Kostyuchenko acid-base state. Acid-base state (ABC). Analysis of acid-base disorders

Prices for Acid-Base State

• Testing the level of carboxyhemoglobin in the blood RUB 500.
• Testing the level of methemoglobin in the blood RUB 500.
• KSH 1100 rub.

Study of acid-base state (ABC) or acid-base status (ABS) is important in the diagnosis and treatment of various emergency conditions, including surgical ones.

Acidity and alkalinity mean the concentration of free hydrogen ions (H +) in a solution, i.e. Blood pH. For the efficient functioning of vital processes, the concentration of free hydrogen ions (H +) must be within strict limits. In fact, the study of acid-base balance includes, along with measuring pH, the determination of physiologically important gases present in the blood (oxygen - O 2 and carbon dioxide - CO 2) and about 20 other parameters. All these indicators and their values ​​are closely interrelated with each other.

Patients in the intensive care unit and operating room may experience significant changes in these indicators over short periods of time. Acoustic acid studies, unlike all other types of laboratory tests, are performed on arterial blood samples.

For the normal functioning of all cells of the body, oxygen (O 2) is required. The decisive role in the transport of oxygen to tissues belongs to the hemoglobin contained in red blood cells. The term “hemoglobin” refers to several forms of hemoglobin that are present in human blood, both normally and in pathology. More than 98% of the oxygen absorbed by the lungs from the inhaled air is transferred to the body's cells in the blood in the form of oxyhemoglobin. Normally, small quantities of hemoglobin fractions are present in the blood that are not capable of carrying O2 - dishemoglobins (sulfhemoglobin, methemoglobin, carboxyhemoglobin).

Methemoglobin is constantly formed as a result of normal metabolism of body cells. Methemoglobin contains ferric iron and is not capable of transporting oxygen! When significant amounts of methemoglobin are formed, the transport function of the blood is sharply disrupted. The body has a mechanism for regulating the level of methemoglobin in the blood, which maintains the proportion of this fraction not higher than 1.0 - 1.5% of total hemoglobin.

Carboxyhemoglobin- a strong compound of hemoglobin (Hb) and carbon monoxide (CO). Carboxyhemoglobin is formed very quickly, since the ability of carbon monoxide to attach to hemoglobin is approximately 200 times higher than that of oxygen. Carboxyhemoglobin is not capable of carrying oxygen to the tissues of the body, therefore, in case of carbon monoxide poisoning, death can quickly occur in a person. Carboxyhemoglobin is formed in large quantities during carbon monoxide poisoning, and in small quantities it is always present in the blood of all smokers and residents of large cities.

Indications:

ABL analysis is required

· To make a diagnosis Blood gas analysis is an integral part of diagnosing respiratory failure and primary hyperventilation. It also detects metabolic acidosis and alkalosis.

· To assess the severity of the disease

· To monitor the effectiveness of treatment Such analysis is very important for selecting oxygen (O2) therapy for patients with chronic respiratory failure type 2 and for optimizing ventilator settings.

An increase in methemoglobin (FMetHb) in the blood develops when:

· poisoning with nitrites, nitrates, nitroso compounds, aniline, sulfonamides, acetanilide, chlorides, bromides, etc.

· hereditary deficiency of NADH-methemoglobin reductase: low enzyme activity manifests itself in early childhood. As a rule, this disease has no clinical consequences, manifesting itself as a minor cosmetic defect.

presence of abnormal variants of hemoglobin, designated hemoglobin M

An increase in carboxyhemoglobin (FCOHb) in the blood develops when:

· carbon monoxide poisoning. When the FСOHb level is above 30%, severe headaches, general weakness, vomiting, shortness of breath, tachycardia are observed, and at a level of 50% - convulsions, coma; above 70%, respiratory failure occurs and death is possible.

Methodology:

Determination of blood gases, acid-base status, oximetry parameters are carried out on the ABL 800 FLEX analyzer from RADIOMETR, Denmark, determination of up to 50 parameters.

Hydrogen value (pH)- negative decimal logarithm of the concentration of hydrogen ions, a quantitative characteristic of the acidity and alkalinity of a solution.

In a neutral solution, pH = 7.0, in an acidic solution - less than 7, in an alkaline solution - more than 7.

This parameter has a significant impact on all biochemical processes in the body, since, first of all, it can change the activity of enzymes. Each enzyme has its own pH optimum (for most it is 7.3-7.4), at which the activity of the enzyme and the rate of the reaction it catalyzes are maximum. Even minor changes in pH in one direction or another cause a decrease in enzyme activity and a decrease in the speed of the biochemical process. Acidic and alkaline components are constantly formed in the cells of organs and tissues, are supplied with food and are excreted from the body, but the normal pH value in the liquid media of the body is precisely maintained within very narrow limits. This is one of the most stable parameters of homeostasis.

