-
Categories
-
Pharmaceutical Intermediates
-
Active Pharmaceutical Ingredients
-
Food Additives
- Industrial Coatings
- Agrochemicals
- Dyes and Pigments
- Surfactant
- Flavors and Fragrances
- Chemical Reagents
- Catalyst and Auxiliary
- Natural Products
- Inorganic Chemistry
-
Organic Chemistry
-
Biochemical Engineering
- Analytical Chemistry
-
Cosmetic Ingredient
- Water Treatment Chemical
-
Pharmaceutical Intermediates
Promotion
ECHEMI Mall
Wholesale
Weekly Price
Exhibition
News
-
Trade Service
During the operation, through blood gas analysis, the anesthesiologist can obtain a number of key data.
One of the most meaningful parameters is the hemoglobin concentration Hb.
However, only a few intermittent data can be obtained through the blood gas analyzer, and continuous real-time monitoring is not possible; I do not know when I heard that continuous Hb monitoring has been achieved abroad, but there are still no available products in China for many years, and I have always felt very puzzled.
, Do not understand why.
A few days ago, I read pages P1396 and P1658 of the 8th edition of Miller Anesthesiology.
While understanding the principle of finger pulse oxygen, I also checked the application status of SpHb monitoring.
The following briefly introduces the principle of finger pulse oxygen measurement and the prospects of SpHb monitoring.
Everyone share.
We know that there are four forms of hemoglobin in the blood: oxyhemoglobin (O2Hb), deoxyhemoglobin (deO2Hb), carboxyhemoglobin, and methemoglobin; the latter two are very small, the total amount is less than 4%, and they are obtained clinically SpO2 is a proportional relationship between the first two.
Scientists described the above four types of hemoglobin with different light absorption rates at different wavelengths (as shown in the figure below), and found that the light absorption rate of deO2Hb at 660nm was significantly greater than that of O2Hb, and the light absorption rate of O2Hb at 940nm was significantly greater than that of deO2Hb.
From the 8th edition of Miller Anesthesiology, the part where light is absorbed through tissues is divided into arterial pulsatile part (AC) and non-pulsatile part (DC).
The AC and DC absorption parts at 660nm and 940nm wavelengths are measured respectively.
Obtain the light absorption ratio R=(AC660/DC660)/(AC940/DC940), and then obtain SpO2 according to the calibration curve of each manufacturer's internal pulse oxygen saturation and R.
Since the following curve is drawn by the manufacturer based on the volunteers breathing low oxygen gas, the SaO2 changes between 70% and 100%, so the error is the smallest when SpO2 is above 70%, and generally does not exceed 4% or even lower.
Derived from the application of the above principles in the 8th edition of Miller Anesthesiology, in addition to monitoring pulse oxygen saturation, scientists have found more applications, including continuous non-invasive measurement of total Hb (SpHb), cerebral oxygen monitoring, and monitoring of pulse variability in volume The index (PVI) and the perfusion index PI (defined as AC940/DC940) can be used to indicate whether there is pain under anesthesia, and so on.
The following only introduces the promising SpHb.
The monitoring principle of SpHb is similar to the principle of peripheral finger pulse oxygen saturation (SpO2).
SpHb monitors the light absorption of other wavelengths (presumably around 800nm, where the deO2Hb and O2Hb extinction coefficients are equal), and the Beer-Lambert law is used to reverse the total hemoglobin Concentration, we will not go into the more detailed process.
Clinically, continuous monitoring of SpHb is achieved through finger spectrophotometry.
The measurement error is generally less than 1.
0~1.
5g/dl; the size of the error depends on the sensor factor and the physiological condition of the finger.
If the blood flow and temperature of the operation rise, the accuracy will be improved.
; If the perfusion index PI is greater than 4% to 5%, the measurement accuracy of SpHb can be significantly improved, and the application of bupivacaine for finger nerve block can achieve the same effect.
The picture is from the Internet.
Although it cannot achieve consistent accuracy, there are studies that the continuous monitoring provided by SpHb will not lead to blood transfusion.
Generally speaking, when the change of SpHb suddenly exceeds 1~2g/dl, you should actively look for the reason and let the anesthesia Doctors intervened earlier; under the existing SpHb monitoring, it is also necessary to intermittently measure the accurate hemoglobin concentration.
Although bedside blood gas analysis is very accurate in detecting hemoglobin, continuous, non-invasive monitoring can dynamically observe and identify fleeting changes in real time.
Any monitoring method should be based on this goal.
Many years ago, blood pressure was non-invasive, intermittent monitoring, and slowly developed into invasive, continuous monitoring.
