Evaluation of continuous positive airway pressure ventilator based on advanced reduced instruction set computer processor

Abstract

Objective To design the continuous positive airway pressure(CPAP) ventilator based on advanced reduced instruction set computer (RISC) machines (ARM) processor for subsequent evaluation of the performance.Methods The performance of the newly designed CPAP ventilator,including the stability of pressure output,and gas leakage compensation and the effects on the work of breathing,was assessed in 4 healthy individuals for comparison to Drager RespiCare CV non-invasive ventilator as control.Results CPAP ventilator was successfuly designed.The levels of pressure output of the newly designed ventilator were adjustable within the range from 2 to 25 cm H2O (1 cm H2O=0.098 kPa) but slightly higher than that set previously.When CPAP levels were set at 4,8 and 12 cm H2O,in the newly designed ventilator the actual airway pressures were higher (all P＜0.05) than those measured by the control ventilator [(4.35±0.32) cm H2O vs (4.27±0.08) cm H2O； (9.65±0.12) cm H2O vs (8.04±0.02) cm H2O and (14.07±0.36)cm H2O vs (12.07±0.36) cm H2O,respectively].Gas leakage test revealed a more significant reduction in thc level of CPAP for the designed ventilator as compared to control ventilator [(2.41 ± 0.03) cm H2O vs (0.29±0.01) cm H2O,P＜0.05].The established ventilator also yielded a markedly higher work of breathing (all P＜0.05) than the control ventilator [(5.93±0.39) cm H2O/L vs (4.41 ±0.77) cm H2O/L； (6.81 ±0.51)cm H2O/L vs (2.16±0.12) cm H2O/L and (9.05±0.40) cm H2O/L vs (4.80±0.31) cm H2O/L] corresponding to the CPAP levels of 4,8 and 12 cm H2O respectively.Conclusion Although the prototype ventilator based on ARM processor results in higher levels of pressure output yet insufficient capacity to compensate for the pressure drop due to gas leakage and reduce the work of breathing,the data indicate that the performance merits the criteria of clinical practice. Key words: Non-invasive ventilation; Continuous positive airway pressure; Advanced reduced instruction set computer machines processor; Ventilator