Article Figures & Data
Figures
- Fig. 1.
Experimental setup. Pao = airway opening pressure. Palv = alveolar pressure. Ppl = pleural pressure.
- Fig. 2.
Definitions of studied variables. DT = inspiratory delay time. DT1 = the time from the onset of inspiration to the lowest airway opening pressure (Pao). DT2 = the time from the lowest Pao to the return to baseline. PTP = pressure-time-product from the area of Pao-time curve below baseline during DT. PTP1 = PTP during DT1. PTP2 = PTP during DT2. ΔPao inspiratory trigger pressure.
- Fig. 3.
Representative tracings of airway pressure-time curves. The dotted lines represent the shortest inspiratory-rise-time settings. The solid lines represent the longest inspiratory-rise-time settings. The ventilator settings were zero PEEP, pressure support 5 cm H2O, and tidal volume 300 mL. The triggering sensitivities were 4 L/min with the Evita XL and −2 cm H2O with the other ventilators.
- Fig. 4.
Effects of inspiratory rise time on pressure-time product (PTP, see text for definitions of PTP1 and PTP2), with the minimum, medium, and maximum inspiratory-rise-time settings. The inspiratory-rise-time scales differed among the tested ventilators. This figure shows the pooled results from all the modeled inspiratory efforts (300 mL, 500 mL, and 700 mL) and pressure-support levels of 5 cm H2O and 10 cm H2O.
- Fig. 5.
Combined effects of triggering sensitivity, pressure-support, and inspiratory-rise-time settings on pressure-time product. Worst = the combination of lowest triggering sensitivity, lowest pressure support (5 cm H2O), and slowest inspiratory rise time. TS = with the maximum triggering sensitivity setting. PS = with the maximum pressure-support setting (10 cm H2O). IRT = with the fastest inspiratory rise time. All = the combination of the highest triggering sensitivity, highest pressure support (10 cm H2O), and fastest inspiratory rise time. This figure shows the pooled results from all the inspiratory efforts (300 mL, 500 mL, and 700 mL).
- Fig. 6.
Effects of inspiratory rise time on inspiratory delay time (DT), with the minimum, medium, and maximum inspiratory rise times. This figure shows the pooled results for all the inspiratory efforts (300 mL, 500 mL, and 700 mL) and pressure-support levels of 5 cm H2O and 10 cm H2O.
- Fig. 7.
Combined effects of triggering sensitivity, pressure support and inspiratory rise time on inspiratory delay time (DT). Worst = the combination of lowest triggering sensitivity, lowest pressure support (5 cm H2O), and slowest inspiratory rise time. TS = with the maximum triggering sensitivity setting. PS = with the maximum pressure-support setting (10 cm H2O). IRT = with the fastest inspiratory rise time. All = the combination of the highest triggering sensitivity, highest pressure support (10 cm H2O), and fastest inspiratory rise time. This figure shows the pooled results from all the inspiratory efforts (300 mL, 500 mL, and 700 mL).
- Fig. 8.
Effects of inspiratory rise time on inspiratory trigger pressure, with the minimum, medium, and maximum inspiratory rise times. This figure shows the pooled results from all the inspiratory efforts (300 mL, 500 mL, and 700 mL) and pressure-support levels of 5 cm H2O and 10 cm H2O.
- Fig. 9.
Combined effects of triggering sensitivity, pressure-support level, and inspiratory rise time on inspiratory trigger pressure. Worst = the combination of lowest triggering sensitivity, lowest pressure support (5 cm H2O), and slowest inspiratory rise time. TS = with the maximum triggering sensitivity setting. PS = with the maximum pressure-support setting (10 cm H2O). IRT = with the fastest inspiratory rise time. All = the combination of the highest triggering sensitivity, highest pressure support (10 cm H2O), and fastest inspiratory rise time. This figure shows the pooled results from all the inspiratory efforts (300 mL, 500 mL, and 700 mL).
- Fig. 10.
Representative flow-time curves from the PB 840 with 3 combinations of pressure-support (PS) level and the inspiratory-rise-time setting. The increase in initial inspiratory flow was more remarkable with the shorter inspiratory rise time than with the higher pressure-support level.
