Hong Yeul Lee’s research while affiliated with Seoul National University Hospital and other places

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Publications (27)


Connective tissue disease is associated with the risk of posterior reversible encephalopathy syndrome following lung transplantation in Korea
  • Article

January 2025

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6 Reads

Acute and Critical Care

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Samina Park

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[...]

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Hong Yeul Lee

Background: Posterior reversible encephalopathy syndrome (PRES) is a rare complication of lung transplantation with poorly understood risk factors and clinical characteristics. This study aimed to examine the occurrence, risk factors, and clinical data of patients who developed PRES following lung transplantation.Methods: A retrospective analysis was conducted on 147 patients who underwent lung transplantation between February 2013 and December 2023. The patients were diagnosed with PRES based on the clinical symptoms and radiological findings. We compared the baseline characteristics and clinical information, including primary lung diseases and immunosuppressive therapy related to lung transplantation operations, between the PRES and non-PRES groups.Results: PRES manifested in 7.5% (n=11) of the patients who underwent lung transplantation, with a median onset of 15 days after operation. Seizures were identified as the predominant clinical manifestation (81.8%, n=9) in the group diagnosed with PRES. All patients diagnosed with PRES recovered fully. Patients with PRES were significantly associated with connective tissue disease-associated interstitial lung disease (45.5% vs. 18.4%, P=0.019, odds ratio=9.808; 95% CI, 1.064–90.386; P=0.044). Nonetheless, no significant variance was observed in the type of immunotherapy, such as the use of calcineurin inhibitors, blood pressure, or acute renal failure subsequent to lung transplantation.Conclusions: PRES typically manifests shortly after lung transplantation, with seizures being the predominant initial symptom. The presence of preexisting connective tissue disease as the primary lung disease represents a significant risk factor for PRES following lung transplantation.


Fig. 1 | Flow chart of dataset construction. a Derivation cohort. b External validation cohort.
Fig. 2 | Dexmedetomidine dosing distribution of the AID policy and clinicians' policy at all 6-h timesteps. a Derivation cohort. b External validation cohort. The outer plot shows the full range of dosages from 0.0 to 1.5 mcg/kg/h, while the inner plot focuses on the dosage range from 0.1 to 1.5 mcg/kg/h. AID artificial intelligence model for delirium prevention.
Fig. 3 | Four representative cases. a A case where delirium did not occur when the AID and clinicians' policies were close. b A case where delirium occurred when the AID and clinicians' policies were discrepant. c A case where delirium did not occur when the AID and clinicians' policies were discrepant. d A case where delirium occurred when the AID and clinicians' policies were close. The RASS ranges from −5 to 4, where higher positive scores indicate increased agitation, and lower negative scores indicate deeper sedation, with a score of 0 representing the appearance of calm and normal alertness. AID artificial intelligence model for delirium prevention, RASS Richmond agitation-sedation scale.
Fig. 4 | Feature importance derived from the SHAP method. a Feature importance of the AID policy. b Feature importance of the clinicians' policy. GCS Glasgow coma scale, F I O2 fraction of inspired oxygen, SBP systolic blood pressure, DBP diastolic blood pressure, hsCRP high-sensitivity C-reactive protein, BT body temperature, SHAP Shapley additive explanations, AID artificial intelligence model for delirium prevention.
Fig. 5 | Feature importance derived from the SHAP method for subgroups stratified by policy matching and delirium occurrence. a Policy-matched subgroup with delirium. b Policy-matched subgroup without delirium. c Policyunmatched subgroup with delirium. d Policy-unmatched subgroup without delirium. BT body temperature, F I O2 fraction of inspired oxygen, DBP diastolic blood pressure, GCS Glasgow coma scale, HCO 3 bicarbonate, Hb hemoglobin, PT prothrombin time, RR respiratory rate, pO 2 partial pressure of oxygen, WBC white blood cell count, hsCRP high-sensitivity C-reactive protein, SBP systolic blood pressure, pCO 2 partial pressure of carbon dioxide, SHAP Shapley additive explanations.

