5. Cuff, Sizing and the Principles of Fitment

5. Cuff, Sizing and the Principles of Fitment

The principle of the Tulip is based upon a totally air and secretion-tight seal being achieved in the oropharynx by an expanding high-volume, low-pressure inflatable balloon-cuff which then allows ventilating pressure to be generated. The balloon-cuff is anatomically designed and provides an anatomical fit. The Tulip is designed to expand in a linear 3D fashion based upon the anatomical enlargement that occurs during Human growth. Hence as the cuff inflates it expands to fit the anatomy correctly. The sizing is achieved by the expanding balloon-cuff sealing the single tube that is the oropharynx, circumferentially. This expanded balloon-cuff provides a large mucosal contact patch and a mass occlusion effect that obstructs the single, tubular oropharynx. This then allows the Tulip to provide the ventilating seal required for airway management. This is possible in everyone theoretically, and allows the Tulip to fit a large number of Humanoid sizes with one Tulip size by simply expanding that balloon-cuff to fit inside that single, tubular oropharynx.

Adult Patients require the single Adult size Tulip, but Paediatric versions of the Tulip are required as those anatomically smaller Patients require a physically smaller airway tube.

The Tulip is designed to be anatomically proportional from 50% of its expected inflation volume to 125% of its intended inflation volume. This means that the range of sizes available to the user is between 50% below – 25% above the “normal” range. This range of sizes may be accommodated by the same size Tulip. The individual variations in Patient size are compensated for by the individual variations in the gas volume used for fitment in each Patient. The Tulip cuff is an expanding balloon, inflate the Tulip to fit.

Fitment is defined as no audible leak at normal ventilating pressures (+/-20cmH2O), but the Tulip is still likely to provide adequate Patient ventilation with adequate ventilation pressures despite any small leak. We may use a small audible leak as a method for limiting excessive or high ventilation pressures, particularly in inexperienced hands.

The pressures within each cuff can be the same, irrespective of Patient size, as the fitment point is individual to each Patient according to the size of each Patient’s oropharyngeal cavity. The intra-cuff pressure should be maintained at 40mmHg (54cmH2O) in each Patient ideally, but it may be elevated to allow higher ventilation pressures (>20cmH2O) as is required, particularly in the case of an emergency.