10,434 research outputs found

    Cardiac reserve during weightlessness simulation and shuttle flight

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    Bedrest deconditioning is suspected to reduce cardiac function. However, quantitation of subtle decreases in cardiac reserve may be difficult. Normal subjects show considerable variability in heart rate response, reflected by a relatively broadband interbeat interval power spectrum. We hypothesized that the deconditioning effects of bedrest would induce narrowing of this spectrum, reflecting a reduction in the autonomically-modulated variability in heart rate. Ten aerobically conditioned men (average 35-50 years) underwent orthostatic tolerance testing with lower body negative pressure pre-bedrest and after 10 days of bedrest, while on placebo and after intravenous atropine. Spectra were derived by Fourier analysis of 128 interbeat interval data sets from subjects with sufficient numbers of beats during matched periods of the protocol. Data suggest that atropine unmasks the deconditioning effect of bedrest in athletic men, evidenced by a reduction in interbeat interval spectral power compared with placebo. Spectral analysis offers a new means of quantitating the effects of bedrest deconditioning and autonomic perturbations on cardiac dynamics

    Implementation of a Deconditioning Prevention Program: Getting Dressed Makes a Difference

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    Implementation of a Deconditioning Prevention Program: Getting Dressed Makes a Difference Seleem R. Choudhury MSN, MBA, RN, CEN, FAEN Purpose. Deconditioning by immobility or bed rest affects essential body systems and diminishes functional capacity. Individuals age 65 and older have more hospital stays than any other age group. they also account for one out of three hospital admissions costing healthcare over $330 Billion annually. Numerous studies demonstrate this age group often struggle to get back to normal level of activity. . Empowering patients to dress and wear their own clothes can prevent deconditioning. Benefits to hospitals include reduced cost through admissions, improved patient flow by reducing their length of stay (LOS) which can lead to timelier admissions for other patients. A longer LOS also raises the probability of a hospital-acquired condition (HAC), which is an undesirable situation or condition that affects a patient during a hospital stay. Finally, patients who get dressed may feel more satisfied with the care they receive. Methods. To prevent deconditioning through the development of promoting activity by getting patients dressed which reduces the risk of deconditioning as measured by three outcomes: 1) LOS, 2) HAC, 3)Patient Satisfaction. LOS and HAC data were collected from chart review. Patient satisfaction was evaluated by HCAHPS metrics. Results. Three months of data were analyzed and compared in 2016 and 2017. The data were also segregated into age groups to analyze any benefit to over 65-year-olds. The comparison did not demonstrate clear correlation that the deconditioning program impacted the LOS and Patient Satisfaction. LOS comparison (n-832) showed improvement in month three in ages 18-59 and over 75. The ages 55-74 showed no decrease in LOS however recalculating the data from median versus mean showed all age groups LOS did decrease. Patient Satisfaction metrics (n-207) showed no clear inference or consistent pattern that deconditioning program improved satisfaction. Scores stayed comparable to previous years, especially among 18-54 age group. The 75 plus age group did see a decline in scores. Hospital Acquired Complications (HAC) was not a reliable indicator with only one incident in a two-year period. Methodological flaws in unreliable data and insufficient ability to separate variables within the electronic health record confounded comparison. Finally, the multi-faceted nature of discharges limited all of the indicators’ validity. Conclusions. The importance of being active is universally understood, yet hospitals struggle to implement this action. Data of 1-year mortalities of over 65 support that hospitals need to do more to improve this outcome. A simple program of getting dressed everyday has the potential to reduce LOS and with further study, improve 1-year mortality. This study also showed that whilst patient satisfaction is not increased, it also does not significantly decrease therefore it’s possible to assume that our patients want hospital staff to be assertive with preventing Deconditioning Syndrome. Finally, whilst not supported in this study future work, could analyze staff’s perception of patient readiness for discharge alongside data gradually demonstrating a decrease of LOS of 75-year old

