Central Hypovolemia Detection During Environmental Stress—A Role for Artificial Intelligence?

The first step to exercise is preceded by the required assumption of the upright body position, which itself involves physical activity. The gravitational displacement of blood from the chest to the lower parts of the body elicits a fall in central blood volume (CBV), which corresponds to the fraction of thoracic blood volume directly available to the left ventricle. The reduction in CBV and stroke volume (SV) in response to postural stress, post-exercise, or to blood loss results in reduced left ventricular filling, which may manifest as orthostatic intolerance. When termination of exercise removes the leg muscle pump function, CBV is no longer maintained. The resulting imbalance between a reduced cardiac output (CO) and a still enhanced peripheral vascular conductance may provoke post-exercise hypotension (PEH). Instruments that quantify CBV are not readily available and to express which magnitude of the CBV in a healthy subject should remains difficult. In the physiological laboratory, the CBV can be modified by making use of postural stressors, such as lower body “negative” or sub-atmospheric pressure (LBNP) or passive head-up tilt (HUT), while quantifying relevant biomedical parameters of blood flow and oxygenation. Several approaches, such as wearable sensors and advanced machine-learning techniques, have been followed in an attempt to improve methodologies for better prediction of outcomes and to guide treatment in civil patients and on the battlefield. In the recent decade, efforts have been made to develop algorithms and apply artificial intelligence (AI) in the field of hemodynamic monitoring. Advances in quantifying and monitoring CBV during environmental stress from exercise to hemorrhage and understanding the analogy between postural stress and central hypovolemia during anesthesia offer great relevance for healthy subjects and clinical populations.

Epidemiology of Musculoskeletal Disorders in Musicians - Systematic Review

Musicians performing over an instrument demands repetitive, awkward postures and postural stress from prolonged sitting or standing. Musicians are found to be more prone to the development of Playing-Related Musculoskeletal Disorders (PRMDs) due to these factors. PRMDs are defined as ‘pain, weakness, numbness, tingling or other symptoms that interfere with their ability to play an instrument’. There is an increasing interest seen in the medical issues faced by the musicians performing over an instrument. There are different type of musicians playing different instruments which means different instrumentalists face different musculoskeletal disorders depending upon many factors. There are intrinsic and extrinsic factors involved which contribute to the development of PRMDs in musicians. Development of PRMDs is seen to be a cause of early termination of musician’s career. The purpose of study is to review the epidemiology of musculoskeletal disorders in musicians. Key words: Musculoskeletal disorders, Musculoskeletal problems, Prevalence of musculoskeletal injuries, Postural disorders, Playing-related strain in instrumentalists and musicians.

A DESCRIPTIVE STUDY ON THE RELATIONSHIP BETWEEN BODY MASS INDEX AND BODY POSTURE IN CLINICIANS

BACKGROUND : Clinicians in the today's world are always under sustained levels of physical exertion. As they form backbone of healthcare setup, the health of clinicians themselves is a very signicant factor towards providing good health to all. AIMS & OBJECTIVES - The objective of the study was to determine the relation of body mass index (BMI) on both static standing as well as dynamic sitting body posture in clinicians. This will establish a relation between obesity and postural stress of clinicians METHODS: The descriptive study was conducted in OPD clinics of our medical college and various private hospitals of Jalandhar. BMI was calculated as ratio of weight (kg) to the square of height (m). Standing posture was assessed with the help of plumb bob passing the line in lateral and posterior aspect of the body nding the correct (YES) or faulty (NO) posture taken for the calculation. Dynamic (work sitting) posture was checked with observation during the OPD work by using the RULA (Rapid Upper Limb Assessment) worksheet. All the values obtained were statistically analysed with Chi square test to determine association. RESULTS: In high BMI group, three-fourths of the clinicians were found to have faulty standing static posture and 79% had faulty dynamic work posture whereas normal BMI group had minimum faulty posture. Female clinicians showed more level of faulty posture than male clinicians. The results also show that with increase in BMI, faulty posture also takes a higher turn. CONCLUSION: BMI is positively related to postural stress in clinicians, especially in the higher age group. This information serves as an awareness and warning signal for the clinicians to safeguard their own health and correct their faulty posture

Assessment tools analysis of work-related musculoskeletal disorders: strengths and limitations

Musculoskeletal disorders are one of the most common occupational diseases, affecting millions of workers in the European Union and costing employers billions of euros. Researching the relationships and possibilities of optimal mutual adaptation, under given conditions, both of human to his work and of work to humans, in order to increase the technical-economic efficiency, to optimize the conditions of satisfaction, motivation and work results, while maintaining the worker’s state of health also involves, as a basic stage, the assessment of the risks of osteomuscular-articular overload. Starting from a statistical synthesis on the incidence of MSD and the characteristic types of demands, the paper systematizes in a unitary vision the categories of methods, techniques and tools available for recording and evaluating the factors of physical and postural stress of workers. The pointed description of three of the most commonly applied ergonomic risk assessment tools, aimed at developing a synthesis of Strengths-Weaknesses type, which highlights the advantages of methods in counterbalance with their limitations, providing a first basis for selection in order to apply them in the practice of companies that are aware that investing in safety means investing in profit and not losing financial resources and implicitly human, material ones.

