Pulse oximetry is a non-invasive method for monitoring a person’s O2 saturation. In its most common (transmissive) application mode, a sensor device is placed on a thin part of the patient’s body, usually a fingertip or earlobe, or in the case of an infant, across a foot.
- Sensor probe
- Alcohol pads
- Nail polish remover, if necessary
Preparation of Equipment
- Review the manufacturer’s instruction for assembly.
- Reinforce the explanation of the procedure to the patient.
Using a finger probe
- Select a finger (usually index finger) on the patient’s nondominant hand, if possible for placement of the probe.
- Remove fake fingernail and nail polish from the test finger.
- Place the transducer (photoprotector) probe over the patient’s finger so the light beams and sensor oppose each other.
- Trim long fingernails or position the probe perpendicular to the finger.
- Position the patient’s hand at heart level.
- Turn on the power switch. If the device is working properly, a beep will sound, a display will light momentarily, and the pulse search light will flash.
- After four to six heartbeats the pulse amplitude indicator will begin tracking the pulse.
- Rotate the sensor site according to the manufacturer’s instructions.
- Clean the probe per facility policy between patients or, if disposable, discard.
- Some machines have a pleth wave. A steady, level, even wave form ensures that the numerical reading is accurate.
- The pulse rate on the oximeter should correspond to the patient’s actual pulse. If it doesn’t, monitor the patient, check the oximeter, and reposition the probe.
- Factors that interfere with accuracy include:
- Elevated carboxyhemoglobin or methemoglobin levels
- Lipid emulsions and dyes
- Excessive light
- Excessive patient movement
- Medications such as dapsone, vasopressors.
- Use the bridge of the nose if the patient has compromised circulation in his extremities.
- If an automatic blood pressure cuff is used on the same extremity as the saturation probe is placed, the cuff will interfere with oxygen saturation readings during inflation.
- If the light is a problem, cover the probes.
- If patient movement is the problem, move the probe or select a different probe.
- Notify the physician of any significant change in the patient’s condition.