The CO2 level in the room is normal. Occupational safety: environmental rules and regulations for office premises. Standards for carbon dioxide (CO2) concentrations in residential premises What to do

Sensors carbon dioxide are integral part building automation systems and, as a rule, control forced ventilation and air conditioning. Power setting supply and exhaust ventilation Previously, it had to be carried out in accordance with established standards, which were focused on maximum design indicators, for example, on the required air exchange rate depending on the type and volume of the building.
An adaptive ventilation system controlled by CO2 sensors consumes 30–50% less electricity compared to a constantly operating forced ventilation system. Indeed, during the required volume of supplied and removed air may be much less than the calculated values. At the same time, the adaptive ventilation system, equipped with CO2 sensors, promptly performs air exchange in the room when required, creating comfortable and safe conditions for living and working.

Why is carbon dioxide dangerous for humans?

Extremely permissible norm CO2 content in the air is only 700 ppm. If this threshold is exceeded by 2.5 times, people breathing carbon dioxide-polluted air experience headaches and fatigue. After just 6 hours of working in such conditions, concentration and performance are greatly reduced. At the same time, the CO2 content in a poorly ventilated room where there is a large number of person, increases in arithmetic progression in a matter of minutes. For example, when about 20 people gather in a small meeting room (about 20 sq. m.), the carbon dioxide concentration will rise to 10,000 ppm within an hour if fresh air is not supplied.

Increased concentrations of CO2 negatively affect human health not only during the day, but also at night, even though all processes in the body slow down. Scientists from the Netherlands have found that for healthy sleep there will be quality is more important air, not sleep duration. Prolonged inhalation of air with a high carbon dioxide content leads to a deterioration of the immune system, the development of acute and chronic diseases of the upper respiratory tract, cardiovascular system, blood, etc.

When are carbon dioxide sensors needed?

CO2 sensors allow you to start ventilation, including emergency ventilation, and other utility systems.

Scope of application:

• adaptation of the operation of forced supply and exhaust ventilation in accordance with the concentration of carbon dioxide in the air in public, industrial and residential buildings, especially in isolated rooms (tunnels, underground garages, motor and test benches, etc.);
• launch alarm in public and industrial buildings;
• reduction of power consumption by ventilation and air conditioning systems;
• monitoring the quality of exhaust air at industrial enterprises for timely troubleshooting.

We present to your attention the line of CO2 sensors from FuehlerSysteme:

The CO2 concentration diagnostic accuracy is 100 ppm. Three different threshold ranges can be configured: 0 – 2000/5000/10000 ppm.

The devices are capable of operating at temperatures from -20 to +50 degrees Celsius. Operating range relative humidity– from 0 to 98%, provided that the air is not condensed and does not contain a large percentage of chemicals.

There is the possibility of both two-wire and three-wire connection. The output signal is 0 - 10 volts or 4 - 20 milliamps. Provided manual setting zero point. Automatic calibration is performed every seven days. Entry into operating mode occurs only after self-diagnosis and startup of the thermostat.

The type of sensor device is non-diffuse infrared (NDIR) measuring element.

Types of FuehlerSysteme carbon dioxide sensors:

External

Duct

Indoor

CO2 and temperature sensors

A line of carbon dioxide sensors has also been developed, additional option which is the ability to measure temperature in the range from 0 to +50°C. CO2 and temperature sensors are presented in three configurations - duct, room, outdoor.

They allow you to automatically trigger alarms, ventilation, heating or thermostats in all types of rooms. The final signal can be given according to two criteria, which is important for industries where it is necessary not only to monitor the concentration of carbon dioxide, but also to strictly observe the temperature regime.

The presented equipment complies with European standards: CE, EAC, RoHS.

Carbon dioxide sensors have the potential to improve people's quality of life and create comfortable conditions labor, preventing the influence harmful concentrations carbon dioxide on the body. They are also indispensable in production when monitoring exhaust air. CO2 sensors can be integrated into the air conditioning system or connected to another type of thermostat if equipped with an additional temperature measurement option. This will allow for stricter control over production processes. In addition, carbon dioxide sensors can significantly reduce maintenance costs compulsory system ventilation, reducing the amount of electricity it consumes. This makes this device an indispensable component in modern automated utility systems.

However, not everyone knows that at this moment there is less and less oxygen in the room. This is because most air conditioning systems can only cool the air that we have breathed for several hours, or maybe even days. The same thing happens in the car.

Symptoms to watch out for:

In the summer everything is fine, but in the winter there is complete apathy. We like to call it seasonal depression.
- in the morning everything is fine, but by the evening the brain refuses to work. Just like a zombie flipping through the Internet. You come home with wild fatigue and plop down on the sofa.
- woke up in the morning without an alarm clock and didn’t get enough sleep
- coffee green tea - do not give the expected effect, you become even angrier.
- you sleep as much as you want, but the dream is still not remembered.
- sometimes you can’t keep something important in your thoughts, it gets forgotten.
- we get up in the morning with extreme fatigue
- It seems that the room is dark.

