Perioperative urinary ketosis and metabolic acidosis in patients fasted for undergoing gynecologic surgery.

BACKGROUND: Our bodies have adaptive mechanisms to fasting, in which glycogen stored in the liver and muscle protein are broken down, but also lipid mobilisation is triggered. As a result, glycerol and fatty acids are released into the bloodstream, increasing the production of ketone bodies in liver. However, there are limited studies on the incidence of perioperative urinary ketosis, the intraoperative blood glucose changes and metabolic acidosis after fasting for surgery in non-diabetic adult patients. METHODS: We conducted a retrospective cohort study involving 1831 patients undergoing gynecologic surgery under general anesthesia from January to December 2022. Ketosis was assessed using a postoperative urine test, while blood glucose levels and acid-base status were collected from intraoperative arterial blood gas analyses. RESULTS: Of 1535 patients who underwent postoperative urinalysis, 912 (59.4%) patients had ketonuria. Patients with ketonuria were younger, had lower body mass index, and had fewer comorbidities than those without ketonuria. After adjustments, younger age, higher body mass index and surgery starting late afternoon were significant risk factors for postoperative ketonuria. Of the 929 patients assessed with intraoperative arterial blood gas analyses, 29.0% showed metabolic acidosis. Multivariable logistic regression revealed that perioperative ketonuria and prolonged surgery significantly increased the risk for moderate-to-severe metabolic acidosis. CONCLUSION: Perioperative urinary ketosis and intraoperative metabolic acidosis are common in patients undergoing gynecologic surgery, even with short-term preoperative fasting. The risks are notably higher in younger patients with lower body mass index. Optimization of preoperative fasting strategies including implementation of oral carbohydrate loading should be considered for reducing perioperative metabolic derangement due to ketosis.

Vasopressor reduction effect of polymyxin B hemoperfusion in patients with peritonitis-induced septic shock: a propensity score-matched analysis.

BACKGROUND: This study aimed to evaluate the effect of polymyxin B hemoperfusion (PMX-HP) in patients with peritonitis-induced septic shock who still required high dose vasopressors after surgical source control. METHODS: This retrospective study included adult patients admitted to the surgical intensive care unit (ICU) at Seoul National University Hospital between July 2014 and February 2021 who underwent major abdominal surgery to control the source of sepsis. Patients were divided into two groups based on whether PMX-HP was applied after surgery or not. The primary and secondary endpoints were the vasopressor reduction effect, and in-ICU mortality, respectively. Propensity score matching was performed to compare the vasopressor reduction effect. RESULTS: A total of 338 patients met the inclusion criteria, of which 23 patients underwent PMX-HP postoperatively, whereas 315 patients did not during the study period. Serum norepinephrine concentration decreased over time regardless of whether PMX-HP was applied. However, it decreased more rapidly in the PMX-HP(+) group than in the PMX-HP(-) group. There were no significant differences in demographics including age, sex, body mass index (BMI), and most underlying comorbidities between the two groups. Risk factors for in-ICU mortality were identified by comparing patient characteristics and perioperative factors between the two groups using multivariate analysis. CONCLUSION: For patients with peritonitis-induced septic shock, PMX-HP rapidly reduces the requirement of vasopressors immediately after surgery, but does not reduce in-ICU mortality. This effect could potentially accelerate recovery from shock, reduce sequelae from vasopressors, and ultimately improve quality of life after discharge.

Real-time machine learning model to predict short-term mortality in critically ill patients: development and international validation.

