The Resistance of Endotracheal Connectors

Resistance to Airflow in Anaesthetic Breathing Systems

“…The resistance to airflow of the components of breathing systems have been examined previously. Tracheal tubes and their connectors have been studied by a number of authors [1,2] and expiratory valves by others [3,4]. Smith [5] examined the resistance of the Magill system for both separate and assembled components.…”

Change in the Work of Breathing Imposed by Five Anaesthetic Breathing Systems

“…Although various anaesthetic breathing systems have been examined to determine whether or not they permit rebreathing, the extra amount of work imposed by an anaesthetic system, on a patient breathing spontaneously, has not been studied in depth. Where the effect of the anaesthetic system on the work demanded from the patient has been studied, methods used have centred on the measurement of the aerodynamic resistance of the components of the system (Orkin, Siegel and Rovenstine, 1954;Galloon, 1957;Hingorani, 1965;Nott and Norman, 1978;Shandro, 1982). This resistance has been assessed by measuring the pressure decrease developed across components at various constant gas flow rates which were, in some instances, greater than those encountered in clinical practice.…”