And if you have similar symptoms at your workplace, then you have poisoning. What kind of poisoning is this? Carbon dioxide poisoning (not to be confused with carbon dioxide!). Carbon dioxide is not so harmless. The processes associated with an increase in its concentration are similar to poisoning. When the acidity of the blood changes, processes in the body proceed intermittently.

Lack of oxygen has an extremely negative effect on human body. We begin to feel tired and lethargic, the desire to do anything physically disappears, and our head completely refuses to work. Attributing the sluggish state to the heat, we continue to sit in a stuffy office or apartment, not suspecting what the true reason for the loss of strength lies.

The main factors that worsen air quality include the following:

• Temperature;


• Various smells;


• Level of gases in the atmosphere.

It is known that the last factor is the most important. Therefore, monitoring the CO2 level indoors is the primary task of every person. The CO2 content in indoor air is determined as follows:

• fresh air intake of 15 cfm = 25.5 m3/hour per person in the room corresponds to a CO2 concentration level of 1000 ppm


• fresh air intake of 20 cfm = 34 m3/hour per person in the room corresponds to a CO2 concentration level of 800 ppm

So, in order not to become a sleepy fly, a person needs a special alarm clock.

What should I do?

With a CO2 analyzer you will forever forget about the problem of oxygen starvation. Usually you work and forget about everything. And this compact companion will remind you every time you need to ventilate the room.

There are three indicators of different colors on the device panel:

Green - there is enough oxygen in the air;
Yellow - there is an increased amount of carbon dioxide in the air (it is advisable to ventilate the room);
Red - the air is oversaturated with carbon dioxide (urgently open the window).

In addition to light sensors, the device is equipped with an audible alarm that sounds every time the indicator switches from one color to another.

Squeaks. Looks like we urgently need to open the window.

The temperature in the room in the morning was pleasant, but I felt something was wrong. The sensor showed 2380 ppm

I opened the window. 10 minutes of ventilation. I close it and measure it.

Carbon dioxide concentration dropped to normal 445 ppm

And temperatures up to 17 degrees Celsius

There are two buttons behind the device. To calibrate and configure the device. The instructions contain a detailed description.

There is an output for microUSB on the side. Can be connected to a computer. Using the ZG VIEW program, you can monitor the state of oxygen and temperature in the room.

When turned on, the device warms up for a few seconds.

And he freezes. Hooray! The room is fresh.

And then it became interesting to me. Is it harmful for the driver to drive for a long time with the heater in recirculation mode? After all, oxygen also leaves and all this can lead to sad consequences. Moreover, many travel this way for a long time.

My recirculation button looks like a “circular arrow”

Freeze at the beginning.

We wait 10 minutes.

We wait 25 minutes. The temperature in the cabin is 30 degrees Celsius. I'm already ready to sleep. The windows were a little foggy.

Wow! The maximum reading of the device Hi (High) is 3000 ppm. I'm already gape and I urgently need to ventilate the interior.

Turn off recirculation. Half an hour passed. One person raised the CO2 concentration to undesirable and, one might say, dangerous. The person feels tired, drowsy and cannot concentrate on driving. As a result, it can lead to an accident. Therefore, it is recommended to turn on this internal recirculation mode for a short time - only if you urgently need to warm up or, conversely, cool the interior in a short time using an air conditioner. It is also used on dusty or heavily polluted road areas.

Fresh and good.

In public places

Now let's test the device in field conditions. Let's go to the Russian post, public transport and shopping center.

At Russian Post, after 5 minutes of standing in line, an uncomfortable feeling arose. CO2 concentration is above average. For comparison, you can see how much the device shows on the street.

The difference is 4 times.

I was traveling alone in a minibus, the performance was average. The driver did not open the windows and the ventilation was turned off. The interior heating was working on recirculation.

In an electric train, during off-peak hours the performance is the same as at the post office. The carriage is half full. It's scary to think about something going on during rush hour.

_____________________________________
The device is provided for testing

This information is intended for healthcare and pharmaceutical professionals. Patients should not use this information as medical advice or recommendations.

Basics of CO 2 monitoring

Practical guide (based on materials from Datex)
Novosibirsk 1995

1.Introduction 2

2.What is a capnogram. 3

3. How CO 2 is formed in exhaled air 4

4.Why is PetCO measured 2 6

5.Diagnostics of hyper- and hypoventilation 7

6. Interpretation of capnogram and trend of CO 2 9

7. Practical guide to CO2 monitoring 15

8.CO2 monitoring in the post-anesthesia period 16

Appendix 18

The practical guide was compiled based on materials from the Datex company by the research and production company LASPEC JSC

Translation and computer layout - D.E. Groshev
Editor Ph.D. - O.V. Grishin.

