An airway resistance for use in an artificial lung

Abstract

An airway resistance for use in an artificial lung was constructed, using stainless steel woven wire gauzes firmly held in an expanded part of the air stream. Pressure differences across the resistance were measured over a wide range of flow rates and the mathematical relationship between resistance and air flow rate determined with the aid of a computer. At flow rates between 0 and 2 l./sec, the resistance remained within 5 per cent of the selected value of 5 cm H2O/l./sec. Changes in temperature appreciably affected the viscosity of air and, as a result, changes in resistance were found to be approximately 0.6%/°C. It is, therefore, essential to maintain the temperature of a resistance at the appropriate level in order to obtain a constant, known value. © 1972 John Sherratt and Son Ltd.