Goal-directed use of balanced solutions for laparoscopic surgery in obese patients

Modern guidelines for infusion therapy in laparoscopic surgery of patients with obesity are ambiguous due to insufficient number of clinical researches. The aim of our work was to evaluate the effect of goal-directed infusion therapy with balanced solutions on hemodynamics, electrolyte balance, renal function and incidence of perioperative complications of laparoscopic surgery in obese patients. Materials and methods. The study included 54 obese patients (BMI >30 kg/m2) who were performed laparoscopic surgery in case of the diaphragmatic hernia, colon tumors, postoperative ventral hernia and morbid obesity. In the group A (n = 26) goal-directed infusion therapy by balanced solutions Gelaspan and Sterofundin (B. Braun, Germany) was used. Impedance measuring technology using the monitor Utas 300 (Ukraine) was used to determine the target stroke volume (SV). In the group B (n = 28) infusion therapy was performed by unbalanced solutions (6 % HES and 0.9 % NaCl), focusing on fluid deficiency according to changes in blood pressure (BP), heart rate (HR), and diuresis. The incidence of hypotension and total volume of infusion therapy (TVIT) were evaluated intraoperatively, changes in BP and HR were compared. After surgery diuresis, blood Na+, K+, Cl– and creatinine concentrations, diuretic use frequency and incidence of cardiac, respiratory, hemorrhagic and infectious complications were controlled. Statistical analysis was performed using the Statistica for Windows software version 6.0. Results. The incidence of hypotension in the group B was almost 2 times more than in the group A (P 0.05). Intraoperative TVIT in the group B was 23 % higher due to crystalloid, and diuresis intensity was twice less than in the group A (P < 0.05). Concentrations of electrolytes and creatinine blood level did not change significantly in the study groups. After surgery in the group B 25 % of patients were prescribed diuretic and in the group A diuretic was not prescribed in any case (P < 0.05). In-hospital mortality in both groups was zero, no serious complications were observed. Conclusions. Goal-directed infusion therapy with balanced solutions in laparoscopic surgery in obese patients halved the incidence of intraoperative hemodynamic instability, reduces the volume loading of crystalloids by 23 % during surgery and provides adequate perioperative diuresis without additional stimulation

Incentive spirometry as a way to prevent pulmonary atelectasis development

The purpose. The purpose of this study was to evaluate the effectiveness of incentive spirometry (IS) as a method of atelectasis prevention in patients with moderate or high risk of PPCs development after upper abdominal surgery. Materials and methods. The study consisted of two stages. The first retrospective stage was to analyze the medical histories data of 51 inpatients, who were included in the comparison group. The prospective part of the study included 39 patients of the study group, who had sessions of the IS during the first 7 days of the postoperative period. Patients of both groups were operated on the upper abdominal organs by open procedure, operation time was more than 2 hours, all patients had an ARISCAT score ≥26 points. Pulmonary atelectasis development was monitored in the groups in the first week of the postoperative period. The statistical analysis of the data was performed using the Microsoft Excel 2013 and Statistica for Windows 6.0 programs. When comparing the groups according to the clinical outcome, the relative risk (RR) and odds ratio (OR) were determined and then confidence intervals (95 % CI) were calculated. Statistical significance of the results was determined depending on the CI values. Results. During the first 7 days, 34 cases of pulmonary atelectasis (67 %) were recorded in the comparison group. In the study group, 9 patients (23 %) were diagnosed with pulmonary atelectasis. The analysis of clinical results showed that when applying incentive spirometry, there was a statistically significant decrease in the relative risk of atelectasis development within the first week of the postoperative period (RR = 0.346, 95 % CI [0.189; 0.634], P = 0.0006). The odds ratio of atelectasis development in the study group was statistically lower than in the group of retrospective study (OR = 0.150, 95 % CI [0.058, 0.386], P = 0.0001). Conclusions. Incentive spirometry is an effective way to prevent pulmonary atelectasis in patients with a moderate or high risk for developing postoperative pulmonary complications according to the ARISCAT scale after upper abdominal surgery

AFM-based approach to establish structure/property type correlations for polymeric functional materials

This work was supported by the RSF (project No. 18-19-00453) and the RFBR (project No. 18-08-01356 A)

Atomic force microscopy in polymeric chemistry’s studies

This work was supported by the RSF (project No. 18-19-00453)

