Consent is a confounding factor in a prospective observational study of critically ill elderly patients.

During analysis of a prospective multinational observation study of critically ill patients ≥80 years of age, the VIP2 study, we also studied the effects of differences in country consent for study inclusion. This is a post hoc analysis where the ICUs were analyzed according to requirement for study consent. Group A: ICUs in countries with no requirement for consent at admission but with deferred consent in survivors. Group B: ICUs where some form of active consent at admission was necessary either from the patient or surrogates. Patients' characteristics, the severity of disease and outcome variables were compared. Totally 3098 patients were included from 21 countries. The median age was 84 years (IQR 81-87). England was not included because of changing criteria for consent during the study period. Group A (7 countries, 1200 patients), and group B (15 countries, 1898 patients) were comparable with age and gender distribution. Cognition was better preserved prior to admission in group B. Group A suffered from more organ dysfunction at admission compared to group B with Sequential Organ Failure Assessment score median 8 and 6 respectively. ICU survival was lower in group A, 66.2% compared to 78.4% in group B (p<0.001). We hence found profound effects on outcomes according to differences in obtaining consent for this study. It seems that the most severely ill elderly patients were less often recruited to the study in group B. Hence the outcome measured as survival was higher in this group. We therefore conclude that consent likely is an important confounding factor for outcome evaluation in international studies focusing on old patients

Reliability of the Clinical Frailty Scale in very elderly ICU patients: a prospective European study.

PURPOSE: Frailty is a valuable predictor for outcome in elderly ICU patients, and has been suggested to be used in various decision-making processes prior to and during an ICU admission. There are many instruments developed to assess frailty, but few of them can be used in emergency situations. In this setting the clinical frailty scale (CFS) is frequently used. The present study is a sub-study within a larger outcome study of elderly ICU patients in Europe (the VIP-2 study) in order to document the reliability of the CFS. MATERIALS AND METHODS: From the VIP-2 study, 129 ICUs in 20 countries participated in this sub-study. The patients were acute admissions ≥ 80 years of age and frailty was assessed at admission by two independent observers using the CFS. Information was obtained from the patient, if not feasible, from the family/caregivers or from hospital files. The profession of the rater and source of data were recorded along with the score. Interrater variability was calculated using linear weighted kappa analysis. RESULTS: 1923 pairs of assessors were included and background data of patients were similar to the whole cohort (n = 3920). We found a very high inter-rater agreement (weighted kappa 0.86), also in subgroup analyses. The agreement when comparing information from family or hospital records was better than using only direct patient information, and pairs of raters from same profession performed better than from different professions. CONCLUSIONS: Overall, we documented a high reliability using CFS in this setting. This frailty score could be used more frequently in elderly ICU patients in order to create a more holistic and realistic impression of the patient´s condition prior to ICU admission

Cumulative Prognostic Score Predicting Mortality in Patients Older Than 80 Years Admitted to the ICU.

OBJECTIVES: To develop a scoring system model that predicts mortality within 30 days of admission of patients older than 80 years admitted to intensive care units (ICUs). DESIGN: Prospective cohort study. SETTING: A total of 306 ICUs from 24 European countries. PARTICIPANTS: Older adults admitted to European ICUs (N = 3730; median age = 84 years [interquartile range = 81-87 y]; 51.8% male). MEASUREMENTS: Overall, 24 variables available during ICU admission were included as potential predictive variables. Multivariable logistic regression was used to identify independent predictors of 30-day mortality. Model sensitivity, specificity, and accuracy were evaluated with receiver operating characteristic curves. RESULTS: The 30-day-mortality was 1562 (41.9%). In multivariable analysis, these variables were selected as independent predictors of mortality: age, sex, ICU admission diagnosis, Clinical Frailty Scale, Sequential Organ Failure Score, invasive mechanical ventilation, and renal replacement therapy. The discrimination, accuracy, and calibration of the model were good: the area under the curve for a score of 10 or higher was .80, and the Brier score was .18. At a cut point of 10 or higher (75% of all patients), the model predicts 30-day mortality in 91.1% of all patients who die. CONCLUSION: A predictive model of cumulative events predicts 30-day mortality in patients older than 80 years admitted to ICUs. Future studies should include other potential predictor variables including functional status, presence of advance care plans, and assessment of each patient's decision-making capacity

Sepsis at ICU admission does not decrease 30-day survival in very old patients: a post-hoc analysis of the VIP1 multinational cohort study.