BACKGROUND: A real-time model for predicting short-term mortality in critically ill patients is needed to identify patients at imminent risk. However, the performance of the model needs to be validated in various clinical settings and ethnicities before its clinical application. In this study, we aim to develop an ensemble machine learning model using routinely measured clinical variables at a single academic institution in South Korea. METHODS: We developed an ensemble model using deep learning and light gradient boosting machine models. Internal validation was performed using the last two years of the internal cohort dataset, collected from a single academic hospital in South Korea between 2007 and 2021. External validation was performed using the full Medical Information Mart for Intensive Care (MIMIC), eICU-Collaborative Research Database (eICU-CRD), and Amsterdam University Medical Center database (AmsterdamUMCdb) data. The area under the receiver operating characteristic curve (AUROC) was calculated and compared to that for the National Early Warning Score (NEWS). RESULTS: The developed model (iMORS) demonstrated high predictive performance with an internal AUROC of 0.964 (95% confidence interval [CI] 0.963-0.965) and external AUROCs of 0.890 (95% CI 0.889-0.891) for MIMIC, 0.886 (95% CI 0.885-0.887) for eICU-CRD, and 0.870 (95% CI 0.868-0.873) for AmsterdamUMCdb. The model outperformed the NEWS with higher AUROCs in the internal and external validation (0.866 for the internal, 0.746 for MIMIC, 0.798 for eICU-CRD, and 0.819 for AmsterdamUMCdb; p < 0.001). CONCLUSIONS: Our real-time machine learning model to predict short-term mortality in critically ill patients showed excellent performance in both internal and external validations. This model could be a useful decision-support tool in the intensive care units to assist clinicians.

Prevalence and outcomes of chronic comorbid conditions in patients with sepsis in Korea: a nationwide cohort study from 2011 to 2016.

BACKGROUND: Chronic comorbid conditions are common in patients with sepsis and may affect the outcomes. This study aimed to evaluate the prevalence and outcomes of common comorbidities in patients with sepsis. METHODS: We conducted a nationwide retrospective cohort study. Using data from the National Health Insurance Service of Korea. Adult patients (age ≥ 18 years) who were hospitalized in tertiary or general hospitals with a diagnosis of sepsis between 2011 and 2016 were analyzed. After screening of all International Classification of Diseases 10th revision codes for comorbidities, we identified hypertension, diabetes mellitus (DM), liver cirrhosis (LC), chronic kidney disease (CKD), and malignancy as prevalent comorbidities. RESULTS: Overall, 373,539 patients diagnosed with sepsis were hospitalized in Korea between 2011 and 2016. Among them, 46.7% had hypertension, 23.6% had DM, 7.4% had LC, 13.7% had CKD, and 30.7% had malignancy. In-hospital mortality rates for patients with hypertension, DM, LC, CKD, and malignancy were 25.5%, 25.2%, 34.5%, 28.0%, and 33.3%, respectively, showing a decreasing trend over time (P < 0.001). After adjusting for baseline characteristics, male sex, older age, use of mechanical ventilation, and continuous renal replacement therapy, LC, CKD, and malignancy were significantly associated with in-hospital mortality. CONCLUSIONS: Hypertension is the most prevalent comorbidity in patients with sepsis, and it is associated with an increased survival rate. Additionally, liver cirrhosis, chronic kidney disease, and malignancy result in higher mortality rates than hypertension and DM, and are significant risk factors for in-hospital mortality in patients with sepsis.

Comparison of postoperative ascites replacement strategies on time to first flatus after living donor liver transplantation: Albumin vs. lactated Ringer's solution.

INTRODUCTION: There is insufficient evidence regarding the optimal regimen for ascites replacement after living donor liver transplantation (LT) and its effectiveness. The aim of this study is to evaluate the impact of replacing postoperative ascites after LT with albumin on time to first flatus during recovery with early ambulation and incidence of acute kidney injury (AKI). METHODS: Adult patients who underwent elective living donor LT at Seoul National University Hospital from 2019 to 2021 were randomly assigned to either the albumin group or lactated Ringer's group, based on the ascites replacement regimen. Replacement of postoperative ascites was performed for all patients every 4 h after LT until the patient was transferred to the general ward. Seventy percent of ascites drained during the previous 4 h was replaced over the next 4 h with continuous infusion of fluids with a prescribed regimen according to the assigned group. In the albumin group, 30% of a total of 70% of drained ascites was replaced with 5% albumin solution, and remnant 40% was replaced with lactated Ringer's solution. In the lactated Ringer's group, 70% of drained ascites was replaced with only lactated Ringer's solution. The primary outcome was the time to first flatus from the end of the LT and the secondary outcome was the incidence of AKI for up to postoperative day 7. RESULTS: Among the 157 patients who were screened for eligibility, 72 patients were enrolled. The mean age was 63 ± 8.2 years, and 73.0 % (46/63) were male. Time to first flatus was similar between the two groups (66.7 ± 24.1 h vs. 68.5 ± 25.6 h, p = .778). The albumin group showed a higher glomerular filtration rate and lower incidence of AKI until postoperative day 7, compared to the lactated Ringer's group. CONCLUSIONS: Using lactated Ringer's solution alone for replacement of ascites after living donor LT did not reduce the time to first flatus and was associated with an increased risk of AKI. Further research on the optimal ascites replacement regimen and the target serum albumin level which should be corrected after LT is required.

