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Monday, August 19, 2019

Investigating High Flow Oxygen For Pneumothorax

Depiction of high flow nasal cannula.
Image taken from Google Images. 
We respiratory therapists are often skeptical. Recently, many doctors are prescribing high flow nasal cannula's (HFNC) for pneumothoraces. A common question is: Does this treatment do any good? Let's investigate.

What is a pneumothorax?

As we all know (or should know), a pneumothorax is a collapsed lung. It's when air seeps into the the space between the lungs and chest wall. It is air that seeps into the pleural space. This air pushes on the lungs to make them collapse. An entire lobe may collapse or just a small portion of it.1-2

A small pneumothorax may cause no symptoms. It may resolve on it's own. A larger pneumothorax may cause symptoms. These include low oxygen levels and shortness of breath. They may also include sharp chest pains, rapid breathing, and rapid heart rate. 

They are either spontaneous or iatrogenic. 
  • Spontaneous (Primary). This means they occur in otherwise healthy individuals.  The cause usually remains inexplicable. Those most likely to develop them are of the tall and lean type. Others at risk may include smoking tobacco or marijuana. 
  • Iatrogenic (Secondary). This means they are secondary to treatment for a disease process. A good example here is secondary to a thorocentesis. The doctor inserts the needle too far and it pierces the lungs. Severe asthma, sarcoidosis, cystic fibrosis, pulmonary fibrosis, and emphysema are also potential secondary causes. Another cause may be barotrauma due to using high pressures during mechanical ventilation  2-4

How do they resolve?

They resolve as air is reabsorbed into nearby tissues. A small pneumothorax may cause no symptoms. These may also resolve on their own. Treatment here is observation. 

A larger pneumothorax may cause some symptoms. In these cases some treatment is probably needed. What to do is dependent on what guidelines you are referring to. Some recommend a needle aspiration to relieve the pneumo. Others recommend insertion of a chest tube. I think here in the U.S. a chest tube is recommended. 3

Oxygen also seems to help. A study in 1983 showed that higher oxygen levels increased the speed of pneumothorax resolution. Previous studies had patients inhaling room air. So, those study results were already known to the researchers. So, their goal was to see if higher oxygen concentrations (i.e. greater than 28%) improved the speed of pneumothorax resolution. 1

Here's what the researchers reported: 
"6 patients with pneumothoraces of less than 30% showed a mean resolution rate of 4.2% per day with reduction to one-third original size in the first 72 h. This was more than three times the rate of resolution (1.25% per day) previously reported with breathing room air alone. In 2 patients who initially received a lower concentration of inspired oxygen via nasal cannula, the rate of absorption increased after placing them on a partial rebreathing mask." 1
They concluded that high flow oxygen speeds up the pneumothorax resolution process. The theory is that oxygen washes out alveolar nitrogen. This in turn lowers the partial pressure of nitrogen. This is good because nitrogen slows absorption of air. So, it's not so much the oxygen that speeds up re absorption, it's the lowered partial pressure of nitrogen that speeds it up. 

At least that's the theory.

Is this theory credible?

This theory seems credible. It was during the 1960s that it was suspected. This was when it was learned that the partial pressure in the capillaries and venous system was the same as atmospheric pressure. However, this changed when 100% oxygen was administered.

With 100% oxygen nitrogen is washed out of alveoli. In the 1960s, it was observed that this effect causes a drop in the partial pressure of alveolar nitrogen from 573 to zero. This is a result of the partial pressure of arterial oxygen increasing from 100 to 640 mmHg. This in effect causes a change in the partial pressure of alveolar oxygen. This in turn changes the partial pressure of oxygen in capillaries.5

While inhaling room air, the partial pressure of capillary oxygen is It's 706 mmHg. While inhaling 100% oxygen, this decreases to 146 mmHg. This is important, as the flow of air travels to areas of higher pressure to lower pressures. So, this change in pressure causes an increased rate of reabsorption of air from the pleural space.5

What are the risks?

The potential risks always have to be weighed against potential benefits. Potential benefits in the case of pneumothorax is recovery. Although, one might speculate this would happen with or without high flow oxygen. Still, high flow oxygen speeds up the process. So, this is definitely a benefit. 

One study showed that wearing a nonrebreather for as little as three hours increased the risk for developing certain cancers. More recent studies link long-term low flow supplemental oxygen use with lung cancer. A common theory explaining this phenomenon is oxidative stress.6-8 

Another risk is hypercarbia. John Haldane (1860-1936) described how oxygen has a higher affinity for hemoglobin than carbon dioxide. So, inhaling 100% FiO2 causes lots of oxygen molecules to enter arterial blood. These oxygen molecules push carbon dioxide off hemoglobin. These carbon dioxide molecules increase the partial pressure of arterial blood. This effect can be toxic to some people with COPD. This theory makes more sense than the hypoxic drive hoax.