BACKGROUND: The number of intensive care patients aged ≥ 80 years (Very old Intensive Care Patients; VIPs) is growing. VIPs have high mortality and morbidity and the benefits of ICU admission are frequently questioned. Sepsis incidence has risen in recent years and identification of outcomes is of considerable public importance. We aimed to determine whether VIPs admitted for sepsis had different outcomes than those admitted for other acute reasons and identify potential prognostic factors for 30-day survival. RESULTS: This prospective study included VIPs with Sequential Organ Failure Assessment (SOFA) scores ≥ 2 acutely admitted to 307 ICUs in 21 European countries. Of 3869 acutely admitted VIPs, 493 (12.7%) [53.8% male, median age 83 (81-86) years] were admitted for sepsis. Sepsis was defined according to clinical criteria; suspected or demonstrated focus of infection and SOFA score ≥ 2 points. Compared to VIPs admitted for other acute reasons, VIPs admitted for sepsis were younger, had a higher SOFA score (9 vs. 7, p < 0.0001), required more vasoactive drugs [82.2% vs. 55.1%, p < 0.0001] and renal replacement therapies [17.4% vs. 9.9%; p < 0.0001], and had more life-sustaining treatment limitations [37.3% vs. 32.1%; p = 0.02]. Frailty was similar in both groups. Unadjusted 30-day survival was not significantly different between the two groups. After adjustment for age, gender, frailty, and SOFA score, sepsis had no impact on 30-day survival [HR 0.99 (95% CI 0.86-1.15), p = 0.917]. Inverse-probability weight (IPW)-adjusted survival curves for the first 30 days after ICU admission were similar for acute septic and non-septic patients [HR: 1.00 (95% CI 0.87-1.17), p = 0.95]. A matched-pair analysis in which patients with sepsis were matched with two control patients of the same gender with the same age, SOFA score, and level of frailty was also performed. A Cox proportional hazard regression model stratified on the matched pairs showed that 30-day survival was similar in both groups [57.2% (95% CI 52.7-60.7) vs. 57.1% (95% CI 53.7-60.1), p = 0.85]. CONCLUSIONS: After adjusting for organ dysfunction, sepsis at admission was not independently associated with decreased 30-day survival in this multinational study of 3869 VIPs. Age, frailty, and SOFA score were independently associated with survival

Relationship between the Clinical Frailty Scale and short-term mortality in patients ≥ 80 years old acutely admitted to the ICU: a prospective cohort study.

BACKGROUND: The Clinical Frailty Scale (CFS) is frequently used to measure frailty in critically ill adults. There is wide variation in the approach to analysing the relationship between the CFS score and mortality after admission to the ICU. This study aimed to evaluate the influence of modelling approach on the association between the CFS score and short-term mortality and quantify the prognostic value of frailty in this context. METHODS: We analysed data from two multicentre prospective cohort studies which enrolled intensive care unit patients ≥ 80 years old in 26 countries. The primary outcome was mortality within 30-days from admission to the ICU. Logistic regression models for both ICU and 30-day mortality included the CFS score as either a categorical, continuous or dichotomous variable and were adjusted for patient's age, sex, reason for admission to the ICU, and admission Sequential Organ Failure Assessment score. RESULTS: The median age in the sample of 7487 consecutive patients was 84 years (IQR 81-87). The highest fraction of new prognostic information from frailty in the context of 30-day mortality was observed when the CFS score was treated as either a categorical variable using all original levels of frailty or a nonlinear continuous variable and was equal to 9% using these modelling approaches (p < 0.001). The relationship between the CFS score and mortality was nonlinear (p < 0.01). CONCLUSION: Knowledge about a patient's frailty status adds a substantial amount of new prognostic information at the moment of admission to the ICU. Arbitrary simplification of the CFS score into fewer groups than originally intended leads to a loss of information and should be avoided. Trial registration NCT03134807 (VIP1), NCT03370692 (VIP2)