Timing of prophylactic antibiotics administration and suspected systemic infection after percutaneous biliary intervention.

BACKGROUND/PURPOSE: Prophylactic antibiotics administration before percutaneous biliary intervention (PBI) is currently recommended, but the underlying evidence is mostly extrapolated from prophylactic antibiotics before surgery. The aim of this study was to evaluate the impact of prophylactic antibiotics administration timing on the incidence of suspected systemic infection after PBI. METHODS: The incidence of suspected systemic infection after PBI was compared in patients who received prophylactic antibiotics at four different time intervals between antibiotics administration and skin puncture for PBI. Suspected post-intervention systemic infection was assessed according to predetermined clinical criteria. RESULTS: There were 98 (21.6%) suspected systemic infections after 454 PBIs in 404 patients. There were significant differences among the four groups in the incidence of suspected systemic infection after the intervention (p = .020). Fever was the most common sign of suspected systemic infection. Administration of prophylactic antibiotics more than an hour before PBI was identified as an independent risk factor of suspected systemic infection after adjusting for other relevant factors (adjusted odds ratio = 10.54; 95% confidence interval, 1.40-78.86). CONCLUSIONS: The incidence of suspected systemic infection after the PBI was significantly lower when prophylactic antibiotics were administered within an hour before the intervention.

Real-time machine learning model to predict in-hospital cardiac arrest using heart rate variability in ICU.

Predicting in-hospital cardiac arrest in patients admitted to an intensive care unit (ICU) allows prompt interventions to improve patient outcomes. We developed and validated a machine learning-based real-time model for in-hospital cardiac arrest predictions using electrocardiogram (ECG)-based heart rate variability (HRV) measures. The HRV measures, including time/frequency domains and nonlinear measures, were calculated from 5 min epochs of ECG signals from ICU patients. A light gradient boosting machine (LGBM) algorithm was used to develop the proposed model for predicting in-hospital cardiac arrest within 0.5-24 h. The LGBM model using 33 HRV measures achieved an area under the receiver operating characteristic curve of 0.881 (95% CI: 0.875-0.887) and an area under the precision-recall curve of 0.104 (95% CI: 0.093-0.116). The most important feature was the baseline width of the triangular interpolation of the RR interval histogram. As our model uses only ECG data, it can be easily applied in clinical practice.

Risk factors of hemodialysis catheter dysfunction in patients undergoing continuous renal replacement therapy: a retrospective study.

