Evaluation by volunteers of respirator characteristics in modes used in non-invasive ventilation

Introduction

We studied the medical personnel's power of distinction various types of respirators in CPAP and CPAP+pressure support (PS) modes.

Materials and methods

Five blindfolded volunteers (2 ICU doctors and 3 nurses) performed random evaluation (5 point scale, -1 = best) of following respirators: Elema Siemens 300 (ES300), Adult Star 2000 (AS 2000) and Bird 8400 STi. All volunteers were comfortably seated and instructed to breathe freely with the respirator through the mouthpiece with the nostrils clipped. Pressure trigger was set at 1 cmH₂O in all respirators and in KS 900 flow trigger was also tested. After 1 min warm-up, 1 min breathing test was performed at the end of which volunteers were asked to classify their satisfaction with respirator. At first, 5 cmH₂O CPAP was tested at random in all four settings (three respirators, in ES 300 for both pressure and flow triggering) and thereafter the evaluation continued similarly with CPAP 5 cmH₂O + 10 cmH₂O pressure support. Data are presented as means ± SD, Kruskal-Wallis test was used for statistical analysis, P < 0.05 was considered significant.

Results

Individual scores and mean values ± SD are listed in Tables 1 and 2.

When CPAP and CPAP+PS were tested together significant differences were found within the group (P < 0.0.5). Generally, CPAP was better tolerated than CPAP+PS. ES 300 and AS 2000 yielded better results than Bird respirator.

Conclusion

ICU personnel may easily differentiate between characteristics of ICU respirators. Respirator with best characteristics may then be used for NIV and possibly also for difficult weaning.

Table 1. CPAP 5 cmH₂O

Table 2. CPAP 5 cm H₂ 0+PS 10 cmH₂ 0