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Reinforcement learning model for optimizing dexmedetomidine dosing to prevent delirium in critically ill patients
  • Article
  • Full-text available

November 2024

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19 Reads

npj Digital Medicine

Delirium can result in undesirable outcomes including increased length of stays and mortality in patients admitted to the intensive care unit (ICU). Dexmedetomidine has emerged for delirium prevention in these patients; however, optimal dosing is challenging. A reinforcement learning-based Artificial Intelligence model for Delirium prevention (AID) is proposed to optimize dexmedetomidine dosing. The model was developed and internally validated using 2416 patients (2531 ICU admissions) and externally validated on 270 patients (274 ICU admissions). The estimated performance return of the AID policy was higher than that of the clinicians’ policy in both derivation (0.390 95% confidence interval [CI] 0.361 to 0.420 vs. −0.051 95% CI −0.077 to −0.025) and external validation (0.186 95% CI 0.139 to 0.236 vs. −0.436 95% CI −0.474 to −0.402) cohorts. Our finding indicates that AID might support clinicians’ decision-making regarding dexmedetomidine dosing to prevent delirium in ICU patients, but further off-policy evaluation is required.

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Figure 1. Flowchart depicting the selection of the study population.
Participant characteristics at baseline for the full analysis set.
Efficacy outcomes for the per protocol set of participants.
Clinical Efficacy and Safety of an Automatic Closed-Suction System in Mechanically Ventilated Patients with Pneumonia: A Multicenter, Prospective, Randomized, Non-Inferiority, Investigator-Initiated Trial

May 2024

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59 Reads

Endotracheal suctioning is an essential but labor-intensive procedure, with the risk of serious complications. A brand new automatic closed-suction device was developed to alleviate the workload of healthcare providers and minimize those complications. We evaluated the clinical efficacy and safety of the automatic suction system in mechanically ventilated patients with pneumonia. In this multicenter, randomized, non-inferiority, investigator-initiated trial, mechanically ventilated patients with pneumonia were randomized to the automatic device (intervention) or conventional manual suctioning (control). The primary efficacy outcome was the change in the modified clinical pulmonary infection score (CPIS) in 3 days. Secondary outcomes were the frequency of additional suctioning and the amount of secretion. Safety outcomes included adverse events or complications. A total of 54 participants, less than the pre-determined number of 102, were enrolled. There was no significant difference in the change in the CPIS over 72 h (−0.13 ± 1.58 in the intervention group, −0.58 ± 1.18 in the control group, p = 0.866), but the non-inferiority margin was not satisfied. There were no significant differences in the secondary outcomes and safety outcomes, with a tendency for more patients with improved tracheal mucosal injury in the intervention group. The novel automatic closed-suction system showed comparable efficacy and safety compared with conventional manual suctioning in mechanically ventilated patients with pneumonia.


Risk factors for progressing to critical illness in patients with hospital-acquired COVID-19

April 2024

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7 Reads

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1 Citation

The Korean Journal of Internal Medicine

Background/Aims: Risk factors for progression to critical illness in hospital-acquired coronavirus disease 2019 (COVID-19) remain unknown. Here, we assessed the incidence and risk factors for progression to critical illness and determined their effects on clinical outcomes in patients with hospital-acquired COVID-19.Methods: This retrospective cohort study analyzed patients admitted to the tertiary hospital between January 2020 and June 2022 with confirmed hospital-acquired COVID-19. The primary outcome was the progression to critical illness of hospital- acquired COVID-19. Patients were stratified into high-, intermediate-, or low-risk groups by the number of risk factors for progression to critical illness.Results: In total, 204 patients were included and 37 (18.1%) progressed to critical illness. In the multivariable logistic analysis, patients with preexisting respiratory disease (OR, 3.90; 95% CI, 1.04–15.18), preexisting cardiovascular disease (OR, 3.49; 95% CI, 1.11–11.27), immunocompromised status (OR, 3.18; 95% CI, 1.11–9.16), higher sequential organ failure assessment (SOFA) score (OR, 1.56; 95% CI, 1.28–1.96), and higher clinical frailty scale (OR, 2.49; 95% CI, 1.62–4.13) showed significantly increased risk of progression to critical illness. As the risk of the groups increased, patients were significantly more likely to progress to critical illness and had higher 28-day mortality.Conclusions: Among patients with hospital-acquired COVID-19, preexisting respiratory disease, preexisting cardiovascular disease, immunocompromised status, and higher clinical frailty scale and SOFA scores at baseline were risk factors for progression to critical illness. Patients with these risk factors must be prioritized and appropriately isolated or treated in a timely manner, especially in pandemic settings.


