Does the tube-compensation function of two modern mechanical ventilators provide effective work of breathing relief?

OBJECTIVE: An endotracheal tube (ETT) imposes work of breathing on mechanically ventilated patients. Using a bellows-in-a-box model lung, we compared the tube compensation (TC) performances of the Nellcor Puritan-Bennett 840 ventilator and of the Dräger Evita 4 ventilator. MEASUREMENTS AND RESULTS: Each ventilator was connected to the model lung. The respiratory rate of the model lung was set at 10 breaths/min with 1 s inspiratory time. Inspiratory flows were 30 or 60 l/min. A full-length 8 mm bore ETT was inserted between the ventilator circuit and the model lung. The TC was set at 0%, 10%, 50%, and 100% for both ventilators. Pressure was monitored at the airway, the trachea, and the pleura, and the data were recorded on a computer for later analysis of the delay time, of the inspiratory trigger pressure, and of the pressure–time product (PTP). The delay time was calculated as the time between the start of inspiration and minimum airway pressure, and the inspiratory trigger pressure was defined as the most negative pressure level. The same measurements were performed under pressure support ventilation of 4 and 8 cmH(2)O. The PTP increased according to the magnitude of inspiratory flow. Even with 100% TC, neither ventilator could completely compensate for the PTP imposed by the ETT. At 0% TC the PTP tended to be less with the Nellcor Puritan-Bennett 840 ventilator, while at 100% TC the PTP tended to be less with the Dräger Evita 4 ventilator. A small amount of pressure support can be equally effective to reduce the inspiratory effort compared with the TC. CONCLUSION: Although both ventilators provided effective TC, even when set to 100% TC they could not entirely compensate for a ventilator and ETT-imposed work of breathing. The effect of TC is less than that of pressure support ventilation. Physicians should be aware of this when using TC in weaning trials

Evacuation Shelter Scheduling Problem

Evacuation shelters, which are urgently required during natural disasters, are designed to minimize the burden of evacuation on human survivors. However, the larger the scale of the disaster, the more costly it becomes to operate shelters. When the number of evacuees decreases, the operation costs can be reduced by moving the remaining evacuees to other shelters and closing shelters as quickly as possible. On the other hand, relocation between shelters imposes a huge emotional burden on evacuees. In this study, we formulate the ``Evacuation Shelter Scheduling Problem,'' which allocates evacuees to shelters in such a way to minimize the movement costs of the evacuees and the operation costs of the shelters. Since it is difficult to solve this quadratic programming problem directly, we show its transformation into a 0-1 integer programming problem. In addition, such a formulation struggles to calculate the burden of relocating them from historical data because no payments are actually made. To solve this issue, we propose a method that estimates movement costs based on the numbers of evacuees and shelters during an actual disaster. Simulation experiments with records from the Kobe earthquake (Great Hanshin-Awaji Earthquake) showed that our proposed method reduced operation costs by 33.7 million dollars: 32%

School Families: A New Formulation of School District Planning Problem

This paper makes a plan to introduce school families. School families refer to a hierarchical system where the junior high school district encompasses the elementary school district. School families have the advantage of promoting efficient cooperation between elementary and junior high schools. Therefore, we formulated a new school district planning problem to introduce school families and created an optimal plan under changing population situations. Our formulation achieves school families by exploiting the continuity constraints of the school district. We also compare two different methods of reorganizing school districts in the simulation experiments: changing school districts by transferring current students in a given year (school-year method) and switching new students' schools over a multi-year period (birth-year method). We examined the cost and computation time of plans obtained with both methods and showed that the method combining the two provides the most significant cost savings

