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Oxygen Saturation Monitoring

What does oxygen saturation mean?

Oxygen saturation refers to the amount of oxygen your child's red blood cells are carrying. If your child is in good health, the majority (95% to 100%) of her red blood cells that have passed through the lungs should be full of, or saturated, with oxygen. If she has a heart condition that prevents the red blood cells (specifically hemoglobin) from picking up oxygen, her saturation level will be lower.

This reduced amount of oxygen in the blood is called hypoxemia or cyanosis​.

People breathing regular air have a saturation of 96% to 98%; anything less than 95% results in hypoxemia, which is cause for concern.

What is oxygen saturation monitoring?

Oxygen saturation monitoring measures the amount of oxygen in your child's blood. It helps the nurses and doctors know if your child’s body is getting the oxygen it needs. It also tells them if your child's body is correctly using the oxygen your child is breathing.

Why does your child's oxygen saturation need to be monitored?

The doctors and nurses have decided that your child's oxygen level needs to be measured constantly. This will give them continuous information about your child's health condition. The monitor also warns the nurse if your child's condition changes.

How does oxygen saturation monitoring work?

A long, thin wire is attached to the monitor. This wire connects to a cover called a probe (also called a sensor). The probe is put over your child's finger or toe. The probe has a small red light on one side and a detector on the other side. The red light shines through your child's finger or toe and is seen by the detector on the other side. The detector measures the amount of oxygen in the blood. This way of checking oxygen is called pulse oximetry .

How else can oxygen in the blood be measured?

Another way to measure the amount of oxygen in the blood is with a test called an arterial blood gas. Blood is drawn from an artery and tested to see how much oxygen is in it. It's like having blood drawn regularly, except that in this case, the blood is not taken from a vein. The doctor may decide to use pulse oximetry or arterial blood gas, or both, to evaluate the amount of oxygen in your child’s blood.

Will the monitor or probe hurt your child?

No. The monitor and the probe are completely safe. The probe will be applied securely but not tightly to your child's finger or toe. This does not hurt. The nurse will probably move the probe to a different finger or toe about every 8 hours. This will help make sure that the probe is still working properly. It also gives a rest to your child's finger or toe.

Who should touch your child's monitor?

Only your child's nurse or doctor should touch the monitor and the stickers or probes attached to your child. Do not change the alarm settings or turn the monitor off. This could be unsafe. It could mean that the nurse is not notified if your child's condition changes.

What makes the monitor alarm go off?

Your child's nurse will set ranges on the monitor based on your child's age, illness, and vital signs. If your child's heart rate or oxygen level go outside these ranges, an alarm will go off. If the monitor alarm goes off, a nurse will come and check your child.

How long will your child be connected to the oxygen saturation monitor?

Most children who need to have their oxygen level measured constantly are connected to the monitor at all times. Some children may only need to be connected to the monitor when they are sleeping. Your child's doctors and nurses will decide how long your child needs to be connected to the monitor.

What happens if your child's oxygen levels are low?

If oxygen levels are found to be low, your child will receive oxygen in concentrations higher than would be present in the regular air we breathe. This is delivered through a face mask or tubes in the nose (nasal cannulae) connected to a mechanical ventilator. This is known as oxygen therapy.

Andrew N. Redington, MD, FRCP (UK), FRCPC

Andrew N. Redington, MD, FRCP (UK), FRCPC