Let's start with a few questions:
Have you had a Spirometry Test?
Have you had an ABG (arterial blood)?
Have you been measuring your Oxygen Sats with an Oximeter?
My guess is the answer to some if not all of these questions is yes. But it helps to know your numbers.
So without having those numbers I can only explain the reasoning behind Oxygen Therapy diagnosis.
According to the American Thoracic Society, every cell in your body needs oxygen to live. Unfortunately, your pulmonologist believes that your lungs can no longer provide the amount of oxygen your body needs. This may be caused by one of two things: either the airways have narrowed and become blocked by mucus or damaged alveoli in the lungs can no longer absorb enough oxygen.
Either way, blood oxygen levels can become dangerously low in your body especially when you are exerting yourself or when you are sleeping or both. Since the body cannot store oxygen, therapy may be used to deliver this life-saving element to your lungs up to 24 hours a day.
Determining How Much Oxygen You Need
Oxygen therapy is used to ensure the amount of oxygen in your bloodstream remains at a healthy level. Breathlessness alone is not a good indicator of whether you need this therapy. Many people who need oxygen therapy don't feel short of breath, yet they lack the oxygen to stay healthy. Your doctor will use more precise methods to find out how much oxygen you need and when you need it. He or she does this by running these tests, according to American Thoracic Society:
Arterial blood gas (ABG): This measures carbon dioxide, oxygen and pH levels in the blood. The test is conducted at an office or hospital where ABG equipment is available.
Pulse oximeter: This is not as precise as an ABG and should only be used as a guide to oxygen therapy. It involves placing a clip on your finger and shining a light through. A tiny computer determines the oxygen level based on the color of the light passing through your finger. Often your pulmonologist will order a sleep oximetry test to find out your oxygen levels during sleep - which tends to be lower than waking hours.
Based on the results of these tests, your doctor can determine the rate of oxygen delivery you need, how many hours a day you should use it and whether you need to use oxygen while you sleep.
If you have a general understanding of what each of the numbers mean, then you won't be in the dark when docs, nurses, or respiratory therapists are throwing these numbers around. You'll have a better understanding of what is going on inside your body.
Oxygen enters the blood inside the lungs and is delivered to each cell in your body. Blood is made up of a bunch of stuff, but for this discussion, we'll focus on red blood cells (RBCs) and plasma. RBCs are what makes your blood red whereas plasma is a clear fluid that the RBCs travel in.
What I've found is that most people don't realize that oxygen is moved from the lungs to the cells in your body inside the blood in TWO ways, not just one.
Oxygen is transported inside the RBCs AND dissolved in the plasma. The pulse-ox number is having a look at how full the RBCs. The ABG is looking at how much oxygen is dissolved in the plasma (like salt dissolves into water). The pulse-ox number is important because about 98% of your oxygen is found inside the RBCs. The ABG number is important because it gives information about how well oxygen is getting into your blood in the first place.
When I describe what the pulse-ox/ABG numbers means, I use a story about washing the dishes.
You fill up the sink with water and you reach for a dry dish rag. You submerge the dry dish rag into the water and pull it out soaking wet; the rag couldn't possibly hold anymore water. You might say that the rag is 100% saturated.
Well you continue on and you wash all of the dishes. When all the dishes are clean, you look down at the floor and realize that you've spilled water all over the place. So you reach for a new dry dish rag and soak the water up off the floor and counter. You notice that the rag is wet, but you could still pick up more water if you needed to; maybe it's 80% saturated.
In this example you can think of the oxygen dissolved in plasma as the water and the RBC as the dishrag. The amount of oxygen (water) available in the plasma determines how much is soaked up by the RBC (dishrag)
The pulseox is telling you how full the RBC is as a percentage and the ABG is giving you a pressure (P) of oxygen (O2) in plasma in pressure units of millimeters of mercury, or mmHg.
Here are the steps that oxygen gets into your blood:
- you breathe a nice deep breath
- the air travels down your windpipe and deep into your lungs
- just like the smell of freshly baked cookies travels from the kitchen to the living room, oxygen travels from the lungs into the plasma of the blood.
- once in the plasma, the oxygen is absorbed by the RBC.
Step 3 is what the ABG results reveal
Step 4 is what the Pulseox reveals
Pulseox reading 99% is approximately PO2 of 100 mmHg
Pulseox reading 96% is approximately PO2 of 80 mmHg
Pulseox reading 90% is approximately PO2 of 60 mmHg
Pulseox reading 75% is approximately PO2 of 40 mmHg
The ABG results also reveal the amount of carbon dioxide in your blood this number is PCO2. P for pressure and CO2 for carbon dioxide. The results also show the pH of your arterial blood.
If your Pulseox is consistently below 90% then otherwise healthy cells in your body are dying prematurely and eventually you will feel sympoms. Also, when your oxygen /CO2 exchange is not working properly you are putting extra stress on the right side of your heart which must use only oxygen rich cells but must pump a lot of blood back around because it's not oxygenated enough. eventually this work will cause the right chamber of your heart to enlarge (Congestive heart failure.)
My recommendation to you, Dear Reader, is to ask your Doctor to explain all of this to you until you 100% get it. If you are still not convinced then get a second opinion. If 2 good pulmonologists are telling you that you need Oxygen Therapy, then by all means - DO IT! It is saving your quality and quantity of Life and although a big lifestyle change, it's well worth it!