Safe Oxygen Levels: What Should My Oxygen Level Be?

Safe Oxygen Levels: What Should My Oxygen Level Be?

safe oxygen levelsIf you’re using supplemental oxygen, it’s important to understand what your oxygen levels should be and when your oxygen levels aren’t safe. Many people with COPD have oxygen levels that are below normal, even when using supplemental oxygen. At what point do your oxygen levels go from being below normal to unsafe? Let’s first explore what it means to have low blood oxygen levels.

Low Blood Oxygen Levels = Hypoxemia

When blood oxygen levels drop below normal, a condition known as hypoxemia occurs. In COPD, hypoxemia is a problem related to your breathing. Hypoxemia is determined by measuring the amount of oxygen present in a blood sample taken from an artery, or an arterial blood gas. It can also be estimated using a pulse oximeter, a small device that attaches to your finger and measures the oxygen saturation level in your blood.

Normal arterial oxygen levels as measured by an arterial blood gas range from 75 to 100 millimeters of mercury (mm Hg). According to the Mayo Clinic, values under 60 mm Hg usually indicate that a person needs supplemental oxygen. Normal oxygen saturation levels as measured by pulse oximetry range from 95% to 100 percent. Values under 90% are considered low.[1]

Blood Oxygen Levels: What’s Unsafe?

Unsafe oxygen levels are determined by your doctor but in general, you qualify for supplemental oxygen according to Medicare guidelines when your arterial blood gas is at or below 55 mm Hg and/or your pulse oximetry reading is at or below 88% under certain conditions. This doesn’t mean that a pulse oximetry reading of 90% is safe for you. Whenever blood oxygen levels drop for more than a short period of time, your organs and tissues don’t get the oxygen they need to function properly. Over time, this can lead to serious health consequences, such as pulmonary hypertension (high blood pressure in the lungs) and polycythemia (increased amount of red blood cells).[2]

Maintaining Safe Oxygen Levels

When you’re given a prescription for supplemental oxygen, your doctor should give you a safe range of oxygen saturation levels that she wants you to maintain. If you consistently fall below this range, you should notify your doctor as an adjustment may need to be made in your oxygen flow rate.

Your doctor may also give you permission to “titrate” your oxygen flow rate according to your oxygen saturation levels. For example, if your doctor determines that your safe oxygen saturation level should be 92% or above, she may advise you to increase your oxygen flow rate if your saturation drops below 92 percent. Maintaining safe oxygen levels is important for your health and well-being and if this becomes a problem for you while on supplemental oxygen, talk to your doctor as soon as possible.

Following Your Doctor’s Order

Although supplemental oxygen is beneficial to patients who need it, some patients fail to use it as prescribed. This is due to many reasons, including lack of a clear understanding of the benefits of supplemental oxygen and the reluctance to wear a nasal cannula or be tied down to an oxygen delivery source.[3] But using supplemental oxygen for more than 15 hours a day improves survival for some patients with COPD. That’s why it’s so important to follow your doctor’s orders.

Never increase or decrease your oxygen flow rate without first consulting with your doctor. Use your oxygen therapy as prescribed and never allow someone else to use your oxygen. If you’re having difficulties using your oxygen the way it’s ordered, talk to your doctor about an alternative oxygen delivery system. Sometimes switching nasal cannulas or oxygen delivery sources is all it takes to improve adherence to oxygen therapy. Finally, if you have any concerns about using supplemental oxygen, discuss them with your doctor.


[1] Mayo Clinic. Hypoxemia (low blood oxygen). December 25, 2015.

[2] Kent, B. D., Mitchell, P. D., & McNicholas, W. T. (2011). Hypoxemia in patients with COPD: cause, effects, and disease progression. International Journal of Chronic Obstructive Pulmonary Disease6, 199–208.

[3] Katsenos, Stamatis and Constantopoulos, Stavros, H. Long-Term Oxygen Therapy in COPD: Factors Affecting and Ways of Improving Patient Compliance. Pulmonary Medicine. 2011.

By Deborah Leader RN, BSN, PHN


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