Preload stress echocardiography by using dynamic postural alteration can identify high risk patients with heart failure with reduced ejection fraction

Funding Acknowledgements Type of funding sources: None. Background Haemodynamic assessment during stress testing is not commonly performed for patients with heart failure with reduced ejection fraction (HFrEF) due to its invasiveness, less feasibility, and safety concerns. Passive leg-lifting (PLL) manoeuvres have been introduced as a simple alternative for non-invasive preload stress testing; however, the haemodynamic load imposed on the cardiovascular system is unsatisfactory, which precludes the accurate assessment of the preload reserve for patients with HF. Purpose The purpose of this study was to assess the haemodynamic characteristics of patients with HFrEF in response to a preload stress during dynamic postural alterations by combining the semi-sitting position (SSP) and PLL. We also evaluated whether combined postural stress could be used for risk stratification for these patients. Methods For this study, 101 patients with HFrEF and 35 age- and sex-matched normal controls were prospectively recruited. At each postural position (i.e., baseline, SSP, and PLL), all standard echocardiographic and Doppler variables were obtained. Adverse cardiac events were prespecified as the combined endpoints of death from or hospitalisation for deteriorated HF, or sudden cardiac death. Clinical follow-up was conducted for a median of 7 months. Results During PLL stress, the stroke volume index (SVi) significantly increased in both controls (from 40 ± 6 to 43 ± 6 mL/m², P = 0.03) and HFrEF patients (from 31 ± 9 to 34 ± 10 mL/m², P = 0.03). Conversely, during SSP stress, the SVi significantly decreased for both controls (from 40 ± 6 to 37 ± 6 mL/m², P = 0.03) and HFrEF patients (31 ± 9 to 28 ± 8 mL/m², P = 0.03). During the follow-up period, 16 patients developed cardiac events. In patients without events, the Frank-Starling mechanism was well preserved (Fig. A). Namely, the SVi significantly increased from 31 ± 9 to 35 ± 10 mL/m² (P = 0.02) during PLL stress, while the SVi significantly decreased from 31 ± 8 to 28 ± 8 mL/m² (P = 0.02) during SSP stress. In contrast, for patients with cardiac events, the SVi did not change during postural alterations (n.s), which indicated that the failing heart operates on the flat portion of the Frank-Starling curve (Fig. A). When patients were divided into three equal sub-groups based on the total difference in the SVi during dynamic postural stress, patients with impaired preload reserve (third trimester, ΔSVi ≤ 3.0 mL/m²) showed significantly worse event-free survival than the other two sub-groups (Fig. B; P < 0.001). In a Cox proportional-hazard analysis, baseline LVEF (hazard ratio 0.93; P = 0.04), and ΔSVi during postural stress (hazard ratio 0.76; P = 0.004) were predictors of future cardiac events. Conclusions The combined assessment of dynamic postural stress during PLL and SPP is a simple, time-saving, and easy-to-use clinical tool for the assessment of preload reserve for patients with HFrEF. Moreover, postural stress echocardiography proved to contribute to the risk stratification for these patients. Abstract Figure.

Evaluating Postural Risk Level of Digitally Represented Workplace: Analyzing Postural Possibilities

Eliminating awkward and stressful working postures through the ergonomics workplace design is important in preventing work-related musculoskeletal disorders. However, effective design tools are currently lacking. Different postural analysis tools have been proposed to help evaluate workplaces in the level of postural stresses experienced by the workers, but they are not capable of supporting the proactive ergonomics in design. In an effort to address the problem, this study presents a novel memory-based workplace evaluation (MBWE) model. When given an input scenario expressed in terms of the worker anthropometric characteristics, the task requirement, and the geometric descriptions of the to-be-evaluated workplace design, the model computes the range of feasible working postures for the scenario, determines their postural stress levels, and presents a report on the overall postural risk level of the input scenario. The MBWE model combines the memory-based posture planning (MBPP) model and the Ovako working posture analysis (OWAS) method.

Lower-limb venous distension reflex and orthostatic tolerance in young healthy humans

Earlier reports suggest that limb venous distension evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) (i.e., venous distension reflex). Our recent report also shows that suction of arterially occluded limb evokes venous distension reflex. We postulate that the venous distension reflex contributes to autonomic responses to orthostatic stress. In this study, we hypothesized that orthostatic tolerance would be linked to the MSNA response seen with lower limb suction. Fifteen healthy subjects were tested in the supine position. Negative pressure (−100 mmHg) was applied on an arterially occluded lower limb for 2 min. MSNA from the peroneal nerve in the limb not exposed to suction, ECG, and BP (Finometer) was recorded throughout the study. Limb occlusion without suction was used as a control trial. In a separate visit, the individual’s orthostatic tolerance was assessed using a graded lower body negative pressure (LBNP) tolerance test. Mean arterial BP and MSNA (18.6 ± 1.9 to 23.6 ± 2.0 bursts/min) significantly (both P < 0.05) increased during limb suction. Orthostatic tolerance index positively correlated ( R = 0.636, P = 0.011) with the MSNA response seen with suction during occlusion. Since the venous distension reflex strength correlates with the level of orthostatic tolerance, we speculate that lower-limb venous distension reflex engagement increases the sympathetic responses during orthostatic challenge and serves to maintain BP with postural stress.