Oxygen meter vital tool to diagnose health

Apr 1, 2013 by Keith Murray

A guests complains he has difficulty breathing. You are several hours from the nearest port so you contact your medical service provider and the doctor instructs you to get the patient’s baseline vitals.

You wonder why the doctor needs this information. Can’t he just do something?

Think of the doctor on the other end of the telephone as a detective trying to solve a mystery. The doctor needs you to provide the clues to help figure out what is wrong with your patient. The vital signs will be the first clue.

One of the vital signs you will be asked for is the patient’s pulse. The pulse is the beat you feel against the wall of an artery when the heart beats. The pulse is the same as your heart rate.

In a normal adult, the pulse will be between 60 and 100 beats per minute. You can manually check the adult with either the carotid (neck) or radial (wrist) pulse but this requires a lot of practice to get it right. I have seen trained nurses struggle to get accurate numbers.

There is an easier way. In fact, there are two ways. Both are by using relatively inexpensive devices that take the patient’s pulse for you.

The first is a digital or automatic blood pressure monitor; it ranges in price from $25-$500.

The second is a pulse oximeter, commonly called a pulse ox; it ranges in price from $30-$300.

A pulse oximeter is a medical device that can monitor the oxygen saturation of your patient’s blood and their pulse (heart rate). The pulse oximeter is a non-invasive medical device that slips on the patient’s finger. It does not hurt.

Once clipped on the end of the patient’s finger, it sends two beams of light across the nail bed. Inside the clip are two diodes. The first diode emits a red light and the second an infrared light. (You will be able to see the red light, but not the infrared.)

These two beams of light enable the pulse oximeter to detect the color of the arterial blood, which helps to calculate the oxygen saturation.

Because a pulse oximeter is easy to use and provides fast results, it plays a vital part in emergency medicine. Often, these are very useful when working with patients with respiratory or cardiac problems such as chronic obstructive pulmonary disease (COPD), a common lung disease.

I spoke with Paramedic Rick Sosa of Stuart (Fla.) Fire Rescue about pulse oximeters. He said his team uses the pulse ox on every patient. The information it gathers is part of the vitals they obtain for every patient they treat. These vitals provide the general condition of the patient and let paramedics know if the patient’s condition is improving, declining or is unchanged.

If you have a telemedicine device onboard, the pulse oximeter should be part of your kit. If you are not sure, now is a good time to open your telemedicine unit or your first aid kit to see what you have. (It’s also a good time for onboard emergency medical training.)

OK, I have a pulse oximeter on my patient’s finger and I want to know what these numbers mean. A healthy person should have an oxygen saturation of 95-100 percent. These numbers may vary with age, health, altitude, and if the patient is connected to an oxygen tank. I am reluctant to talk about “normal” pulse or “normal” oxygen rates in too much detail as it is always best to let trained medical professionals interpret these readings.

A good pulse oximeter is a vital part of every first aid kit. If yours does not include one, now is a great time to invest in one. Make certain you show all crew members how to use it, and let them see what normal readings look like.

Please note that the pulse oximeter will not provide accurate oxygen saturation information if the patient has been exposed to carbon monoxide. Carbon monoxide is a colorless, odorless gas that is produced by fires and exhaust from engines. If you believe your patient has been exposed to carbon monoxide, alert your medical provider immediately.

The pulse oximeter may not perform well on patients with circulation issues, irregular or weak pulse rates or in brightly lit areas. Bright lights as may provide inaccurate readings since this device uses light to measure.


Keith Murray, a former firefighter EMT, owns The CPR School, a first-aid training company. He provides onboard training for yacht captains and crew and sells and services AEDs. Contact him at 877-6-AED-CPR, 877-623-3277 or www.TheCPRSchool.com. Comments on this column are welcome at editorial@the-triton.com.