BACKGROUND: Continuous renal replacement therapy is a relatively common modality applied to critically ill patients with renal impairment. To maintain stable continuous renal replacement therapy, sufficient blood flow through the circuit is crucial, but catheter dysfunction reduces the blood flow by inadequate pressures within the circuit. Therefore, exploring and modifying the possible risk factors related to catheter dysfunction can help to provide continuous renal replacement therapy with minimal interruption. METHODS: Adult patients who received continuous renal replacement therapy at Seoul National University Hospital between January 2019 and December 2021 were retrospectively analyzed. Patients who received continuous renal replacement therapy via a temporary hemodialysis catheter, inserted at the bedside under ultrasound guidance within 12 h of continuous renal replacement therapy initiation were included. RESULTS: A total of 507 continuous renal replacement therapy sessions in 457 patients were analyzed. Dialysis catheter dysfunction occurred in 119 sessions (23.5%). Multivariate analysis showed that less prolonged prothrombin time (adjusted OR 0.49, 95% CI, 0.30-0.82, p = 0.007) and activated partial thromboplastin time (adjusted OR 1.01, 95% CI, 1.00-1.01, p = 0.049) were associated with increased risk of catheter dysfunction. Risk factors of re-catheterization included vascular access to the left jugular and femoral vein. CONCLUSIONS: In critically ill patients undergoing continuous renal replacement therapy, less prolonged prothrombin time was associated with earlier catheter dysfunction. Use of left internal jugular veins and femoral vein were associated with increased risk of re-catheterization compared to the right internal jugular vein.

The effect of audiovisual feedback of monitor/defibrillators on percentage of appropriate compression depth and rate during cardiopulmonary resuscitation.

BACKGROUND: High quality cardiopulmonary resuscitation (CPR) is one of the key elements of the survival chain in cardiac arrest. Audiovisual feedback of chest compressions have been suggested to be beneficial by increasing the quality of CPR in the simulated cardiac arrests. METHODS: A prospective before and after study was performed to investigate the effect of a real-time audiovisual feedback system on CPR quality during in-hospital cardiac arrest in intensive care units from November 2018 to February 2022. In the feedback period, CPR was performed with the aid of the real-time audiovisual feedback system. The primary outcome was the percentage of compressions with both adequate depth (5.0-6.0 cm) and rate (100-120/minute). RESULTS: A total of 27,295 compressions in 30 cardiac arrests in the no-feedback period and 27,965 compressions in 30 arrests in the feedback period were analyzed. The percentage of compressions with both adequate depth and rate was 11.8% in the feedback period and 16.8% in the no-feedback period (P < 0.01). The percentage of compressions with adequate rate in the feedback period was lower than that in the no-feedback period (67.3% vs. 75.5%, P < 0.01). The percentage of beyond-target depth with the feedback was significantly higher than that without feedback (64.2% vs. 51.4%, P < 0.01). CONCLUSION: Real-time audiovisual feedback system did not increase CPR quality and was associated with a higher percentage of compression depth deeper than the recommended 5.0-6.0 cm. It is essential to explore more effective ways of implementing feedback in real clinical settings to improve of the quality of CPR. TRIAL REGISTRATION: NCT03902873 (study start: Nov. 2018, initial release April 2019, retrospectively registered).

The Association Between Institutional Case Volume of Hematopoietic Stem Cell Transplantation and Mortality.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is a complex, high-risk procedure with significant morbidity and mortality. The positive impact of higher institutional case volume on survival has been reported in various high-risk procedures. The association between annual institutional HSCT case volume and mortality was analyzed using the National Health Insurance Service database. METHODS: Data on 16,213 HSCTs performed in 46 Korean centers between 2007 and 2018 were extracted. Centers were divided into low- or high-volume centers using an average of 25 annual cases as the cut-off. Adjusted odds ratios (OR) for 1-year mortality after allogeneic and autologous HSCT were estimated using multivariable logistic regression. RESULTS: For allogeneic HSCT, low-volume centers (≤25 cases/y) were associated with higher 1-year mortality (adjusted OR 1.17, 95% CI 1.04-1.31, P = .008). However, low-volume centers did not show higher 1-year mortality (adjusted OR 1.03, 95% CI 0.89-1.19, P = .709) for autologous HSCT. Long-term mortality after HSCT was significantly worse in low-volume centers (adjusted hazard ratio [HR] 1.17, 95% CI, 1.09-1.25, P < .001 and adjusted HR 1.09, 95% CI, 1.01-1.17, P = .024, allogeneic and autologous HSCT, respectively) compared with high-volume centers. CONCLUSION: Our data suggest that higher institutional HSCT case volume seems to be associated with better short- and long-term survival.

Early Postoperative Fever and Atelectasis in Patients Undergoing Upper Abdominal Surgery.