階層ベイズ言語モデルと条件付確率場の統合による半教師あり形態素解析

Open House, ISM in Tachikawa, 2012.6.15統計数理研究所オープンハウス（立川）、H24.6.15ポスター発

Chemoradiotherapy with miriplatin

Background: The prognosis for patients with unresectable advanced hepatocellular carcinoma (HCC) is poor. Miriplatin is a hydrophobic platinum compound that has a long retention time in lesions after transarterial chemoembolization (TACE). We investigated anti-tumor activity of miriplatin combined with irradiation on HCC cells, and its underlying mechanism of apoptosis. We also analyzed the effectiveness of miriplatin-TACE and radiotherapy for locally advanced HCC. Methods: Human HCC cell lines HepG2 and HuH-7 were treated with DPC (active form of miriplatin) and radiation, and synergy was evaluated using a combination index (CI). Apoptosis-related proteins and cell cycles were analyzed by western blotting and flowcytometry. We retrospectively analyzed treatment outcomes in 10 unresectable HCC patients with vascular/bile duct invasion treated with miriplatin-TACE and radiotherapy. Results: DPC or X-ray irradiation decreased cell viability dose-dependently. DPC plus irradiation decreased cell viability synergistically in both cell lines (CI<1 respectively). Cleaved PARP expression was induced much more strongly by DPC plus irradiation than by each treatment alone. Expression of p53 up-regulated modulator of apoptosis (PUMA) was significantly induced by the combination, and knockdown of PUMA with siRNA significantly decreased apoptosis in both cell lines. DPC plus irradiation caused sub-G1, G2/M, and S phase cell arrest in those cells. The combination of miriplatin-TACE and radiotherapy showed a high response rate for patients with locally advanced HCC despite small number of patients. Conclusions: Miriplatin plus irradiation had synergistic anti-tumor activity on HCC cells through PUMA-mediated apoptosis and cell cycle arrest. This combination may possibly be effective in treating locally advanced HCC

Time definition of reintubation most relevant to patient outcomes in critically ill patients: a multicenter cohort study

Background: Reintubation is a common complication in critically ill patients requiring mechanical ventilation. Although reintubation has been demonstrated to be associated with patient outcomes, its time definition varies widely among guidelines and in the literature. This study aimed to determine the association between reintubation and patient outcomes as well as the consequences of the time elapsed between extubation and reintubation on patient outcomes. Methods: This was a multicenter retrospective cohort study of critically ill patients conducted between April 2015 and March 2021. Adult patients who underwent mechanical ventilation and extubation in intensive care units (ICUs) were investigated utilizing the Japanese Intensive Care PAtient Database. The primary and secondary outcomes were in-hospital and ICU mortality. The association between reintubation and clinical outcomes was studied using Cox proportional hazards analysis. Among the patients who underwent reintubation, a Cox proportional hazard analysis was conducted to evaluate patient outcomes according to the number of days from extubation to reintubation. Results: Overall, 184,705 patients in 75 ICUs were screened, and 1849 patients underwent reintubation among 48,082 extubated patients. After adjustment for potential confounders, multivariable analysis revealed a significant association between reintubation and increased in-hospital and ICU mortality (adjusted hazard ratio [HR] 1.520, 95% confidence interval [CI] 1.359–1.700, and adjusted HR 1.325, 95% CI 1.076–1.633, respectively). Among the reintubated patients, 1037 (56.1%) were reintubated within 24 h after extubation, 418 (22.6%) at 24–48 h, 198 (10.7%) at 48–72 h, 111 (6.0%) at 72–96 h, and 85 (4.6%) at 96–120 h. Multivariable Cox proportional hazard analysis showed that in-hospital and ICU mortality was highest in patients reintubated at 72–96 h (adjusted HR 1.528, 95% CI 1.062–2.197, and adjusted HR 1.334, 95% CI 0.756–2.352, respectively; referenced to reintubation within 24 h). Conclusions: Reintubation was associated with a significant increase in in-hospital and ICU mortality. The highest mortality rates were observed in patients who were reintubated between 72 and 96 h after extubation. Further studies are warranted for the optimal observation of extubated patients in clinical practice and to strengthen the evidence for mechanical ventilation.Tanaka A., Shimomura Y., Uchiyama A., et al. Time definition of reintubation most relevant to patient outcomes in critically ill patients: a multicenter cohort study. Critical Care 27, 378 (2023); https://doi.org/10.1186/s13054-023-04668-3