How Much PEEP Does High Flow Deliver via Tracheostomy? A Literature Review and Benchtop Experiment

Table 2

Factors affecting PEEP in HFT.

Patient factors	(i) Age/gender; (ii) Lung volumes/capacity and respiratory rate; (iii) Respiratory tract dimension; (iv) Respiratory tract resistance; (v) Respiratory tract compliance; (vi) Anatomical and pathological variations of respiratory tract; (vii) Percentage of respiratory lumen occupied by tracheostomy tube determines amount of leak and patient comfort
Instrument factors	(i) Flow and density of air oxygen mixture; (ii) Length, diameter, and type of tracheostomy tube used; (iii) Angle between axis of connector and delivery tube (60° for Fischer and Paykell Optiflow™) determines turbulence of flow; (iv) Pressure at the exhalation port, as this determines the blowoff pressure. Normally, this is atmospheric pressure