Now non-invasive, continuous monitoring of blood pressure has been achieved.
I believe that with the improvement of SpHb monitoring technology, monitoring hemoglobin is as simple as blood oxygen saturation.
Accurate and fast.
Recommendation: What is the error in measuring upper limb non-invasive blood pressure in the lateral position? Will the length of the left main bronchus really not change?
One of the most meaningful parameters is the hemoglobin concentration Hb.
However, only a few intermittent data can be obtained through the blood gas analyzer, and continuous real-time monitoring is not possible; I do not know when I heard that continuous Hb monitoring has been achieved abroad, but there are still no available products in China for many years, and I have always felt very puzzled.
, Do not understand why.
A few days ago, I read pages P1396 and P1658 of the 8th edition of Miller Anesthesiology.
While understanding the principle of finger pulse oxygen, I also checked the application status of SpHb monitoring.
The following briefly introduces the principle of finger pulse oxygen measurement and the prospects of SpHb monitoring.
Everyone share.
We know that there are four forms of hemoglobin in the blood: oxyhemoglobin (O2Hb), deoxyhemoglobin (deO2Hb), carboxyhemoglobin, and methemoglobin; the latter two are very small, the total amount is less than 4%, and they are obtained clinically SpO2 is a proportional relationship between the first two.
Scientists described the above four types of hemoglobin with different light absorption rates at different wavelengths (as shown in the figure below), and found that the light absorption rate of deO2Hb at 660nm was significantly greater than that of O2Hb, and the light absorption rate of O2Hb at 940nm was significantly greater than that of deO2Hb.
From the 8th edition of Miller Anesthesiology, the part where light is absorbed through tissues is divided into arterial pulsatile part (AC) and non-pulsatile part (DC).
The AC and DC absorption parts at 660nm and 940nm wavelengths are measured respectively.
Obtain the light absorption ratio R=(AC660/DC660)/(AC940/DC940), and then obtain SpO2 according to the calibration curve of each manufacturer's internal pulse oxygen saturation and R.
Since the following curve is drawn by the manufacturer based on the volunteers breathing low oxygen gas, the SaO2 changes between 70% and 100%, so the error is the smallest when SpO2 is above 70%, and generally does not exceed 4% or even lower.
Derived from the application of the above principles in the 8th edition of Miller Anesthesiology, in addition to monitoring pulse oxygen saturation, scientists have found more applications, including continuous non-invasive measurement of total Hb (SpHb), cerebral oxygen monitoring, and monitoring of pulse variability in volume The index (PVI) and the perfusion index PI (defined as AC940/DC940) can be used to indicate whether there is pain under anesthesia, and so on.
The following only introduces the promising SpHb.
The monitoring principle of SpHb is similar to the principle of peripheral finger pulse oxygen saturation (SpO2).
SpHb monitors the light absorption of other wavelengths (presumably around 800nm, where the deO2Hb and O2Hb extinction coefficients are equal), and the Beer-Lambert law is used to reverse the total hemoglobin Concentration, we will not go into the more detailed process.
Clinically, continuous monitoring of SpHb is achieved through finger spectrophotometry.
The measurement error is generally less than 1.
0~1.
5g/dl; the size of the error depends on the sensor factor and the physiological condition of the finger.
If the blood flow and temperature of the operation rise, the accuracy will be improved.
; If the perfusion index PI is greater than 4% to 5%, the measurement accuracy of SpHb can be significantly improved, and the application of bupivacaine for finger nerve block can achieve the same effect.
The picture is from the Internet.
Although it cannot achieve consistent accuracy, there are studies that the continuous monitoring provided by SpHb will not lead to blood transfusion.
Generally speaking, when the change of SpHb suddenly exceeds 1~2g/dl, you should actively look for the reason and let the anesthesia Doctors intervened earlier; under the existing SpHb monitoring, it is also necessary to intermittently measure the accurate hemoglobin concentration.
Although bedside blood gas analysis is very accurate in detecting hemoglobin, continuous, non-invasive monitoring can dynamically observe and identify fleeting changes in real time.
Any monitoring method should be based on this goal.
Many years ago, blood pressure was non-invasive, intermittent monitoring, and slowly developed into invasive, continuous monitoring.
Now non-invasive, continuous monitoring of blood pressure has been achieved.
I believe that with the improvement of SpHb monitoring technology, monitoring hemoglobin is as simple as blood oxygen saturation.
Accurate and fast.
Recommendation: What is the error in measuring upper limb non-invasive blood pressure in the lateral position? Will the length of the left main bronchus really not change?
