In the fields of clinical monitoring and routine health monitoring, pulse oximeters are crucial physiological parameter monitoring devices, with their core function being the measurement of Spo2 sensor. To deeply understand the significance of this indicator, it is essential to begin with the basic physiological processes of the human body.
The maintenance of life activities depends on a continuous energy supply, and energy production is inseparable from intracellular aerobic metabolism. Oxygen, as a key participant in this process, needs to enter the human body through the respiratory system and is transported by hemoglobin in the blood. Hemoglobin is a protein with a special structure; whether or not it binds to oxygen changes its optical properties. Specifically, oxygen-carrying hemoglobin is called oxyhemoglobin, while oxygen-free hemoglobin is called deoxyhemoglobin. They exhibit significant differences in their absorption rates of light in the visible red and infrared regions-oxyhemoglobin has a higher absorption rate of infrared light and a lower absorption rate of red light; deoxyhemoglobin, on the other hand, has the opposite. This physical characteristic forms the physical basis for the operation of blood oxygen sensors.
Based on the above principles, modern spo2 sensor primarily employ non-invasive optical measurement technology, namely pulse oximetry. A typical sensor usually consists of one or more light-emitting diodes (LEDs) and a photodetector. The sensor is worn on a part of the body rich in capillaries, such as the fingertip, earlobe, or forehead. During operation, the sensor alternately emits red and infrared light of specific wavelengths. After the light penetrates the body tissue, it is received by the photodetector on the other side. During the light's path, besides a portion being absorbed by arterial blood, venous blood, and surrounding tissues, the remaining light is captured by the detector. Crucially, with the heartbeat, arterial blood undergoes periodic pulsations, and its volume changes accordingly, resulting in a synchronous periodic change in the amount of light absorbed. Therefore, the intensity of the light signal captured by the detector also exhibits a pulsatile characteristic.
Subsequent signal processing circuits and algorithms precisely analyze the absorption change ratio of these two wavelengths of light signals during pulsation. By establishing an empirical calibration curve between this ratio and blood oxygen saturation (this curve is usually derived by comparing a large amount of invasive blood test data with non-invasive optical measurement data), the device can calculate and display the current blood oxygen saturation value in real time. Therefore, what the blood oxygen sensor measures is the percentage of oxygenated hemoglobin in arterial blood relative to the total oxygen-binding hemoglobin, which is commonly referred to as SpO₂. In a healthy individual, the SpO₂ value at rest should typically be maintained between 95% and 100%. When this value is below 94%, it may indicate a risk of hypoxia; if it is below 90%, it is usually considered clinical hypoxemia and requires immediate medical attention.
In medical practice, spo2 sensor are widely used. Their central role in hospital environments is particularly prominent, forming the foundation of modern medical safety monitoring networks.
In the operating room and during anesthesia, spo2 sensor are indispensable monitoring devices for ensuring patient safety. General anesthesia significantly suppresses a patient's spontaneous breathing, and procedures such as endotracheal intubation and mechanical ventilation inherently carry risks. Pulse oximeters provide continuous SpO₂ readings, offering crucial oxygenation status feedback to anesthesiologists. In cases of insufficient ventilation, tubing dislodgement, or oxygen supply interruption, the drop in blood oxygen levels often precedes changes in vital signs such as heart rate and blood pressure, providing valuable intervention time for medical staff and effectively preventing brain damage and other organ dysfunction caused by severe hypoxemia.
In the intensive care unit, spo2 sensor data is crucial for assessing the cardiopulmonary function of critically ill patients. For patients with acute respiratory distress syndrome, severe pneumonia leading to respiratory failure, or heart failure causing insufficient circulatory perfusion, continuous pulse oximetry monitoring not only reflects the severity of the underlying disease but is also a key indicator for evaluating the appropriateness of ventilator settings, drug efficacy, and fluid management. By observing the dynamic trends in SpO₂, medical staff can adjust treatment plans promptly, achieving refined management of critically ill patients.
In conclusion, spo2 sensor, with their non-invasive, continuous, and reliable monitoring characteristics, have been deeply integrated into various key diagnostic and treatment processes in hospitals. This sophisticated instrument continuously provides vital objective data for clinical decision-making, becoming an indispensable technological cornerstone for modern hospitals to ensure patient safety and improve the quality of medical care.