Temporary cardiointerval organization with varying degrees of acute normobaric hypoxia in a healthy person

2021 ◽  
Author(s):  
M.I. Bocharov

The influence of acute normobaric hypoxia (ANH) on the male heart chronotropic effects was studied. Thus, a mild degree of ANH (14.5 % O2, 20 min), causing a decrease in blood oxygenation by 6.3 abs. %, accompanied by an initial (by 5 min) decrease in the RR and QT intervals. The average degree of ANH (12.3% O2) leads to a decrease in blood oxygenation by 19.7 abs. %. At the same time, in inverse relationship to the developing hypoxemia, RR and QT significantly decrease. Corrected values (Pc, PQc, QRSc, QTc) increase during the action period of an average degree of hypoxia, indicating an increase in the proportion of atrial contraction time, atrioventricular conduction of excitation and electrical ventricular systole in the total RR duration, which, apparently, provides optimal systolic heart effect. Key words: human, hypoxia, blood oxygenation, cardiointervals.

Author(s):  
M.I. Bocharov ◽  
A.S. Shilov

Despite much available information on the heart activity under acute normobaric hypoxia (ANH), there are no data on the leading ECG components and the criteria for predicting their deviations at various stages of ANH and depending on its duration. The aim of the paper is to determine the leading ECG components and the dependence of their deviations on the initial parameters at different stages of acute normobaric hypoxia and depending on its duration in a healthy person. Materials and Methods. The shifts in parameter indicators were determined in two groups of men (aged 18–26) under 20-minute mild (14.5 % O2, n1=30) and medium (12.3 % O2, n2=29) ANH. During the study the authors used 7 ECG parameters and oximetry. Statistica 10.0 software package was used for data processing. The authors determined normality of distribution, they also used factor analysis, correlation, and regression. Results. For all ANH degrees, the leading factor included QT, T1II, and (with one exception) RR. In case of mild ANH, the 1st factor was supplemented by P1II at the 5th minute of exposure, and in case of medium ANH at the 20th minute. The second most important factor in case of mild ANH was determined by BAR and RII at the 5th and 20th min and by BAR at the 10th min. In case of medium ANH it was supplemented by P1II at the 5th min, by RII and BAR at the 10th min, and by BAL at the 20th min. It was shown that in case of mild ANH P1II, RII, BAR, and RR deviations reliably depend on the initial parameters; for medium ANH, such dependence is observed for RR and QT at the 5th and 10th min, for RII at the 10th and 20th min, and for P1II at the 20th min. Conclusion. The main markers of heart bioelectrical processes under ANH are QT, T1II and RR, other parameters are variable. The availability to predict deviations of ECG parameters by their initial parameters depends on ANH stage. Key words: human, hypoxia, oximetry, electrocardiography, factorial, correlation, regression analysis. Несмотря на имеющиеся многочисленные сведения о деятельности сердца при острой нормобарической гипоксии (ОНГ), данные о ведущих компонентах ЭКГ и критериях прогнозирования их отклонений при разной степени ОНГ и в зависимости от ее длительности отсутствуют. Цель работы – определить ведущие компоненты ЭКГ и зависимости их отклонений от исходных величин при разных степенях острой нормобарической гипоксии и в зависимости от её длительности у здорового человека. Материалы и методы. С помощью ЭКГ (7 параметров) и оксигемометрии определены сдвиги их показателей у мужчин (18–26 лет) двух групп при легкой (14,5 % О2, n1=30) и средней (12,3 % О2, n2=29) ОНГ в течение 20 мин. Материал обработан с помощью программного пакета Statistica 10.0. Определяли нормальность распределения, применяли факторный анализ, корреляцию, регрессию. Результаты. При всех степенях ОНГ ведущий фактор включал QT, T1II и (с одним исключением) RR. При легкой ОНГ 1-й фактор на 5-й мин воздействия дополняется P1II, а при средней ОНГ на 20-й мин – P1II. Второй по весомости фактор при легкой ОНГ на 5-й и 20-й мин определяется BAR и RII, на 10-й мин – BAR, а при средней ОНГ на 5-й мин – P1II, на 10-й мин – RII и BAR, на 20-й мин – BAL. Показано, что при легкой ОНГ от исходных данных достоверно зависят отклонения P1II, RII, BAR и RR, при средней ОНГ такая зависимость наблюдается для RR и QT на 5-й и 10-й мин, для RII на 10-й и 20-й мин и для P1II на 20-й мин. Выводы. Основными маркерами биоэлектрических процессов сердца при ОНГ являются QT, T1II и RR, остальные параметры отличаются вариабельностью. Возможность прогноза отклонений параметров ЭКГ по их исходным величинам зависит от степени ОНГ. Ключевые слова: человек, гипоксия, оксигемометрия, электрокардиография, факторный, корреляционный, регрессионный анализы.


2014 ◽  
Vol 116 (7) ◽  
pp. 945-952 ◽  
Author(s):  
Normand A. Richard ◽  
Inderjeet S. Sahota ◽  
Nadia Widmer ◽  
Sherri Ferguson ◽  
A. William Sheel ◽  
...  

