• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.101-109
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• 2005

Background: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile and non-pulsatile circulation to coronary artery flow and myocardial preservation in cardiac arrest condition. Material and Method: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing $25\~35$ kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extra-corporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of < 0.05. Result: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p < 0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p < 0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p < 0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the coronary sinus blood. Conclusion: In cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• 순환기질환의공학회:학술대회논문집
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• 2006.10a
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• pp.36-37
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• 2006

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.477-483
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• 2018

Transcranial doppler is a non-invasive method that measures the blood flow velocity and the direction of cerebral blood vessels through the doppler principle. The pulsatility index is an index for measuring the transcranial doppler that reflects the distal vascular resistance and is used as an index for the presence and diffusion of cerebral small vessel diseases. The purpose of this study was to evaluate the risk factors affecting the basilar artery pulsatility index in ischemic stroke patients. From January 2014 to May 2015, 422 patients were selected by measuring the transcranial doppler pulsatility index, considering their basilar artery pulsatility index. Univariate analysis was performed using the basilar artery pulsatility index as a dependent variable. Multiple regression analysis was performed considering the factors affecting the pulsatility index as variables. Univariate analysis revealed age, presence of hypertension, presence of diabetes mellitus, presence of hyperlipidemia, and hematocrit (P<0.1) as factors. Multiple regression analysis showed statistically significant results with age (P<0.001), presence of diabetes (P=0.004), and presence of hyperlipidemia (P=0.041). The risk factors affecting the basilar artery pulsatility index of transcranial doppler were age, diabetes, and hyperlipidemia. Further research will be needed to increase the cerebral pulsatility index as a surrogate marker of the elderly, diabetes, and hyperlipidemia.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.113-116
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• 1995

Steady and physiological flows of a Newtonian fluid and blood in the bifurcated arterial vessel are numerically simulated. Distributions of velocity, pressure and wall shear stress in the bifurcated arterial vessel are calculated to investigate the differences between steady and physiological flows. For the given Reynolds number physiological flow characteristics of a Newtonian fluid and blood in the bifurcated arterial vessel are quite different from those of steady flows. No flow separation or flow reversal in the bifurcated region in the downstream after stenosis appears during the acceleration phase. Also, no recirculation region is seen for steady flows. However, during the deceleration phase the flow began to exhibit flow reversal, which is eventually extended to the entire wall region.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.57-60
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• 1995

The objective of this investigation is to understand the role of hemodynamics in the formation and development of atherosclerosis lesions in the human left coronary artery This study also aims to compare the blood flow characteristics of steady and physiological flows. Three dimensional, steady and physiological flows of blood in the left coronary artery are simulated using the Finite Volume Method. Apparent viscosity of blood is represented as a function of shear rate by the Carreau model. Distributions of velocity, pressure and shear stress in tile left coronary artery bifurcation are presented to compare tile steady and physiological flow characteristics.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.1-10
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• 2004

Background: Currently, the cardiopulmonary machine with non-pulsatile pumps, which are low in internal circuit pressure and cause little damage to blood cells, is widely used. However, a great number of experimental studies shows that pulsatile perfusions are more useful than non-pulsatile counterparts in many areas, such as homodynamic, metabolism, organ functions, and micro-circulation. Yet, many concerns relating to pulsatile cardiopulmonary machines, such as high internal circuit pressure and blood cell damage, have long hindered the development of pulsatile cardiopulmonary machines. Against this backdrop, this study focuses on the safety and effectiveness of the pulsatile cardiopulmonary machines developed by a domestic research lab. Material and Method: The dual-pulsatile cardiopulmonary bypass experiment with total extracorporeal circulation was conducted on six calves, Extracorporeal circulation was provided between superior/inferior vena cava and aorta. The membrane oxygenator, which was placed between the left and right pumps, was used for blood oxygenation. Circulation took four hours. Arterial blood gas analysis and blood tests were also conducted. Plasma hemoglobin levels were calculated, while pulse pressure and internal circuit pressure were carefully observed. Measurement was taken five times; once before the operation of the cardiopulmonary bypass, and after its operation it was taken every hour for four hours. Result: Through the arterial blood gas analysis, PCO2 and pH remained within normal levels. PO2 in arterial blood showed enough oxygenation of over 100 mmHg. The level of plasma hemoglobin, which had total cardiopulmonary circulation, steadily increased to 15.87 $\pm$ 5.63 after four hours passed, but remained below 20 mg/㎗. There was no obvious abnormal findings in blood test. Systolic blood pressure which was at 97.5$\pm$5.7 mmHg during the pre-circulation contraction period, was maintained over 100 mmHg as time passed. Moreover, diastolic blood pressure was 72.2 $\pm$ 7.7 mmHg during the expansion period and well kept at the appropriate level with time passing by. Average blood pressure which was 83$\pm$9.2 mmHg before circulation, increased as time passed, while pump flow was maintained over 3.3 L/min. Blood pressure fluctuation during total extracorporeal circulation showed a similar level of arterial blood pressure of pre-circulation heart. Conclusion: In the experiment mentioned above, pulsatile cardiopulmonary machines using the doual-pulsatile structure provided effective pulsatile blood flow with little damage in blood cells, showing excellence in the aspects of hematology and hemodynamic. Therefore, it is expected that the pulsatile cardiopulmonary machine, if it becomes a standard cardiopulmonary machine in all heart operations, will provide stable blood flow to end-organs.

