Critical care medicine
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Critical care medicine · Nov 1989
Prediction of arterial oxygen partial pressure from intrapulmonary venous admixture.
A short program was developed to predict the PaO2 at a given FIO2 by using arterial and mixed venous blood gas data obtained at an FIO2 of 1.0. Our program resolves Adair's equation and the shunt equation inversely, on the assumption that intrapulmonary venous admixture and the arteriovenous oxygen content difference remain constant during the study. ⋯ The PaO2 values were predicted more accurately by our program than those calculated by PaO2/PaO2. Because our program is simple enough to be carried out with a pocket computer, it may be helpful in a bedside decision of lowering FIO2, especially in patients who require a high FIO2 level to maintain sufficient arterial oxygenation.
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Critical care medicine · Nov 1989
Case Reports Comparative Study Clinical Trial Controlled Clinical TrialProspective evaluation of combined high-frequency ventilation in post-traumatic patients with adult respiratory distress syndrome refractory to optimized conventional ventilatory management.
This study explores the value of combined high-frequency ventilation (CHFV) in a prospective clinical trial of 35 patients suffering from severe post-traumatic and/or septic adult respiratory distress syndrome (ARDS) who were refractory to conventional controlled mechanical ventilatory (CMV) support. The severity of ARDS was quantified by lung mechanics and gas exchange variables and the patients were classified on clinical grounds as well as on the basis of their respiratory index/pulmonary shunt relationship [RI/(Qsp/Qt)]. During the same time period as the CHFV study, data from these patients were compared to those from 88 ARDS patients who had quantitatively similar degrees of respiratory insufficiency, but who were treated only with controlled mechanical ventilation (CMV). ⋯ In surviving ARDS patients treated with CHFV, an improvement in blood gases at reduced FIO2, without decreased cardiac output, was produced. The CHFV technique was used for less than or equal to 25 days and resulted in 23% survival of patients who were clinically and physiologically indistinguishable from the patients in the ARDS nonsurvivor group who were treated by CMV only. In surviving CHFV patients the decrease in Paw permitted a sustained, or increased, cardiac output with a rise in the oxygen delivery/oxygen consumption ratio, thus allowing for a higher PaO2 for any given level of pulmonary shunt.