Articles: ventilators.
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Critical care medicine · Mar 1983
Pressure-time relationships of pressure-limited neonatal ventilators.
A pressure-limited ventilator (Bourns BP-200, Anaheim, CA) and a simple, manually operated constant flow ventilator were studied using a commercially available infant lung simulator (Bourns LS-130, Anaheim, CA). The characteristics of inspiratory pressure-time relationships during ventilation with these ventilators were analyzed. ⋯ Qualitatively similar tracings were obtained with the BP-200 during normal ventilation, with simulated airway obstruction and thoracic restriction. These findings suggest that monitoring pressure-time relationships may be useful in the qualitative assessment of resistance and compliance during pressure-limited ventilation of neonates.
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One hundred seventy-one patients admitted to a Medical ICU and who received treatment for respiratory failure with mechanical ventilation were studied for the development of pulmonary barotrauma (PBT) as manifested by pneumomediastinum, subcutaneous emphysema, or pneumothorax. Fourteen patients (8%; group A) developed this complication; they were younger, had higher maximal peak inspiratory airway pressures (PIP); and higher levels of maximal PEEP. We conclude that for medical patients treated for respiratory failure with mechanical ventilation, the incidence of PBT is 8% and that younger age, higher levels of PIP and PEEP seem to pose an increased risk for developing PBT.
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Am. Rev. Respir. Dis. · Dec 1982
Case ReportsDynamic hyperinflation and ventilator dependence in chronic obstructive pulmonary disease.
In advanced chronic obstructive pulmonary diseases, functional residual capacity (FRC) can be markedly increased by dynamic mechanisms involving expiratory flow limitation. We studied respiratory mechanics in a seated ventilator-dependent patient with such changes. Relaxed expiration was flow-limited; pressures of 9 to 27 cm H2O (varying with lung volume) could be applied to the airway opening (Pao) without decreasing expiratory flow rate. ⋯ More importantly, recoil pressures at end inspiration and end expiration, respectively, were 6.5 and 1.5 cm H2O for the lung, 33 and 11 cm H2O for chest wall, and 38 and 12 cm H2O for the respiratory system. Thus the chest wall recoiled inward at all times, pleural pressure was always substantially positive (11 to 33 cm H2O), expiratory flow was maximal, and jugular veins were always full and nonpulsating. Inspiratory work was about 0.27 kg-m per breath (7 times normal), most of it elastic work done on the chest wall.
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Review Comparative Study Historical Article
Ventilation and ventilators.
The history of ventilation is reviewed briefly and recent developments in techniques of ventilation are discussed. Operating features of ventilators have changed in the past few years, partly as the result of clinical progress; yet, technology appears to have outstripped the clinician's ability to harness it most effectively. ⋯ Ergonomics of ventilators and their controls and the provision of alarms need special attention. Microprocessors are likely to feature prominently in the next generation of designs.