Torsional fluctuations in columnar DNA assemblies

In columnar assemblies of helical bio-molecules the azimuthal degrees of freedom, i.e. rotations about the long axes of molecules, may be important in determining the structure of the assemblies especially when the interaction energy between neighbouring molecules explicitly depends on their relative azimuthal orientations. For DNA this leads to a rich variety of mesophases for columnar assemblies, each categorized by a specific azimuthal ordering. In a preceding paper [A. Wynveen, D. J. Lee, and A. A. Kornyshev, Eur. Phys. J. E, 16, 303 (2005)] a statistical mechanical theory was developed for the assemblies of torsionally rigid molecues in order to determine how thermal fluctuations influence the structure of these mesophases. Here we extend this theory by including torsional fluctuations of the molecules, where a DNA molecule may twist about its long axis at the cost of torsional elastic energy. Comparing this with the previous study, we find that inclusion of torsional fluctuations further increases the density at which the transition between the hexagonal structure and the predicted rhombic phase occurs and reduces the level of distortion in the rhombic phase. As X-ray diffraction may probe the 2-D lattice structure of such assemblies and provide information concerning the underlying interaction between molecules, we have also calculated correlation functions for the azimuthal ordering which are manifest in an x-ray scattering intensity profiles.Comment: 33 pages, 8 figure

Efficacy of regional analgesia techniques in abdominal surgery patients with obesity

Abstract The use of regional anesthetic techniques in abdominal surgery is an essential component of the multimodal approach to perioperative analgesia, yet data on their use in obese patients remains limited. The aim of this study is to determine the effectiveness of the epidural analgesia (EA) and the transversus abdominis plane block (TAP-block) in laparoscopic obese patients, as well as to evaluate the possibility of using the rectus sheath block (RSB) as a “rescue” anesthetic technique after laparotomy in obese patients. Materials and methods. The data on the 102 obese patients operated on esophageal hiatal diaphramgmatic hernia, colon tumor, postoperative ventral hernia, morbid obesity and choledocholithiasis were analyzed. In laparoscopic surgery 20 patients received EA (EA group), 21 patients – TAP-block (TAP group), 21 patients – opioids and non-steroidal anti-inflammatory drugs (NSAIDs) without any regional anesthesia techniques (group TIVA1). In laparotomic surgery 16 patients received RSB (RSB group) and 24 patients – only opioids and NSAIDs (TIVA2 group). After the surgery the following was estimated: the time of extubation, the total dose of opioids, the level of pain according to the 10-point numeric range score (NRS), the incidence of dyspnea using the monitor Utas 300 (Ukraine), the incidence of postoperative nausea and vomiting (PONV), the time of active patient mobilization, and the level of satisfaction with analgetic regimen. For the RSB group, the complexity of the RSB and the mean time to achieve adequate analgesia (pain intensity ≤3 points per NRS) were determined additionally. The statistical analysis was performed using the Statistica for Windows version 6.0 software. Results. In the EA group, the intraoperative dose of fentanyl was twice lower, and patients were extubated two times faster than in the TAP, TIVA1, RSB, TIVA2 groups (P < 0.05). At the same time, none of the patients in the EA group required the restoration of neuromuscular conduction with neostigmine (P < 0.05). After the surgery, the pain level was 2–3 times higher in the TIVA1, RSB, and TIVA2 groups than in the EA and TAP groups (P < 0.05). “Rescue” analgesia in the RSB group was performed from the first attempt in all the patients in 5–10 minutes and provided an adequate effect in 3 (2–4) min. The complexity level of RSB was defined as “easy” in 12 (75 %) patients, as “average” in 4 (25 %) patients (P < 0.05). The incidence of dyspnea and opioid doses after surgery in the EA, TAP and RSB groups of patients were 2 times lower, and the incidence of PONV was 3 to 4 times lower than in the TIVA1 and TIVA2 patients’ groups (P < 0.05). In the EA and TAP groups, patients became mobile after 8–13 hours after surgery, in the group TIVA1 – after 16–22 hours, in the group RSB – after 18–36 hours, in the group TIVA2 – after 48–96 hours (P < 0.05). 100 % of the respondents from the EA, TAP and RSB groups were satisfied with the analgesic regimen at the “excellent – good” level. In the TIVA1 and TIVA2 groups, 20–25 % of respondents identified analgesic comfort as “good”, 60–65 % of respondents – as “satisfactorily”, about 15 % of respondents – as “unsatisfactorily” (P < 0.05). Conclusions. In laparoscopic surgery the use of EA or TAP-block in obese patients significantly reduces the level of postoperative pain, the need for opioids, the incidence of dyspnea and PONV, which leads to the possibility of patients’ mobilization within 8–13 hours after surgery. After laparotomic surgery in obese patients RSB effectively “rescues” from pain and prevents excessive use of opioids, which reduces the number of adverse reactions and increases satisfaction with the quality of analgesia

Atomic force microscopy in the model’s development of polymeric functional materials formation on inert supports

This work was supported by the RFBR (project No. 18-08-01356 A)

