What are the main measurement indicators of the portable oximeter? The main measurement indicators of the portable oximeter are pulse rate, blood oxygen saturation, and perfusion index (PI). According to medical analysis, the oxygen content in the blood is greater than or equal to 95, which is a normal indicator; the pulse rate is between 60-100 beats per minute, which is a normal indicator. The factors that affect the accuracy of the portable oximeter monitoring results include finger cuff shift, fingertip skin cold, blood supply disorder of monitoring limbs, abnormal fingertip skin or color, application of vasoactive drugs, poor line contact, etc.
Measurement index of portable finger pulse oximeter
- 1. Blood oxygen saturation: Normal human arterial blood oxygen saturation is 98%, and venous blood is 75%. It is an important indicator that reflects the oxygen status in the body. It is generally believed that the normal value of blood oxygen saturation should not be less than 94%, and it is regarded as insufficient oxygen supply below 94%.
- 2. Pulse rate: Pulse refers to the pulsation of superficial arteries. The pulse and heartbeat of a normal person are the same. Heart rate is how often the heartbeats. The average person is between 60-120 times per minute. However, people may experience rapid heartbeat under conditions such as exercise and tension. Pulse rate is the number of pulses per minute. Under normal circumstances, the pulse rate and the heart rate are the same. When atrial fibrillation or frequent pre-period contractions, the pulse rate is lower than the heart rate.
- 3. Perfusion Index (PI): The PI value reflects the pulsating blood flow, that is, it reflects the blood perfusion ability. The greater the pulsating blood flow, the greater the pulsating component and the greater the PI value. Therefore, the measurement site (skin, nails, bones, etc.) and the patient’s own blood perfusion (arterial blood flow) will affect the PI value. Since sympathetic nerves affect heart rate and arterial blood pressure (influencing pulse arterial blood flow), the human body’s neuromodulation system or mental state will also indirectly affect the PI value. Therefore, under different anesthesia states, the PI value will be different.
- 4. Evaluation of test results: According to medical analysis, the oxygen content in the blood is greater than or equal to 95, which is a normal indicator; the pulse rate is between 60-100 beats per minute, which is a normal indicator. If your detected values do not meet the above two indicators, please test 2-3 times at different time points and keep the continuous testing for 2-3 days. If the values still do not meet the standard, you are recommended to go to the hospital for a detailed consultation.
Factors affecting the accuracy of portable oximeter monitoring results
- 1. Finger shift
SPO2 measurement is to fix the probe finger cuff on the nail bed of the patient’s fingertip, use the finger as a transparent container for hemoglobin, use red light with a wavelength of 660 nm and near-infrared light with a wavelength of 940 nm as the incident light source, and measure the light transmission through the tissue bed. Intensity, to calculate the hemoglobin concentration and blood oxygen saturation. If the nail bed is not directly facing the red light, the probe will not be too deep or too shallow to sense the changes in blood oxygen saturation, and the blood oxygen saturation reading will be low or not displayed. The main reason is that the patient is agitated, uncooperative, or pulling the SPO2 finger cuff connection when turning over, causing the finger cuff to shift.
- 2. Cold skin on fingertips
Intraoperative exposure time is long, causing chills and cold skin, resulting in low or no display of SPO2 value read at the fingertips. Care should be taken to keep the limbs warm and keep the temperature at 24-28°C. If necessary, cover with a quilt or use a hot water bottle to keep warm.
- 3. Monitoring of limb blood supply disorders
The blood oxygen sensor is clamped on the limb of the arterial puncture or blood pressure cuff. When the blood pressure cuff is inflated, it affects peripheral blood circulation. The drop of SPO2 in such patients is a transient alarm. After the blood pressure is measured once, it will return to normal, Just replace the limb that monitors blood pressure.
- 4. Abnormal skin or color on the fingertips
Patients with nail polish, false nails, nail lesions such as thick nail beds caused by onychomycosis, etc. There are data showing that blue, green, and black nails can cause the pulse portable oximeter to display low false readings, resulting in 3% to 6% error effects on SPO2 test results.
- 5. Application of vasoactive drugs
Long-term application of dopamine, norepinephrine, and other drugs can make the peripheral blood vessels constrict, and the pulse volume wave will be significantly reduced, which can cause serious distortion or no display of the SpO2 waveform. In addition to dopamine, procaine, prilocaine, lidocaine, but cocaine, and other drugs can cause serious deviations in blood oxygen measurement.
- 6. Poor line contact
The blood oxygen saturation monitoring by the portable oximeter can reflect the change of arterial blood oxygen to a certain extent, but its accuracy is easily affected by many factors. Taking corresponding intervention measures can improve the accuracy and help medical staff to make a diagnosis of the condition. Accurate judgment.