The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

THE EFFECTS OF VARYING SET HUMIDIFIER TEMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE HUDSON RCI CONCHATHERM IV HEATED HUMIDIFIER.

Russell T. Reid, RRT, CPFT The Methodist Hospital, Houston, Texas and Mark Goldstein, RRT, Mercy 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 ConchaTherm IV heated humidification system. Methods: A ConchaTherm IV heated humidifier (Hudson RCI Model 400-00, Temecula, CA ** unit contained a recent software upgrade incorporated in all production units) equipped with a low compliance humidification chamber (Hudson RCI Model 780-32) and 72" dual heated wire circuit (Hudson RCI Model 382-30) was attached to a Hamilton Veolar (Reno, Nevada) mechanical ventilator. The mechanical ventilator was placed in the volume control mode with a square inspiratory flow wave form and set tidal volume of 1.0 liter. A heated humidity chamber (HC), 37.1 C° (± 2.2 C°), was constructed to accommodate the probe of a capacitance type digital hygrometer (Curtin-Matheson Scientific, Model # 244-355, Brisbane, CA). Inspiratory gas passed through the HC for relative humidity measurement. The heated wire controller was set for 0 C° temperature differential between the humidifier chamber and the proximal airway. A thermocouple thermometer (Baxter Inc., Duo Temp, Round Lake, IL) continuously displayed temperature from two areas within the ventilator circuit 1) adjacent to the Hudson RCI ConchaTherm IV humidifier chamber temperature probe and; 2) adjacent to the humidifier temperature probe on the inspiratory side of the patient wye. Stabilized, repeat measures were collected at 1 minute intervals until 5 measurements at each variation of temperature and set ventilator flow rate were complete. 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 < 0.05.

Set Ventilator Hygrometer Relative Absolute Humidity

Temperature Flowrate Temperature Humidity (mg H_{2}O/L±SD)

(C°) (L/min) (C° ±SD) (% ±SD)

32 40 31.57(±0.20) 95.49(±0.35) 31.56(±0.33)

34 40 33.61(±0.21) 92.48(±0.61) 34.14(±0.61)

36 40 35.01(±0.16) 96.93(±2.82) 38.39(±1.07)

38 40 37.03(±0.08) 100.0(±0.00) 44.08(±0.17)

32 60 31.66(±0.08) 93.88(±0.30) 31.25(±0.16)

34 60 33.21(±0.07) 98.08(±0.36) 35.41(±0.25)

36 60 35.10(±0.08) 100.0(±0.00) 39.73(±0.03)

38 60 36.31(±0.72) 100.0(±0.00) 42.50(±1.57)

32 80 31.38(±0.15) 95.45(±0.75) 31.31(±0.23)

34 80 33.26(±0.09) 98.80(±0.31) 35.77(±0.20)

36 80 35.37(±0.36) 100.0(±0.00) 40.21(±1.02)

38 80 36.28(±0.16) 100.0(±0.00) 42.48(±0.35)

32 100 31.36(±0.08) 95.81(±0.37) 31.34(±0.13)

34 100 33.25(±0.09) 99.03(±0.32) 35.80(±0.21)

36 100 35.30(±0.12) 100.0(±0.00) 39.79(±0.02)

38 100 36.97(±0.11) 100.0(±0.00) 43.69(±0.67)

Conclusion: The Hudson RCI ConchaTherm IV met the American National Standards Institute (ANSI) heated humidifier output standard of 30 mg H_{2}O/L under all test conditions.

OF-97-144

You are here: RCJournal.com » Past OPEN FORUM Abstracts » 1997 Abstracts » THE EFFECTS OF VARYING SET HUMIDIFIER TEMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE HUDSON RCI CONCHATHERM IV HEATED HUMIDIFIER.