Предупреждение венозного тромбоэмболизма у хирургических больных с ожирением

Венозная тромбоэмболия (ВТЭ) — одна из основных причин заболеваемости и смертности у госпитализированных пациентов. Там где это уместно, основанные на доказательствах методы профилактики используются, и количество ВТЭ может быть существенно снижено. Ожирение, в том числе морбидное, связано с высоким риском ВТЭ и, к сожалению, фиксированные дозы рекомендуемых антикоагулянтов, в том числе нефракционированного гепарина, низкомолекулярных гепаринов и ингибиторов фактора Ха, не могут обеспечить оптимальный способ профилактики ВТЭ у этих пациентов. Увеличивающийся объем литературы и накопление доказательств свидетельствуют о том, что для оптимизации фармакодинамической активности антикоагулянта и уменьшения риска ВТЭ доза препарата у пациентов с ожирением должна корригироваться индивидуально. Для решения этого вопроса мы предлагаем использовать “Point of Care” мониторинг гемостаза с помощью низкочастотной пьезотромбоэластографии.Venous thromboembolism (VTE) is one of the main causes of morbidity and mortality of hospitalized patients. Evidence-based prevention methods are used where it is appropriate and the amount of VTE can be significantly reduced. Obesity is an independent risk factor for VTE for both men and women. This relates to hemostasis disorders characterized in general as a prothrombotic state and requiring adequate perioperative correction to prevent VTE. Unfortunately, fixed doses of recommended anticoagulants including unfractionated heparin, low-molecular heparins and inhibitors of Xa factor can’t provide an optimal way to prevent VTE in patients with obesity. Increasing amount of literature and evidences accumulation indicate that the dose of the drug in patients with obesity should be individually corrected to optimize pharmacodynamic activity of the anticoagulant and to reduce the risk of VTE, possibly by using “Point of Care” (POC) monitoring. However, thromboelastography (TEG) and rotational thromboelastomethry (ROTEM) are not available in everyday practice and are used more often in critical situations. To solve this issue we propose to use POC monitoring of hemostasis with low-frequency piezothromboelastography (LPTEG)

Влияние эпидуральной аналгезии на гемостатический потенциал после абдоминальных операций у пациентов с ожирением

Current recommendations for the prevention of venous thromboembolism (VTE) in obese patients have a low level of evidence. That’s why the use of other techniques of influence on hemostatic potential (GP) is actual. Aim. To evaluate the effect of epidural analgesia (EA) on hemostatic system parameters after laparoscopic operations in obese patients. Material and methods. GP parameters were measured in 52 patients with BMI>30 kg/m2 using the method of low-frequency piezoelectric thromboelastography (LPTEG). The initial GP level was determined and its changes were compared on the 3rd day after surgery between the group of total intravenous anesthesia (TBA, n=26) and EA-group (n=25). Statistical analysis was conducted using Statistica for Windows version 6.0. Results. The initial level of GP didn’t differ significantly between the study groups. In TBA-group hypercoagulation and inhibition of fibrinolysis with a moderate decrease in platelet aggregation were present on the 3rd day after surgery (p<0.05). In EA-group there was an improvement in coagulation and fibrinolysis but aggregation rates reached the lower limit of the norm (p<0.05). Conclusion. Perioperative use of EA in abdominal laparoscopic surgery of patients with obesity helps to normalize coagulation and fibrinolytic GP components and reduces the aggregation of formed blood elements.Современные рекомендации по профилактике венозного тромбоэмболизма у пациентов с ожирением имеют низкий уровень доказательности, поэтому актуально применение других техник влияния на гемостатический потенциал (ГП). Цель. Оценить влияние эпидуральной аналгезии (ЭА) на показатели системы гемостаза после лапароскопических операций у пациентов с ожирением. Материалы и методы. Показатели ГП измеряли у 52 пациентов с индексом массы тела > 30 кг/м2 с помощью методики низкочастотной пьезоэлектрической тромбоэластографии. Определяли исходный уровень ГП и сравнивали его изменения на 3-и сутки после операции между группой тотальной внутривенной анестезии (ТВА, n=26) и группой ЭА (n=25). Статистический анализ проведен с помощью программы Statistica for Windows версия 6.0. Результаты. Исходный уровень ГП достоверно не различался между группами исследования. В группе ТВА гиперкоагуляция и угнетение фибринолиза на фоне умеренного снижения агрегации тромбоцитов сохранялись на 3-и сутки после операции (p<0,05). В группе ЭА происходило улучшение показателей коагуляции и фибринолиза, а показатели агрегации достигли нижней границы нормы (p<0,05). Выводы. Периоперационное использование ЭА в абдоминальной лапароскопической хирургии у пациентов с ожирением способствует нормализации коагуляционной и фибринолитической составляющей ГП, но уменьшает агрегацию форменных элементов крови

Surface structuring features of polymeric membranes based on chitosan according to atomic force microscopy

С целью выявления механизмов структурообразования модифицированных полимерных мембран на основе хитозана на каждом этапе модификации с помощью метода атомно-силовой микроскопии изучена серия промежуточных образцов.For to reveal surface structuring mechanisms of modified polymeric membranes based on chitosan, a series of intermediate samples was studied using atomic force microscopy at each modification stage.Работа выполнена при финансовой поддержке Российского научного фонда в рамках проекта № 15-19-10057