The Venturi mask using the "Venturi flow principle" to control the mixture of 100% oxygen from the wall and room air to deliver a fixed Fi02.

If you ever get a chance to put it on yourself ---do it. It is great to clean out your sinuses.

You require time for expiration and a high Fi02. A low tidal volume is fine. You will just have to titrate the Pa02 and accept a high PaC02.

Also look for a high inspiratory flow (80 to 100l/min) and peak insp pressure <30cm H20.

Easier said than done.

As a percentage of the volume going into the 2 patients the first patient is getting more of the 100% 02. So in a variable 02 delivery system, and the Hudson mask is an example, the patient breathing faster and deeper is actually getting a lower Fi02.

Note in the picture from the "Alien" movie---there is no 02 tubing attached.

A marvellous invention of the 1920s but unfortunately inpractical.

BiPAP can be very useful in patients with acute respiratory conditions that cause an elevated PaC02.

Oxygen is stored in the solid form of Sodium Chlorate. Pulling down on the mask fires a pin which ignites a primer. The primer creates extreme heat which makes Sodium Chlorate to break down into oxygen and table salt. The oxygen then goes through a filter and down the oxygen tubing into the mask. There you go!!

Non re breather masks entrain far less room air. Importantly the reservior bag needs to be filled before placing it on the patient. Depending on the patients minute ventilation it can potentially deliver a quite high % of O2.

In Type 2 there is low Pa02 and an elevated PaC02. Typically Venturi masks are used in patients with CAL and chronically elevated PaC02. They are able to give a predictable mildly increased Fi02 without removing these patient's "hypoxic drive to breathe".

02 bars have been around since the mid 90s but under water 02 bars where you can walk around, play games and breathe scented 02 are the next step.

My research says it costs US$38.