Journal of critical care
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Recent advances in the field of molecular biology have revolutionized our understanding of the functioning of living organisms and facilitated the development of robust tools for both diagnosis and treatment of diseases. With particular reference to the field of critical care medicine, development of molecular biology techniques have aided in the following: (1) rapid and highly specific detection of pathogenic infectious agents (eg, Mycobacterium tuberculosis, Pneumocystis carinii, cytomegalovirus, Legionella); (2) development of assays for measurement of circulating cytokines such as tumor necrosis factor (TNF) and interleukin (IL)-1 that has helped our understanding of the pathogenesis of the sepsis syndrome; (3) administration of antibodies or soluble receptors to attempt to prevent untoward effects of cytokines such as TNF or IL-1; and (4) the administration of recombinant deoxyribonucleic acid (DNA) or proteins to patients in an attempt to alter the course of a disease such as antioxidant enzymes (superoxide dismutase). The rapidity of progress in this field has been staggering, which necessitates frequent updating of our knowledge for clinicians to put these molecular tools to their best use. This brief review attempts to explain the basic principles of commonly used techniques in molecular biology including recombinant DNA, polymerase chain reaction, DNA libraries, gene therapy, and protein biochemistry in a manner that is understandable to those without an in-depth knowledge of the field.
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Journal of critical care · Sep 1995
Inspiratory tidal volume sparing effects of tracheal gas insufflation in dogs with oleic acid-induced lung injury.
Tracheal gas insufflation (TGI) improves the efficiency of conventional mechanical ventilation (CMV) by reducing the series dead space of the airways. Consequently, application of TGI as an adjunct to CMV may permit reducing tidal volume (VT) while limiting CO2 retention. We tested the extent to which panexpiratory TGI allows reduction of VT while maintaining PaCO2 constant in an oleic acid-induced lung injury model. ⋯ We conclude that TGI can be a useful adjunct to CMV during acute lung injury to limit VT while avoiding CO2 retention.
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Journal of critical care · Sep 1995
Randomized Controlled Trial Clinical TrialContinuous oscillation: outcome in critically ill patients.
To compare turning by an oscillating bed to standard 2-hour turning. Outcomes were survival, length of stay (LOS), duration of mechanical ventilation, and incidence of pneumonia. ⋯ In selected critically ill patients oscillating therapy may improve survival and improve airway clearance. The frequency and degree of turning needed to prevent complications and improve outcome remains unclear. These newer beds should be used with discrimination so as to not increase hospital costs unnecessarily.
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The high mortality associated with sepsis syndrome and multiple organ dysfunction syndrome has persisted despite extraordinary research efforts in the laboratory and the intensive care unit. These syndromes produce systemic tissue damage that is likely to result from widespread inflammation and subsequent endothelial injury. ⋯ As a result of systemic inflammation and nonmetabolic oxygen use, oxidative stress may occur both outside and inside the cell. The consequences of these oxidative processes during sepsis may be ongoing cell damage mediated by reactive oxygen and nitrogen oxide species that culminates in multisystem organ failure.
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Journal of critical care · Sep 1995
Distinct behavior of portal venous and arterial vascular waterfalls in porcine liver.
Hepatic dysfunction is associated with morbidity and mortality in critically ill patients. Understanding liver hemodynamics in pathological states requires characterization of the normal portal venous and hepatic arterial circulations. Using pressure flow analysis, we tested the hypothesis that vascular waterfalls determine blood flows in the normal liver. ⋯ Both critical closing pressures and incremental resistances showed markedly different responses to increased outflow pressures in the portal venous and hepatic arterial circulations. The results provide the physiological basis to analyze hemodynamic changes in the liver under normal and pathological conditions.