Fig. 3. Adjusted odds ratio for in-hospital mortality according to LOS quartile groups. Patients were divided into quartiles according to their hospital LOS (Q1: LOS < 1.17 days; Q2: 1.17 ≤ LOS < 5.55 days; Q3: 5.55 ≤ LOS < 15.81 days; Q4: LOS ≥ 15.81 days). Adjusted odds ratio for in-hospital mortality by quartile groups were Q1: 0.67 (95% CI, 0.47-0.94; P = 0.019), Q2: 0.73 (95% CI, 0.52-1.02; P = 0.066), Q3: 1.16 (95% CI, 0.84-1.59; P = 0.375), Q4: 1.72 (95% CI, 1.24-2.38; P = 0.001). P for trend calculated by generalized linear regression was < 0.001. LOS = length of hospital stay, CI = confidence interval.
Infection characteristics by exposure to prolonged hospitalization
Association between exposure to prolonged hospitalization and in-hospital mortality
Pre-Sepsis Length of Hospital Stay and Mortality: A Nationwide Multicenter Cohort Study

March 2024

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39 Reads

Journal of Korean medical science

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 late-onset 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 (P for 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.


Early Sepsis-Associated Acute Kidney Injury and Obesity

February 2024

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29 Reads

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11 Citations

JAMA Network Open

Importance The prevalence of obesity is increasing in the intensive care unit (ICU). Although obesity is a known risk factor for chronic kidney disease, its association with early sepsis-associated acute kidney injury (SA-AKI) and their combined association with patient outcomes warrant further investigation. Objective To explore the association between obesity, early SA-AKI incidence, and clinical outcomes in patients with sepsis. Design, Setting, and Participants This nationwide, prospective cohort study analyzed patients aged 19 years or older who had sepsis and were admitted to 20 tertiary hospital ICUs in Korea between September 1, 2019, and December 31, 2021. Patients with preexisting stage 3A to 5 chronic kidney disease and those with missing body mass index (BMI) values were excluded. Exposures Sepsis and hospitalization in the ICU. Main Outcomes and Measures The primary outcome was SA-AKI incidence within 48 hours of ICU admission, and secondary outcomes were mortality and clinical recovery (survival to discharge within 30 days). Patients were categorized by BMI (calculated as weight in kilograms divided by height in meters squared), and data were analyzed by logistic regression adjusted for key characteristics and clinical factors. Multivariable fractional polynomial regression models and restricted cubic spline models were used to analyze the clinical outcomes with BMI as a continuous variable. Results Of the 4041 patients (median age, 73 years [IQR, 63-81 years]; 2349 [58.1%] male) included in the study, 1367 (33.8%) developed early SA-AKI. Obesity was associated with a higher incidence of SA-AKI compared with normal weight (adjusted odds ratio [AOR], 1.40; 95% CI, 1.15-1.70), as was every increase in BMI of 10 (OR, 1.75; 95% CI, 1.47-2.08). While obesity was associated with lower in-hospital mortality in patients without SA-AKI compared with their counterparts without obesity (ie, underweight, normal weight, overweight) (AOR, 0.72; 95% CI, 0.54-0.94), no difference in mortality was observed in those with SA-AKI (AOR, 0.85; 95% CI, 0.65-1.12). Although patients with obesity without SA-AKI had a greater likelihood of clinical recovery than their counterparts without obesity, clinical recovery was less likely among those with both obesity and SA-AKI. Conclusions and Relevance In this cohort study of patients with sepsis, obesity was associated with a higher risk of early SA-AKI and the presence of SA-AKI modified the association of obesity with clinical outcomes.