1. Introduction.

These guidelines are designed for anesthesiologists and resuscitators who are not familiar with CO 2 monitoring, and aim to answer in a simple form the question: “why and how is CO 2 monitoring performed?” Mastering several basic principles of CO 2 monitoring provides the doctor with rich information about the condition patient and the functioning of anesthesia equipment. A list of literature recommended for more detailed study is given in the “Reference Literature” section.

Carrying out CO 2 monitoring in anesthesiology and resuscitation is considered very important and even a necessary condition for effective monitoring of patients with controlled or impaired breathing, as well as with normal breathing when there is a threat of its impairment. The rapid growth in popularity of CO 2 monitoring reflects its importance in ensuring patient safety. With its help, many potentially dangerous situations are detected at the earliest stages of development, providing the doctor with sufficient time to analyze and correct the developing critical condition. In addition, monitoring the end-tidal CO 2 concentration (PetCO 2) and analyzing its trend provide the most objective diagnostic information about the patient’s condition during anesthesia.

The table provides an assessment of the relative importance of a number of techniques for identifying critical situations. (Whitzer C. et al. Anasthetic mishaps and the cost of monitoring: a proposed standard for monitoring equipment. J. Clin Monit 1988; 4:5-15p.).

2.What is a capnogram.

The curve of changes in CO 2 concentration over time is called a capnogram. It reflects the different stages of exhalation. The capnogram is an important diagnostic tool, since its shape is almost the same in healthy people. Therefore, any change in the shape of the capnogram should be analyzed.

*Dead space called the part of the airways where gas exchange does not occur. In the case of hardware monitoring of CO 2, they take part in the formation of the exhalation capnogram: following types dead space. Mechanical or hardware dead space - consists of an endotracheal tube and connecting hoses. Anatomical dead space - consists of the trachea and bronchi. Alveolar dead space - makes up the part of the respiratory tract in which gas exchange does not occur, although it is ventilated.

What is PetCO 2?

The maximum concentration of CO 2 at the end of tidal expiration PetCO 2 (end-tidal CO 2) is very closely related to the alveolar concentration of CO 2, since it is recorded during the flow of air from the alveoli.

3. How CO 2 is formed in exhaled air.

A comparative analysis of arterial blood and alveolar air shows that the PetCO 2 value quite closely tracks the level of CO 2 tension in the blood (PaCO 2), but they are still not equal. Normally PetCO 2 is 1-3 mmHg. lower than PaCO 2. However, in patients with pulmonary pathology, the differences can be significantly greater. The reasons for this are complex, and identifying an increase in this difference gives us an additional diagnostic parameter: the arterial-alveolar difference (aADCO 2). In fact, aADCO 2 can be considered as a quantitative indicator of alveolar dead space, so significant changes in it should be further investigated.

Small arterial-alveolar difference.

The arterial-alveolar difference is the result of the characteristics of the processes of ventilation and perfusion of the pulmonary alveoli. Even in a healthy patient, ventilation-perfusion ratios differ in different parts of the lungs. During anesthesia, the ventilation-perfusion mismatch usually increases slightly, but this is usually not clinically significant.

The main reasons for the increase in aADSO 2.

A decrease in the level of gas exchange occurs in that part of the respiratory parts of the lungs that do not have sufficient perfusion, but are nevertheless well ventilated. When you exhale, air from these areas of the lungs will mix with CO 2 -rich alveolar air from the rest of the lungs, reducing PetCO 2 . In this case, aADCO 2 will be increased. This type of ventilation is called alveolar dead space ventilation.

Possible reasons causing an increase in aASO 2 are:

patient position (side position)

pulmonary hypoperfusion

pulmonary thromboembolism.

Drawing A illustrates the effect of alveolar dead space ventilation. Half of the lungs have no perfusion and therefore no gas exchange. When you exhale, the alveolar gas mixes and the resulting concentration of PetCO 2 will be half that of PaCO 2 in the blood. For comparison, figure IN illustrates the ideal situation when perfusion occurs throughout the entire volume of the lungs and PetCO 2 =PACO 2 =PaCO 2 .

4. Why is PetCO 2 measured?

CO 2 monitoring provides information both on the patient’s condition and on the ventilation system. Since CO 2 concentration depends on many factors, it is rarely sufficient to make a specific diagnosis. However, CO 2 monitoring with a quick indication and display of the CO 2 concentration in each exhalation provides sufficient time to take the necessary corrective measures.

Clinical benefits of CO 2 monitoring.

