The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

THE EFFECTS OF VARYING SET HUMIDIFIER TEMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE MARQUEST SCT 3000 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 Marquest SCT 3000 heated humidification system. Methods: A Marquest SCT-3000 heated humidifier (Englewood, CO) equipped with a high flow humidification chamber (Marquest Model 541030, Englewood, CO) and 72" inspiratory heated wire circuit (Marquest Model 157610, Englewood, CO) was attached to a Hamilton Veolar (Reno, NV) mechanical ventilator. The mechanical ventilator was placed in the volume control mode with a square inspiratory flow wave form and a tidal volume of 1.0 L. A heated humidity chamber (HC), 37.0 C[infinity], (± 2.58) 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[infinity] 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 Marquest SCT-3000 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 < 0.0001.

Set Temperature Flow Hygrometer

(C[infinity]) (L/min) Temperature

(C[infinity] ±SD)

32 40 30.06 (±0.08)

34 40 31.49 (±0.09)

36 40 32.90 (±0.06)

38 40 34.42 (±0.05)

32 60 31.49 (±0.06)

34 60 31.53 (±0.09)

36 60 33.40 (±0.06)

38 60 34.42 (±0.23)

32 80 31.36 (±0.07)

34 80 31.52 (±0.06)

36 80 33.50 (±0.06)

38 80 34.60 (±0.04)

32 100 31.39 (±0.02)

34 100 31.60 (±0.05)

36 100 33.57 (±0.03)

38 100 34.57 (±0.09)

Set Temperature Relative Absolute

(C[infinity]) Humidity Humidity

(% ±SD) (mg H_{2}O/L ±SD)

32 87.52 (±0.29) 27.50 (±0.16) *

34 90.70 (±0.57) 29.93 (±0.57) *

36 80.41 (±0.25) 28.57 (±0.17) *

38 86.74 (±0.54) 33.39 (±0.30)

32 84.72 (±0.45) 27.92 (±0.16) *

34 91.06 (±0.42) 30.09 (±0.57)

36 82.15 (±0.24) 30.06 (±0.24)

38 88.13 (±0.07) 33.93 (±0.43)

32 86.28 (±0.25) 28.27 (±0.16) *

34 91.07 (±0.45) 30.05 (±0.13)

36 84.12 (±0.11) 30.91 (±0.12)

38 89.31 (±0.15) 34.74 (±0.11)

32 87.84 (±0.50) 28.82 (±0.16) *

34 91.60 (±0.09) 30.40 (±0.11)

36 84.37 (±0.40) 31.14 (±0.15)

38 90.65 (±0.18) 35.16 (±0.14)

* - Failed to meet ANSI Standards

Conclusion: The Marquest SCT-3000 humidifier failed to meet the American National Standards Institute (ANSI) heated humidifier output standard of 30 mg H_{2}O/L for 6 of the conditions tested.

The 44th International Respiratory Congress Abstracts-On-Disk®, November 7 - 10, 1998, Atlanta, Georgia.

You are here: RCJournal.com » Past OPEN FORUM Abstracts » 1998 Abstracts » THE EFFECTS OF VARYING SET HUMIDIFIER TEMPERATURE AND VENTILATOR FLOW RATE ON THE RELATIVE HUMIDITY DELIVERED BY THE MARQUEST SCT 3000 HEATED HUMIDIFIER.