Critical care medicine
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Critical care medicine · Aug 1983
Static pressure-volume curves and effect of positive end-expiratory pressure on gas exchange in adult respiratory distress syndrome.
Fifteen patients with adult respiratory distress syndrome (ARDS) were studied: 11 in the early stage of ARDS (group 1); 4 in the late stage (group 2). The inspiratory and expiratory static pressure-volume (P-V) curves of the respiratory system were compared to the pulmonary shunt (Qsp/Qt) when PEEP was increased; cardiac output was kept constant. ⋯ Expiratory P-V curve can be used to determine: first, whether a patient should be ventilated with PEEP; second, the PEEP level which can be set on the respirator. In group 1 patients, when PEEP was set to a value corresponding to the inflexion point, i.e., the point of departure from the exponential shape (mean value 14.6 +/- 2.8 cm H2O), Qsp/Qt compared to zero PEEP was abruptly decreased to 87.6 +/- 6%; further increase in PEEP had little advantage.
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Critical care medicine · Aug 1983
Case ReportsDiagram for easy volume setting of an infant ventilator.
A pressure-volume diagram with isocompliance lines allows quick, accurate volume setting of the piston-driven infant ventilator Bourns LS. A line parallel with the machine compliance line and an intercept on the ordinate equal to the tidal volume, serves as a guideline for initial volume setting and subsequent adaptation according to the patient's lung compliance. This diagram is particularly useful when the lung compliance is low; changes consistently during controlled ventilation.