Under conditions of a stable patient condition (ventilation combined with normal hemodynamics), the CO 2 concentration is closely related to the change in CO 2 tension in the blood and, therefore, is a non-invasive method of monitoring PaCO 2. The release of CO 2 is a fairly stable value, so sudden changes in PetCO 2 usually reflect either changes in blood circulation in the pulmonary circulation (for example, pulmonary embolism) or pulmonary ventilation (for example, tube disconnection or excessive ventilation - hyperventilation).

• Quickly determine the correctness of tracheal intubation.

Quickly identify abnormalities in the air tract (endotracheal tube connector, endotracheal tube, airway) or in the air supply system (ventilator).

Objectively, continuously, non-invasively monitor the adequacy of ventilation.

Recognize disorders in gas exchange, pulmonary circulation and metabolism.

Provides control safe use low-flow anesthesia techniques with their inherent economical consumption of inhalational anesthetics.

Reduces the need for frequent routine blood gas testing because the PetCO 2 trend mirrors the PaCO 2 trend. Blood gas analysis becomes necessary in cases of significant deviation of the PetCO 2 trend.

Common terms for CO 2 monitoring

“kapno” means the level of CO 2 when exhaling (from the Greek “kapnos” to smoke); “hyper” means too much; “hypo” means too little.

Using PetCO 2 to control ventilation.

Normally, during quiet natural breathing, the gas exchange function of the lungs provides partial pressure CO 2 in the blood (PaCO 2) is about 40 mm Hg. This happens by regulating the frequency and depth of breathing. With an increase in CO 2 release (for example, during physical activity), the frequency and depth of breathing increases proportionally. During anesthesia with muscle relaxants, the anesthesiologist must ensure adequate levels of ventilation. Typically this level is estimated by calculating the required ventilation using nomograms. Much more effective method control of adequate ventilation is based on CO 2 monitoring.

Physiological factors controlling CO 2 removal.

Removal of CO 2 depends on 3 factors: metabolic rate, the state of the pulmonary circulatory system and the state of the alveolar ventilation system.

It must be remembered that these 3 factors are interconnected. Changes in the acid-base balance (or state of the CBS), caused by various reasons, can also affect the removal of CO 2.

Experience in diagnosing various critical situations during mechanical ventilation comes quite quickly. Thus, if the steady-state value of CO 2 increases with constant ventilation, changes in PetCO 2 usually arise from changes in the pulmonary circulation. In this case, you should pay attention to changes in metabolism or CBS.

During anesthesia, the metabolic rate usually changes little (the main exception is the rare case of malignant hyperthermia, which causes a sharp increase PetCO 2.)

What is alveolar ventilation.

When the ventilation level is established, maintaining a stable and within the normal PetCO 2 limits, then there is no need to carry out any calculations. However, in order to be prepared for any situation, it is useful to know the features of pulmonary ventilation. As already mentioned, part of the air during breathing does not reach the alveoli and remains in the mechanical (connector, valve box, endotracheal tube) and anatomical (trachea, bronchial tree) dead space, where gas exchange does not occur. To calculate the volume of alveolar ventilation in l/min, which actually provides gas exchange in the lungs, it is necessary to subtract the volume of total dead space from the tidal volume. By multiplying the volume of air entering the alveolar spaces by the respiratory rate, one can obtain alveolar minute ventilation - an indicator of effective ventilation.

5. Diagnosis of hyper- and hypoventilation.

After the initiation of anesthesia and tracheal intubation, anesthesia is usually maintained by an artificial ventilation system in a steady state of CO 2 release. Note that during a long operation (more than 1.5 hours), due to the inhibitory effect of anesthetics and developing hypothermia, the patient’s metabolism slightly decreases and a gradual decrease in PetCO 2 is observed

Normocapnia and normoventilation.

Alveolar ventilation is usually set to ensure normocapnia - that is, PetCO 2 should be in the range of 4.8 - 5.7% (36 -43 mmHg). This type of ventilation is called normal ventilation, since it is typical for healthy people. Sometimes alveolar ventilation during mechanical ventilation is established with mild hyperventilation (PetCO 2 4-5%, 30-38 mm Hg).

Advantages of normoventilation.

When maintaining normal ventilation, the development of critical situations is much easier to recognize: disturbances of alveolar ventilation, blood circulation or metabolism. Spontaneous breathing is restored more easily. In addition, recovery in the post-anesthesia period is much faster.

Hypocapnia and hyperventilation.

A PetCO 2 level below 4.5% (34 mmHg) is called hypocapnia. Under anesthesia most a frequent occurrence hypocapnia is too high alveolar ventilation (hyperventilation).

In the post-anesthesia period, hypocapnia during spontaneous breathing of the patient may be the result of hyperventilation caused by fear, pain or developing shock.

Disadvantages of prolonged hyperventilation.