    The Physiological Consequences of Bed Rest

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    Bed rest often is used to treat a wide variety of medical conditions. However, bed rest results in profound deconditioning of the body. Bed rest reduces the hydrostatic pressure gradient within the cardiovascular system, reduces muscle force production, virtually eliminates compression on the bones, and lowers total energy expenditure. This review focuses on the deconditioning that occurs in the cardiovascular, muscular, and skeletal systems following bed rest. Reduction in plasma volume reduces cardiac preload, stroke volume, cardiac output, and ultimately, maximal oxygen consumption. Skeletal muscle volume, muscle cross sectional area, and fiber cross sectional area decrease, which results in diminished muscular strength. These changes are most pronounced in the antigravity muscles. Increased bone resorption leads to a negative calcium balance and eventually decreased bone mass, particularly in the lower limbs. Diminished bone mass coupled with decreased muscular strength increases the risk of bone fractures, even with minor falls. It is important for clinicians to recognize these negative consequences of bed rest, which can be explained independent of disease or disorder. With this in mind, bed rest can be minimized as much as possible and early ambulation and physical activity may be prescribed to limit the deconditioning effects of bed rest

    Early changes in rat diaphragm biology with mechanical ventilation

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    To better characterize the effects of 24-hour mechanical ventilation on diaphragm, the expression of myogenic transcription factors, myosin heavy chains, and sarcoplasmic/endoplasmic reticulum calcium-ATPase pumps was examined in rats. In the diaphragm of mechanically ventilated animals, the mRNA of MyoD, myosin heavy chain-2a and -2b, and sarcoplasmic/endoplasmic reticulum calcium-ATPase-1a decreased, whereas myogenin mRNA increased. In the diaphragm of anesthetized and spontaneously breathing rats, only the mRNA of MyoD and myosin heavy chain-2a decreased. MyoD and myogenin protein expression followed the changes at the mRNA, whereas the myosin heavy chain isoforms did not change. Parallel experiments involving the gastrocnemius were performed to assess the relative contribution of muscle shortening versus immobilization-induced deconditioning on muscle regulatory factor expression. Passive shortening produced no additional effects compared with immobilization-induced deconditioning. The overall changes followed a remarkably similar pattern except for MyoD protein expression, which increased in the gastrocnemius and decreased in the diaphragm while its mRNA diminished in both muscles. The early alterations in the expression of muscle protein and regulatory factors may serve as underlying molecular basis for the impaired diaphragm function seen after 24 hours of mechanical ventilation. Whether immobilization-induced deconditioning and/or passive shortening play a role in these alterations could not be fully unraveled

    An evaluation of intermittently inflated extremity cuffs in preventing the cardiovascular deconditioning of bedrest and water immersion

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    Inflatable tourniquet effects on cardiovascular deconditioning during bed rest and water immersion studies on human

    Physiological cost of walking in those with chronic fatigue syndrome

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    <b>Purpose:</b> To examine the physiological cost of walking in subjects with chronic fatigue syndrome (CFS) and a matched control group, walking at their preferred and at matched walking speeds. <b>Methods:</b> Seventeen people with CFS and 17 matched-controls participated in this observational study of physiological cost during over-ground gait. Each subject walked for 5 min at their preferred walking speed (PWS). Controls then walked for 5 min at the same pace of their matched CFS subject. Gait speed and oxygen uptake, gross and net were measured and oxygen uptake was expressed per unit distance ambulated. CFS subjects completed the CFS-Activities and Participation Questionnaire (CFS-APQ). <b>Results:</b> At PWS the CFS group walked at a slower velocity of 0.84 ± 0.21 m s<sup>-1</sup> compared to controls with a velocity of 1.19 ± 0.13 m s<sup>-1</sup> (p < 0.001). At PWS both gross and net oxygen uptake of CFS subjects was significantly less than controls (p = 0.023 and p = 0.025 respectively). At matched-velocity both gross and net physiological cost of gait was greater for CFS subjects than controls (p = 0.048 and p = 0.001, respectively). <b>Conclusion:</b> The physiological cost of walking was significantly greater for people with CFS compared with healthy subjects. The reasons for these higher energy demands for walking in those with CFS have yet to be fully elucidated

    Knowledge of Staff Nurses on Management of Deconditioning in Older Adults: A Cross- Sectional Study

