Temporal change in repolarization parameters after surgical correction of valvular heart diseases.

BACKGROUND: Ventricular tachyarrhythmia is a potentially fatal outcome of cardiac surgery. Abrupt changes in the hemodynamics after surgical correction of valvular heart disease (VHD) can lead to alterations in ventricular repolarization. We compared the difference between temporal changes in repolarization parameters after correction of left-sided VHD. METHODS: We retrospectively analyzed the electrograms of patients who underwent surgical correction of isolated VHD between 2006 and 2015 at Asan Medical Center, including mitral stenosis (MS), mitral regurgitation (MR), aortic stenosis (AS), and aortic regurgitation (AR). Ventricular repolarization parameters were measured at pre-specified time intervals after index surgery using a custom-made ECG analysis program. We compared repolarization parameters, including QT and corrected QT intervals, T peak-to-end interval, and corrected T peak-to-end interval. RESULTS: Analysis of 8265 ECGs from 2110 patients (266 MS, 1059 MR, 421 AS, and 364 AR) was performed. Patients with AS were characterized by older age and more comorbidities than other VHDs. The corrected QT interval showed a peak value immediately after surgery and decreased thereafter in the AS groups. However, a gradual increase over 1 month after surgery in AR, MS, and MR groups was observed. The corrected T peak-to-end interval increased in the MS and MR groups and was unchanged in the AS and AR groups. CONCLUSIONS: The repolarization parameters of surgery changed dynamically after left-sided valvular surgery. Understanding differential temporal change of repolarization parameters according to the type of VHD would help clinicians avoid fatal arrhythmias related to the repolarization changes.

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.

Development of a Portable Respiratory Gas Analyzer for Measuring Indirect Resting Energy Expenditure (REE).

OBJECTIVE: A rapidly growing home healthcare market has resulted in the development of many portable or wearable products. Most of these products measure, estimate, or calculate physiologic signals or parameters, such as step counts, blood pressure, or electrocardiogram. One of the most important applications in home healthcare is monitoring one's metabolic state since the change of metabolic state could reveal minor or major changes in one's health condition. A simple and noninvasive way to measure metabolism is through breath monitoring. With breath monitoring by breath gas analysis, two important indicators like the respiratory quotient (RQ) and resting energy exposure (REE) can be calculated. Therefore, we developed a portable respiratory gas analyzer for breath monitoring to monitor metabolic state, and the performance of the developed device was tested in a clinical trial. Approach. The subjects consisted of 40 healthy men and women. Subjects begin to measure exhalation gas using Vmax 29 for 15 minutes. After that, subjects begin to measure exhalation gas via the developed respiratory gas analyzer. Finally, the recorded data on the volume of oxygen (VO2), volume of carbon dioxide (VCO2), RQ, and REE were used to validate correlations between Vmax 29 and the developed respiratory gas analyzer. RESULTS: The results showed that the root-mean-square errors (RMSE) values of VCO2, VO2, RQ, and REE are 0.0315, 0.0417, 0.504, and 0.127. Bland-Altman plots showed that most of the VCO2, VO2, RQ, and REE values are within 95% of the significance level. CONCLUSIONS: We have successfully developed and tested a portable respiratory gas analyzer for home healthcare. However, there are limitations of the clinical trial; the number of subjects is small in size, and the age and race of subjects are confined. The developed portable respiratory gas analyzer is a cost-efficient method for measuring metabolic state and a new application of home healthcare.

Long-term outcomes after sacrocolpopexy with or without transobturator tape.

INTRODUCTION AND HYPOTHESIS: The aim of this study was to report the long-term outcomes after sacrocolpopexy (SCP) with or without transobturator tape (TOT). METHODS: We conducted a planned secondary analysis of a prospective, observational study comparing urinary outcomes in women who underwent SCP with or without TOT based on the results of a prolapse-reduction stress test. Patients were enrolled between November 2008 and December 2011 and were followed up 5 years after surgery. The primary outcomes were 5-year success rates for stress urinary incontinence (SUI) and pelvic organ prolapse (POP) estimated using the Kaplan-Meier method. SUI success was defined as a negative cough stress test, no bothersome SUI symptoms, and no additional anti-incontinence surgery. POP success was defined as no vaginal bulge symptoms, no apical descent greater than one-third of the total vaginal length or anterior or posterior vaginal wall prolapse beyond the hymen, and no retreatment for prolapse. RESULTS: Of 240 women enrolled, 175 (73%) completed 5 years of follow-up. The estimated SUI success rate was 91.1% in the TOT group and 56.5% in the no TOT group (difference, 34.6%; 95% confidence interval, 24.1 to 45.1). The estimated POP success rate was 90.0% in the TOT group and 92.9% in the no TOT group (difference, -2.9%; 95% confidence interval, -10.7 to 4.9). CONCLUSIONS: The advantage of concomitant TOT for SUI after SCP that was seen at 2 years remained at 5 years. Long-term POP failure rates after SCP are low and not affected by concomitant TOT.