• Journal of Chest Surgery
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• v.39 no.5 s.262
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• pp.354-358
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• 2006

Background: Pulsatile pumps for extracorporeal circulation have been known to be better for tissue perfusion than non-pulsatile pumps but be detrimental to blood corpuscles. This study is intended to examine the risks and benefits of $T-PLS^{TM}$ through the comparison of clinical effects of $T-PLS^{TM}$ (pulsatile pump) and $Bio-pump^{TM}$ (non-pulsatile pump) used for coronary bypass surgery. Material and Method: The comparison was made on 40 patients who had coronary bypass using $T-PLS^{TM}\;and\;Bio-pump^{TM}$ (20 patients for each) from April 2003 to June 2005. All of the surgeries were operated on pump beating coronary artery bypass graft using cardiopulmonary extra-corporeal circulation. Risk factors before surgery and the condition during surgery and the results were compared. Result: There was no significant difference in age, gender ratio, and risk factors before surgery such as history of diabetes, hypertension, smoking, obstructive pulmonary disease, coronary infarction, and renal failure between the two groups. Surgery duration, hours of heart-lung machine operation, used shunt and grafted coronary branch were little different between the two groups. The two groups had a similar level of systolic arterial pressure, diastolic arterial pressure and mean arterial pressure, but pulse pressure was measured higher in the group with $T-PLS^{TM}\;(46{\pm}15\;mmHg\;in\;T-PLS^{TM}\;vs\;35{\pm}13\;mmHg\;in\;Bio-pump^{TM},\;p<0.05)$. The $T-PLS^{TM}$-operated patients tended to produce more urine volume during surgery, but the difference was not statistically significant $(9.7{\pm}3.9\;cc/min\;in\;T-PLS^{TM}\;vs\;8.9{\pm}3.6\;cc/min\;in\;Bio-pump^{TM},\;p=0.20)$. There was no significant difference in mean duration of respirator usage and 24-hour blood loss after surgery between the two groups. Plasma free Hb was measured lower in the group with $T-PLS^{TM}\;(24.5{\pm}21.7\;mg/dL\;in\;T-PLS^{TM}\;versus\;46.8{\pm}23.0mg/dL\;in\;Bio-pump^{TM},\;p<0.05)$. There was no significant difference in coronary infarction, arrhythmia, renal failure and morbidity rate of cerebrovascular disease. There was a case of death after surgery (death rate of 5%) in the group tested with $T-PLS^{TM}$, but the death rate was not statistically significant. Conclusion: Coronary bypass was operated with $T-PLS^{TM}$ (Pulsatile flow pump) using a heart-lung machine. There was no unexpected event caused by mechanical error during surgery, and the clinical process of the surgery was the same as the surgery for which $Bio-pump^{TM}$ was used. In addition, $T-PLS^{TM}$ used surgery was found to be less detrimental to blood corpuscles than the pulsatile flow has been known to be. Authors of this study could confirm the safety of $T-PLS^{TM}$.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.78-82
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• 2020

Carotid web is a disease that is rarely found in patients with ischemic stroke, whereas it is more frequently observed in cryptogenic stroke patients. Fibromuscular dysplasia is known as the cause of carotid web, and it has been reported that carotid web causes blood flow disturbance, resulting in both thrombus and embolic stroke. Carotid web is confused with carotid dissection because fibromuscular dysplasia causes relatively rigid fibrous structures to grow into the lumen of the carotid artery and this creates a double lumen that is seen on duplex sonography. In addition, carotid web is web-shaped and may be confused with other carotid artery diseases such as ulcerative plaque. However, carotid web tends to be thicker at the beginning and thinner at the end, and it also has no flutter. Therefore, this study reports on four cases of carotid web with the overall description of the carotid web and the characteristic findings of duplex sonography in patients with carotid web.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.684-693
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• 2007

Previous trials for development of a pulsatile-Extracorporeal Life Support had some defects such as insufficient blood flow, high pressure at its membrane oxygenator and the high risk of blood cell damage. To solve those problems of previous pulsatile-ECLSs, we suggest dual pulsatile blood pump structure for the new pulsatile-ECLS. Two pulsatile pumps areconnected in a parallel manner and this new structure raises the inflow capacity and efficiency and it decreases the high blood pressure at membrane oxygenator. In in-vitro experiments, The Energy Equivalent Pressure Increment(EEP inc.) was 10%, and it showed that its pulsatilty was $5{\sim}10$ times higher than other commercial ECLS In in-vivo experiments, we had applied a new pulsatile-ECLS to 30 Kg pigs and a new pulsatile-ECLS couldsupport high blood flow and pulsatility above 2 L/min, 10% EEP inc.