1.Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation
Jae Kyeom SIM ; Sang-Min LEE ; Hyung Koo KANG ; Kyung Chan KIM ; Young Sam KIM ; Yun Seong KIM ; Won-Yeon LEE ; Sunghoon PARK ; So Young PARK ; Ju-Hee PARK ; Yun Su SIM ; Kwangha LEE ; Yeon Joo LEE ; Jin Hwa LEE ; Heung Bum LEE ; Chae-Man LIM ; Won-Il CHOI ; Ji Young HONG ; Won Jun SONG ; Gee Young SUH
Acute and Critical Care 2024;39(1):91-99
Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.
2.Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation
Jae Kyeom SIM ; Sang-Min LEE ; Hyung Koo KANG ; Kyung Chan KIM ; Young Sam KIM ; Yun Seong KIM ; Won-Yeon LEE ; Sunghoon PARK ; So Young PARK ; Ju-Hee PARK ; Yun Su SIM ; Kwangha LEE ; Yeon Joo LEE ; Jin Hwa LEE ; Heung Bum LEE ; Chae-Man LIM ; Won-Il CHOI ; Ji Young HONG ; Won Jun SONG ; Gee Young SUH
Acute and Critical Care 2024;39(1):91-99
Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.
3.Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation
Jae Kyeom SIM ; Sang-Min LEE ; Hyung Koo KANG ; Kyung Chan KIM ; Young Sam KIM ; Yun Seong KIM ; Won-Yeon LEE ; Sunghoon PARK ; So Young PARK ; Ju-Hee PARK ; Yun Su SIM ; Kwangha LEE ; Yeon Joo LEE ; Jin Hwa LEE ; Heung Bum LEE ; Chae-Man LIM ; Won-Il CHOI ; Ji Young HONG ; Won Jun SONG ; Gee Young SUH
Acute and Critical Care 2024;39(1):91-99
Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.
4.Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation
Jae Kyeom SIM ; Sang-Min LEE ; Hyung Koo KANG ; Kyung Chan KIM ; Young Sam KIM ; Yun Seong KIM ; Won-Yeon LEE ; Sunghoon PARK ; So Young PARK ; Ju-Hee PARK ; Yun Su SIM ; Kwangha LEE ; Yeon Joo LEE ; Jin Hwa LEE ; Heung Bum LEE ; Chae-Man LIM ; Won-Il CHOI ; Ji Young HONG ; Won Jun SONG ; Gee Young SUH
Acute and Critical Care 2024;39(1):91-99
Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.
5.ChatGPT Predicts In-Hospital All-Cause Mortality for Sepsis: In-Context Learning with the Korean Sepsis Alliance Database
Namkee OH ; Won Chul CHA ; Jun Hyuk SEO ; Seong-Gyu CHOI ; Jong Man KIM ; Chi Ryang CHUNG ; Gee Young SUH ; Su Yeon LEE ; Dong Kyu OH ; Mi Hyeon PARK ; Chae-Man LIM ; Ryoung-Eun KO ;
Healthcare Informatics Research 2024;30(3):266-276
Objectives:
Sepsis is a leading global cause of mortality, and predicting its outcomes is vital for improving patient care. This study explored the capabilities of ChatGPT, a state-of-the-art natural language processing model, in predicting in-hospital mortality for sepsis patients.
Methods:
This study utilized data from the Korean Sepsis Alliance (KSA) database, collected between 2019 and 2021, focusing on adult intensive care unit (ICU) patients and aiming to determine whether ChatGPT could predict all-cause mortality after ICU admission at 7 and 30 days. Structured prompts enabled ChatGPT to engage in in-context learning, with the number of patient examples varying from zero to six. The predictive capabilities of ChatGPT-3.5-turbo and ChatGPT-4 were then compared against a gradient boosting model (GBM) using various performance metrics.