Impact of a custom-made 3D printed ergonomic grip for direct laryngoscopy on novice intubation performance in a simulated easy and difficult airway scenario-A manikin study.

Direct laryngoscopy using a Macintosh laryngoscope is the most widely used approach; however, this skill is not easy for novices and trainees. We evaluated the performance of novices using a laryngoscope with a three-dimensional (3D)-printed ergonomic grip on an airway manikin. Forty second-year medical students were enrolled. Endotracheal intubation was attempted using a conventional Macintosh laryngoscope with or without a 3D-printed ergonomic support grip. Primary outcomes were intubation time and overall success rate. Secondary outcomes were number of unsuccessful attempts, first-attempt success rate, airway Cormack-Lehane (CL) grade, and difficulty score. In the easy airway scenario, intubation time, and the overall success rate were similar between two group. CL grade and ease-of-use scores were significantly better for those using the ergonomic support grip (P < 0.05). In the difficult airway scenario, intubation time (49.7±37.5 vs. 35.5±29.2, P = 0.013), the first-attempt success rate (67.5% vs. 90%, P = 0.029), number of attempts (1.4±0.6 vs. 1.1±0.4, P = 0.006), CL grade (2 [2, 2] vs. 2 [1, 1], P = 0.012), and ease-of-use scores (3.5 [2, 4] vs. 4 [3, 5], P = 0.008) were significantly better for those using the ergonomic support grip. Linear mixed model analysis showed that the ergonomic support grip had a favorable effect on CL grade (P<0.001), ease-of-use scores (P<0.001), intubation time (P = 0.015), and number of intubation attempts (P = 0.029). Our custom 3D-printed ergonomic laryngoscope support grip improved several indicators related to the successful endotracheal intubation in the easy and difficult scenario simulated on an airway manikin. This grip may be useful for intubation training and practice.

Evaluation of Mobile Health Applications Developed by a Tertiary Hospital as a Tool for Quality Improvement Breakthrough.

OBJECTIVES: To evaluate the mobile health applications (apps) developed by a single tertiary hospital in Korea with a particular focus on quality and patient safety. METHODS: Twenty-three mobile health apps developed by Asan Medical Center were selected for analysis after exclusion of the apps without any relationship with healthcare or clinical workflow, the apps for individual usage, and the mobile Web apps. Two clinical informaticians independently evaluated the apps with respect to the six aims for quality improvement suggested by the United States Institute of Medicine. All discrepancies were resolved after discussion by the two reviewers. The six aims observed in the apps were reviewed and compared by target users. RESULTS: Eleven apps targeted patients, the other 12 were designed for healthcare providers. Among the apps for patients, one app also had functions for healthcare providers. 'My cancer diary' and 'My chart in my hand' apps matched all the six aims. Of the six aims, Timeliness was the most frequently observed (20 apps), and Equity was the least observed (6 apps). Timeliness (10/11 vs. 10/12) and Patient safety (10/11 vs. 9/12) were frequently observed in both groups. In the apps for patients, Patient-centeredness (10/11 vs. 2/12) and Equity (6/11 vs. 0/12) were more frequent but Efficiency (5/11 vs. 10/12) was less frequent. CONCLUSIONS: Most of the six aims were observed in the apps, but the extent of coverage varied. Further studies, evaluating the extent to which they improve quality are needed.

Computer-aided diagnosis of solid breast nodules: use of an artificial neural network based on multiple sonographic features.

A computer-aided diagnosis (CAD) algorithm identifying breast nodule malignancy using multiple ultrasonography (US) features and artificial neural network (ANN) classifier was developed from a database of 584 histologically confirmed cases containing 300 benign and 284 malignant breast nodules. The features determining whether a breast nodule is benign or malignant were extracted from US images through digital image processing with a relatively simple segmentation algorithm applied to the manually preselected region of interest. An ANN then distinguished malignant nodules in US images based on five morphological features representing the shape, edge characteristics, and darkness of a nodule. The structure of ANN was selected using k-fold cross-validation method with k = 10. The ANN trained with randomly selected half of breast nodule images showed the normalized area under the receiver operating characteristic curve of 0.95. With the trained ANN, 53.3% of biopsies on benign nodules can be avoided with 99.3% sensitivity. Performance of the developed classifier was reexamined with new US mass images in the generalized patient population of total 266 (167 benign and 99 malignant) cases. The developed CAD algorithm has the potential to increase the specificity of US for characterization of breast lesions.

Computer-aided diagnosis of solid breast nodules on ultrasound with digital image processing and artificial neural network.

A computer-aided diagnosis algorithm identifying breast nodule malignancy using multiple ultrasonography features and artificial neural network classifier was developed from a database of 584 histologically-confirmed cases containing 300 benign and 284 malignant breast nodules. The features were extracted from sonographic images through digital image processing. An artificial neural network then distinguished malignant nodules based on those features. The trained artificial neural network showed the normalized area under the receiver operating characteristic curve of 0.95.