How does a medical monitor measure edema

Edema is a common symptom in critically ill patients, and the monitoring of edema helps to assess the severity of the patient. At present, there are many methods to detect edema, which is a qualitative assessment of the degree of edema of patients by medical staff through visual observation. Medical staff will grade the degree of edema of patients based on experience. How to measure edema by medical monitor? Monitor manufacturer will give you specific explanation.

1. Circumferential measurement

It is mainly used for the detection of lymphedema. Medical staff calculate the volume of lymphedema in patients by circumferential measurement. The method uses a soft ruler to measure the circumference of the patient's arm from the wrist to the shoulder, and then calculates the volume of the lymphedema using existing formulas. This estimation method is more objective than the empirical grading method, but it has the following disadvantages: This method is only applicable to the assessment of lymphedema, and the measurement process is time-consuming and time-consuming, which is not convenient for frequent detection, so it is difficult to achieve real-time monitoring of patients.

2, drainage measurement method

Used to measure the leg edema volume, medical personnel by measuring the volume of the discharged liquid edematous tissue to evaluate the volume of edema, the downside of this approach is that it is a kind of detection method, and is not conducive to applied to the monitoring of critically ill patients, the test method is only applicable to certain parts of edema.

3. Optical coherence tomography

It is a non-invasive detection method, which can image the tissue in real time, and its resolution is close to that of ultrasonic image. Corneum, epidermis, accessory structures and vascular layers can be distinguished from optical coherence tomography images. This method can better detect the volume and shape of patients' edema, but it has the following disadvantages: this method can only be carried out in a special testing room, and can not be used for bedside monitoring, nor for real-time monitoring of patients. The detection cost of this method is high.

Many medical monitors and near-infrared spectroscopy have been used in studies on skin edema detection, which classifies and quantifies the status of skin edema and imagines skin edema using photodetector arrays. The study also quantified the erythema of skin edema by measuring oxygenated and deoxygenated hemoglobin concentrations as a factor in assessing the severity of edema.