So, these are two risks worthy of consideration.

What to make of this?

There is ample evidence supporting oxygen use for treating pneumothorax patients. The goal is to exceed 28% FiO2, although higher FiO2s seem to prove beneficial for these patients. I have yet to see any studies of HFNCs for these patients. So, at the present time, it's my conclusion that HFNCs are recommended mainly due to patient comfort. They allow delivery of high oxygen levels without having to wear an uncomfortable mask. If you are aware of any such studies please let me know in the comments below. As we learn more we will be sure to keep you posted. 

  1. Chadha T.S., Chon M.A., "Noninvasive Treatment of Pneumothorax with Oxygen Inhalation," Respiration, 1983,, accessed 8/18/19
  2. Currie, et al, "Pneumothorax: An Update," Postgraduate medical Journal, 2007, July,, accessed 8/18/19
  3.  Choi, Won-II, "Pneumothorax," Tuberculosis And Respiratory Disease (Seoul), 2014, March,, accessed 8/18/19
  4. Johnson, Jon, "Pneumothorax: Causes, Symptoms, And Treatment," 2017, June,, accessed 8/18/19
  5. Northfield, T.C., "Oxygen Therapy for Spontaneous Pneumothorax," British Medical Journal, 1971,, accessed 8/18/19
  6. Garcia, et al., "Lung Cancer in COPD patients on Home Oxygen Therapy, European Respiratory Journal, 2016,, accessed 8/18/19
  7. Valavanidis, et al., "Pulmonary oxidative stress, inflammation and cancer: respirable particulate matter, fibrous dusts and ozone as major causes of lung carcinogenesis through reactive oxygen species mechanisms," International Journal of Environmental Research and Public Health, 2013, August 27,, accessed 8/18/19
  8. "Can Inhaled Oxygen Cause Cancer," Science Daily, 2015, January 13,, accessed 8/18/19

Monday, August 12, 2019

Many Changes To How Asthma Is Classified

Over the past 20 years, there have been many changes to the ways asthma is classified. The most significant change is that away from the idea of asthma as a homogeneous disease. The shift was toward the idea of asthma as a heterogeneous disease. This lead to the redefining of asthma as a single disease to one with many subgroups (phenotypes /endotypes).

As a homogeneous disease, all asthmatics were treated the same. They were all treated as allergic asthmatics. They were all assumed to have allergies. And the treatment for them were inhaled corticosteroids and bronchodilators. These were the recommendations of many of the original asthma guidelines from the late 1980s.

This strategy worked great for about 85-90% of asthmatics. It helped them obtain ideal, or at least better, asthma control. The problem was that about 10-15% continued to have poorly controlled asthma despite optimal treatment. And it was treatment for this group that encompassed a majority of the overall healthcare cost for treating asthma as a disease nationally and worldwide.

So, this group encompassed a majority of asthma research funds over the past several years. And this research seems to be showing promise. The best evidence of this is the discovery of over 100 asthma genes. Researchers now believe every asthmatic has a random assortment of these genes. And that may explain why each asthmatic experiences it in different ways. For instance, one doctor once chimed, "If you've seen one asthmatic you've seen one asthmatic."

Still, this research has resulted in the creation of asthma subgroups. Fancy terms for this are phenotypes and endotypes. Subgroups loop asthmatics with similar presentations into certain groups. For instance, childlhood-onset and allergic asthmatics are lumped under the subgroup Allergic Asthma. The 10-15% of asthmatics who continue to have poorly controlled asthma despite the best treatment are lumped under the subgroup severe asthma.

Some asthma subgroups are now well accepted. These include allergic asthma, exercise induced asthma, eosinophilic asthma, severe asthma. Others are not so well accepted, such as neutrophilic asthma, premenopausal asthma, obesity associated asthma, Aspirin exacerbated respiratory disease, and nervous asthma. For these less recognized subgroups you'll see various names bandied about mainly due to the fact these are poorly understood.

And that is the reason for doing more research, so all of the different subgroups can be better. understood. And when they are understood better, specific treatments may be developed to better help asthmatics of a given subgroup. And this will lead to better, more specific guidelines for each subgroup. This is all in an effort to help all asthmatics obtain ideal asthma control.

Thursday, August 8, 2019

A Unique Asthma Presentation: Not All Asthmatics Wheeze

What if there is no wheeze? It still might be asthma. 
So, we are taught the standard presentation of asthma. We are taught auscultate and listen for wheezing. If wheezing is present we determine the symptoms are caused by asthma. The treatment is a breathing treatment with albuterol.