Results:
From the KSA database, 4,786 patients formed the 7-day mortality prediction dataset, of whom 718 died, and 4,025 patients formed the 30-day dataset, with 1,368 deaths. Age and clinical markers (e.g., Sequential Organ Failure Assessment score and lactic acid levels) showed significant differences between survivors and non-survivors in both datasets. For 7-day mortality predictions, the area under the receiver operating characteristic curve (AUROC) was 0.70–0.83 for GPT-4, 0.51–0.70 for GPT-3.5, and 0.79 for GBM. The AUROC for 30-day mortality was 0.51–0.59 for GPT-4, 0.47–0.57 for GPT-3.5, and 0.76 for GBM. Zero-shot predictions using GPT-4 for mortality from ICU admission to day 30 showed AUROCs from the mid-0.60s to 0.75 for GPT-4 and mainly from 0.47 to 0.63 for GPT-3.5.
Conclusions
GPT-4 demonstrated potential in predicting short-term in-hospital mortality, although its performance varied across different evaluation metrics.
6.Early Prediction of Mortality for Septic Patients Visiting Emergency Room Based on Explainable Machine Learning: A Real-World Multicenter Study
Sang Won PARK ; Na Young YEO ; Seonguk KANG ; Taejun HA ; Tae-Hoon KIM ; DooHee LEE ; Dowon KIM ; Seheon CHOI ; Minkyu KIM ; DongHoon LEE ; DoHyeon KIM ; Woo Jin KIM ; Seung-Joon LEE ; Yeon-Jeong HEO ; Da Hye MOON ; Seon-Sook HAN ; Yoon KIM ; Hyun-Soo CHOI ; Dong Kyu OH ; Su Yeon LEE ; MiHyeon PARK ; Chae-Man LIM ; Jeongwon HEO ; On behalf of the Korean Sepsis Alliance (KSA) Investigators
Journal of Korean Medical Science 2024;39(5):e53-
Background:
Worldwide, sepsis is the leading cause of death in hospitals. If mortality rates in patients with sepsis can be predicted early, medical resources can be allocated efficiently. We constructed machine learning (ML) models to predict the mortality of patients with sepsis in a hospital emergency department.
Methods:
This study prospectively collected nationwide data from an ongoing multicenter cohort of patients with sepsis identified in the emergency department. Patients were enrolled from 19 hospitals between September 2019 and December 2020. For acquired data from 3,657 survivors and 1,455 deaths, six ML models (logistic regression, support vector machine, random forest, extreme gradient boosting [XGBoost], light gradient boosting machine, and categorical boosting [CatBoost]) were constructed using fivefold cross-validation to predict mortality. Through these models, 44 clinical variables measured on the day of admission were compared with six sequential organ failure assessment (SOFA) components (PaO 2 /FIO 2 [PF], platelets (PLT), bilirubin, cardiovascular, Glasgow Coma Scale score, and creatinine).The confidence interval (CI) was obtained by performing 10,000 repeated measurements via random sampling of the test dataset. All results were explained and interpreted using Shapley’s additive explanations (SHAP).
Results:
Of the 5,112 participants, CatBoost exhibited the highest area under the curve (AUC) of 0.800 (95% CI, 0.756–0.840) using clinical variables. Using the SOFA components for the same patient, XGBoost exhibited the highest AUC of 0.678 (95% CI, 0.626–0.730). As interpreted by SHAP, albumin, lactate, blood urea nitrogen, and international normalization ratio were determined to significantly affect the results. Additionally, PF and PLTs in the SOFA component significantly influenced the prediction results.
Conclusion
Newly established ML-based models achieved good prediction of mortality in patients with sepsis. Using several clinical variables acquired at the baseline can provide more accurate results for early predictions than using SOFA components. Additionally, the impact of each variable was identified.
7.Pre-Sepsis Length of Hospital Stay and Mortality: A Nationwide Multicenter Cohort Study
Joong-Yub KIM ; Hong Yeul LEE ; Jinwoo LEE ; Dong Kyu OH ; Su Yeon LEE ; Mi Hyeon PARK ; Chae-Man LIM ; Sang-Min LEE ;
Journal of Korean Medical Science 2024;39(9):e87-
Background:
Prolonged length of hospital stay (LOS) is associated with an increased risk of hospital-acquired conditions and worse outcomes. We conducted a nationwide, multicenter, retrospective cohort study to determine whether prolonged hospitalization before developing sepsis has a negative impact on its prognosis.