BACKGROUND: Atelectasis is a common complication after upper abdominal surgery and considered as a cause of early postoperative fever (EPF) within 48 hours after surgery. However, the pathophysiologic mechanism of how atelectasis causes fever remains unclear. STUDY DESIGN: Data for adult patients who underwent elective major upper abdominal surgery under general anesthesia at Seoul National University Hospital between January and December of 2021 were retrospectively analyzed. The primary outcome was the association between fever and atelectasis within 2 days after surgery. RESULTS: Of 1,624 patients, 810 patients (49.9%) developed EPF. The incidence of atelectasis was similar between the fever group and the no-fever group (51.6% vs 53.9%, p = 0.348). Multivariate analysis showed no significant association between atelectasis and EPF. Culture tests (21.7% vs 8.8%, p < 0.001) and prolonged use of antibiotics (25.9% vs 13.9%, p < 0.001) were more frequent in the fever group compared to the no-fever group. However, the frequency of bacterial growth on culture tests and postoperative pulmonary complications within 7 days were similar between the two groups. CONCLUSIONS: EPF after major upper abdominal surgery was not associated with radiologically detected atelectasis. EPF also was not associated with the increased risk of postoperative pulmonary complications, bacterial growth on culture studies, or prolonged length of hospital stay.

Impact of institutional case volume on intensive care unit mortality.

The primary aim of this review is to explore current knowledge on the relationship between institutional intensive care unit (ICU) patient volume and patient outcomes. Studies indicate that a higher institutional ICU patient volume is positively correlated with patient survival. Although the exact mechanism underlying this association remains unclear, several studies have proposed that the cumulative experience of physicians and selective referral between institutions may play a role. The overall ICU mortality rate in Korea is relatively high compared to other developed countries. A distinctive aspect of critical care in Korea is the existence of significant disparities in the quality of care and services provided across regions and hospitals. Addressing these disparities and optimizing the management of critically ill patients necessitates thoroughly trained intensivists who are well-versed in the latest clinical practice guidelines. A fully functioning unit with adequate patient throughput is also essential for maintaining consistent and reliable quality of patient care. However, the positive impact of ICU volume on mortality outcomes is also linked to complex organizational factors, such as multidisciplinary rounds, nurse staffing and education, the presence of a clinical pharmacist, care protocols for weaning and sedation, and a culture of teamwork and communication. Despite some inconsistencies in the association between ICU patient volume and patient outcomes, which are thought to arise from differences in healthcare systems, ICU case volume significantly affects patient outcomes and should be taken into account when formulating related healthcare policies.

The Profile of Early Sedation Depth and Clinical Outcomes of Mechanically Ventilated Patients in Korea.

BACKGROUND: Current international guidelines recommend against deep sedation as it is associated with worse outcomes in the intensive care unit (ICU). However, in Korea the prevalence of deep sedation and its impact on patients in the ICU are not well known. METHODS: From April 2020 to July 2021, a multicenter, prospective, longitudinal, noninterventional cohort study was performed in 20 Korean ICUs. Sedation depth extent was divided into light and deep using a mean Richmond Agitation-Sedation Scale value within the first 48 hours. Propensity score matching was used to balance covariables; the outcomes were compared between the two groups. RESULTS: Overall, 631 patients (418 [66.2%] and 213 [33.8%] in the deep and light sedation groups, respectively) were included. Mortality rates were 14.1% and 8.4% in the deep and light sedation groups (P = 0.039), respectively. Kaplan-Meier estimates showed that time to extubation (P < 0.001), ICU length of stay (P = 0.005), and death (P = 0.041) differed between the groups. After adjusting for confounders, early deep sedation was only associated with delayed time to extubation (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.55-0.80; P < 0.001). In the matched cohort, deep sedation remained significantly associated with delayed time to extubation (HR, 0.68; 95% CI, 0.56-0.83; P < 0.001) but was not associated with ICU length of stay (HR, 0.94; 95% CI, 0.79-1.13; P = 0.500) and in-hospital mortality (HR, 1.19; 95% CI, 0.65-2.17; P = 0.582). CONCLUSION: In many Korean ICUs, early deep sedation was highly prevalent in mechanically ventilated patients and was associated with delayed extubation, but not prolonged ICU stay or in-hospital death.

