СОЧЕТАННАЯ АНЕСТЕЗИЯ ПРИ РЕЗЕКЦИИ ЛЕГКИХ

In order to improve outcomes of surgical treatment of thoracic diseases, the peri-operative protection is to be constantly enhanced. Goal: to assess the effect of combined anesthesia with thoracic epidural analgesia in the peri-operative period on hemodynamics and respiratory exchange during radical pulmonary surgery. Subjects and methods. The prospective randomized study was performed aiming to assess the effect of various options of anesthesia in 46 patients who had planned radical pulmonary surgery. The patients were randomly divided into two groups. Group 1 (n = 23) had combined anesthesia. Analgesia was provided through segmental epidural block on the level of Th4 ‒Th5 by intermittent bolus dosing of 0.75% solution of ropivacaine (0.7-0.8 mg/kg) and fentanyl (1.3-1.5 mcg/kg), and during the surgery, the mixture of 0.02% solution of ropivacaine and fentanyl (4 mcg/kg) was continuously infused at the rate of 4-6 ml/h. In Group 2 (n = 23), analgesia was provided by infusions of fentanyl, epidural analgesia was used in the post-operative period as a component of multi-modal post-operative pain relief. In both groups, the cortical component was provided by the low-flow inhalation of sevoflurane under BIS monitoring. Pipecuronium bromide solution was intermittently administered in order to provide muscle relaxation. Conclusion. The positive impact on hemodynamics and respiratory exchange was observed when using combined anesthesia based on thoracic epidural analgesia and inhalation anesthesia with sevoflurane. Для улучшения результатов оперативного лечения торакальных пациентов необходимо постоянное совершенствование их периоперационной защиты. Цель: оценить влияние сочетанной анестезии с применением грудной эпидуральной анальгезии в периоперационном периоде на гемодинамику и газообмен при радикальных оперативных вмешательствах на легких. Материалы и методы. Проведено проспективное рандомизированное исследование влияния различных вариантов анестезии у 46 пациентов, перенесших радикальное оперативное вмешательство на легких в плановом порядке, на периоперационное состояние системной гемодинамики и газообмена. Больные рандомизированы на две группы. В 1-й группе (n = 23) анестезия была сочетанной. Формирование анальгезии осуществляли сегментарной эпидуральной блокадой на уровне Th4 ‒Th5 дробным болюсным введением 0,75%-ного раствора ропивакаина (0,7−0,8 мг/кг) и фентанила (1,3–1,5 мкг/кг), во время операции проводили постоянную инфузию смеси 0,2%-ного раствора ропивакаина и фентанила (4 мкг/мл) со скоростью 4–6 мл/ч. Во 2-й группе (n = 23) анальгетический компонент достигался системным применением фентанила, эпидуральную анальгезию начинали использовать в послеоперационном периоде в качестве компонента мультимодального послеоперационного обезболивания. Корковый компонент в обеих группах достигался ингаляцией севофлурана в низком потоке под контролем BIS-мониторинга. Миорелаксация осуществлялась фракционным введением раствора пипекурониума бромида. Заключение. Выявлено благоприятное влияние сочетанной анестезии на основе грудной эпидуральной анальгезии и ингаляционной анестезии севофлураном на системную гемодинамику и газообмен.

COMBINED ANESTHESIA IN PULMONARY RESECTION

In order to improve outcomes of surgical treatment of thoracic diseases, the peri-operative protection is to be constantly enhanced. Goal: to assess the effect of combined anesthesia with thoracic epidural analgesia in the peri-operative period on hemodynamics and respiratory exchange during radical pulmonary surgery. Subjects and methods. The prospective randomized study was performed aiming to assess the effect of various options of anesthesia in 46 patients who had planned radical pulmonary surgery. The patients were randomly divided into two groups. Group 1 (n = 23) had combined anesthesia. Analgesia was provided through segmental epidural block on the level of Th4 ‒Th5 by intermittent bolus dosing of 0.75% solution of ropivacaine (0.7-0.8 mg/kg) and fentanyl (1.3-1.5 mcg/kg), and during the surgery, the mixture of 0.02% solution of ropivacaine and fentanyl (4 mcg/kg) was continuously infused at the rate of 4-6 ml/h. In Group 2 (n = 23), analgesia was provided by infusions of fentanyl, epidural analgesia was used in the post-operative period as a component of multi-modal post-operative pain relief. In both groups, the cortical component was provided by the low-flow inhalation of sevoflurane under BIS monitoring. Pipecuronium bromide solution was intermittently administered in order to provide muscle relaxation. Conclusion. The positive impact on hemodynamics and respiratory exchange was observed when using combined anesthesia based on thoracic epidural analgesia and inhalation anesthesia with sevoflurane

Dynamic System Transfer Function Identification Based on the Experimental Results

The paper deals with identifying linear dynamical systems from the experimental data obtained through applying the test signals to the system. The paper objective is to determine both the form and the coefficients of the transfer function retrieved from the hodograph samples experimentally at bench test. The order of the frequency transfer function of the system being identified was assumed to be unknown. It was expected that in obtaining the frequency characteristics of a real system there would be noise during the experiment as a result of which the points of the experimentally obtained hodograph would be randomly shifted. As a model, a certain transfer function of the system was adopted. The authors proposed to find a solution of the identification problem in the class of hodographs specified by the model of the system. The search for unknown coefficients of the transfer function of the system model is carried out by minimizing a proximity criterion (measure) - described and published earlier by one of the authors - between the experimentally received system hodograph and the system model on an entire set of the experimental points of the system hodograph and the hodograph of the system model. The solution of linear dynamic system identification from the frequency hodograph was reduced to solving a system of equations of the system model frequency transfer function that is linear with respect to unknown parameters.The proposed identification algorithm allows us to determine the order of the frequency transfer function of the identified system from the experimentally obtained samples of the frequency hodograph of the system. For dynamic systems of the fifth order at most there is software developed to simulate the process providing the pseudo-experimental data with random errors and determining the parameters of such systems.A computational experiment has been carried out to evaluate the error with which the proposed algorithm determines the parameter values of the system to be identified. The illustrative computational experiment has shown that using the proposed algorithm for identifying a linear dynamic system from the frequency hodograph the error in determining the coefficient values of the frequency transfer function of the system is comparable with a range of measuring error in the experimental samples of the hodograph of this system. In known sources on identification of linear dynamic systems there is no method of identification this publication describes. This identification method of linear dynamic systems can find application in experimental testing, verification tests in situ and iron bird tests for vehicles of various purposes.</p