Figure 3 : Univariate regression modelling estimates of pressure for each length of tubing for flow rates up to 20 L/min.

Solid lines and data points are experimental measures. Dotted lines are linear regression modelling for each experimental length of tubing. Recommended therapeutic PEP range of 10 cm H2O to 20 cm H20 and physiological flow rate range is shown. PEP, positive expiratory pressure; cm H20, centimetres of water pressure; L/min, litres per minute; mm, millimetres; cm, centimetres.

Boden et al.Pulmonology and Respiratory Research  2017 5:1DOI : 10.7243/2053-6739-5-1