Аналіз технічних характеристик мережі з можливістю до самоорганізації

At present, wireless technology is widely used in our everyday life and in military networks. In the sources, in the future, their percentage will only increase, according to an the analysis conducted. In this article, the analysis of technical characteristics and the classification of network routing protocols with the possibility of self-organization based on the main features of the organization and the mechanisms of the operation of the protocols. These mechanisms include the mechanism for updating route information, based on the method of storing route information, the topology of information organization and the use of protocols specific resources. The authors of the famous scientific papers in which the simulation was conducted do not fully describe the dependence of the influence of such criteria as the speed of the nodes, change of the network area, change of the number nodes in the network, change of the number of hops to the addressee to work routing protocols. The analysis of modern research directions in scientific editions and the tendencies of the development of routing protocols, analysis of routing protocols modeling data provided by the authors of the simulation was conducted. While the review of the simulation results, a description of the behavior of the protocols in different scenarios of modeling and commenting on the logic of the work of the protocols is carried out in accordance with the given classification, which subsequently makes it possible to determine the appropriate features of the protocols in accordance with the categories. Analysis of the advantages and disadvantages of network routing protocols with the ability to self-organization when changing the following criteria affecting the operation of protocols such as change the number of nodes in the network with the possibility of self-organization, the operation of protocols depending on the intensity of change in topology (speed of nodes), change the size of the area the network, which in turn also affects the number of nodes that redirect packets for delivery to the addressee. The dependence of the routing protocols on the use of higher level TCP and UDP protocols was also analyzed, where the coefficient of delivery of packets from the source to the addressee was analyzed. The main advantages and disadvantages of the main routing protocols of networks with possible self-organization that were considered by the authors of scientific works in modeling, such as AODV, DSDV, OLSR, and DSR, are highlighted. The definition of the actual and perspective direction of scientific work in further researches was conducted.На теперішній час технології бездротових мереж широко використовуються у нашому повсякденному житті та в мережах військового призначення. Як свідчить проведений в джерелах аналіз, в подальшому їх відсоткова частка буде лише збільшуватися. В цій статті проводиться аналіз технічних характеристик та класифікація протоколів маршрутизації мереж з можливістю самоорганізації за основними особливостями організації та механізмів роботи протоколів,такими як механізм оновлення інформації маршруту, спосіб зберігання інформації маршруту, топологія організації інформації та на основі використання протоколами конкретних ресурсів. Авторами відомих наукових праць в яких проводилося моделювання, проведено неповний опис залежності впливу таких критеріїв як швидкість руху вузлів, зміна площі мережі, зміна кількості вузлів в мережі, зміна кількості пересилаємих пакетів до адресату на роботу протоколів маршрутизації. Проведено аналіз сучасних напрямків дослідження в наукових виданнях та тенденції розвитку протоколів маршрутизації, аналіз даних з моделювання протоколів маршрутизації, які надані авторами моделювання. Під час огляду результатів моделювання проводився опис поведінки протоколів у різних сценаріях моделювання та коментування логіки роботи протоколів відповідно до наданої класифікації, що в подальшому надало можливість визначення особливостей протоколів у відповідності до категорій. Аналіз переваг та недоліків протоколів маршрутизації мереж з можливістю до самоорганізації при зміні критеріїв, що впливають на роботу протоколів,таких як зміна кількості вузлів в мережі з можливою самоорганізацією, робота протоколів у залежності від інтенсивності зміни топології (швидкості переміщення вузлів), зміни розміру області мережі, яка в свою чергу також впливає на кількість вузлів, що перенаправляють пакети за для доставки до адресату. Проаналізовано також залежність роботи протоколів маршрутизації щодо використання протоколів вищого рівня TCP та UDP, зокрема проаналізовано коефіцієнт доставки пакетів від джерела до адресату. Виділено основні переваги та недоліки основних протоколів маршрутизації мереж з можливою самоорганізацією, які розглядалися авторами наукових праць із моделювання, таких як AODV, DSDV, OLSR та DSR. Проведено визначення актуального та перспективного напрямку наукової роботи в подальших дослідженнях

