EMT with pressure and volume question that might save lives

In summary, the patient may be receiving less oxygen than they are supposed to with the daisy chaining method using limited oxygen concentrators. It may be helpful to measure the output of the oxygen concentrators to ensure they are actually delivering the correct amount of oxygen.
  • #1
I am an EMT and have a concern. Some patients require high volumes of oxygen (as high as 15 liters per minute sometimes). Many times oxygen concentrators only go up to 5 lpm. It may be misleading to say 5 lpm because the machines have to operate based upon pressure rather than volume. 5 lpm is only what you'll get directly out of the nozzle. With a long hose, patients will receive about 1 lpm less per 5 or 6 feet. This is not exact, but I have witnessed this first hand. At nursing homes where they have these limited O2 concentrators, it is common practice to run a line out of each concentrator. These three lines are connected to two lines by three prong adapters. The two lines are connected to a single line nasal cannula using one three prong adapter. In this situation, is the patient actually receiving 15 lpm of O2? If a patient had three nasal cannulas in their nose simultaneously from three separate O2 concentrators at 5 lpm, would they be receiving 15 lpm of O2?

Diagram
__
__ --- ___
__ ---

Any help on this matter is greatly appreciated, as I am not convinced the daisy chaining method is actually getting patients the oxygen they need.
 
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  • #2
I do not believe 15 l/m O2 can be delivered via canula for the dilution. If you are concerned with the flow restriction of small gauge tubing then larger tubing is needed for the low delivery pressure.

IIRC, flow restriction is proportional to D/L
 
  • #3
I'm not an expert on medical oxygen concentrators but I see they are based on pressure swing absorption (PSA) technology. It sounds like you're eluding to the concentrator flow being affected by the pressure on the outlet of the machine which could very well be the case for a PSA. The higher the discharge pressure of the PSA, the lower the flow capacity. If that's the case, then as Doug mentions, increasing the diameter of the tubing might help. This assumes the primary restriction is through that tubing of course, and not through the device at the nasal cannula.

It should be easy enough to measure the output of these oxygen concentrators using a rotameter (flowmeter). You can purchase one from McMaster Carr for about $100. Click on "For Use With: Oxygen" and "Flow Measured In: Liters".
http://www.mcmaster.com/#flow-rate-meters/=velohg
 
  • #4
The cannula and tubing lumen are similar. At significant flow velocities the restrictions at the joints may be significant. When I built piping systems the total restriction was of concern and might militate to larger diameters.
 
  • #5
Thanks for your replies! There is actually a flowmeter on the outside of the oxygen concentrator that looks just like some of the ones you linked me to. Doug, I think you're right about not being able to deliver 15 lpm via nasal cannula. We typically switch to a non-rebreather over 6 lpm. I certainly believe the tubing and joints to be limiting. Maybe there are tubes with higher diameter. If 5 lpm is coming out each of the three concentrators (as in my diagram), will it add up to 15 lpm going to the patient(assuming the cannula, non-rebreather, connectors, or tubes aren't choke points)? It seems that, according to Boyle's law, it should add up to 15 lpm. The issue is trying to put all that volume through a small diameter. Pressure might be forced to increase due to choke points, decreasing volume at the final output location. Do I have this right?
 

1. What is EMT with pressure and volume and how does it save lives?

EMT with pressure and volume is a medical technique used by emergency medical technicians (EMTs) to treat patients who are in shock or experiencing respiratory distress. It involves using a bag-valve-mask device to deliver oxygen to the patient's lungs while simultaneously monitoring their vital signs and adjusting the pressure and volume of the oxygen being delivered. This technique can quickly stabilize a patient's condition and prevent further deterioration, potentially saving their life.

2. When is EMT with pressure and volume used?

EMT with pressure and volume is used in emergency situations where a patient is in shock or experiencing respiratory distress. This can be due to a variety of reasons such as trauma, heart attack, or severe allergic reaction. EMTs may also use this technique during transport to a hospital or while waiting for advanced medical care to arrive.

3. What are the potential risks or complications of using EMT with pressure and volume?

While EMT with pressure and volume is generally considered a safe and effective technique, there are some potential risks and complications. These include barotrauma (injury to the lungs from too much pressure), gastric distension (air entering the stomach), and hyperventilation (breathing too rapidly). EMTs are trained to monitor for these complications and make adjustments as needed.

4. How is the pressure and volume adjusted during EMT with pressure and volume?

EMTs use a bag-valve-mask device, which consists of a bag that is squeezed to deliver oxygen to the patient's lungs, a valve that controls the flow of oxygen, and a mask that is placed over the patient's mouth and nose. The EMT will squeeze the bag at a rate and pressure that is appropriate for the patient's condition, while also adjusting the valve to control the volume of oxygen being delivered. They will also monitor the patient's vital signs and adjust the pressure and volume as needed.

5. Can anyone perform EMT with pressure and volume or does it require special training?

EMT with pressure and volume should only be performed by trained and certified EMTs. This technique requires knowledge of proper bag-valve-mask technique, as well as understanding of when and how to adjust the pressure and volume to meet the patient's needs. It is an important skill for EMTs to have, but it should not be attempted by someone without proper training and certification.

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