Notice! SpO2 is measured every day. Do you know these influencing factors?

author: Raisa Zhang
25/03/2022
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SpO2 is an important physiological parameter that reflects respiratory and circulatory function. The monitoring of SpO2 is widely used in clinical medicine, surgery, and intensive care units. Because it is non-invasive, rapid, and can continuously and dynamically observe the oxygenation of the body, it can detect early hypoxemia early, and provide the basis for clinical rescue and nursing.

Influencing factors and treatment measures

01 Finger shift
The principle of SpO2 measurement is to use the characteristics of the absorption spectrum of hemoglobin. If the red light is not aligned correctly, the probe can not be probed too deep, too shallow or too loose to sense the change of SpO2, so the reading of SpO2 will be low or not displayed.
Treatment measures: Adjust the position of the finger and the finger cover so that the red light is facing the nail bed.

02 Cold skin on fingertips
Intraoperative exposure time is long, causing patients to shiver and cold skin, resulting in low or no display of SpO2 readings from the fingertips.
Treatment measures: pay attention to keeping the limbs warm. Keep at room temperature and keep warm with a quilt or a hot water bottle if necessary.

03 Abnormal skin or color on the fingertips
Nail polish, dirt on the fingertips, thick nail bed, onychomycosis, etc. will affect the accuracy of SpO2.
Treatment measures: The fingernails should be cleaned during monitoring.

04 Monitoring limb blood oxygen disturbances
The patient's use of restraint belts that are too tight, excessive bending of limbs, long-term fixation on one finger for monitoring, frequent monitoring, etc. will block the current and affect the results of SpO2 monitoring.

Treatment measures: The simultaneous monitoring of the pressure measuring limbs should be avoided, the fingers should be replaced frequently for monitoring, and the tightness of the restraint belt should be appropriate.

05 Use of vasoactive drugs
Extravasation of vasoactive drugs results in tissue redness.
Treatment measures: The infusion site should be observed for exudation, redness and swelling in time, and the fluid path should be replaced in time.

06 Poor contact with the subject
When the patient turns over and changes positions, the SpO2 monitoring line is stretched and loosened.
Treatment measures: Insert the bottom in alignment with the slot.

07 Oxygen tubes blocked or half-blocked by secretions
Oxygen cannot enter or can not enter the alveoli smoothly, resulting in tissue hypoxia or ineffective oxygen supply, resulting in decreased SpO2 .
Treatment measures: The oxygen pipe should be replaced and cleaned in time.

08 Oxygen tube prolapsed or pressurized
The oxygen tube comes out after the patient coughs, or the oxygen tube is twisted and compressed after the patient rolls over.
Treatment measures: Fix the position of the oxygen tube in time, and check whether the position of the oxygen tube is unobstructed.

09 Mechanical factor
The position of the probe is wrong, the probe or lead is falling off, and there is a mechanical failure.
Treatment measures: Check the position of the probe in time, place the probe in a suitable position, check the connection between the probe and the lead wire, and between the lead wire and the monitor, to ensure that the connection is tight and not loose, and the monitor should be replaced immediately for mechanical failures.

10 Patient factors
For example, during cardiopulmonary bypass, cardiac arrest in critically ill patients, undetectable pulselessness, diabetes, arteriosclerosis, and reduced pulsatile blood flow will all affect the decrease in pulse oxygen saturation.