The Science Journal of the American Association for Respiratory Care

1996 OPEN FORUM Abstracts

THE EFFECTS OF VARYING SET HUMIDIFIER TAMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE HUDSON/RCI CONCHA IV

Russell T. Reid, RRT CPFT, and Mark Goldstein, RRT. Mercy American River/San Juan Hospital, Carmichael, California

This study examined the effect of varying ventilator flow rate and set humidifier temperature on the relative humidity delivered by the Hudson/RCI (Temecula, CA) Concha IV heated humidification system. Methods: A Hudson Concha IV heated humidifier equipped with a low compressible volume chamber (Hudson/RCI Model 385-30) and 72" heated wire circuit (Hudson/RCI Model 780-32) was attached to a Hamilton Veolar (Reno, NV) mechanical ventilator. The volume control mode with a square inspiratory flow wave form was used. A heated humidity chamber (HC), 37.3 C°(±2.1 C/), was constructed to accommodate the probe of a capacitance type digital hygrometer (CM Scientific, Brisbane, CA, Model #244-355) with integral thermistor. Inspiratory gas passed through the HC for relative humidity measurement. The heated wire controller was set for 0 C° differential. Five repeat, stabilized measures, were collected at 1 minute intervals at all combinations of flow rate and temperature. Prior to testing, all equipment was calibrated to the manufacturer's specifications. Results: Data was analyzed using Analysis of Variance (ANOVA). Statistical significance existed within and between all groups p < 0.001.

Set Ventilator Hygrometer Relative Humidity Absolute Humidity

Temp Flow Rate Temperature (% ± SD) (mg H2O/L ± SD)

(Cº) (L/min) (Cº ±SD)

32 40 30.62(±0.05) 30.45(±0.46) 9.56(±0.16)?

34 40 33.37(±0.20) 68.12(±0.88) 29.40(10.37)?

36 40 33.77(±0.06) 82.39(±0.68) 30.72(±0.21)

38 40 37.71(±0.28) 90.81(±0.36) 41.41(±0.67)

32 60 31.21(±0.23) 36.95(±1.22) 12.02(±0.32)?

34 60 33.56(±0.03) 73.18(±0.35) 26.97(±0.18) ?

36 60 35.24(±0.04) 82.22(±0.43) 35.33(±0.75)

38 60 37.36(±0.18) 99.88(±0.26) 44.79(±0.46)

32 80 31.27(±0.15) 41.46(±0.43) 13.51(±0.15)?

34 80 33.31(±0.18) 82.22(±4.46) 29.90(±1.46)?

36 80 35.33(±0.75) 84.83(±0.20) 34.62(±1.96)

38 80 35.45(±2.70) 100.00(±0.0) 40.90(±5.56)

32 100 31.54(±0.14) 43.52(±0.29) 14.39(±0.21)?

34 100 33.03(±0.41) 80.25(±0.22) 28.72(±0.56)?

36 100 35.37(±0.09) 87.30(±0.54) 35.36(±1.05)

38 100 37.28(±0.18) 100.00(±0.0) 44.58(±0.42)

?- Unable to meet the ANSI Standards for heated humidification.

Conclusion: The Hudson RCI Concha IV was unable to meet the American National Standards Institute (ANSI) standards for heated humidification with any of the four flowrate combinations at set temperatures of 32 C° and 34 C°

Reference: OF-96-091

You are here: RCJournal.com » Past OPEN FORUM Abstracts » 1996 Abstracts » THE EFFECTS OF VARYING SET HUMIDIFIER TAMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE HUDSON/RCI CONCHA IV