Factors influencing sleep quality in the intensive care unit: a descriptive pilot study

August 2023

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82 Reads

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7 Citations

Acute and Critical Care

Background: As sleep disturbances are common in the intensive care unit (ICU), this study assessed the sleep quality in the ICU and identified barriers to sleep. Methods: Patients admitted to the ICUs of a tertiary hospital between June 2022 and December 2022 who were not mechanically ventilated at enrollment were included. The quality of sleep (QoS) at home was assessed on a visual analog scale as part of an eight-item survey, while the QoS in the ICU was evaluated using the Korean version of the Richards-Campbell Sleep Questionnaire (K-RCSQ). Good QoS was defined by a score of ≥50. Results: Of the 30 patients in the study, 19 reported a QoS score <50. The Spearman correlation coefficient showed no meaningful relationship between the QoS at home and overall K-RCSQ QoS score in the ICU (r=0.16, P=0.40). The most common barriers to sleep were physical discomfort (43%), being awoken for procedures (43%), and feeling unwell (37%); environmental factors including noise (30%) and light (13%) were also identified sources of sleep disruption. Physical discomfort (32 [28-38] vs. 69 [42-80]; P=0.004), patient care interactions (36 [20-48] vs. 54 [36-80]; P=0.044), and feeling unwell (31 [18-42] vs. 54 [40-76]; P=0.013) were associated with lower K-RCSQ scores. Conclusions: In the ICU, physical discomfort, patient care interactions, and feeling unwell were identified as barriers to sleep.


Fig. 1 Study design. Early and delayed admission indicate admission to the ICU within 6 h or beyond 6 h, respectively. Hospital-onset sepsis was defined as sepsis diagnosed in the general ward
Association between the timing of ICU admission and mortality in patients with hospital-onset sepsis: a nationwide prospective cohort study

April 2023

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121 Reads

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6 Citations

Journal of Intensive Care

Background: Based on sparse evidence, the current Surviving Sepsis Campaign guideline suggests that critically ill patients with sepsis be admitted to the intensive care unit (ICU) within 6 h. However, limited ICU bed availability often makes immediate transfer difficult, and it is unclear whether all patients will benefit from early admission to the ICU. Therefore, the purpose of this study was to determine the association between the timing of ICU admission and mortality in patients with hospital-onset sepsis. Methods: This nationwide prospective cohort study analyzed patients with hospital-onset sepsis admitted to the ICUs of 19 tertiary hospitals between September 2019 and December 2020. ICU admission was classified as either early (within 6 h) or delayed (beyond 6 h). The primary outcome of in-hospital mortality was compared using logistic regression adjusted for key prognostic factors in the unmatched and 1:1 propensity-score-matched cohorts. Subgroup and interaction analyses assessed whether in-hospital mortality varied according to baseline characteristics. Results: A total of 470 and 286 patients were included in the early and delayed admission groups, respectively. Early admission to the ICU did not significantly result in lower in-hospital mortality in both the unmatched (adjusted odds ratio [aOR], 1.35; 95% confidence interval [CI], 0.99-1.85) and matched cohorts (aOR, 1.38; 95% CI, 0.94-2.02). Subgroup analyses showed that patients with increasing lactate levels (aOR, 2.10; 95% CI, 1.37-3.23; P for interaction = 0.003), septic shock (aOR, 2.06; 95% CI, 1.31-3.22; P for interaction = 0.019), and those who needed mechanical ventilation (aOR, 1.92; 95% CI, 1.24-2.96; P for interaction = 0.027) or vasopressor support (aOR, 1.69; 95% CI, 1.17-2.44; P for interaction = 0.042) on the day of ICU admission had a higher risk of mortality with delayed admission. Conclusions: Among patients with hospital-onset sepsis, in-hospital mortality did not differ significantly between those with early and delayed ICU admission. However, as early intensive care may benefit those with increasing lactate levels, septic shock, and those who require vasopressors or ventilatory support, admission to the ICU within 6 h should be considered for these subsets of patients.