Analysis of Mathematical Models of Mobility of Communication Systems of Special Purpose Radio Communication Systems

The object of research is the military radio communication system. One of the problems in improving the effectiveness of military radio communication systems is the correct description of the movement process in them. Efficient routing protocols are only possible if reliable information on network topology for network nodes is available. Thus, with this information, packets can be forwarded correctly between the sender and the recipient. Given that the mobility of individual nodes is insignificant in special wireless networks, nodes in the network show the mobility properties of a group of nodes. This observation is directly related to the very existence of military wireless networks with the ability to organize themselves, that is, to support group cooperation and group activities. In this work the problem of analysis (decomposition) of the mobility models of military radio communication networks with the possibility of self-organization is solved. The classification of mobility patterns, the description of individual mobility models and the analysis of various aspects currently available, as well as those properties lacking in the attempt to simulate the movement of individual nodes, have been carried out. During the research, the analysis of random, semi-deterministic and deterministic models was carried out. The advantages and disadvantages of the above models have been identified. In the course of the research, the authors of the work used the main principles of the theory of mass service, the theory of automation, the theory of complex technical systems, as well as general scientific methods of knowledge, namely analysis and synthesis. The research results will be useful in: ‒ synthesis of mathematical models of node mobility; ‒ evaluation of the effectiveness of the science-based tool for assessing the mobility of nodes; ‒ validation of recommendations to improve the efficiency of mobile radio networks; ‒ analysis of the radio-electronic situation during the conduct of military operations (operations); ‒ creating advanced technologies to improve the efficiency of mobile radio networks

Development of A Method of Adaptive Control of Military Radio Network Parameters

A method of adaptive control of military radio network parameters has been developed. This method allows predicting suppressed frequencies by electronic warfare devices, determining the topology of the military radio network. Also, this method allows determining rational routes of information transmission and operating mode of radio communications. Forecasting of the electronic environment is characterized by recirculation of input data for one count, resampling on a logarithmic time scale, finding a forecast for the maximum value of entropy and resampling the forecast on the exponential time scale. The developed method allows choosing a rational network topology. The choice of topology of the military radio communication system is based on the method of ant multi-colony system. The main idea of the new option of ant colony optimization is that instead of one colony of the traditional ant algorithm several colonies are used that work together in a common search space. However, this procedure additionally takes into account the type of a priori uncertainty and the evaporation coefficient of the pheromone level. The proposed method allows choosing a rational route for information transmission. The proposed procedure is based on an improved DSR algorithm. This method uses several operating modes of radio communications, namely the technology of multi-antenna systems with noise-like signals, with pseudo-random adjustment of the operating frequency and with orthogonal frequency multiplexing. The developed method provides a gain of 10‒16 % compared to conventional management approache

Analysis of Methods for Increasing the Efficiency of Dynamic Routing Protocols in Telecommunication Networks with the Possibility of Self-organization

The object of research is the military radio communication system. Effective operation of routing protocols is possible only if there is reliable information about the network topology for network nodes, given that the mobility of individual nodes is insignificant in special purpose wireless networks. Because nodes in the network demonstrate the mobility property of the node groups. This paper solves the problem of the analysis (decomposition) of methods of protocols efficiency increase of dynamic routing in telecommunication networks with a possibility to self-organization. In the course of the research, the authors used the main provisions of the queuing theory, the theory of automation, the theory of complex technical systems and general scientific methods of cognition, namely analysis and synthesis. This research analyzes various methods to increase the efficiency of dynamic routing protocols. Energy efficiency methods focus on three main components in energy management: battery management, transmission energy management and system energy management methods. Reliable multicast has become indispensable for the successful deployment of special purpose wireless networks, such as in tactical military operations and emergency operations. The results of the research will be useful in: – development of new routing algorithms; – substantiation of recommendations for improving the efficiency of the route selection process in networks with the possibility of self-organization; – analysis of the electronic situation during hostilities (operations); – while creating promising technologies to increase the efficiency of mobile radio networks. Areas of further research will focus on the development of a methodology for the operational management of interference protection of intelligent military radio communication systems