The Partial pressure of oxygen PaO2 is one of the parameters measured during the measurement of the Arterial blood Gas Test.
Arterial blood gas test is used in the measurement of the oxygen concentration of oxygen and carbon(iv)oxide in the blood. It can also be used in the determination of the acidity or alkalinity of the blood.
What is Partial Pressure of Oxygen Test (PaO2)
The partial pressure of oxygen(PaO2) test is used to measure the pressure at which the oxygen in blood flows, more important to note is that the partial pressure of oxygen in the blood can be altered by very serious illnesses.
Reasons for Taking Partial Pressure of Oxygen Test
There are so many reasons why your doctor will recommend the partial pressure of oxygen test for you and one of the reasons is to test the actual effect of breathing difficulties on oxygen supply in the body.
The supply of oxygen in the body must be monitored at all times, this is because oxygen is a very vital component in respiration hence any parameter that can obstruct the supply of oxygen in the body deserves to be monitored.
The aftermath of this test will help determine if the patient will be placed on an artificial supply of oxygen, a medical condition called Artificial oxygen supplementation or respiratory support.
So you see why the partial pressure of oxygen test is very important when trying to diagnose the effect of PaO2 on oxygen supply and circulation in the body during breathing difficulties.
Apart from the determination of the effect of breathing difficulties on oxygen supply, there are other reasons why your doctor will recommend the PaO2 test at any point in time during a medical intervention or around the hospital premises.
Partial Pressure of Oxygen(Pao2)Test: Uses, Procedures, Risks, and Contraindications
The other reasons include;
- Myocardial infarction- This happens when one of the coronary arteries, a network of arteries that supplies blood to the heart becomes blocked.
- Cardiac failure- This is also known as congestive heart failure which happens when the heart fails to pump blood sufficiently to maintain the body’s oxygen needs.
- Loss of consciousness
- Trauma on the lungs
- Shortness of breath
- Respiratory diseases like Asthma.chronic obstructive pulmonary disease, cystic fibrosis, etc
Just as mentioned earlier, the reason for conducting the PAO2 test is to determine the effect of breathing difficulties on oxygen supply in the body in order to either apply breathing support for the patient or not.
But in a situation where the patient is already placed on mechanical oxygen support, a follow-up test is recommended to ascertain if there is an improvement or not so that the doctor in charge can make adjustments in the treatments.
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Risk and Contraindications of PaO2 Test
Just like every other laboratory test, there not many risks or contraindications you are going to experience either before or after the test, this is because the site for puncture and drawing of blood is the artery and not the vein that has a slight risk of bleeding.
Nevertheless, it is also very important to keep in mind in case you have any bleeding disorder that could lead to bleeding after the puncture. If you have any, you will need to inform your doctor ahead so he can take precautions or avoid the test for another alternative.
Aside from this, the test is almost risk-free and it is among the simplest test you can ever do!
Procedures for the Partial Pressure of Oxygen Test
The partial pressure of oxygen tests just like every other laboratory test have procedures that must be followed in order to ensure an accurate result and diagnose so that the best treatment approach can be applied.
For the sake of clarity and understanding, the procedures for the test will be divided into stages as this will enable you to get prepared and organize yourself for the test without missing any details.
Hence the procedures for the test will be divided into;
- What to expect before the test
- What to expect during the test
- What to do or expect after the test
What to expect before the test
As a patient preparing for the PaO2 test there is a list of things to look out for during your preparations, as they will enable you to make well informed and guided preparations.
There are a lot of things you need to do and prepare for before your test, they are;
- Duration- how long does the test takes
- How to dress
Before the PaO2 test, you must book an appointment with your doctor except in cases where there is an emergency breathing difficulty.
When you are hospitalized and having this test to monitor your treatment or to follow the progression of your illness, it may be scheduled to be done at a certain time in relation to your treatment (such as when your oxygen support is being adjusted).
- How long does the test takes?
The collection of a blood sample for this test takes about 10 minutes except when the test is conducted in an outpatient station then you have to at least add an extra 55 minutes to the time to ensure that you have enough time to make payments and waiting for your turn.
If you are working with your doctor directly, then 5 minutes is enough to collect your blood samples for the test.
- How to Dress
Because the blood from the test will be drawn from the radial artery on your wrist, it is important that you wear a cloth that will allow for easy access to your radial artery. You can wear a short-sleeved shirt or a long sleeve that can easily fold up.
- Cost and what to bring to the hospital
Before the PaO2 test, it is important to confirm with your doctor or healthcare provider to know if your health insurance will cover the cost of your test. If not then go to the clinic with your evidence of payment.
If the health insurance covers the cost of the test then it is important to bring your health insurance card to your doctor
What to Expect During The Test
During the test, there is also a list of things to expect as they will form the main part of the reason to which you found yourself in the hospital in the first place.
Well here is a list of what you should expect at the time of the test, they are not many but they are very important;
- Checking your pulse
During the test, the doctor, nurse or laboratory technician will have to, first of all, check your pulse, if your pulse is normal then blood is drawn from the radial artery in your wrist, but if your pulse is weak then the brachial artery or femoral artery will be used.
- Drawing blood
After your pulse has been checked, the next thing to do is to clean up the puncture site.
This is done with cotton wool dipped in methylated spirit or an alcohol pad, once the puncture site has been properly cleaned a needle fixed with a tube will be inserted into your body and the blood is gently drawn out.
The pain seems a little more than when blood is drawn from the vein but generally, it is bearable for most people.
Because blood pumps rapidly through the arteries the desired quantity of blood will be collected quickly, once that is done the needle is removed and cotton placed on the puncture site, Your doctor or technician will also help in applying pressure to help stop the bleeding.
What to Expect After the Test
After the PaO2 test, a bandage will be placed over the puncture site. After the test, your wrist will feel sore for some days such that you might have difficulties in lifting, eating or performing other tasks but you will be able to resume full activities after some days.
If you still feel sore after some days, you can gently place an ice pack over the puncture wound to reduce the soreness you can also ask your doctor if you can take mild pain killer but be careful with blood thinners like aspirin because they can increase bleeding.
Possible Side effects and how to manage them
Afte the PaO2 test, there are few side effects that you may experience but not to worry because they are minor and can be handled easily.
Once you experience any side effects, it is important that you alert your doctor for proper attention.
Here are the side effects you may experience;
- Severe wrist, hand, or arm pain
- Persistent bleeding
- Pale or bluish color of your fingers or hand
- Numbness, tingling, or diminished sensation of your hand or fingers
- Swelling of your fingers, hand, or arm
- A weakness of your fingers, hand, or arm
Knowing the outcome of your Pao2 test
When the body is functioning normally, PaO2 is between 75 and 100 mmHg (at sea level).5 A result in this range means a sufficient amount of oxygen flowing from the alveoli to the blood.
consequently, a result below or above the above range means an insufficient amount of oxygen flowing from the alveoli to the blood, and to this treatment will be required.
Follow up PaO2 test
You may need to have a follow up PaO2 test, especially if your symptoms don’t improve. You may also need a follow-up test when it’s time to change your oxygen supply or ventilation assistance.
Often, when respiratory support is decreased due to improvement, PaO2 is rechecked to confirm that breathing and oxygenation remain at optimal levels even with less support.
We hope you have learned one or two things reading through this article, wed wish to assure you that PaO2 is quite easy and mild although a little uncomfortable but you can bear it, we also hope that you have learned the things you need to prepare for and what you should expect from this article as this will help you to prepare for your visit to the hospital or clinic confidently.