But, when no wheezes are heard, we often diagnose the patient as having anxiety or some other disorder. Here, no breathing treatment is indicated. Still, we often give one for the psychosomatic effect.

Here, I would like to contend that not all asthmatics wheeze. This is a view that not many health experts have expressed. I have discussed this with many of my coworkers. They have lectured me about if airways are narrow, you will hear a wheeze.

But, I spend lots of time in asthma communities. Many of my asthmatic friends contend that they don't wheeze. Some say they were poorly treated because their healthcare teams heard no wheezing. So, when this happens, and the person truly does have asthma, it can lead to poorly controlled asthma. It can lead to death.

So, let's go with the notion that not all asthmatics wheeze. I can tell you for a fact that I rarely wheeze. I did as a kid, but rarely does this happen as an adult.

I said this to a friend of mine. He said, "Well, if that's the case, then your doctor should do a PFT. If your lung function is diminished you have asthma. Or, if you did a peak flow, your peak flows should go down. That would prove that you have asthma."

I said, "In 1997 I ended up in the hospital for 10 days for severe asthma. My peak flows were 750 on the day I was admitted. If your theory holds true, then why did my peak flows not drop?"

He had no answer.

And I didn't mean to put him on the spot. I was just trying to make the point that not all asthmatics present the same. And that means that some asthmatics don't wheeze. And some asthmatics do not have drops in peak flows. Their FEV1 may be normal even during their worse asthma attacks.

And why would this be? A doctor did explain this to me once. She said that it's because my asthma is occurring in my smallest airways. Peak flows and spirometry measure flow through your larger airways. They do not measure flow in your deepest airways. So, if this is where your asthma is occurring, you will not wheeze. Your peak flows will probably be normal. Yet you are still having asthma.

To add to this, most inhalers do not get that deep. For instance, I was taking Advair for the longest time I had pretty good asthma control. But, it wasn't as controlled as I liked. When I sprinted, for example, my chest would get tight. I was still able to do it, but the chest tightness irritated me.

So, I did some research. I learned that HFA inhalers got deeper into airways than CFC inhalers. Likewise, HFA inhalers get deeper into airways than DPI inhalers. By deeper I mean better airway distribution. HFA particles seem to get into the smallest airways, or deeper down than the other types of inhalers.

I discussed with with my doctor. He changed by prescription to Symbicort. Since then I have not experienced this tightness when running. I have had better asthma control. So, I think this is because Symbicort gets deeper into my lungs.

Now, my control still isn't perfect. But, it's far better than if I would be if I didn't do my own research. It's far better than if I wasn't my own best advocate. It's way better than, say, if I didn't present with these symptoms until adulthood, and my doctor said I didn't have asthma because I don't present like a typical asthmatic.

So, some asthmatics do not present as typical asthmatics. Some of us have unique asthma presentations. When this happens, it's best to not brush us off as having anxiety. Sure, it could be anxiety. But, if a patient says they have asthma, it's best to listen to your patient. What you were taught should be heeded. But, what your patient says should be heeded as well.

Monday, August 5, 2019

The Flyp Nebulizer

Can be used anywhere.
It's called the Flyp Portable Hand-Held Nebulizer. It's the most impressive nebulizer I've ever used.

It's a mesh nebulizer. As you can see by the picture, it's quite compact. It has no tubing. Like an inhaler or iPhone you can hold it in one hand. You can easily store it in a pocket or purse. And using it is as easy as 1-2-3:
  1. Open the reservoir cover on the back.
  2. Gently lift the stopper and squirt in your medicine.
  3. Close the stopper and lift the mouthpiece. 
Then you push a button. A nice mist is produced. Particle sizes of the medicine are right around the 0.5 micron range. This is the same as those produced by jet nebulizers. Treatment times average 7 minutes. That's less than jet nebulizer treatment times of up to 20 minutes. 

I charged the device for about 2 hours. I got 15 treatments out of it. I took one in my car and one at work. I took one while writing this article. It's so easy to use.

It comes with quality packaging.
It's so quiet!

You can't say that about jet nebulizers.

So, say you wake up in the middle of the night. Your wife and kids are sleeping. Jet nebulizers are  so noisy. You literally had to get out of bed to take a treatment. You had to go to the living room. Even then you had to hope it didn't wake up the kids. 

With the Flyp you don't even have to get out of bed. The reason is because it's whisper quiet. It would not wake up a fly. You could lie there in bed. You could do a quick treatment and go back to sleep. Nice!

My coworkers loved it!

