Artificial organs
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Comparative Study
Different low constant flows can equally determine the lower inflection point in acute respiratory distress syndrome patients.
Among the possible techniques to obtain the pressure-volume (P x V) curve at the bedside the low constant flow (CF) is the easiest and quickest one. However, the best value for CF to perform a good semi-static P x V curve is still to be determined. The purpose of this study was to evaluate the influence of 4 different CFs (1, 2, 5, and 10 L/min) on determination of lower inflection point of the P x V curve (L-Pflex) and upper inflection point of the P x V curve (U-Pflex) on the maximum slope and on the inspiratory work of breathing (up to volume of 1.35 L; inspiratory work L/cm H2O), comparing the volume estimated from the CF with the measured volume obtained by the respiratory inductive plethysmograph. ⋯ The inspiratory work did not increase with the increment of the flow either in the estimated volume (p = 0.217) or in the measured volume (p = 0.149). The U-Pflex differed among the trials (p = 0.003) and the methods used for its calculation (p < 0.01). Constant flows from 1 to 10 L/min can equally determine L-Pflex in ARDS patients and is an easy and quick way to obtain the L-Pflex in order to optimize positive end expiratory pressure (PEEP) in ARDS patients.