Unfortunately, hyperventilation of the patient is still a common practice during mechanical ventilation, which, according to generally accepted opinion, is necessary to ensure adequate oxygenation and even to deepen anesthesia. However, modern medicines and monitoring techniques can provide better oxygenation and anesthesia without hyperventilation “just in case.”

Hyperventilation has quite serious disadvantages:

vasoconstriction, leading to decreased coronary and cerebral blood flow;

excessive respiratory alkalosis;

depression of the respiratory centers;

All these factors lead to a more difficult and prolonged recovery in the post-anesthesia period.

Hypercapnia and hypoventilation.

Exceeding the PetCO 2 level of 6.0% (45 mm Hg at Ratm = 760) is called hypercapnia. The most common cause of hypercapnia during anesthesia is insufficiency of alveolar ventilation (hypoventilation), caused by a low level of tidal volume and (or) respiratory rate. In addition, in a closed ventilator circuit, prolonged hypercapnia can be caused by insufficiently complete absorption of CO 2. On the capnogram, this is manifested in the fact that the CO 2 concentration in the inhalation phase does not fall to zero.

In the post-anesthesia period, prolonged hypercapnia during spontaneous breathing of the patient can be caused by:

residual neuromuscular block;

drug suppression of respiratory centers;

painful restriction of breathing (especially after surgery on the abdominal organs).

Note that hypercapnia can be accompanied by hypoxia, but this is not necessary. The hypoxic state occurs later than hypercapnia with more low values alveolar ventilation.

Additional clinical manifestations of hypercapnia are: tachycardia, the appearance of perspiration, increased tension, headache, anxiety. With prolonged hypercapnia, undesirable side effects occur, such as a tendency to cardiac arrhythmias (with exposure to volatile anesthetics), increased cardiac output, increased intracranial pressure, pulmonary vasoconstriction and peripheral vasodilation.

6. Interpretation of capnogram and CO 2 trend.

CO 2 monitors typically display a real-time CO 2 trace of each exhalation (capnogram) and a 30-minute PetCO 2 trend. Abrupt changes in CO 2 emissions are clearly visible on an exhalation capnogram, while gradual changes are better visible on the CO 2 trend.

Normal capnogram.

Capnogram healthy person with artificial ventilation it has a normal shape. Any significant deviation from the normal shape of the capnogram reflects a violation in respiratory system, complex or mechanical disorders in the ventilator circuit.

CO 2 suddenly ceased to be detected.

If the capnogram had a normal appearance, and then abruptly stopped to zero, during one exhalation, the most likely cause is a violation of the tightness of the ventilation circuit.

Another possible cause is complete obstruction of the airway, for example caused by a kinked endotracheal tube.

Exponential Decline PetCO 2.

A rapid drop in PetCO 2 over several breaths may indicate:

• severe pulmonary embolism
• cardiac arrest
• significant drop in blood pressure (severe blood loss)
• severe hyperventilation (due to mechanical ventilation).

Stepwise drop in PetCO 2 level

Moving the endotracheal tube into one of the main bronchi (for example, when the patient's position changes).

• Sudden partial airway obstruction.

Gradual reduction of PetCO 2.

Gradual increase PetCO 2

A gradual increase in PetCO 2 over several minutes can be caused by the onset of hypoventilation, an increase in metabolic rate as a result of the patient’s reaction to stress (pain, fear, injury, etc.).

Esophageal intubation.

Malignant hyperthermia.

The CO 2 monitor is a fast-acting indicator of malignant hyperthermia. A rapid increase in metabolic rate is easily detected by the increase in PetCO 2 (inspiratory CO 2 remains zero).

Incomplete muscle relaxation.

With incomplete muscle relaxation and insufficient depth of anesthesia, the patient retains his own breathing, “working” against mechanical ventilation. This shallow spontaneous breathing causes dips in the capnogram.

Partial airway obstruction.

A distorted capnogram (slow rise rate) may indicate partial airway obstruction. Possible causes of obstruction may be:

generalized bronchospasm,

mucus in respiratory tract,

kinking of the endotracheal tube.

Rebreathing effect.

An increase in the inhalation CO 2 concentration reflects the effect of recurrent breathing, which consists in the fact that the patient inhales CO 2 exhaled by him into a closed ventilator circuit (incomplete absorption of CO 2 in the ventilator circuit).

Capnogram oscillations during cardiac contractions.

With weak breathing (especially in the second half of exhalation with extreme low speeds flow) heart contractions may appear in the falling portion of the capnogram. Capnogram oscillations occur due to the movement of the heart against the diaphragm, causing an intermittent flow of air towards the endotracheal tube.

Restoring natural breathing.

In a critical situation, the patient is usually manually ventilated with 100% oxygen. At the same time, PetCO 2 is deliberately allowed to grow in order to trigger spontaneous respiration. After which the patient with unimpaired ventilation quickly achieves satisfactory alveolar ventilation.