Impact of institutional case volume of solid organ transplantation on patient outcomes and implications for healthcare policy in Korea.

Solid organ transplantation is distinguished from other high-risk surgical procedures by the fact that it utilizes an extremely limited and precious resource and requires a multidisciplinary team approach. For several decades, institutional experience, as quantified by center volume, has been shown to be strongly associated with patient outcomes and graft survival after solid organ transplantation. The United States has implemented a minimum case volume requirement and performance standards for accreditation as a validated transplantation center. Solid organ transplantation in Europe is also governed by the European Union, which monitors patient outcomes and organ allocation. The number of solid organ transplantation cases in Korea is increasing, with patient outcomes comparable to international standards. However, Korea has outdated regulations regarding hospital facilities, and performance indicators including patient outcomes after transplantation are not monitored. Therefore, centers perform solid organ transplantation with no meaningful oversight. In this review, data regarding the impact of institutional case volume of kidney, liver, lung, and heart transplantation are summarized, followed by a description of current transplantation center regulations in the United States and Europe. The basis for the necessity of adequate transplantation center regulations in Korea is presented.

Continuous versus intermittent infusion of human antithrombin III concentrate in the immediate postoperative period after liver transplantation.

Antithrombin-III (AT-III) concentrates have been used in the immediate postoperative period after liver transplantation to prevent critical thrombosis. We aimed to investigate a more appropriate method for AT-III concentrate administration to maintain plasma AT-III activity level within the target range. In this randomized controlled trial, 130 adult patients undergoing living-donor liver transplantation were randomized to either the intermittent group or continuous group. In the intermittent group, 500 international units (IU) of AT-III concentrate were administered after liver transplantation and repeated every 6 h for 72 h. In the continuous group, 3000 IU of AT-III were continuously infused for 71 h after a loading dose of 2000 IU over 1 h. Plasma AT-III activity level was measured at 12, 24, 48, 72, and 84 h from the first AT-III administration. The primary outcome was the target (80%-120%) attainment rate at 72 h. Target attainment rates at other timepoints and associated complications were collected as secondary outcomes. A total of 107 patients were included in the analysis. The target attainment rates at 72 h post-dose were 30% and 62% in the intermittent group and continuous group, respectively (p = 0.003). Compared to the intermittent group, patients in the continuous group reached the target level more rapidly (12 vs. 24 h, median time, p < 0.001) and were more likely to remain in the target range until 84 h. For maintaining the target plasma AT-III activity level after living-donor liver transplantation, continuous infusion of AT-III seemed to be more appropriate compared to the conventional intermittent infusion regimen.

Risk prediction models incorporating institutional case volume for mortality after hip fracture surgery in the elderly.

INTRODUCTION: While higher institutional case volume is associated with better postoperative outcomes in various types of surgery, institutional case volume has been rarely included in risk prediction models for surgical patients. This study aimed to develop and validate the predictive models incorporating institutional case volume for predicting in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly. MATERIALS AND METHODS: Data for all patients (≥ 60 years) who underwent surgery for femur neck fracture, pertrochanteric fracture, or subtrochanteric fracture between January 2008 and December 2016 were extracted from the Korean National Health Insurance Service database. Patients were randomly assigned into the derivation cohort or the validation cohort in a 1:1 ratio. Risk prediction models for in-hospital mortality and 1-year mortality were developed in the derivation cohort using the logistic regression model. Covariates included age, sex, type of fracture, type of anaesthesia, transfusion, and comorbidities such as hypertension, diabetes, coronary artery disease, chronic kidney disease, cerebrovascular disease, and dementia. Two separate models, one with and the other without institutional case volume as a covariate, were constructed, evaluated, and compared using the likelihood ratio test. Based on the models, scoring systems for predicting in-hospital mortality and 1-year mortality were developed. RESULTS: Analysis of 196,842 patients showed 3.6% in-hospital mortality (7084/196,842) and 15.42% 1-year mortality (30,345/196,842). The model for predicting in-hospital mortality incorporating the institutional case volume demonstrated better discrimination (c-statistics 0.692) compared to the model without the institutional case volume (c-statistics 0.688; likelihood ratio test p value < 0.001). The performance of the model for predicting 1-year mortality was also better when incorporating institutional case volume (c-statistics 0.675 vs. 0.674; likelihood ratio test p value < 0.001). CONCLUSIONS: The new institutional case volume incorporated scoring system may help to predict in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly population.

