The BathRC model: a method to estimate flow restrictor size for dual ventilation of dissimilar patients

Andrew R Plummer; Jonathan l du Bois; Siu Man Lee; Patrick Magee; Jens Roesner; Harinderjit S Gill

The different best-fit lines are generated by forcing one or more of the coefficients to zero. With C2=0, the function becomes linear. With C0=0 as well, the function becomes proportional, and it is this fit that is used, C1 being the resistance value. In both cases there are clear errors caused by assuming flow and pressure are proportional. The characteristic for the non-return valve is nearly linear, but there is a cracking pressure of about 1 cmH20. The adjustable valve has a pressure drop which is proportional to the square of the flow. The significance of the linear resistance approximation will be can be judged in Section 4. Resistance, cmH20/(L/s) Compliance, L/(cmH20), Test lung 1 (R, C) 12 0.040 Test lung 2(R, C) 12 0.030 Ventilator tubing system (Rv, Cv) 22 0.004 Fixed flow restrictor (Rr) 12 -Adjustable* flow restrictor (Rr) 33 -*Note: only used in at one setting in these tests (position 1) Figure 7 . Flow restrictor testing All rights reserved. No reuse allowed without permission. the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.