• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.16-22
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• 2009

Objective : This study was designed to investigate automated pressure-controlled discography (APCD) findings, to calculate the elastance of intervertebral discs, and to assess the relationship between the calculated elastance and disc degeneration. Methods : APCD was performed in 19 patients. There were a total of 49 intervertebral discs treated. Following intradiscal puncture, a dye was constantly injected and the intradiscal pressure was continuously measured. The elastance of the intervertebral disc was defined as unit change in intradiscal pressure per fractional change in injected dye volume. Disc degeneration was graded using a modified Dallas discogram scale. Results : The mean elastance was 43.0${\pm}$9.6 psi/mL in Grade 0, 39.5${\pm}$8.3 psi/mL in Grade 1, 30.5${\pm}$22.3 psi/mL in Grade 2, 30.5${\pm}$22.3 psi/mL in Grade 3, 13.2${\pm}$8.3 psi/mL in Grade 4 and 6.9${\pm}$3.8 psi/mL in Grade 5. The elastance showed significant negative correlation with the degree of degeneration ($R^2$=0.529, P=0.000). Conclusion: APCD liberates the examiner from the data acquisition process during discography. This will likely improve the quality of data and the reliability of discography. Elastance could be used as an indicator of disc degeneration.

• Korean Circulation Journal
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• 제53권6호
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• pp.418-420
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• 2023

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.889-890
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.891-892
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• 2012

• Tuberculosis and Respiratory Diseases
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• 제84권1호
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• pp.67-73
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• 2021

Background: Pleurodesis fails in 10%-40% of patients with recurrent malignant pleural effusions malignant pleural effusion and dyspnea. This study aimed to assess the values of pleural elastance (P_EL) after the aspiration of 500 mL of pleural fluid and their relation to the pleurodesis outcome, and to compare the pleurodesis outcome with the chemical characteristics of pleural fluid. Methods: A prospective study was conducted in Kasr El-Aini Hospital, Cairo University, during the period from March 2019 to January 2020. The study population consisted of 40 patients with malignant pleural effusion. The measurement of P_EL after the aspiration of 500 mL of fluid was done with "P_EL 0.5" (cm H₂O/L), and the characteristics of the pleural fluid were chemically and cytologically analyzed. Pleurodesis was done and the patients were evaluated one month later. The P_EL values were compared with pleurodesis outcomes. Results: After 4-week of follow-up, the success rate of pleurodesis was 65%. The P_EL 0.5 was significantly higher in failed pleurodesis than it was in successful pleurodesis. A cutoff point of P_EL 0.5 >14.5 cm H₂O/L was associated with pleurodesis failure with a sensitivity and specificity of 93% and 100%, respectively. The patients with failed pleurodesis had significantly lower pH levels in fluid than those in the successful group (p<0.001). Conclusion: P_EL measurement was a significant predictor in differentiating between failed and successful pleurodesis. The increase in acidity of the malignant pleural fluid can be used as a predictor for pleurodesis failure in patients with malignant pleural effusion.

• Journal of Dental Anesthesia and Pain Medicine
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• 제22권1호
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• pp.11-18
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• 2022

Background: The vasoconstrictive effect of epinephrine in local anesthetics affects the heart, which leads to hesitation among dentists in injecting local anesthetics into patients with cardiovascular disease. Due to its vasoconstrictive effects, the present study investigated the effects of vasopressin administration on cardiac function in rats. Methods: Experiment 1 aimed to determine the vasopressin concentration that could affect cardiac function. An arterial catheter was inserted into the male Wistar rats. Next, 0.03, 0.3, and 3.0 U/mL arginine vasopressin (AVP) (0.03V, 0.3V, and 3.0V) was injected into the tongue, and the blood pressure was measured. The control group received normal saline only. In Experiment 2, following anesthesia infiltration, a pressure-volume catheter was placed in the left ventricle. Baseline values of end-systolic elastance, end-diastolic volume, end-systolic pressure, stroke work, stroke volume, and end-systolic elastance were recorded. Next, normal saline and 3.0V AVP were injected into the tongue to measure their effect on hemodynamic and cardiac function. Results: After 3.0V administration, systolic blood pressures at 10 and 15 min were higher than those of the control group; they increased at 10 min compared with those at baseline. The diastolic blood pressures at 5-15 min were higher than those of the control group; they increased at 5 and 10 min compared with those at baseline. The preload decreased at 5 and 10 min compared to that at baseline. However, the afterload increased from 5 to 15 min compared with that of the control group; it increased at 10 min compared with that at baseline. Stroke volume decreased at 10 and 15 min compared with that of the control group; it decreased from 5 to 15 min compared with that at baseline. Stroke work decreased from 5 to 15 min compared with that of the control group; it decreased from 5 to 15 min compared with that at baseline. Conclusion: Our results showed that 3.0 U/mL concentration of vasopressin resulted in increased blood pressure, decreased stroke volume and stoke work, decreased preload and increased afterload, without any effect on myocardial contractility.