Methods:
We analyzed data from 19 tertiary referral or university-affiliated hospitals between September 2019 and December 2020. Adult patients with confirmed sepsis during hospitalization were included. In-hospital mortality was the primary outcome. The patients were divided into two groups according to their LOS before the diagnosis of sepsis: early- (< 5 days) and late-onset groups (≥ 5 days). Conditional multivariable logistic regression for propensity score matched-pair analysis was employed to assess the association between lateonset sepsis and the primary outcome.
Results:
A total of 1,395 patients were included (median age, 68.0 years; women, 36.3%).The early- and late-onset sepsis groups comprised 668 (47.9%) and 727 (52.1%) patients.Propensity score-matched analysis showed an increased risk of in-hospital mortality in the late-onset group (adjusted odds ratio [aOR], 3.00; 95% confidence interval [CI], 1.69–5.34).The same trend was observed in the entire study population (aOR, 1.85; 95% CI, 1.37–2.50).When patients were divided into LOS quartile groups, an increasing trend of mortality risk was observed in the higher quartiles (Pfor trend < 0.001).
Conclusion
Extended LOS before developing sepsis is associated with higher in-hospital mortality. More careful management is required when sepsis occurs in patients hospitalized for ≥ 5 days.
8.Unenhanced Breast MRI With Diffusion-Weighted Imaging for Breast Cancer Detection: Effects of Training on Performance and Agreement of Subspecialty Radiologists
Yeon Soo KIM ; Su Hyun LEE ; Soo-Yeon KIM ; Eun Sil KIM ; Ah Reum PARK ; Jung Min CHANG ; Vivian Youngjean PARK ; Jung Hyun YOON ; Bong Joo KANG ; Bo La YUN ; Tae Hee KIM ; Eun Sook KO ; A Jung CHU ; Jin You KIM ; Inyoung YOUN ; Eun Young CHAE ; Woo Jung CHOI ; Hee Jeong KIM ; Soo Hee KANG ; Su Min HA ; Woo Kyung MOON
Korean Journal of Radiology 2024;25(1):11-23
Objective:
To investigate whether reader training improves the performance and agreement of radiologists in interpreting unenhanced breast magnetic resonance imaging (MRI) scans using diffusion-weighted imaging (DWI).
Materials and Methods:
A study of 96 breasts (35 cancers, 24 benign, and 37 negative) in 48 asymptomatic women was performed between June 2019 and October 2020. High-resolution DWI with b-values of 0, 800, and 1200 sec/mm 2 was performed using a 3.0-T system. Sixteen breast radiologists independently reviewed the DWI, apparent diffusion coefficient maps, and T1-weighted MRI scans and recorded the Breast Imaging Reporting and Data System (BI-RADS) category for each breast. After a 2-h training session and a 5-month washout period, they re-evaluated the BI-RADS categories. A BI-RADS category of 4 (lesions with at least two suspicious criteria) or 5 (more than two suspicious criteria) was considered positive.The per-breast diagnostic performance of each reader was compared between the first and second reviews. Inter-reader agreement was evaluated using a multi-rater κ analysis and intraclass correlation coefficient (ICC).
Results:
Before training, the mean sensitivity, specificity, and accuracy of the 16 readers were 70.7% (95% confidence interval [CI]: 59.4–79.9), 90.8% (95% CI: 85.6–94.2), and 83.5% (95% CI: 78.6–87.4), respectively. After training, significant improvements in specificity (95.2%; 95% CI: 90.8–97.5; P = 0.001) and accuracy (85.9%; 95% CI: 80.9–89.8; P = 0.01) were observed, but no difference in sensitivity (69.8%; 95% CI: 58.1–79.4; P = 0.58) was observed. Regarding inter-reader agreement, the κ values were 0.57 (95% CI: 0.52–0.63) before training and 0.68 (95% CI: 0.62–0.74) after training, with a difference of 0.11 (95% CI: 0.02–0.18; P = 0.01). The ICC was 0.73 (95% CI: 0.69–0.74) before training and 0.79 (95% CI: 0.76–0.80) after training (P = 0.002).
