The number of Covid infections in Italy continues to rise. Yesterday, Saturday 31 October, 31,758 new cases were recorded compared to 215,085 swabs processed, 801 more than the previous day. 297 deaths. Once again Lombardy is the most affected region (+8.819), followed by Campania (+3.669), Piedmont (+2.887), Veneto (+2.697), Tuscany (+2.540), Lazio (+2.289) and from Emilia Romagna (+2,046). Waiting for new Dpcm which will be launched on Monday 2 November, the Ministry of Health is studying the possibility of delivering a oximeter, or a tool capable of identifying the risk of pneumonia (one of the most fearful consequences of the coronavirus) to each family. Luca Richeldi, primary pulmonologist at the Gemelli hospital in Rome, president of the Italian Society of Pulmonology and member of the CTS, said that this opportunity was also discussed in the Technical Scientific Committee. But let’s see together how this object that could save life works.
Also known as a pulse oximeter or oximeter, the oximeter is a medical device that allows you to measure the degree of saturation of oxygen hemoglobin present in peripheral arterial blood (defined by the abbreviation “SpO2”). At the same time it also allows the measurement of heart rate. Normal oxygen values above 95% are considered. Lower values indicate that the patient is in a state of hypoxemia. The latter, in turn, is mild when the measured values are between 91% and 94%, average if oxygen levels fluctuate between 86% and 90%. Finally, this condition is serious if the values are equal to or less than 85%. Under normal conditions, i.e. in the absence of oxygen administration, a value equal to 100% could be an expression of hyperventilation.
There are several components that characterize the oximeter. First of all, a probe generally in the shape of a caliper that measures in contact with the subject (finger of a hand, earlobe and foot in infants). Another calculation and data processing unit that collects those of the probe and then sends them to the appropriate monitor. The operating principle is identical to that of the spectrophotometry. The probe, in fact, is equipped with two light-emitting diodes on one arm of the clamp and a detector on the opposite arm. Diodes emit beams of light at precise wavelengths that fall in the red and infrared range. During the journey, the light radiation is absorbed by hemoglobin. Oxyhemoglobin (bound to oxygen) mainly absorbs infrared light. The unbound one, on the other hand, acquires red light in particular. By exploiting this difference in absorption, the calculation unit is able to provide the saturation value.
The use of the oximeter is essential to quickly identify the presence of conditions dangerous to health. In detail, its use is useful in order to evaluate the respiratory function of an individual in general during specialist visits, to constantly monitor the degree of saturation and heart rate of hospitalized subjects, to measure the parameters of patients suffering from airway diseases, such as pneumonia, chronic bronchitis, BPCO, bronchial asthma, sleep apnea. Still to determine the presence or absence of any damage to the respiratory function in people exposed to pollutants. Using the oximeter is simple. After turning it on, the probe should be placed on a finger, earlobe or foot in the case of a newborn. Once the measurement has started, the result will appear on the monitor.
The disadvantages of this medical device are represented exclusively by the presence of certain conditions, including: peripheral vasoconstriction, patient movements, anemia, presence of methylene blue in the bloodstream. An important limitation of the oximeter is that it cannot discriminate between oxyhemoglobin (hemoglobin bound to oxygen) and carboxyhemoglobin (hemoglobin bound to carbon monoxide). Here, then, that an individual with an intoxication from this toxic compound, could manifest normal oxygen saturation levels, when this is not the case. In order to stem this problem, the so-called puls-CO-oximeters have been created relatively recently.
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