Normal pH values ​​for various body fluids:

Arterial blood - 7.35-7.45

Venous blood - 7.26-7.36

Lymph - 7.35-7.40

Intercellular fluid - 7.26-7.38

Intraarticular fluid - 7.3.

The constancy of pH in the body is maintained by 4 blood buffer systems - bicarbonate, phosphate, protein, hemoglobin. Chemically, they are a mixture of a weak acid and a salt of this acid. Buffer systems ensure the movement of ions from the places of their formation to the places of excretion (kidneys, lungs) without disturbing the blood pH, since changes in blood pH above 7.8 or below 6.8 are incompatible with life and are practically not observed in the clinic.

The acid-base state, in addition to pH, is characterized by the indicators of buffer systems, primarily bicarbonate, as the most labile (reaction time - 30 seconds).

Standardbicarbonate, SB is an indicator of the capacity of the bicarbonate system. Determined by the concentration of HCO 3 ions in the blood, balanced by a standard gas mixture.

Normal values:

arterial blood - 20-27 mmol/l,

venous blood - 22-29 mmol/l.

Topical bicarbonate, AB is the concentration of HCO 3 ions in the blood plasma.

The normal value is 19-25 mmol/l.

Buffergrounds, BB is the capacity of buffer systems, i.e. the sum of bicarbonate ions and protein anions in whole blood.

The normal value is 40-60 mmol/l.

Excessordeficitreasons BE - shows how many mmol of acid or base should be added to a liter of extracellular fluid to restore normal pH.

Normal values:

capillary blood, men - from -2.7 to +2.5 mM/l,

women - from -3.4 to +1.4 mM/l,

arterial blood, children under 3 years of age - from -4.0 to +2.0 mM/l,

men - from -1.0+ 3.1 mmol/l,

women - from -1.8 to + 2.8 mmol/l.

Positive values ​​indicate a relative deficiency of non-carboxylic acids and loss of hydrogen ions; negative values ​​indicate a relative excess of non-carboxylic acids, an increase in the content of hydrogen ions.

Carbon dioxide voltage(pCO 2) - concentration of carbon dioxide in the blood.

Normal values: capillary and arterial blood -

men - 35-45 mm Hg. Art. or 4.7-6.0 kPa,

women - 32-43 mm Hg. Art. or 4.3-5.7 kPa,

venous blood - 46.0-58.0 mm. rt. Art.

Oxygen tension (pO 2) - reflects the concentration of O 2 dissolved in plasma.

Normal values:

arterial blood, men - 9.6-13.7 kPa

or 72-106 mm Hg. Art.

Determination of acid-base balance indicators is carried out, in most cases, in a hospital in case of emergency conditions caused by shock, cardiac arrest, large blood loss, severe heart or pulmonary failure, poisoning, diabetic coma and other acute diseases that cause:

1) violation of the removal of carbon dioxide by the lungs,

2) excessive production of acidic products by tissues,

3) impaired excretion of bases in the urine. Often these mechanisms operate in combination; this may cause:

a) decrease in pH - acidosis (enrollment),

b) increase in pH - alkalosis (alkalinization).

If the blood pH value is close to the extreme limits of normal, and all changes concern buffer systems and pCO 2, then acidosis or alkalosis is assessed as compensated. If the pH is outside the normal range, then acidosis or alkalosis is considered decompensated, which requires surgical correction.

Respiratory acidosis- occurs due to the slow elimination of carbon dioxide by the lungs when the respiratory center is depressed, pulmonary edema, severe pneumonia, emphysema, bronchial asthma, etc.

Respiratory alkalosis- occurs relatively rarely and occurs as a result of increased breathing (hyperventilation), as well as when breathing in a rarefied atmosphere, anemia, carbon monoxide poisoning.

Metabolicacidosis- occurs when there is excess production or intake of H + ions, a violation of their excretion, or loss of bases. This is the most common violation of acid-base balance, which can occur with shock, pulmonary and heart failure, diabetes mellitus with ketoacidosis (increased levels of ketone bodies due to the predominant use of fats for energy production), hypoxia accompanied by lactic acidosis (excessive formation of lactic acid), with increased gastric acidity juice, prolonged diarrhea (intestinal acidosis due to increased loss of bicarbonates), nephritis, renal failure, excessive doses of diuretics, thyroid insufficiency, on the 7-10th day of fasting, increased protein breakdown and increased concentration of amino acids in the blood.

