"After the patient eliminated the instrument failure and the puncture needle mistakenly entered the vein, it was found that the change of SaO2 was seriously inconsistent with SpO2. The reason for the analysis of the difference was that SaO2 was the percentage of oxygen content and oxygen capacity, and its value was correlated with PaO2 within a certain range."


    "Based on this principle, the blood gas analyzer calculates the actual SaO2 value by measuring PaO2 in blood."


    "SpO2 is measured by photoplethysmography based on the principle that different wavelengths of light will attenuate differently after passing through arterial blood."


    Wu Mian began to talk about the basic principle of blood oxygen saturation measurement. Several veteran anesthesiologists were confused.


    Although monitors have been used for decades, they only know how to use them. They really don''t know the principle of specific construction machinery at all.


    "It really can''t be explained clearly in plain words." Wu Mian also saw the confusion of several directors, and he immediately said, "it involves the principle of Mechanical Engineering... By the way, did you all learn medical devices at school?"


    "Miss Wu, No." several people shook their heads one after another.


    "Then I''ll try to be simple." Wu Mian hesitated and said.


    In fact, what he said before is about medical principles, which is difficult for ordinary people to understand, just like the reaction of several directors when talking about the principles of medical devices.


    "One side of the pulse oxygen saturation monitoring probe simultaneously emits red light with a wavelength of 660nm and infrared light with a wavelength of 940nm. The absorption of oxidized hemoglobin and reduced hemoglobin to the above two lights is different, so the blood oxygen saturation can be measured and displayed on the machine of the monitor."


    "Based on this difference, the photoelectric sensor on the other side of the probe measures the light intensity of infrared light and red light passing through the tissue, determines the absorption of infrared light and red light by spectrophotometry, and then converts the ratio into SpO2."


    "The difference between SaO2 and SpO2 measurement methods may lead to the inconsistency between the two in the case of severe hypoxemia. The following situations will lead to the false increase of SpO2."


    "First, there is an increase in carboxyhemoglobin in the blood. The absorbance of carboxyhemoglobin is close to that of oxygenated hemoglobin, while the pulse oximeter can only distinguish oxygenated hemoglobin and hemoglobin, and cannot exclude carboxyhemoglobin. Therefore, the value of SpO2 will be high."


    "Second, methemoglobinemia may also lead to this situation.


    Patients with methemoglobinemia have large absorption coefficients of red and infrared light, and their light absorption coefficients at 660nm wavelength are similar to those of hemoglobin, while at 940nm wavelength, the light absorption coefficients of metHb are higher than those of hemoglobin and oxygenated hemoglobin.


    Therefore, if the actual arterial oxygen saturation is low, the SpO2 reading will be falsely high. On the contrary, the SpO2 reading will be falsely low. "


    "Third, patients with severe anemia may also have a similar situation..."


    "Fourth..."


    "Fifth..."


    "Sixth..."


    "Twelfth, hereditary fetal hemoglobinemia..."


    "According to Lao Ren''s medical history, I consider that this patient is more likely to have hereditary fetal hemoglobinemia. It is recommended to check after postoperative recovery. However, it is estimated that the patient will refuse. After all, it has no impact."


    Everyone, including president Zhao, was silly. They stared at Wu Mian with a head of dew.


    Director Liu, in particular, witnessed all the process at the scene. I thought it was a supernatural event. However, when Mr. Wu said so, he found that more than a dozen diseases may induce the inconsistency between the blood oxygen saturation monitored on the monitor and the actual oxygen concentration.


    Is this the gap between ordinary practitioners and top practitioners?


    As for what hereditary fetal hemoglobinemia, several people have never heard of it.


    Originally, Wu Mian thought he was just shaking smart, but he talked about more than a dozen possibilities. After listening, all the clinicians present were in a cold sweat.


    There is a clinical saying - no accident, that is, less surgery.


    Now, this sentence is really the experience summarized by predecessors.


    In the past, it was thought that Mr. Wu Mian became the editorial board member of the latest edition of diagnostics by relying on Mr. Wu. Now everyone understands that Mr. Wu is a person with real and great skills.


    In such a rare situation, which has not been encountered by several directors who have been on the battlefield for a long time, Mr. Wu talked about it, from medicine to medical devices, back to diagnosis, and cited more than a dozen diseases that can lead to this abnormal situation


    It''s really speechless.


    Without comparison, there is no harm.


    Everyone present felt that one critical hit injury after another appeared on his head, and the blood bar had been cleared instantly.


    Only Ren Haitao listened attentively and saw what he meant. If conditions permit, he must take a small book and write down what teacher Wu said.


    After Wu Mian finished, Ren Haitao continued to ask about the diagnostic criteria of hereditary fetal hemoglobinemia.


    "Lao Ren, let''s talk about it when we go back." Wu Mian said with a smile. "We''ll go back after a meal on our plane this afternoon."


    "Oh, good." Ren Haitao has some regrets. Everyone can see his unwillingness.


    This man is really a fool. There are not many people who are crazy about technology now. President Zhao looked at Ren Haitao curiously and thought that the anesthesiologist named Ren Haitao had such a low Eq. where did Mr. Wu draw the baby?


    However, thanks to Ren Haitao, the person who changed the "smart" point was afraid that he would not care at all at that time. After all, under the circumstances at that time, there was no evidence to prove that the patient had a problem. Everything was quiet. Who knows that the patient has been on the edge of life and death.


    Mr. Wu was very interesting, and the people he found were also very interesting. With a smile, Mr. Zhao personally opened a bottle of wine and poured a cup for Wu Mian and Ren Haitao.


    The demonstration operation was smooth, the cooperation between the two hospitals was smooth, and a medical hidden danger was solved. A patient who may have hypoxic brain death was "fished" back. The meal was particularly happy.


    Wu Mian was also good at dancing at the wine table. He had a good talk with president Zhao and finalized the next cooperation plan.


    "Mr. Wu, your level is really high. Let me toast you." director Liu raised his glass to Wu Mian.


    "You''re welcome." Wu Mian said with a smile, "there''s no level. It''s all clinical wrestling. It''s normal."


    "Er..." director Liu was puzzled. Is Mr. Wu serious? Clinical wrestling is directly related to age. Mr. Wu is less than 30. Why does he say that?


    "Director Liu, please sit down." Wu Mian took a sip of wine and said, "I met something in the gastrointestinal endoscopy room during my College internship."