• The Korean Journal of Nuclear Medicine
• /
• v.33 no.3
• /
• pp.247-261
• /
• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• Tuberculosis and Respiratory Diseases
• /
• v.54 no.4
• /
• pp.429-438
• /
• 2003

Background : The mortality from acute respiratory distress syndrome(ARDS) is >40-50%. Although some prospective trials have failed to demonstrate a survival benefit of steroids in the early stages of ARDS, there are some reports showing some success with steroids in the later stages. This study observed the changes in the physiologic parameters with time in late ARDS patients who were treated with steroids. Methods : The medical charts of 28 intensive care unit patients(male:female=24:4; mean age 64 years), who had been diagnosed with refractory late ARDS ($PaO_2/FIO_2$ <200) and were treated with corticosteroids from December 1999 to July 2002, were retrospectively reviewed. The patients were divided into two groups: the weaned group(n=14), which included the patients who had been successfully weaned from a ventilator after corticosteroid therapy, and the failed group(n=14), which included the patients who had failed weaning. The physiologic parameters included the $PaO_2/FIO_2$ ratio, the positive end-expiratory pressure(PEEP) level, the $PaCO_2$, compliance, the sequential organ failure assessment(SOFA) score, the acute physiologic and the chronic health evaluation(APACHE) II score, and the Murray Lung Injury Score(LIS) in the two groups were compared from the day of mechanical ventilation(Dmv) to 7 days after the corticosteroid therapy. Results : There was no significant difference in the clinical characteristics and the physiologic parameters between the two groups prior to the corticosteroid therapy except for the SOFA score at Dmv(weaned group : $6.6{\pm}2.5$ vs failed group : $8.8{\pm}2.9$, p=0.047). However, within 7 days after corticosteroid therapy, there was significant improvement in the $PaO_2/FIO_2$ ratio, the PEEP level, the $PaCO_2$, the SOFA score, the APACHE II score, and the LIS of the weaned group compared to the failed group. Conclusions : During corticosteroid therapy in late ARDS, the continuation of corticosteroid therapy should be determined carefully in patients who do not show improvement in their physiologic parameters by day 7.

• Journal of The Korean Society of Emergency Medicine
• /
• v.29 no.5
• /
• pp.465-473
• /
• 2018

Objective: We evaluated the clinical characteristics and prognoses of patients with septic shock who transferred to the emergency department (ED) in a tertiary referral center. Methods: This study was performed using a prospective, multi-center registry of septic shock, with the participation of 11 tertiary referral centers in the Korean Shock Society between October 2015 and February 2017. We classified the patients as a transferred group who transferred from other hospitals after meeting the inclusion criteria upon ED arrival and a non-transferred group who presented directly to the ED. Primary outcome was hospital mortality. We conducted multiple logistic regression analysis to assess variables related to in-hospital mortality. Results: A total of 2,098 patients were included, and we assigned 717 patients to the transferred group and 1,381 patients to the non-transferred group. The initial Sequential Organ Failure Assessment score was higher in the transferred group than the non-transferred group (6; interquartile range [IQR], 4-9 vs. 6; IQR, 4-8; P<0.001). Mechanical ventilator (29% vs. 21%, P<0.001) and renal replacement therapy (12% vs. 9%, P=0.034) within 24 hours after ED arrival were more frequently applied in the transferred group than the non-transferred group. Overall hospital mortality was 22% and there was no significant difference between transferred and non-transferred groups (23% vs. 22%, P=0.820). Multivariable analysis showed an odds ratio for in-hospital mortality of 1.00 (95% confidence interval, 0.78-1.28; P=0.999) for the transferred group compared with the non-transferred group. Conclusion: The transferred group showed higher severity and needed more organ support procedures than the non-transferred group. However, inter-hospital transfer did not affect in-hospital mortality.

