Ask Mark …


Mark Mangus, RRT EFFORTS Board

Rose Ann B. from EFFORTS asks Mark if it is possible to have her oxygen set too high? Will it make her more short of breath?

Mark explains, The short answer is an emphatic No! If you are still short of breath while using a reasonable and adequate flow setting and are observing saturations in the mid-90s, then the shortness of breath (SOB) you are experiencing can be from a variety of causes.

First, oxygen does not completely relieve SOB. If you have SOB at rest and are saturating well, you could be experiencing an exacerba- tion or flare up, in which case, getting in touch with your doctor is in order. A common reason for SOB during exertion is a drop in oxy- gen saturation to below 90 percent – which often occurs as a result of dynamic hyperinflation (DH). DH happens when you breathe faster and breathe in more air than you can breathe out with each breath – resulting in trapping increasing amounts of air in your lungs. image104-1This increases the size of your lungs more and more. The process leaves too little room left in your lungs for fresh air to come in with each breath, raising carbon dioxide levels and stimulating your body to try to breathe more. You can no longer adequately clear carbon dioxide – even though your oxygen pressure may remain fairly high – and the outcome is SOB.

Keep in mind when measuring your oxygen saturation that any ‘real’ drop in oxygen saturation cannot be fully illuminated until you have been continuously active for at least 90 seconds or more – a mistake most folks make in trying to assess themselves for any significant drop in their saturation when they get up, move around or do chores. These are not the only causes of SOB. There are more factors that can contribute to SOB as well.


Ron from Texas writes, he is having a difficult time maintaining his body weight and would appreciate thoughts on this subject.

Mark writes, Yours is a common problem among those with COPD of the severity you seem to have. The cause is burning up more calories thanks mostly to an increase in your work of breathing. It adds up to more energy (calories) burned than total calories you are taking in, coupled with the effects of chronic low blood oxygen levels on your metabolism.

image106What we often recommend is to add a nutritional supplement to one’s intake – a supplement that is high in calories, but with calories packed dense enough to  reduce volume of  intake. Years ago, I worked with a nutritionist/licensed dietitian who had a particular interest and study in nutritional requirements for COPD. A consortium of nutritional experts recently completed an extensive study of the literature to devise guidelines for nutrition for those with COPD.

Common among most dietary recommendations has been the addition of ‘high-fat’ food components to the diet, preferably in the form of recommended standard dietary components that are high in healthy fats (mono- and poly- unsaturated fats along with healthier saturated fats). Recommendations also include supplementing fats through higher fat-containing nutritional drinks. With regard to food components, things like peanut butter and avocados are highly recommended. I have had a nutritional supplemental drink published on EFFORTS (www. and elsewhere for many years that consists of Instant Breakfast with added components of ice cream and based in whole milk for the higher-fat content of the milk. The drink contains upward of 700 calories in 12 to 14 ounces which is consumed a bit at a time throughout the day along with regular dietary components.

One other recommendation that accompanies some guidelines is the reduction in carbohydrate consumption. Carbs break down into carbon dioxide (CO2) and water as waste components; the CO2 adds to respiratory workload and actually fostering a higher rate of muscle wasting. The muscles actually ‘eat themselves’ (called catabolism) into a condition of lower mass. The objective is not so much to cut carbs, but rather to reduce their proportion within a food component, in this case the nutritional supplement. Raising the fat component to 40 or 45 percent along with increasing protein as a proportion is the objective, resultantly lowering carb proportion to or below 50 percent.

There are also commercial nutritional supplements that very nicely increase fat content/lower carb content that can be purchased, though they can be quite an expense if employed as a greater part of one’s dietary intake. (My opinion only.) One is a supplement made by Nestle called Nutren® Pulmonary formula specifically for those with COPD and other lung diseases that are accompanied by body mass and weight loss. You can get a case of 24 Nutren Pulmonary packets online for as low as $57 (with free shipping, Blowout Medical). Each container holds 8.5 ounces and provides 375 calories. Unfortunately, Medicare does not tend to cover the cost of this supplement. There are yet others – some also specifically targeting those with pulmonary disease. So, you have several choices if you decide to try commercial supplements. The bottom line is to do what’s necessary to stop weight loss and hopefully to affect weight-gain. I would strongly recommend collaborating with your doctor in your efforts.

Jean had a recent six minute walk test and asks if it was appropriate for her to be allowed to stop and use her oxygen to finish.

image108-1Mark says, Over many years, I have lamented that most walk tests are simply not done correctly – or at least not according to the American Thoracic Society’s protocol for the six minute walk test (6 MWT). According to the protocol, you are supposed to walk without aid, interference or intervention from or by the clinician conducting the test. If oximetry is done, you should carry the monitor and only show the clinician the measurement at intervals while walking. You should walk for the full 6 minutes without interruption. You should not be using oxygen during the test unless it is well-documented that you exhibit low oxygen levels at rest. When one has been diagnosed as exhibiting resting desaturation, they should do the test using their resting prescribed flow of oxygen and be allowed to desaturate from that point. You, not the clinician, should determine if, when and for how long you need to stop and recoup/rest along the way. While the test is not supposed to be a “maximum effort” test, you should walk at a reasonable and moderately brisk pace in order to produce data that has the best chance to produce potential drops in your saturation. If your oxygen saturation drops – even to and below 85 percent – during the walk, there is no recommendation to stop the walk. There is no recommended acceptable low saturation point or point at which the walk should arbitrarily be stopped. A decision to stop you when you are at say 85 percent is strictly the choice of the clinician conducting the test. It is not based on data or any kind of recommendation or safety concern. There is rarely, if ever, any concern for any imminent danger or harm from even desaturation down below 80 percent for the short period of the test. Uncomfortable? Yes! But, dangerous or injurious, not likely.

The major reason we do a 6 MWT is to determine how low your saturation drops with continuous, unhindered walking over the full six minutes duration. It includes both walking and any rest time. As well, when subjects determine that they must stop and rest/recoup, that too is counted in the results of the test.

We determine average walking distance based upon the full six minutes – including rest time. So, if subject walks 500 feet in 6 minutes but must use 2.5 of those minutes to rest and recoup, the average distance walked is 500/6, or about 83 ft/ minute. Yet, I have seen reports saying that the subject walked about 143 ft/minute because the clinician divided the 500 by the 3.5 minutes the person actually walked.

For the momentary drop in saturation into the 70s, the likelihood of that causing you any harm is remote. You should not perform the test if you feel unstable or ill. One point to consider is that unless you are allowed to desaturate to your lowest point during the six minute period, we never know how badly you can desaturate. Knowing that data goes a long way to help us determine what oxygen level you may require to maintain adequate saturation with supplemental oxygen during sustained activity. The 6 MWT should be separate from the titration test that determines what oxygen flow rates you need to use.