of rewarming. Ten min after weaning, the animal was sacrif;cod. One-to-2g portions of the following tissues were rapidly d:ssected and water contents were examined and compared among gr ups: brain, cervical spinal cord, kidney, duodenum, lung, heart, liver, spleen, pancreas. stomach. Statistical significances were analyzed by Kruskal-Wallis nonparametric test. Results: CPB with CA was successfully performed in all cases. Flow rate of 60-100 mlfkgfmin was able to be maintained throughout CPB. During CPB, no significant metabolic acidosis was detected and aortic pressure ranged between 35-55 mmHg. After weaning from CPB, all hearts resumed normal beating spontaneously. There were no statistically significant differences in the water contents of tissues including brain among the three experimental groups. Conclusion: These results indicate (1) CPB can be reliably administered in rabbits if proper technique is used, (2) the effect of steroid on the protection of brain edema related to Trendelenburg position during CA is not established within the scope of this experiment.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.12C
• /
• pp.1288-1298
• /
• 2002

To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

• Journal of Chest Surgery
• /
• v.39 no.3 s.260
• /
• pp.201-207
• /
• 2006

Background: Percutaneous cardiopulmonary support (PCPS) provides passive support of gas exchange and perfusion, allowing the use of other methods of care for organ recovery, and saves lives of patients with severe cardiopulmonary failure in a wide variety of clinical settings with a minimal risk of bleeding and need for chest re~ exploration. We summarized a single center's experiences with PCPS in patients with cardiogenic shock or cardiac arrest due to the ischemic heart disease. Material and Method: Among the 20 consecutive patients with cardiogenic shock or cardiac arrest from May 1999 to June 2005, Biopump (Medtronic, Inc, Minneapolis, MN) was used in 7 patients and the self-priming, heparin-coated circuit of EBS (Terumo, Japan) was applied to remaining 13 patients. Most of cannulations were performed percutaneously via femoral arteries and veins. The long venous cannulas of DLP (Medtronic inc. Minneapolis, MN) or the RMI (Edwards's lifescience LLC, Irvine, CA) were used with the arterial cannulae from 17 Fr to 21 Fr and the venous cannula from 21 Fr to 28 Fr. Result: The 20 consecutive patients who were severely compromised and received PCPS for the purpose of resuscitation were comprised of 13 cardiac arrests and 7 cardiogenic shocks in which by-pass surgery was performed in 11 patients and 9 ongoing PCls under the cardiopulmonary support. The mean support time on the PCPS was 38$\pm$42 hours. Of the 20 patients implanted with PCPS, 11 patients ($55\%$) have had the PCPS removed successfully; overall, 8 of these patients ($40\%$) were discharged from the hospital in an average surviving time for 27$\pm$17 days after removing the PCPS and survived well with 31$\pm$30 months of follow-up after the procedure. Conclusion: The use of PCPS appears to provide the hemodynamic restoration, allowing the survival of patients in cardiac arrest or cardiogenic shock who would otherwise not survive, and patients receiving PCPS had a relatively long-term survival.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.14 no.5
• /
• pp.394-402
• /
• 2021

The entry of an aging society and the extension of human life expectancy, the increasing interest in women's social advancement and men's appearance, and the natural interest in K-culture through media media, while receiving worldwide attention, Focus on K-Bueaty. Recently, looking at the occupation of the medical tourism field, in the case of aesthetic medicine tourism such as molding and dermatology, it has gained popularity not only in Asia such as China and Japan, but also in North America and Europe. The first external confirmation of human aging is the wrinkles on the skin of the face. Clean, wrinkle-free, elastic and healthy skin is a desire of most people. Skin condition and condition such as focused ultrasonic stimulation (HIFU: High Intensity Focused Utrasound) and low frequency, high frequency (RF: Radio Frequency), galvanic therapy using microcurrent, cryotherapy using rapid cooling, etc. Depending on the method of management, the effect of the treatment differs depending on the output and the stimulation site, etc., even in the treatment of medical equipment and beauty equipment using the same mechanism. In this research, in order to develop invasive high-frequency dermatological devices using a large number of beauty medical devices and microneedles of beauty devices, the international standards IEC 60601-2 (standards for individual medical devices) and MFDS (Ministry of) We designed and developed a high-frequency output device in compliance with the high-frequency stimulation standard announced in the Food and Drug Safety (Ministry of Food and Drug Safety). The circuit design consists of an amplifier (AMP: Amplifier) using Class-A Topology and a power supply device using Half-Bridge Topology. As a result of measuring the developed high-frequency output device, an average efficiency of 63.86% was obtained, and the maximum output was measured at 116.7W and 50.67dBm.

• Journal of Chest Surgery
• /
• v.42 no.4
• /
• pp.473-479
• /
• 2009

Background: Retrograde autologous priming (RAP) is known to be useful in decreasing the need of transfusions in cardiac surgery because it prevents excessive hemodilution due to the crystalloid priming of cardiopulmonary bypass circuit. However, there are also negative side effects in terms of blood conservation. We analyzed the intraoperative blood-conserving effect of RAP and also investigated the efficacy of autotransfusion and ultrafiltration as a supplemental method for RAP. Material and Method: From January 2005 to December 2007, 117 patients who underwent isolated coronary artery bypass operations using cardiopulmonary bypass (CPB) were enrolled. Mean age was 63.9$\pm$9.1 years (range 36$\sim$83 years) and 34 patients were female. There were 62 patients in the RAP group and 55 patients in he control group. Intraoperative autotransfusion was performed via the arterial line. RAP was done just before initiating CPB using retrograde drainage of the crystalloid priming solution. Both conventional (CUF) and modified (MUF) ultrafiltrations were done during and after CPB, respectively. The transfusion threshold was less than 20% in hematocrit. Result: Autotransfusions were done in 79 patients (67.5%) and the average amount was 142.5$\pm$65.4 mL (range 30$\sim$320 mL). Homologous red blood cell (RBC) transfusion was done in 47 patients (40.2%) and mean amount of transfused RBC was 404.3$\pm$222.6 mL. Risk factors for transfusions were body surface area (OR 0.01, 95% CI 0.00 $\sim$ 0.63, p=0.030) and cardiopulmonary bypass time (OR 1.04, 95% CI 1.01 $\sim$ 1.08, p=0.019). RAP was not effective in terms of the rate of transfusion (34.5% vs 45.2%, p=0.24). However, the amount of transfused RBC was significantly decreased (526.3$\pm$242.3ml vs 321.4$\pm$166.3 mL, p=0.001). Autotransfusion and ultrafiltration revealed additive and cumulative effects decreasing transfusion amount (one; 600.0$\pm$231.0 mL, two; 533.3$\pm$264.6 mL, three; 346.7$\pm$176.7 mL, four; 300.0$\pm$146.1 mL, p=0.002). Conclusion: Even though RAP did not appear to be effective in terms of the number of patients receiving intraoperative RBC transfusions, it could conserve blood in terms of the amount transfused and with the additive effects of autotransfusion and ultrafiltration. If we want to maximize the blood conserving effect of RAP, more aggressive control will be necessary - such as high threshold of transfusion trigger or strict regulation of crystalloid infusion, and so forth.