• Korean Circulation Journal
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• 제53권6호
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• pp.406-417
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• 2023

Background and Objectives: Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement. Methods: In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity. Results: Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO₂] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO₂ was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results. Conclusions: We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

• 대한핵의학회지
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• 제35권3호
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• pp.152-160
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• 2001

목적: 게이트 심근 SPECT를 이용하여 좌심실심근의 최대탄성률을 측정하는 방법의 재현성을 조사하고 단일 압력-부피 고리방법과 매개변수 최적화 방법으로 얻었을 때 재현성의 차이를 조사하였다. 대상 및 방법: 관상동맥질환이 의심되는 47명 (남자 42명, 여자 5명, 평균나이 53세, 좌심실구혈률 22-68%)에서 Tc-99m MIBI게이트 심근 SPECT와 동시에 요골동맥 긴장도를 측정하였다. 이 중 11명에서는 누운 자리에서 움직이지 않고 연이어 두번 측정하였다. 최대탄성률과 영점부피를 Lee 등이 제안한 단일 압력-부피 고리 방법과 Yoshizawa 등이 제안한 선형근사에 의한 매개변수 최적화 방법으로 추정하였다. 결과: 최대탄성률(상관계수 0.96)과 영점부피(상관계수 0.99)의 재현성은 단일 압력-부피 고리 방법이 매개변수 최적화 방법(최대탄성률 0.89, 영점부피 0.64)보다 좋았다. 두 방법으로 추정한 최대탄성률의 상관계수는 0.77, 영점부피의 상관계수는 0.65이었다. 결론: 게이트 심근 SPECT와 동맥긴장도 측정법으로 얻어 단일 압력-부피 고리 방법으로 추정한 좌심실 심근의 최대탄성률의 재현성은 매우 우수하였다. 매개변수 최적화 방법으로 얻은 최대탄성률도 우수하나 단일 압력-부피 고리 방법보다 못하였다.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.43-48
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• 1996

We investigated the energistics of the physiological heart model by comparing predictive indexes of the myocardial oxygen consumption (MOC), such as tension-time index (R), tension-time or force-time inteual (FTI), rate-pressure product (RPP), pressure-work index, and systolic pressure-volume area (PVA) when using the electro-hydraulic left ventricular device (LVAD). We developed the model of LVAD incorporated the closed-loop cardiovascular system with a baroreceptor which can control heart rate and time-varying elastance of left and right ventricles. On considering the benefit of the LVAD, the effects of various operation modes, especially timing of assistance, were evaluated using this coupled computer model. Overall results of the computer simulation shows that our LVAD can unload the ischemic (less contractile) heart by decreasing the MU and increasing coronary flow. Because the pump ejection at the end diastolic phase of the natural heart may increase the afterload of the left ventricle, the control scheme of our LVAD must prohibit ejecting at this time. Since the increment of coronary flow is proportional to the peak aortic pressure after ventricle contraction, the LVAD must eject immediately following the closure of the aortic valve to increase oxygen availability.

• 대한핵의학회지
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• 제39권4호
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• pp.224-230
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• 2005

목적: 심근의 최대탄성도는 전부하 후부하에 독립적인 지표로서 SPECT를 이용하여 좌심실의 국소탄성도($rE_{max}$)를 비침습적으로 측정하였다. 게이트 심근 SPECT 영상에서 국소부피변화를 얻고, 요골동맥 긴장도를 측정하여 중심동맥의 압력 곡선을 얻어 측정한 최대탄성도를 관상동맥우회로 수술 전후 환자를 대상으로 수술전후 관류 및 기능지표와 비교하여보았다. 대상 및 방법: 관상동맥우회로 수술이 결정되어 시행한 환자 21명(남:여=17:4, $58{\pm}12$세)을 대상으로 $^{201}TI$ 휴식기 영상과 디피리다몰 부하 $^{99m}Tc$-sestamibi 게이트 SPECT를 수술전과 수술 후 3개월째 시행하였다. 동시에 요골동맥으로부터 압력곡선을 얻었다. 기능과의 관계를 보기 위해서 관류와 심벽두꺼워짐을 탄성도와 비교하였으며, 심벽두꺼워짐이 20%미만일 때 수술 후 10%이상 호전되지 않는 기능이상 분절에 대해 수술 전후의 탄성도를 비교하였다. 결과: 수술 전 탄성도가 $2.41{\pm}1.64$ mmHg/mL에서 $2.78{\pm}1.83$ mmHg/mL 으로 수술 후에 증가하였으나, 관류와 심벽두꺼워짐과는 낮은 상관성을 보였다. (r=0.35, p<0.001). 관류 60% 이상의 분절에서는 $2.65{\pm}1.67$ mmHg/mL 이었으나, 관류나 낮은 분절의 탄성도는 $1.30{\pm}1.24$ mmHg/mL 였다. 심벽두꺼워짐이 40% 이상 되는 분절의 수술 전 탄성도는 $3.01{\pm}1.92$ mmHg/mL 였고, 기능이 조금 약한 부분인 40%에서 20% 사이의 심벽두꺼워짐 값을 가진 분절에서는 $2.40{\pm}1.19$ mmHg/mL로 심각한 기능이상을 반영하는 20%미만 분절의 탄성도는 $1.13{\pm}0.89$ mmHg/mL의 분포를 보였다. 수술 전 심벽두꺼워짐이 20% 미만일 때 수술 후 10%이상 회복을 보인 생존심근와 그렇지 않은 비생존심근사이의 수술 전후 탄성도는 $1.27{\pm}1.07$ mmHg/mL에서 $1.79{\pm}1.48$ mmHg/mL, $0.97{\pm}0.59$ mmHg/mL에서 $1.22{\pm}0.71$ mmHg/mL로 생존심근의 수술 후 값의 향상이 조금 더 높았다. 그러나, 심벽두꺼워짐의 정도가 탄성도 높아짐의 정도 사이에는 상관성이 없었다(r=0.007). 결론: 수술 전 $rE_{max}$는 관류와 심벽두꺼워짐과 상관성이 약하게 있었다. 기능이상이면서 생존능이 있는 심근의 탄성도는 수술 후 증가하였지만 심벽두꺼워짐의 향상과는 상관성이 없었다. 심근기능의 전부하 후부하에 독립적인 지표인 탄성도는 실제 부피의 증가와 연관되지 않으면서도 생존능이 있는 심근의 기준과 일치하는 양상을 보였으므로 독립적인 매개변수로 사용될 수 있을 것으로 기대한다.