Effect of Hospital Case-Volume on Mortality after Ovarian Cancer Surgery: A Population-Based Retrospective Cohort Study.

OBJECTIVES: The goal of ovarian cancer surgery has recently shifted from optimal cytoreduction to more complete resection. This study attempted to reassess and update the association between surgical case-volume and both in-hospital and long-term mortality after ovarian cancer surgery using recent data. DESIGN: This study is a population-based retrospective cohort study. Participants/Material: Data from all adult patients who underwent ovarian cancer surgery in Korea between 2005 and 2019 were obtained from the national database. A total of 24,620 patients underwent ovarian cancer surgery in 362 hospitals during the period. SETTING: In-hospital and 1-, 3-, 5-year mortality were set as primary and secondary outcomes. METHODS: Hospitals were categorized into high-volume (>90 cases/year), medium-volume (20-90 cases/year), and low-volume (<20 cases/year) centers considering overall distribution of case-volume. Postoperative in-hospital and long-term mortality were analyzed using logistic regression after adjusting for potential risk factors. RESULTS: Compared to high-volume centers (0.54%), in-hospital mortality was significantly higher in medium-volume (1.40%; adjusted odds ratio, 2.92; confidence interval, 1.82-3.73; p < 0.001) and low-volume (1.61%; adjusted odds ratio, 2.94; confidence interval, 2.07-4.17; p < 0.001) centers. In addition, 1-year mortality was 6.26%, 7.06%, and 7.94% for high-volume, medium-volume, and low-volume centers, respectively, and the differences among the groups were significant. However, case-volume effect was not apparent in 3- and 5-year mortality after ovarian cancer surgery. LIMITATIONS: Lacking clinical information such as staging or histologic diagnosis due to the nature of the administrative data should be considered in interpreting the data. CONCLUSIONS: Case-volume effect was observed for in-hospital and 1-year mortality after ovarian cancer surgery, while it was not clearly found in 3- or 5-year mortality. Dilution of the case-volume effect might be attributed to the high accessibility to care.

Institutional case volume and mortality after aortic and mitral valve replacement: a nationwide study in two Korean cohorts.

BACKGROUND: There are only a handful of published studies regarding the volume-outcome relationship in heart valve surgery. We evaluated the association between institutional case volume and mortality after aortic valve replacement (AVR) and mitral valve replacement (MVR). METHODS: Two separate cohorts of all adults who underwent AVR or MVR, respectively, between 2009 and 2016 were analyzed using a Korean healthcare insurance database. Hospitals performing AVRs were divided into three groups according to the average annual case volume: the low- (< 20 cases/year), medium- (20-70 cases/year), and high-volume centers (> 70 cases/year). Hospitals performing MVRs were also grouped as the low- (< 15 cases/year), medium- (15-40 cases/year), or high-volume centers (> 40 cases/year). In-hospital mortality after AVR or MVR were compared among the groups. RESULTS: In total, 7875 AVR and 5084 MVR cases were analyzed. In-hospital mortality after AVR was 8.3% (192/2318), 4.0% (84/2102), and 2.6% (90/3455) in the low-, medium-, and high-volume centers, respectively. The adjusted risk was higher in the low- (OR 2.31, 95% CI 1.73-3.09) and medium-volume centers (OR 1.53, 95% CI 1.09-2.15) compared to the high-volume centers. In-hospital mortality after MVR was 9.3% (155/1663), 6.3% (94/1501), and 2.9% (56/1920) in the low-, medium-, and high-volume centers, respectively. Compared to the high-volume centers, the medium- (OR 1.97, 95% CI 1.35-2.88) and low-volume centers (OR 2.29, 95% CI 1.60-3.27) showed higher adjusted risk of in-hospital mortality. CONCLUSIONS: Lower case volume is associated with increased in-hospital mortality after AVR and MVR. The results warrant a comprehensive discussion regarding regionalization/centralization of cardiac valve replacements to optimize patient outcomes.