In-hospital mortality according to the changes in the initial Lac-SOFA score and Delta Lac-SOFA score. Patients were divided into five or six subgroups based on 5-point intervals of the (a) initial Lac-SOFA or (b) Delta Lac-SOFA scores. The numbers above the bar show the in-hospital mortality rate. ICU intensive care unit, SOFA Sequential Organ Failure Assessment score, Lac-SOFA sum of the SOFA score and the Lac-score, Delta Lac-SOFA sum of the Lac-SOFA ICU day-3 and Delta Lac-scores.
The survival probability from inclusion to day 28 according to initial SOFA, Lac-SOFA, and Lac-scores. Kaplan–Meier plots according to (a) class of the initial SOFA score (by 5-point intervals) [S], (b) class of the initial Lac-SOFA score (by 5-point intervals) [L], (c) initial Lac-score, (d) class of both initial SOFA [S] and initial Lac-SOFA [L] scores. The survival differences were analyzed using the two-tailed log-rank test. SOFA Sequential Organ Failure Assessment score, Lac-SOFA sum of the SOFA score and the Lac-score.
Serial evaluation of the serum lactate level with the SOFA score to predict mortality in patients with sepsis

April 2023

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117 Reads

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10 Citations

In patients with sepsis, outcome prediction plays an important role in influencing therapeutic decision making. In this nationwide, prospective, observational cohort study of sepsis patients conducted between September 2019 and December 2020, we evaluated a novel scoring system using serial Sequential Organ Failure Assessment (SOFA) scores and serum lactate to accurately predict mortality in sepsis. Based on the serum lactate score (Lac-score), patients were assigned to 5 categories: lactate < 2, ≥ 2 to < 4, ≥ 4 to < 8, ≥ 8 to < 12, and ≥ 12 mmol/L. Lac-SOFA score was defined as the sum of Lac-score and SOFA score. After screening 7113 patients, 379 were excluded and 6734 were included in analysis. In-hospital mortality AUROC for serial Lac-SOFA score from initial to ICU day 3 was significantly higher than that for serial SOFA score (initial, 0.679 vs. 0.656, day 1, 0.723 vs. 0.709, day 2, 0.760 vs. 0.747, and day 3, 0.797 vs. 0.781; DeLong's test, p < 0.001). The initial Lac-SOFA score significantly correlated with in-hospital mortality when the patients were divided into five classes based on 5-point intervals (p < 0.05). Serial evaluation of lactate levels with the SOFA score may improve the predictive accuracy of the SOFA score for determining mortality risk in sepsis patients.


Citations (18)


... Lee et al. [11] presented background data and perspectives on risk stratification for hospital-acquired COVID-19 cases that will likely progress to a critical condition. They also discussed the management of nosocomial COVID-19 transmission. ...

Reference:

A novel strategy for predicting critical illness in hospital-acquired COVID-19
Risk factors for progressing to critical illness in patients with hospital-acquired COVID-19
  • Citing Article
  • April 2024

The Korean Journal of Internal Medicine

... Studies have stated that obesity is associated with an increased risk of AKI in areas such as acute respiratory distress syndrome or after cardiac surgery [18,19]. In a recent study involving critically ill septic patients in the ICU, obesity patients were found to have a higher chance of developing early sepsis-associated AKI [20]. The literature supports our findings on the characteristics that will be used in the development of a model to predict AKI in septic patients. ...

Early Sepsis-Associated Acute Kidney Injury and Obesity
  • Citing Article
  • February 2024

JAMA Network Open

... Among a group of factors affecting sleep, Noise, light and nursing interventions were reported to be the three most common disruptive factors in ICUs, and the most frequent sources of noise were the ventilator alarm, heart monitor alarm, oxygen monitor probe and talking. Furthermore, bedside phones, gender, age, the severity of illness and the use of steroids were associated with poor QoS (Ahn et al. 2023;Bihari et al. 2012;Sinha et al. 2018;Shohani et al. 2021). ...