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    Introduction: A significant issue facing today’s acute care nurse is the ability to respond to the rising number of  older adults admitted to the hospital, while simultaneously preventing complications of hospitalization, specifically deconditioning. Objective: The aim of this paper was to examine knowledge of staff nurses on management of deconditioning in older adults, in Baguio- Benguet area in the Philippines. Methods: The study made use of cross- sectional design. Sampling technique used was total enumeration, where 130 out of 135 nurses met the inclusion criteria. A 65 item questionnaire was used in gathering data. Data was subjected to statistical treatment where T- test and F- test were used accordingly. Results: Number of years of nursing experience tends to deteriorate the staff nurses’ knowledge on deconditioning management. Hospital affiliation is a significant factor that affects the knowledge of staff nurses on deconditioning management. Continuing education improves the knowledge of staff nurses on deconditioning management. Conclusion: Study suggests that it is important to establish gerontology continuing education programs with a core component on deconditioning treatment and prevention to enhance nurses’ knowledge on management of deconditioning so as to improve the care provided to older adults. Keywords: Continuing Education, Deconditioning Management, Gerontological Nursing, Gerontological Program, Staff Nurses and Older adults

    A numerical model to assess deconditioning of the cardiovascular system in long-term exposure to microgravity. Verification and simulation of Mars mission scenarios

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    Numerical simulations of the cardiovascular system are particularly important in scenarios where it is difficult to experiment different weightlessness exposure conditions. Technological advances in terms of computational power in the last years, and improvement of algorithms have recently made these techniques more reliable. We report in this paper results from extensive simulations undertaken in a computing facility in our University (UPC BarcelonaTech) aimed at evaluate the risks involved in a long-term exposure to reduced gravity loads for a very extensive range of possible mission scenarios. The simulation allows to introduce different levels of exposure to hypo or hypergravity, and analyze the consequences on relevant figures of cardiovascular deconditioning, such as heart rate, mean stroke volume or vascular resistance. Neurological or thermic stress or aerobic exercise can also be applied in order to better emulate a realistic long-term space mission comprising, for example, Extra Vehicular Activities (EVA) or physical exercise as countermeasures. Gender differences have also been studied, with significant different recommendations given as outcomes of the simulation, for both men and female astronauts. Our model is based on the previous works form Melchier et al. or Heldt et al. who described in analytical terms the process of orthostatic intolerance due to gravity alterations being applied on a human subject. We incorporated these Runge-Kutta equations by using Matlab® and Simulink® software. Results from these models were validated in parabolic flight. We later developed this model to take into account all control system parts involved in the human cardiovascular system, and we finally achieved an electrical-like control model in which we could easily measure the output of the system (vascular resistance, blood volume etc.) as a means to assess the level of cardiovascular deconditioning. Step-by-step changes of gravity and thermal stress were later applied, as well as other real-like mission inputs. Different scenarios of Moon and Mars exploration missions are considered, and their associated risks are quantified. The more relevant results are provided, including the finding that the vascular resistance deconditioning appears to be alike in both microgravity and the reduced gravity at the level of the Moon; which raises concerns for a successful manned Mars mission scenario. This work may contribute to a better understanding of the underlying processes involved for both women in man adaptation to long-term microgravity, and shows the potential of such numerical simulations for designing manned mission scenarios.Peer ReviewedPostprint (published version

    Monomorphic Ventricular Arrhythmias in Athletes.

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    Ventricular arrhythmias are challenging to manage in athletes with concern for an elevated risk of sudden cardiac death (SCD) during sports competition. Monomorphic ventricular arrhythmias (MMVA), while often benign in athletes with a structurally normal heart, are also associated with a unique subset of idiopathic and malignant substrates that must be clearly defined. A comprehensive evaluation for structural and/or electrical heart disease is required in order to exclude cardiac conditions that increase risk of SCD with exercise, such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Unique issues for physicians who manage this population include navigating athletes through the decision of whether they can safely continue their chosen sport. In the absence of structural heart disease, therapies such as radiofrequency catheter ablation are very effective for certain arrhythmias and may allow for return to competitive sports participation. In this comprehensive review, we summarise the recommendations for evaluating and managing athletes with MMVA
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