Children's capnogram.

The figure shows a typical capnogram obtained using the Jakson-Rees breathing system in pediatric anesthesia. The initial rebreathing was caused by insufficient purification of the gas flow, which was subsequently corrected. A distinct alveolar plateau confirms that the “real” PetCO2 value is being recorded.

Heart failure.

A rapid decline in the height of the capnogram, while maintaining the correct shape, shows a sharp drop in pulmonary perfusion due to weak cardiac output (1). During cardiac asystole, CO 2 is not transported to the alveoli by the pulmonary bloodstream (2). Effective cardiopulmonary resuscitation begins (3). The restoration of blood flow is confirmed by an increase in the capnogram.

CO 2 trend and real-time capnogram will help you evaluate the entire procedure and its effectiveness.

7. Practical guide to CO 2 monitoring.

CO 2 monitors use small amounts of gas to measure, which are continuously withdrawn from the patient's air tract (150 - 200 ml/min). The side gas monitor can be used with all types of anesthesia circuits. A nasal adapter is used to monitor CO2 during natural breathing.

The basic rule for placing a gas sampler.

Place the gas sampling adapter as close to the patient's mouth or nose as possible. This way, you eliminate unwanted “dead space” between the gas sampling site and the patient, and the measured PetCO 2 concentration will more accurately correspond to the alveolar CO 2 level.

When a heater and moisture exchanger are used to heat and humidify inspired air, the gas sampling adapter should be located between the endotracheal tube and the heater and moisture exchanger.

In particular, when closed circuit ventilation is used, the gas sampling adapter should be located near the endotracheal tube to prevent mixing of purified and expired gases.

Connecting tubes should not be cleaned after use. Cleaning with chemicals can damage the inside of the tubes and increase resistance to gas flow.

Steel gas sampling adapters are reusable and can be sterilized, but plastic adapters are intended for single patient use only.

Use only original tubes and adapters. Using other samples may result in incorrect measurements.

Air tubes and adapters must be visually inspected prior to use.

Removing gas from the monitor output.

Gas comes out of the outlet fitting of the device with sufficient pressure. To prevent contamination of the room air with anesthetic gases, the monitor outlet tube must be connected to an exhaust ventilation hose.

Monitoring at low air flows.

Small volumes of gas that are sampled for monitoring are usually removed. However, if in closed system ultra-low flows are used, the gas after analysis must be returned to the exhalation branch of the breathing circuit.

8. CO 2 monitoring in the post-anesthesia period.

Using a nasal CO 2 gas sampling adapter, the monitor allows continuous measurement of PetCO 2 in a spontaneously breathing patient. At the same time, CO 2 monitoring is an excellent method for identifying apnea or depression of the respiratory centers.

If the patient remains under artificial ventilation The CO 2 monitor allows you to assess the patient's required level of ventilation continuously and non-invasively.

Often, a violation of the ventilation-perfusion relationship caused by pulmonary pathology manifests itself in the arterial-alveolar difference (aADSO 2). Measuring the concentration of CO 2 in arterial blood and comparing it with PetCO 2 provides an assessment of lung health. The reasons for changes in aADSO 2 must be clarified.

Nunn JF. Applied Respiratory Physiology, 2nd edition London: Butterworth, 1977.

Smalhout B, Kalenda Z. An Atlas of Capnography, 2nd edition. The Netherlands: Kerckedosh-Zeist,1981

Kalenda Z. Mastering Ifrared Capnography. The Netherlands: Kerckebosh-Zeist,1989

Paloheimo M, Valli M, Ahjopalo H. A Guide to CO2 Monitoring. Helsinki,Finland: Datex Instrumentarium Corp,1983

Lindoff B, Brauer K. Klinick Gasanalys. Lund, Sweden: KF-Sigma, 1988

Lillie PE, Roberts JG. Garbon Dioxide Monitoring. Anaesth Intens Care 1988;16:41-44

Salem MR. Hypercapnia, Hypocapnia and Hypoxemia. Seminars in Anesthesia 1987;3:202-15

Swedlow DB. Capnometry and Capnograpny: The Anesthesia Disaster Early Warning System. Seminars in Anesthesia 1986;3:194-205

Ward S.A. The Capnogram: Scope and Limitations. Seminars in Anesthesia 1987;3:216-228

Gravenstein N, Lampotang S, Beneken JEM. Factors influencing capnography in the Bain circuit. J Clin Monit 1985;1:6-10

Badgwell JM et al. Fresh Gas Formulae does not accurately predict End-Tidal PCO2 in Pediatric Patients. Can J Anaesth 1988;35:6/581-6

Lenz G, Kloss TH, Schorer R. Grundlagen und anwendungen der Kapnometrie. Anasthesie und Intensivmedizin 4/1985; vol 26: 133-141

Annex 1

“HARVARD STANDARD” for minimal anesthetic monitoring (1985).

