|HBOT PARTIAL PRESSURES OF OXYGEN TABLE|
|Room Air||Nasal Cannula||Simple Mask||EWOT Mask||93% Oxygen|
|1.0 ATA||105mmHg (1.0)||121mmHg (1.2)||306mmHg (2.9)||450mmHg (4.3)||613mmHg (5.8)|
|1.3 ATA||144mmHg (1.4)||172mmHg (1.6)||413mmHg (3.9)||600mmHg (5.7)||812mmHg (7.7)|
|1.5 ATA||175mmHg (1.7)||207mmHg (2)||485mmHg (4.6)||700mmHg (6.7)||945mmHg (9)|
- Room Air – table is based on 21% oxygen at sea level (760mmHg)
- Nasal Cannula – 24% oxygen delivery at 2L/min flow rate (at 4L/min oxygen delivery is 36%)
- Simple Mask – 50% oxygen delivery at 6L/min flow rate
- EWOT Mask – 70% oxygen delivery at 10L/min with Exercise With Oxygen Therapy mask (non-Rebreather mask)
- Pure Oxygen – 100% oxygen delivery sufficient to meet user’s needs
- HBOT is at sea level where 1.0 ATA is equivalent to 760 mmHg (millimeters of mercury)
- Arterial and venous oxygen concentrations are roughly 76% and 30% of listed oxygen pressures respectively
- Oxygen Pressure = Atmospheric Pressure (760mmHg- 47mmHg) X ATA X Percent Delivered Oxygen
- Oxygen Multiple in Parenthesis = Oxygen Pressure/Oxygen Partial Pressure (105mmHg)
- The pressure at 1.3 ATA is equivalent to being 3m under water
- The pressure at 1.5 ATA is equivalent to being 5m feet under water
Types of oxygen masks:
Simple Oxygen Face Mask
Oxygen concentration in normal room is about 21%. An oxygen mask is suitable for oxygen concentration of 30% - 60% which is necessary for medical treatment. These masks are usually made of plastic. An oxygen mask often has a capacity of holding 100-200 ml of gas in itself and requires an oxygen flow of 5-6 l/min to avoid carbon di oxide accumulation inside the mask. These masks fix on the patient’s mouth with an elasticated headband. Simple masks like Allied Simple Medium Concentration Oxygen Mask contain holes for carbon dioxide to escape and fresh air to mix with the oxygen.
These masks have a reservoir attached to them. Both non-breather masks and partial re-breather masks come under this category. Reservoir masks are used for delivering higher concentration of oxygen. The partial re-breather mask is used to deliver 70 – 90 percent oxygen concentration, while a non-re-breather mask delivers 90 percent of oxygen concentration or more. Reservoir masks do not contain any openings to restrict the inflow of outside air.
A re-breathing mask has a soft plastic reservoir bag attached at the end that saves one third of a person’s exhaled air, while the rest of the air gets out via side ports covered with one-way valves.
This allows the person to “re-breathe” some of the carbon dioxide which acts as a way to stimulate breathing.
Non re-breathing mask
A non-re-breathing mask has several one way valves in the side ports. This type of mask also has a reservoir bag attached, but the bag has a one way valve that prevents the exhaled carbon dioxide from getting into the reservoir.
This type of mask does not allow for the re-breathing of exhaled air as it escapes through the side ports.
The purpose of such a mask is to deliver high amounts of oxygen in an emergency eg hypoxia, respiratory disease, cardiac disease etc.