Critical Care and Shock

Use of venturi entrainment to deliver nasal high flow oxygen



Objective: To evaluate the use of an adjustable venturi device with standard wall oxygen supply to deliver nasal high flow oxygen.

Design: We set up a circuit using a standard 15 L/min oxygen rotameter connected to a wall outlet, 2 m standard oxygen tubing, an adjustable venturi device, humidification chamber and nasal high flow circuit and cannulae. Delivered FiO2 and total gas flow rates were measured over a range of oxygen flow rates and venturi settings. The study was conducted in two parts – a bench-top study to define the usable range and using a human subject to assess loaded performance of the circuit.

Setting: Royal Adelaide Hospital Intensive Care Unit.

Participants: One study author.

Results: A clinically useful range of total flow rates (30-50 L/min) and delivered FiO2 (0.4-0.6) was achieved using the circuit described. The variation in performance seen with loading of the circuit was clinically insignificant. We have calibrated this ‘Fisher and Paykel’ adjustable venturi device for use with the Fisher and Paykel heater chamber and circuit.

Conclusion: We demonstrated that nasal high flow oxygen can be delivered in a clinically useful and predictable manner using a venturi entrainment device.

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