The presence of an anesthesiologist is mandatory during the entire period of general and regional anesthesia.

Blood pressure and pulse rate (every 5 minutes).

Electrocardiography.

Continuous monitoring/ventilation and hemodynamics/.

for ventilation: monitoring the size of the breathing bag, auscultation of respiratory sounds, monitoring of inhaled and exhaled gases (PetCO2).

for blood circulation: palpation of the pulse, auscultation of heart sounds, observation of the blood pressure curve, pulse plethysmography or oximetry.

Monitoring of depressurization of the breathing circuit with an audible signal.

Oxygen analyzer with a preset alarm level for the minimum oxygen concentration.

Temperature measurement.

Ecology of consumption. Health: Although you can often hear from people that they do not have enough oxygen, in fact the problem is...

Although you can often hear from people that they do not have enough oxygen, in fact, the problem in stuffy rooms is most often with another gas - carbon dioxide.

Today we will talk about excess carbon dioxide in the body (hypercapnia), which awaits us in many stuffy rooms (and not only) and is the cause of many troubles.

Carbon dioxide CO2 is part of the earth's atmosphere. Its average concentration in the air is about 0.035%, or 350 ppm - parts per million. Geochemical studies have shown that approximately this level - within a few hundredths of a percent - has remained unchanged for hundreds of thousands of years.

But the atmosphere of places of mass human habitation - cities, and especially megalopolises - is really formed with our direct participation. In the second half of the last century, the concentration of CO2 in rural areas was the same “average” 350 ppm, in small cities 500 ppm, in large industrial centers 600-700 ppm. And this, however, was not the limit.

You know that we inhale oxygen (O2) and exhale carbon dioxide (CO2) and our breathing depends on the type of activity (table).

Carbon dioxide indoors is formed only as a waste product of humans, who exhale 100 times more CO2 than they inhale. Consuming about 30 liters of oxygen per hour, each of us emits 20-25 liters of carbon dioxide. A person indoors produces approximately 35.2 grams of CO2 per hour, and accordingly, if a room with an area of ​​20 m2 is 2.5 meters high, then without good ventilation every hour the concentration of carbon dioxide will increase by 584 ppm every hour.

A slight increase in the concentration of carbon dioxide causes people to feel stuffy and stuffy. We clearly feel this when we come from the street into a room. But our respiratory center is flexible and after 10 minutes we stop noticing it. With a more significant increase in concentration, the symptoms become worse: “heavy” head, dizziness, headaches, and even irreversible changes in the human body. At the same time, most of us are familiar with the feeling of stuffiness in the room and the symptoms associated with it, i.e. fatigue, drowsiness, irritability. Many people associate this condition with a lack of oxygen. In fact, these symptoms are caused by excess levels of carbon dioxide in the air. There is still enough oxygen, but carbon dioxide is already in excess.

Symptoms in healthy adults

Carbon dioxide concentration

• Normal level outdoors 350 - 450 ppm
• Acceptable levels< 600 ppm
• Complaints about not Fresh air 600 - 1000 ppm
• Maximum level of ASHRAE and OSHA standards 1000 ppm
• General sluggishness 1000 - 2500 ppm
• Possible undesirable health effects 2500 - 5000 ppm
• Maximum permissible concentration during an 8-hour working day
• 5000 ppm

Where is the limit to which we can not worry about our health? The question is relevant because most Modern man, and above all a city dweller, still spends his life in rooms whose microclimate and atmosphere differ significantly from the conditions open space. At the same time, it is known that a significant (tens of times) increase in CO2 content in the air causes a sharp deterioration in health, and a concentration of more than 5% (50,000 ppm) becomes fatal for humans.

The proliferation of plastic windows has exacerbated the carbon dioxide problem. Why in the apartment high level CO2? Three main reasons: plastic windows, non-working hood and lack of supply ventilation, non-compliance with sanitary standards - a large number of people in a small room. I repeat once again: plastic windows without valves - source higher level CO2 in the apartment

The CO2 indicator is an indicator of the quality of ventilation in general!

Today, the level of CO2 concentration in a room serves as the main indicator of air quality. It acts as an indicator gas, which can be used to judge not only other pollutants, but also how well the ventilation system in the building is working. Research in a school classroom has shown that if there are volatiles in the air, in addition to carbon dioxide, organic compounds and formaldehydes, then it is enough to monitor only CO2. If ventilation copes with it, then other pollutants also remain at low levels. Moreover, CO2 can also be used to judge the number of bacteria in the air. The more carbon dioxide, the worse the ventilation is and the more different bacteria and fungi there are in the air. This is especially noticeable in winter, when the intensity of ventilation decreases and the number of respiratory infections increases.