I showed it to all my friends at work. They were very impressed. My asthmatic coworker said she was, "jealous." She added "I want one."

I said that it costs $199. I figured that would be a downside to this nebulizer. Traditional jet nebulizers cost under $40. Portable jet nebulizers cost $100. But, my asthmatic friend said she thought that price was quite reasonable.

She said, "Inhalers today are expensive. If you bought one Flyp, and it lasted one year, it would be more than worth it."

So I told her there was a three year warranty. She said, "That's icing on the cake." 

It comes with a nice carrying bag. 
The three year warranty is proof that the manufacturer has confidence in their product.

Is there  downside? 

It costs more than a traditional jet nebulizer. Medicare and insurance companies will not pay for one. Still, my friends thought $199 was very reasonable.

It will require cleaning after each use. This will definitely take some discipline. But, it must be done because you will want to keep the mesh disc clean. Medicine particles can build up on it over time. Cleaning it after each use can prevent this from happening. So, it must be cleaned as recommended. 

It is going to take some maintenance. It must also be charged regularly. The nebulizer disk must be properly maintained. It must not be touched with a finger or cotton swab. You can only clean it with distilled water. So, it definitely takes some care.

Thankfully, cleaning it is pretty easy. It's just a matter of doing it. 

What to make of this? 

The Flyp Nebulizer is a nice nebulizer. I have never seen anything quite like it. It's pocket-size like an inhaler or iPhone. It's pretty and quiet. You can take treatments any place and any time. All you have to do is charge it and you're ready to go.

At the present time it's only available in the U.S.. It's ideal for anyone who uses nebulizers. 

Thursday, August 1, 2019

Ultrasonic Versus Mesh Nebulizer

Cool Mist Humidifier
T'here are many small-portable nebulizers on the  market. Some claim to be ultrasonic nebulizers. Some of these sell for as little as $30. Some claim to be mesh nebulizers. Most of these are $150-300. So, what's the difference between ultrasonic nebulizers and mesh nebulizers?

What are ultrasonic nebulizers? 

They are often referred to as cool mist nebulizers. On the bottom of the cup is a crystal transducer. This sends vibrations through the solution. These vibrations go to the surface of the water. This is what transfers water to a mist. 

Aura Portable Mesh Nebulizer
Some of these are pretty inexpensive to make. The problem is they are only good for certain types of medicines. For example, they are not meant for medicines like Pulmicort. You will find various ultrasonic nebulizers on the market. Some are selling for as little as $30. Although, most are usually only used as humidifiers. 
What are mesh nebulizers? 

There are two different types of mesh nebulizers. The ones most commonly used are vibrating mesh nebulizers. The mesh plate contains a piezo element. This vibrates as "ultrasonic frequencies." But, it is not an ultrasonic nebulizer. It's a mesh nebulizer. The piezo element vibrates so fast that water passing through it turns into a mist.

Mesh nebulizers cost more than ultrasonic nebulziers. But, they are good for all respiratory medicines. So this makes them ideal for respiratory medicines. So, it is mesh nebulizers that are the wave of the nebulizer future. 

Tuesday, July 30, 2019

What are mesh nebulizers?

This is the Flyp Mesh Nebulizer
We are all familiar with pneumatic jet nebulizers. These are the small volume nebulizers (SVNs) we RTs have been using in hospitals for years. Many asthmatics and COPDers use them in the home setting. They are simple to use. They are inexpensive. And it's quite possible they may soon be phased out. Replacing them will be Mesh Nebulizers. So, what are mesh nebulizers? Here's all you need to know.

What are vibrating mesh nebulizers? 

The first mesh nebulizer entered the market in 1993. Like many others, I failed to notice. In fact, I never even heard of mesh nebulizers until 2018. I was having lunch with my fellow RT coworkers. Joining us was a seasoned pharmacist who was new to our facility. He said, "Have you guys heard of the Aerogen. Where I worked before we decided to try them. Our respiratory therapists fell in love with them."

He discussed the Aerogen in detail. He said it's whisper quiet and easy to use. In fact, all you do is squirt in the medicine and push a button. Then you just leave the room. It shuts off itself. And, as we old people do so often, we shunned off the idea. What do we need that for? What we have already works just fine.

Lo and behold, the company I work for purchased Aerogens. Just like that pharmacist said, they are nice. We quickly fell in love with them.

What other mesh nebulizers are available? 

The Aerogen
Aerogens are marketed only for hospitals. Other brands marketed their products for patients. Some products include: Respironics Innospire,  Flyp, Omron Portable MicroAir Nebulizer, and Aura Portaneb.