Hospital case-volume and mortality after lung cancer surgery: A population-based retrospective cohort study.

OBJECTIVES: Recent advances in lung cancer treatment warrants reassessment of the volume-outcome association in lung cancer surgery. This study reassessed the relationship between surgical case-volume and both in-hospital and long-term mortality after lung cancer surgery using a current database to reflect recent advances. MATERIALS AND METHODS: Using the database of the National Health Insurance Service in Korea, data of all adult patients who underwent lung cancer surgery in Korea between 2005 and 2019 were obtained. Hospitals were categorized by the annual number of lung cancer surgeries. Risk-adjusted in-hospital and 1, 3, 5-year mortality after surgery were assessed. RESULTS: A total of 84,194 lung cancer surgeries were performed in 163 centers during the study period. High-volume centers were defined as > 200 cases/year, medium-volume centers as 60-200 cases/year, and low-volume centers as < 60 cases/year. After adjustment, in-hospital mortality was significantly lower in high-volume centers (1.03%) compared to medium-volume centers (2.06%, adjusted odds ratio [OR], 1.43; 95% confidence interval [CI], 1.23-1.65; P < 0.001), and low-volume centers (3.08%, OR, 1.32; 95% CI, 1.16-1.51; P < 0.001). Long-term mortality was also significantly lower in high-volume centers compared to the other groups. CONCLUSION: High-volume centers showed lower in-hospital and long-term mortality compared to centers with less case-volume.

Efficacy of nutritional support protocol for patients with pressure ulcer: comparison of before and after the protocol.

OBJECTIVES: Because most patients who develop pressure ulcer (PU) are malnourished, additional nutritional support is important for PU improvement. The aim of this study was to investigate the potential benefit of a simple nutritional support protocol in PU improvement. METHODS: This study was a comparative before-and-after study, prospectively performed from May to December 2020. Participants were inpatients of Seoul National University Hospital (SNUH), South Korea. Among the patients who developed PU from May to December 2020, those on enteral nutrition were included in the protocol group. Application of the nutritional support protocol was established in May 2020 in SNUH. Serum levels of prealbumin, transferrin, cholesterol, and zinc were measured initially and 2 and 4 wk after protocol application to evaluate clinical course. A tailored regimen that adjusted the amount of protein and trace elements was provided according to consultation with the nutritional support team. Size and Pressure Ulcer Scale for Healing was evaluated every 2 wk by the same nurse in charge of PU. To validate the efficacy of the protocol, patients who developed PU from May to December 2018, were hospitalized for >2 wk, and who received enteral nutrition were selected as a control group. RESULTS: Sixty-one patients were included in the protocol group and 100 were in the control group. The protocol group had a higher proportion of PU improvement (85.2 versus 50%; P < 0.001), daily protein intake (1.6 ± 3.2 versus 0.9 ± 0.4; P = 0.048), Braden scale (12.9 ± 1.8 versus 12.3 ± 1.8; P = 0.025), and baseline albumin level (3.1 ± 0.5 versus 2.8 ± 0.4; P = 0.001) when compared with the control group. Multivariate analysis showed that implementation of the nutritional support protocol was the most effective factor in improving PU (odds ratio, 0.18; 95% confidence interval, 0.089-0.366; P < 0.001). CONCLUSIONS: A simple nutritional support protocol was easy to develop and its application contributed significantly to the recovery of PU.