[1996][Open Forum Abstract]THE EFFECTS OF HUMIDIFIER TEMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE FISCHER & PAYKEL MR-730 HUMIDIFICATION SYSTEM USING TWO HUMIDIFICATION CHAMBERS
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 F&P (Auckland, New Zealand) MR-730 heated humidification system using two different humidification chambers.
Methods: A F&P MR-730 heated humidifier equipped with either a F&P MR-390 or MR-290 humidifcation chamber and Isothermal 72" heated wire circuit (Valencia, CA Model 1704-HO7) 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), 37.7 C° (±1.8 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 Vent Hygrometer Hygrometer Absolute Absolute
Temp Flow Temp Temp Humidity Humidity
(Cº) Rate MR-390 MR-290 MR-390 MR-290
(L/min) (C/±SD) (C/±SD) (mg H2O/L ±SD) (mg H2O/L ±SD)
32 40 31.73(± 0.03) 31.99(± 0.07) 18.23(± 0.24)? 33.94(± 0.14)
34 40 33.19(± 0.31) 32.61(± 0.10) 33.37(± 0.42) 35.08(± 0.20)
36 40 34.68(± 0.15) 34.59(± 0.21) 34.93(± 0.41) 38.85(± 0.53)
38 40 36.22(± 0.75) 36.11(± 0.06) 38.92(± 1.65) 40.66(± 1.15)
32 60 31.64(± 0.04) 31.96(± 0.02) 19.35(± 0.17)? 33.79(± 0.00)
34 60 33.03(± 0.05) 32.85(± 0.10) 34.15(± 0.36) 35.48(± 0.00)
36 60 35.04(± 0.03) 34.76(± 0.12) 36.06(± 0.11) 39.13(± 0.35)
38 60 37.07(± 0.02) 35.94(± 0.05) 41.63(± 0.09) 42.05(± 0.00)
32 80 31.55(± 0.05) 31.72(± 0.18) 20.94(± 0.24)? 33.39(± 0.33)
34 80 33.07(± 0.04) 32.77(± 0.06) 33.43(± 0.16) 35.37(± 0.12)
36 80 34.80(± 0.41) 34.74(± 0.07) 37.32(± 0.66) 39.07(± 0.13)
38 80 37.00(± 0.59) 36.06(± 0.03) 41.85(± 1.29) 42.05(± 0.00)
32 100 31.41(± 0.10) 31.53(± 0.16) 26.59(± 0.41)? 33.10(± 0.27)
34 100 32.96(± 0.06) 32.43(± 0.26) 33.77(± 0.26) 34.72(± 0.57)
36 100 35.10(± 0.01) 34.77(± 0.05) 38.22(± 0.12) 39.24(± 0.33)
38 100 36.31(± 0.37) 35.95(± 0.47) 41.28(± 0.50) 41.41(± 1.21)
?-Did not meet the ANSI standards for heated humidification. Conclusion: The F&P MR-390 humidification chamber failed to meet the American National Standards Institute standard for heated humidifiers of 30 mg H2O/L for all flow rates at 32 C°
Reference: OF-96-092
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