In principle, in order for the air to remain clean, it is enough to establish an exchange with the external atmosphere at the rate of 30 m3 per hour per person. Such initial data are laid down during the design ventilation systems office, as well as residential premises, which should provide that very comfortable 600 ppm and no more. Although some researchers express very serious doubts about the comfort of this level.

For example, the Englishman D. Robertson claims that the fauna existing on Earth, including humans, was formed in a certain temperature-gas environment in which the carbon dioxide content did not exceed 300-350 ppm. According to Robertson's calculations, which he published in the Journal of the Indian Academy of Sciences, the maximum safe level of CO2 for humans is 426 ppm. In a city of this level, there cannot even be a park, alas.

In September 2016, the concentration of carbon dioxide in the Earth's atmosphere exceeded the psychologically significant mark of 400 ppm (parts per million). This makes the plans of developed countries to prevent the Earth's temperature from rising by more than 2 degrees questionable.

Global warming is an increase in average temperature climate system Earth. During the period from 1906 to 2005, the average air temperature near the planet's surface increased by 0.74 degrees, and the rate of temperature increase in the second half of the century was approximately twice as high as for the period as a whole. For all the time of observation, 2015 is considered the hottest year, when all temperature indicators by 0.13 degrees higher than in 2014, the previous record holder. IN various parts globe temperatures change differently. Since 1979, temperatures over land have risen twice as much as over the ocean. This is explained by the fact that the air temperature over the ocean grows more slowly due to its high heat capacity.

Movement of carbon dioxide in the atmosphere

Human activity is considered the main cause of global warming. Indirect research methods have shown that until 1850, for one or two thousand years, the temperature remained relatively stable, albeit with some regional fluctuations.

Thus, the onset of climate change practically coincides with the onset of the industrial revolution in most Western countries. The main reason today is considered to be greenhouse gas emissions. The fact is that part of the energy that planet Earth receives from the Sun is re-radiated back into outer space in the form of thermal radiation.

Greenhouse gases hinder this process by absorbing some of the heat and trapping it in the atmosphere.

Adding greenhouse gases to the atmosphere leads to even greater heating of the atmosphere and an increase in temperature at the surface of the planet. The main greenhouse gases in the Earth's atmosphere are carbon dioxide (CO 2) and methane (CH 4). As a result of human industrial activity, the concentration of these gases in the air increases, which leads to annual growth temperature.

Since climate warming threatens literally all of humanity, attempts are being made repeatedly around the world to bring this process under control. Until 2012, the main settlement agreement to counteract global warming was the Kyoto Protocol.

It covered more than 160 countries and accounted for 55% of global greenhouse gas emissions. However, after the end of the first stage of the Kyoto Protocol, the participating countries were unable to agree on further actions. Part of the obstacle to the drafting of the second phase of the treaty is that many participants avoid using a budgetary approach to determining their CO 2 emissions obligations. CO 2 emission budget is the amount of emissions over a certain period of time, which is calculated from the temperature that participants must not exceed.

According to the Durban decisions, no binding climate agreement will be in place until 2020, despite the need for urgent efforts to reduce gas emissions and reduce emissions. Research shows that at present, the only way to ensure a “reasonable probability” of limiting warming to 2 degrees (characterizing dangerous climate change) is to limit the economies of developed countries and transition to an anti-growth strategy.

And in September 2016, according to the Mauna Loa Observatory, another psychological barrier for the emission of greenhouse gas CO 2 was overcome - 400 ppm (parts per million). It must be said that this value has been exceeded many times before,

but September is traditionally considered the month with the lowest concentration of CO 2 in the Northern Hemisphere.

This is explained by the fact that green vegetation manages to absorb a certain amount of greenhouse gas from the atmosphere over the summer before the leaves fall from the trees and some of the CO 2 returns. Therefore, if the psychologically important threshold of 400 ppm was exceeded in September, then, most likely, monthly indicators will never be lower than this value.

“Is it possible that in October this year the concentration will decrease compared to September? Completely excluded

— Ralph Keeling, a fellow at the Scripps Institution of Oceanography in San Diego, explains in his blog. “Short-term drops in concentration levels are possible, but monthly averages will now always exceed 400 ppm.”

Keeling also notes that tropical cyclones can reduce CO 2 concentrations for a short time. Gavin Schmidt, chief climate scientist, agrees: “In the best case, we can expect some balance, and CO 2 levels will not rise too quickly. But, in my opinion, CO 2 will never fall below 400 ppm.”

According to the forecast, by 2099 the concentration of CO 2 on Earth will be 900 ppm, which will be about 0.1% of the entire atmosphere of our planet. As a result, the average daily temperature in cities such as Jerusalem, New York, Los Angeles and Mumbai will be close to +45°C. In London, Paris and Moscow, temperatures will exceed +30°C in summer.