Demonstration of a method to characterize and develop airway access devices for total liquid ventilation

Devices are being developed to carry out perfluorocarbon total liquid ventilation (TLV) in adult-sized animals or patients. A limiting factor in the clinical application of TLV lies in the ability to administer adequate tidal volumes of oxygenated perfluorocarbon through airway access devices. A single number, the M-number, is demonstrated in this paper as a systematic method for ranking the flow characteristics of currently available airway access devices, such as endotracheal or tracheostomy tubes, and for designing new airway access devices exclusively for TLV. The M-number of several commonly used endotracheal and tracheostomy tubes is determined as a demonstration of the use of the M-number. Two nomograms are presented based on the M-number, and a description for their use in the clinical and laboratory settings is given.