Factors influencing sleep quality in the intensive care unit: a descriptive pilot study

Acute and Critical Care

... Despite the recognized benefits of early stabilization in critical care settings, research on its impact in non-intensive acute care is significantly lacking [13,14]. Early stabilization in ICUs has been extensively studied, demonstrating clear advantages in mortality reduction and quicker recovery times [6,15,16]. However, non-intensive settings, which serve patients needing more care than standard wards but not full critical care resources, have not received the same attention in the literature. ...

Association between the timing of ICU admission and mortality in patients with hospital-onset sepsis: a nationwide prospective cohort study

Journal of Intensive Care

... Plasma ALT levels can be used for early diagnosis of sepsis-related liver injury (26), and its elevation is significantly associated with the prognosis of patients with sepsis (27,28). Lactate represents a significant clinical concern, especially in sepsis, serving as a marker of tissue hypoperfusion and metabolic derangement (29). Lactate accumulation indicates a shift towards anaerobic metabolism due to inadequate tissue oxygenation, a characteristic of septic shock (30). ...

Serial evaluation of the serum lactate level with the SOFA score to predict mortality in patients with sepsis

... K. aerogenes was isolated from a single case (patient 22), whilst P. aeruginosa was responsible for three cases (patients 3, 16 and 17). Burkholderia cepacia complex infection was also identified in patients 3 and 16, this complex includes opportunistic bacteria that cause ventilator-associated pneumonia (VAP) and have been associated with severe illness and death in patients with COVID-19 36,37 . Antibiotics were administered to 23 of the 24 patients, and a change in regimen was required in 9 cases. ...

Incidence and clinical outcomes of bacterial superinfections in critically ill patients with COVID-19

... This result was concordant in both the direct and indirect evidence, the outcome of reintubation was judged of critical relevance, and the certainty of the evidence supporting this specific finding was moderate. However, the results of our analysis should be taken with caution because the only three studies 6,33,34 investigating HFO were single-center RCTs, including a total of 482 patients, with a small event rate for the outcome reintubation and judged at "high risk of bias" 33,34 or "some concerns." 6 The results indicate the need for further studies on the role of HFO as a SBT method. ...

Effect of high-flow oxygen versus T-piece ventilation strategies during spontaneous breathing trials on weaning failure among patients receiving mechanical ventilation: a randomized controlled trial

Critical Care

... 3,13-43 Table 1 displays the features of every included study that is a part of the current meta-analysis. Bias in the outcome measurement was low in 24 studies, 3,[13][14][15][16][17][18][19][22][23][24][25][26][27][29][30][31][32][33][34]36,[39][40][41][42][43] moderate in five studies, 20,28,35,37,38 and high risk of bias in two studies (Fig. 2). 21,39 Outcomes A total of 31,277 patients were included in the analysis from 31 studies meeting inclusion criteria. ...

Comparison of mNUTRIC-S2 and mNUTRIC scores to assess nutritional risk and predict intensive care unit mortality

Acute and Critical Care

... Mg is an intracellular cation that has a critical role in many metabolic reactions. It serves as a cofactor in many enzymatic reactions such as ATP metabolism, muscle contraction and relaxation, blood pressure regulation, neuronal activity and neurotransmitter release [18]. The prevalence of hypomagnesemia increases in elderly individuals. ...

The effects of hypomagnesemia on delirium in middle-aged and older adult patients admitted to medical intensive care units

Acute and Critical Care

... The built environment, namely the human-made surroundings, has been thought to play a role in inciting delirium, including design factors such as single or multibed rooms (18), window access (19,20), and light and sound levels (21). Increasingly, the design of healthcare buildings is being recognized as a valid medical intervention given the impact on health outcomes (22). ...

Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit

Acute and Critical Care