• Journal of Korea Water Resources Association
• /
• v.55 no.10
• /
• pp.761-774
• /
• 2022

Accurate hydrologic prediction is essential to analyze the effects of drought, flood, and climate change on flow rates, water quality, and ecosystems. Disentangling the uncertainty of the hydrological model is one of the important issues in hydrology and water resources research. Hydrologic data assimilation (DA), a technique that updates the status or parameters of a hydrological model to produce the most likely estimates of the initial conditions of the model, is one of the ways to minimize uncertainty in hydrological simulations and improve predictive accuracy. In this study, the two ensemble-based sequential DA techniques, ensemble Kalman filter, and particle filter are comparatively analyzed for the daily discharge simulation at the Yongdam catchment using airGRdatassim. The results showed that the values of Kling-Gupta efficiency (KGE) were improved from 0.799 in the open loop simulation to 0.826 in the ensemble Kalman filter and to 0.933 in the particle filter. In addition, we analyzed the effects of hyper-parameters related to the data assimilation methods such as precipitation and potential evaporation forcing error parameters and selection of perturbed and updated states. For the case of forcing error conditions, the particle filter was superior to the ensemble in terms of the KGE index. The size of the optimal forcing noise was relatively smaller in the particle filter compared to the ensemble Kalman filter. In addition, with more state variables included in the updating step, performance of data assimilation improved, implicating that adequate selection of updating states can be considered as a hyper-parameter. The simulation experiments in this study implied that DA hyper-parameters needed to be carefully optimized to exploit the potential of DA methods.

• Tuberculosis and Respiratory Diseases
• /
• v.58 no.6
• /
• pp.562-569
• /
• 2005

Background : The severity scoring system is useful for predicting the outcome of critically ill patients. However, the system is quite complicated and cost-ineffective. Simple serologic markers have been proposed to predict the outcome, which include troponin-I, lactate and C-reactive protein(CRP). The aim of this study was to evaluate the prognostic values of troponin-I, lactate and CRP in critically ill non-cardiac patients. Methods : From September 2003 to June 2004, 139 patients(Age: $63.3{\pm}14.7$, M:F = 88:51), who were admitted to the MICU with non-cardiac critical illness at Gyeongsang National University Hospital, were enrolled in this study. This study evaluated the severity of the illness and the multi-organ failure score (Acute Physiologic and Chronic Health EvaluationII, Simplified Acute Physiologic ScoreII and Sequential Organ Failure Assessment) and measured the troponin-I, lactate and CRP within 24 hours after admission in the MICU. Each value in the survivors and non-survivors was compared at the 10th and 30th day after ICU admission. The mortality rate was compared at 10th and 30th day in normal and abnormal group. In addition, the correlations between each value and the severity score were assessed. Results : There were significantly higher troponin-I and CRP levels, not lactate, in the non-survivors than in the survivors at 10th day($1.018{\pm}2.58ng/ml$, $98.48{\pm}69.24mg/L$ vs. $4.208{\pm}10.23ng/ml$, $137.69{\pm}70.18mg/L$) (p<0.05). There were significantly higher troponin-I, lactate and CRP levels in the non-survivors than in the survivors on the 30th day ($0.99{\pm}2.66ng/ml$, $8.02{\pm}9.54ng/dl$, $96.87{\pm}68.83mg/L$ vs. $3.36{\pm}8.74ng/ml$, $15.42{\pm}20.57ng/dl$, $131.28{\pm}71.23mg/L$) (p<0.05). The mortality rate was significantly higher in the abnormal group of troponin-I, lactate and CRP than in the normal group of troponin-I, lactate and CRP at 10th day(28.1%, 31.6%, 18.9% vs. 11.0%, 15.8 %, 0%) and 30th day(38.6%, 47.4%, 25.8% vs. 15.9%, 21.7%, 14.3%) (p<0.05). Troponin-I and lactate were significantly correlated with the SAPS II score($r^2=0.254$, 0.365, p<0.05). Conclusion : Measuring the troponin-I, lactate and CRP levels upon admission may be useful for predicting the outcome of critically ill non-cardiac patients.