A bench evaluation of fraction of oxygen in air delivery and tidal volume accuracy in home care ventilators available for hospital use

Abstract

Background: Turbine-powered ventilators are not only designed for long-term ventilation at home but also for hospital use. It is important to verify their capabilities in delivering fraction of oxygen in air (F_IO₂) and tidal volume (V_T).

Methods: We assessed the F_IO₂ accuracy and the V_T delivery in four home care ventilators (HCV) on the bench. The four HCV were Astral 150, Elisée 150, Monnal T50 and Trilogy 200 HCV, which were connected to a lung model (ASL 5000). For assessing F_IO₂ accuracy, lung model was set to mimic an obstructive lung and HCV were set in volume controlled mode (VC). They supplied with air, 3 or 15 L/min oxygen and F_IO₂ was measured by using a ventilator tester (Citrex H4^TM). For the V_T accuracy, the lung model was set in a way to mimic three adult configurations (normal, obstructive, or restrictive respiratory disorder) and one pediatric configuration. Each HCV was set in VC. Two V_T (300 and 500 mL) in adult lung configuration and one 50 mL V_T in pediatric lung configuration, at two positive end expiratory pressures 5 and 10 cmH₂O, were tested. V_T accuracy was measured as volume error (the relative difference between set and measured V_T). Statistical analysis was performed by suing one-factor ANOVA with a Bonferroni correction for multiple tests.

Results: For Astral 150, Elisée 150, Monnal T50 and Trilogy 200, F_IO₂ averaged 99.2%, 93.7%, 86.3%, and 62.1%, respectively, at 15 L/min oxygen supplementation rate (P<0.001). Volume error was 0.5%±0%, -38%±0%, -9%±0%, -29%±0% and -36%±0% for pediatric lung condition (P<0.001). In adult lung configurations, Monnal T50 systematically over delivered V_T and Trilogy 150 was sensitive to lung configuration when V_T was set to 300 mL at either positive end-expiratory pressure (PEEP).

Conclusions: HCV are different in terms of F_IO₂ efficiency and V_T delivery.

Keywords: Home care ventilators (HCV); fraction of oxygen in air (FIO2); intermediate care; life support; tidal volume (VT).

Figure 1

Schematic drawing of the measurement set-up with settings of ASL 5000 lung model and conditions tested. The symbols indicate inspiratory and expiratory valves. C, compliance in mL/cmH₂O; R, resistance in cmH₂O/L/s; i, inspiration; e, expiration; F_IO₂, fraction of oxygen in air; VT, tidal volume; PEEP, positive end-expiratory pressure.

Figure 2

Tracing of fraction of oxygen in air (F_IO₂) over time at three rates of oxygen supplementation with the Elisée 150 ventilator. Arrows indicate the time at which the rate of oxygen supplementation was changed.

Figure 3

Values for the percentage error in tidal volume (V_T) delivery for V_T set to 300 and 500 mL across all ventilators for normal, obstructive and restrictive lung at both 5 and 10 cmH₂O positive end-expiratory pressure (PEEP). Rectangles are the mean. Horizontal bars are standard deviations if greater than mean. White rectangles Astral 150, crossed-marked rectangles Elisée 150, grey rectangles Monnal 50 and hatched Trilogy 200 ventilator.

Figure 4

Values of percentage error in tidal volume (V_T) delivery for V_T set to 50 mL across all ventilators for pediatric condition at both 5 and 10 cmH₂O positive end-expiratory pressure (PEEP). Rectangles are the mean. Horizontal bars are standard deviations if greater than mean. White rectangles Astral 150, crossed-marked rectangles Elisée 150, and grey rectangles Monnal 50 and hatched Trilogy 200 ventilator. *, P<0.05 vs. Elisée; ^†, P<0.05 vs. Monnal; ^‡, P<0.05 vs. Trilogy.