Conclusion
Brief reader training improved the performance and agreement of interpretations by breast radiologists using unenhanced MRI with DWI.
9.Short-term and long-term outcomes of critically ill patients with solid malignancy: a retrospective cohort study
Su Yeon LEE ; Jin Won HUH ; Sang-Bum HONG ; Chae-Man LIM ; Jee Hwan AHN
The Korean Journal of Internal Medicine 2024;39(6):957-966
Background/Aims:
With the global increase in patients with solid malignancies, it is helpful to understand the outcomes of intensive care unit (ICU) admission for these patients. This study evaluated the risk factors for ICU mortality and the shortand long-term outcomes in patients with solid malignancies who had unplanned ICU admission.
Methods:
This retrospective cohort study included patients with solid malignancies treated at the medical ICU of a single tertiary center in South Korea between 2016 and 2022.
Results:
Among the 955 patients, the ICU mortality rate was 23.5%. Lung cancer was the most common cancer type (34.2%) and was significantly associated with increased ICU mortality (odd ratio [OR] 1.58, p = 0.030). Higher Sequential Organ Failure Assessment scores at ICU admission (OR 1.11, p < 0.001), the need for mechanical ventilation (OR 6.74, p < 0.001), or renal replacement therapy during the ICU stay (OR 2.49, p < 0.001) were significantly associated with higher ICU mortality. The 1-year survival rate after ICU admission was 29.3%, with a median survival of 37 days for patients requiring mechanical deviaventilation, and 23 days for patients requiring renal replacement therapy.
Conclusions
This study showed that critically ill patients with solid malignancies had poor 1-year survival despite relatively low ICU mortality. These findings highlight the need for careful consideration of ICU admission in patients with solid malignancy, and decision-making should be based on an understanding of the expected short- and long-term prognosis of ICU admission after an informed discussion among patients, families, and physicians.
10.Vessel-Derived Decellularized Extracellular Matrices (VdECM):Novel Bio-Engineered Materials for the Wound Healing
Chae Rim LEE ; Yoon Jae LEE ; Bo Young KWON ; Su Jin LEE ; Yeon Hee RYU ; Jong-Won RHIE ; Suk-Ho MOON
Tissue Engineering and Regenerative Medicine 2023;20(1):59-67
BACKGROUND:
Decellularized extracellular matrix (dECM) is a non-cellular scaffold with various functions in tissue engineering and regenerative medicine. Elastin is related to tissue elasticity and scarless wound healing, abundantly found in lung and blood vessel tissues. We studied the characteristics of blood vessel-derived dECM (VdECM) and its effect in wound healing.
METHODS:
VdECM was prepared from porcine blood vessel tissue. Weight percentages of elastin of VdECM and atelocollagen were analyzed. Migratory potential of VdECM was tested by scratch assay. VdECM in hydrogel form was microscopically examined, tested for fibroblast proliferation, and examined for L/D staining. Cytokine array of various growth factors in adipocyte-derived mesenchymal stem cell (ASC) media with VdECM was done. Animal wound model showed the wound healing effect of VdECM hydrogel in comparison to other topical agents.
RESULTS:
VdECM contained 6.7 times more elastin than atelocollagen per unit weight. Microscopic view of 0.35% VdECM hydrogel showed consistent distribution. Compared to 3% atelocollagen, 0.35% VdECM showed superior results in fibroblast migration. Fluorescent microscopic findings of L/D assay had highest percentage of cell survival in 1% VdECM compared to atelocollagen. Growth factor expression was drastically amplified when VdECM was added to ASC media. In the animal study model, epithelialization rate in the VdECM group was higher than that of control, oxytetracycline, and epidermal growth factor ointments.
CONCLUSION
VdECM contains a high ratio of elastin to collagen and amplifies expressions of many growth factors. It promotes fibroblast migration, proliferation, and survival, and epithelialization comparable to other topical agents.

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