We examined the control of breathing, cardiorespiratory effects, and the incidence of acute mountain sickness (AMS) in humans exposed to hypobaric hypoxia (HH) and normobaric hypoxia (NH), and under two control conditions [hypobaric normoxia (HN) and normobaric normoxia (NN)]. Exposures were 6 h in duration, and separated by 2 wk between hypoxic exposures and 1 wk between normoxic exposures. Before and after exposures, subjects ( n = 11) underwent hyperoxic and hypoxic Duffin CO2 rebreathing tests and a hypoxic ventilatory response test (HVR). Inside the environmental chamber, minute ventilation (V̇e), tidal volume (Vt), frequency of breathing ( fB), blood oxygenation, heart rate, and blood pressure were measured at 5 and 30 min and hourly until exit. Symptoms of AMS were evaluated using the Lake Louise score (LLS). Both the hyperoxic and hypoxic CO2 thresholds were lower after HH and NH, whereas CO2 sensitivity was increased after HH and NH in the hypoxic test and after NH in the hyperoxic test. Values for HVR were similar across the four exposures. No major differences were observed for V̇e or any other cardiorespiratory variables between NH and HH. The LLS was greater in AMS-susceptible than in AMS-resistant subjects; however, LLS was alike between HH and NH. In AMS-susceptible subjects, fB correlated positively and Vt negatively with the LLS. We conclude that 6 h of hypoxic exposure is sufficient to lower the peripheral and central CO2 threshold but does not induce differences in cardiorespiratory variables or AMS incidence between HH and NH.


2021 ◽  
Vol 14 (3) ◽  
Author(s):  
A Fayazov ◽  
D Tulyaganov ◽  
U Kamilov ◽  
A Mirzakulov ◽  
A Khalilov

Aim. improving the results of treatment of victims with electrical injury, through early diagnosis of the depth and extent of the lesion and the introduction of methods of active surgical tactics.Material and methods. We examined 674 patients with electrical injuries admitted to the RSCEMP in the period from 2001 to 2017. the patients used the methods of bilateral comparative dermal thermometry and X-ray densitometry. To assess the severity of burn shock, the indicators of central and peripheral hemodynamics, blood oxygenation, Frank’s index, thermometry and neutrophil-lymphocyte index were assessed. The calculation of statistical indicators was carried out using the Microsoft Excel 2010 software package, including built-in statistical processing functions. The significance of differences between the groups in the quantitative values of the parameters was determined by the Student’s test. Statistical indicators were considered reliable, with p <0.05. Results. It was found that the temperature difference in the armpit and the first interdigital space of the foot by 0.5-1.5 ° C corresponds to a mild degree of burn shock, and in severe and extremely severe burn shock, the temperature difference in these zones was 1.6 -4 ° С and above 4 ° С. It is noted that active surgical tactics by early fasciotomy on the first day of injury and early necrectomy contributes to a significant decrease in the frequency of amputation and disarticulation of the extremities from 55.8 to 9.8%, makes it possible to perform early autodermoplasty, improves the survival rate of autografts and shortens the period of inpatient treatment. Active surgical tactics contributed to an improvement in the engraftability of autografts (95.2% versus 87.4%), a 2.6-fold decrease in the frequency of repeated autodermoplasty at sites of non-engraftment, a significant decrease in the frequency of mutilation operations (amputation and disarticulation of the extremities) and a reduction in the duration of inpatient treatment with 41.1 ± 12.3 to 37.7 ± 10.4 days. Conclusions. Early fasciotomy on the first day of injury and early necrectomy contribute to a significant decrease in the frequency of amputation and disarticulation of the extremities from 55.8 to 9.8%, make it possible to perform autodermoplasty in the shortest possible time and reduce the time of inpatient treatment. The process of osteonecrosis is completed within 2 weeks after the injury, and by this time it is possible to start osteonecrectomy, including one-stage radical osteonecrectomy over the entire surface of osteonecrosis.


2004 ◽  
Vol 36 (4) ◽  
pp. 316-317 ◽  
Author(s):  
Peter Schiellerup ◽  
Karen Krogfelt ◽  
Åse Bengård Andersen

2018 ◽  
Vol 22 (5) ◽  
pp. 9-16 ◽  
Author(s):  
M. Z. Gasanov

In recent decades, the main pathogenetic mechanisms for maintaining muscle mass and strength have been discovered. Most of the scientific papers on the molecular aspects of the  pathogenesis of sarcopenia were focused on the Akt-signaling  pathway. The subject of the study were people of elderly and senile  age, immobilized patients, patients with CKD 1-4 stages, animals. However, recently more attention has been paid to the role  of protein – the mammalian target of rapamycin mTOR. It seems to be a key link in the control of muscle mass and is a promising  marker in understanding the mechanisms of the pathogenesis of  sarcopenia. Its importance in protein metabolism in patients with  end stage kidney disease is not studied and requires further research. The presented scientific review contains  information on the role of mTOR and its components – mTORC1 and mTORC2 in maintaining muscle mass and strength in a healthy  person and in the formation of sarcopenia in patients with CKD. The  general aid of mTORC1 complex is regulation of protein production  which is necessary for cell growth and differentiation. mTORC2  complex functions are not enough studied. It is established that it  plays important role in such biological processes as cytoskeleton  organization, intracellular homeostasis maintaining, so it provides  cell resistance and cell survivability in negative external and internal  impulses. mTOR protein can be considered as promising molecular  marker in diagnostics of protein metabolism early disturbances in  patients with CKD and also as additory factor of sarcopenia severity assessment.


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