Shock Ventilation Research Articles

Energy-efficiency impacts of an air-quality feedback device in residential buildings: An agent-based modeling assessment

A key factor to energy-efficiency of heating in buildings is the behavior of households, in particular how they ventilate rooms. Energy demand can be reduced by behavioral change; devices can support this by giving feedback to consumers on their behavior. One such feedback device, called the ‘CO2 meter’, shows indoor air-quality in the colors of a traffic light to motivate so called ‘shock ventilation’, which is energy-efficient ventilation behavior. The following effects of the ‘CO2 meter’ are analyzed: (1) the effect of the device on ventilation behavior within households, (2) the diffusion of ‘CO2 meter’ to other households, and (3) the diffusion of changed behavior to households that do not adopt a ‘CO2 meter’. An agent-based model of these processes for the city of Bottrop (Germany) was developed using a variety of data sources. The model shows that the ‘CO2 meter’ would increase adoption of energy-efficient ventilation by c. 12% and reduce heating demand by c. 1% within 15 years. Technology diffusion was found to explain at least c. 54% of the estimated energy savings; behavior diffusion explains up to 46%. These findings indicate that the ‘CO2 meter’ is an interesting low-cost solution to increase the energy-efficiency in residential heating.

Therapeutic effects of hyperoxic ventilation during shock

SUMMARYDecreased availability of oxygen to metabolizing cells is a major feature of circulatory shock that leads to tissue damage and multiple organ dysfunctions. A wish to alleviate tissue hypoxia underlies the common clinical use of hyperoxic ventilation in shock. Yet, this straightforward approach is met by skepticism that is based on the potential pro‐inflammatory effects of hyperoxia and the acknowledged roles of reactive oxygen species and oxidative stress in tissue injury. A steadily growing body of experimental data indicates that hyperoxia exerts an extensive profile of physiologic and pharmacologic effects that improve tissue oxygenation, exert anti‐inflammatory and antibacterial effects, augment tissue repair mechanisms, and may also decrease oxidative stress during shock. The currently available preclinical information on the benefits of early use of safe regimens of hyperoxic ventilation alone or in combination with other commonly employed modalities sets the stage for renewal of careful clinical evaluation of oxygen therapy in resuscitation of circulatory shock.

Analysis of ventilation shock losses by finite element method

This paper presents an analysis of ventilation shock losses using the two-dimensional finite element method. It outlines the finite element formulation, in which the ventilation air flow is assumed to be a steady-state, viscous, incompressible and fully developed turbulent flow. In addition, the modified version of Van Driest model is assumed for the effective kinematic viscosity.

Diaphragmatic fatigue and blood flow distribution in shock.

Placing the respiratory muscles at rest in patients in shock has a strong theoretical and experimental basis, both to avoid the complication of respiratory failure and to improve the prognosis. From our studies we may conclude that early institution of mechanical ventilation in shock will reduce respiratory muscle activity, will reduce respiratory muscle oxygen requirements, will avoid muscle fatigue and respiratory failure, will increase blood flow and oxygen availability to essential organs, will decrease the severity of lactic acidosis which may be associated with an improved prognosis and will decrease the demand of the failing myocardium whose own blood and oxygen supply may be critically reduced.