These nebulizers are mesh nebulizers. They have microscopic disks. These disks have a piezo element. It vibrates at ultrasonic frequencies. This creates turns the medicine solution into a mist.

Particle sizes are similar to those produced by jet nebulizers.

They are small, hand-held devices.

Like inhalers, you can keep them in your pocket or purse.

Unlike jet nebulizers, they are relatively silent.

Jet nebulizer treatments take 10-20 minutes. Mesh nebulizer treatments are only 7 minutes. Some mesh nebulizers are even faster.

And, did I say, they are easily portable.

They don't require a power source (although they do need to be charged occasionally).

Oh, and no tubing.

So why do we still use jet nebulizers? 

In the hospital setting: cost. The aerogen pro x controller costs $1300. The individual nebulizers cost $40 each. Compare that with $2.00 for a jet nebulizer.

In the home setting: mesh nebulizers might be more affordable. Why do I say this? Inhalers cost a lot of money. For me, my Symbicort has a copay of $50 per month. Multiply that by twelve and you get $600 per year.

Now, buy a Mesh nebulizer for $200. Or, buy a DeVilbiss portable nebulizer for $100. Both are nice products. But, if you use your nebulizser a lot, that extra $100 is worth it. Plus, you don't have to buy albuterol inhalers, which cost anywhere from $16-50 copay.

Surely, as they gain in popularity, prices will come down. And when this happens, the mesh nebulizer market may wipe away the jet nebulizer market.

What to make of this? 

Researchers are already in love with mesh nebulizers. They are considering only using them for future clinical trials. So, mesh nebulizers certainly do seem like the wave of the future. What do you think?

  1. Gardenhire, Douglas S. et al., “A Guide To Aerosol Delivery Devices for Respiratory Therapists,” 4th Edition,, accessed 7/19/19
  2. Kacmarek, Robert M, James K. Stoller, Albert J. Heuer, “Egan, Fundamentals of Respiratory Care,” 10th Edition, 2013, Elsevier, pages 836-837
  3. Pritchard, et al., “Mesh nebulizers have become the first choice for new nebulized pharmaceutical drug developments,” 2018, January 12,, accessed 7/19/19
  4. Hatley, R.H.M., L.D.H. Hardaker, S. Byrne, "Ultrasonic and Mesh Nebulizers Are Not the Same – Delivery of a Budesonide Suspension," The Aerosol Society,, accessed 7/30/19

Thursday, July 4, 2019

Here's How Insurance Companies Gained Control Over Doctors and YOU

So, my pharmacist says I can only get one inhaler a month. I cannot buy one until it's been 30 days since I bought that last one. So, what gives insurance companies the power to control you like this? Let's discuss.

I'm going to borrow a quote from the Heritage Foundation, "The Cure: How Capitalism Can Solve The Healthcare Crisis." Here is the quote.
"There is the golden rule: He who controls the gold makes the rules. If the gold is controlled by the government, the government will make the rules, and you will do exactly as you are told. That's how it works. It's a law of nature. It's like the law of gravity: It's not something you can escape. That's the reality."
 In America we have a system of only a few insurance companies. This is not the fault of capitalism. It is the fault of too much government. I explained this in my post, "Discussing Healthcare Solutions."

If you have too many regulations on insurance companies, only those with the most money will be able to continue on. These wealthy insurance companies can afford to lobby Congress. They champion for more regulations as they know this will make it impossible for their smaller competitors to continue. And eventually all we are left with is these larger insurance companies.

We let this happen. It was the result of too much government control. Government control is what we wanted as this was supposed to fix the problem. But, it has only made it worse. And, to go back to our quote above, "He who controls the gold controls you."

That is how insurance companies get to tell you what you can get and how much you can get.

Back when there was lots of competition, these insurance companies did not have this power. So, in that older system insurance companies yearned to offer a product you wanted at a price you could afford.

If this meant filling the prescription exactly as ordered by the doctor, then so be it. That was how I was able to get three albuterol inhalers every time I picked up a prescription at the pharmacy. And sometimes I did this more than once a month. The insurance company wanted to keep me happy so I continued to stay with them.

Today, however, toss making us happy out the window. With little competition, these insurance companies have grown large. They are, in essence, monopolies. And they get to set the rules. And one of their rules is you can only get one inhaler a month, even if your doctor orders more; even if you NEED more.

So, now you know. It is not capitalism that allowed this to happen. It was our eagerness to allow Congress to fix the problem. And usually this means more government, not less. And therein lies the problem. Many blame capitalism. But, the truth is is, capitalism is the solution. Get rid of or at least cut back regulations. Create space for smaller competitors to enter the market. This is the only way to gain control back from these insurance monopolies.