Metabolicalkalosis- is rare and occurs with large losses of gastric juice as a result of frequent vomiting, pyloric stenosis, with increased excretion of H* ions due to lack of potassium, with citrated blood transfusion, etc.

Biochemical indicators for acid-base disorders

Note:

N - norm, T - increase, ↓ - decrease in indicator compared to the norm.

Compensated forms of acidosis and alkalosis can occur latently and for quite a long time, however, a constant load on the compensatory systems can lead to their decompensation, which, first of all, will manifest itself as metabolic disorders not only within the cell, but also the whole organism. Thus, an increase in the concentration of glucose, ketone bodies, ammonia, uric acid and a number of other substances always occurs against the background of a violation of acid base, although without a change in blood pH. Therefore, for the successful treatment of many diseases, it is necessary to know and, if necessary, preliminarily adjust the acid-base balance. For the body, a state approaching mild compensated alkalosis is preferable, since under these conditions the processes of energy formation, protein and lipid synthesis, mineral metabolism, etc. occur more actively. In reality, a state close to compensated acidosis is more common. The most accessible and objective indicator of acid-base balance in each specific period is urine pH, which clearly reflects the acid-base balance of the body.

Ph blood, its norm for a healthy person is clearly indicated, is an important laboratory test. Ph is the level of acid-base balance and is an important indicator of human blood health. This is the concentration of hydrogen in the body. If its content does not exceed the norm, then all systems and organs operate in the required mode. When the balance is disturbed, a failure occurs: it can lead to the development of serious pathological processes that can even threaten life. When the acid-base balance may be disturbed, what consequences can this have?

What is Ph level and its norm

This indicator indicates the health of the body and normal immunity. Therefore, it is advisable to maintain the acid-base balance and regularly undergo analysis of its level. Only if the body has a sufficient amount of vitamins and minerals will it not quickly age and get sick.

The normal blood pH ranges from 7.35 to 7.45. The blood of a healthy adult should have 7.42 units.

These indicators may be negatively affected by:

• poor nutrition;
• unfavorable environmental situation;
• alcohol abuse, smoking;
• constant stress;
• incorrect daily routine.

These factors lead to a blood test showing low Ph. Some of them can be influenced by humans. For example, you can balance your diet and monitor the quality of food.

If the acid-base balance is disturbed, problems such as:

• disruption of the digestive system;
• deterioration in the functioning of the lungs and kidneys, which purify the air and substances entering the body;
• the main regulatory organ - the liver - begins to work poorly;
• chronic pathologies develop.

All this negatively affects a person’s appearance. He is starting to age quickly.

If hydrogen ions are in the body in normal quantities, then the body is fine. The lungs, liver and kidneys are responsible for the acid-base state. These organs remove toxic substances and maintain the required concentration of acids and alkalis. It is very important to monitor its level in order to notice the development of serious diseases in time.

How is human blood pH and deviations determined?

During a preventive examination, doctors usually recommend that the patient determine the acidity of the blood. This will help the specialist assess the person’s health status and identify pathology. Hydrogen content is also determined at home. Anyone can buy a special device for this.

Laboratory research is carried out using the electrometric method. Capillary blood is used for the study. It contains a stable acid-base environment. Therefore, you can get accurate information without errors. The amount of hydrogen is determined by special glass electrodes. At the same time, they also take into account how much carbon dioxide is in the blood cells.

Determining Ph in laboratory conditions will provide more information, and specialists can decipher the result. If it is not possible to visit the hospital, you can buy a special device at the pharmacy that will show the condition of the blood.

The acid balance may increase or decrease. A diagnosis of alkalosis is made if the levels are higher than the permissible norm. If the test results are low, the person is said to have acidosis.

Alkalosis

This condition leads to disruption of metabolic processes in the body.

Its reasons are:

• prolonged vomiting, which releases stomach acid;

• abuse of foods high in alkaline compounds;
• constant stress;
• excess body weight;
• pathologies of the cardiovascular system.

You can get rid of the problem only by eliminating the causes that affected Ph.

Usually, breathing exercises and various solutions are prescribed to increase the level. You cannot treat yourself; drugs and their dosage should only be prescribed by a doctor.

Acidosis

A mild form of acidosis in adults can only be detected after testing.

A progressive problem can make itself felt:

• signs of diabetes;
• lack of oxygen in the body and the resulting consequences;
• constant nausea and vomiting;
• breathing problems;
• shock state in the presence of other chronic pathologies.

Severe acidosis requires immediate medical attention, as this condition can be life-threatening. You can eliminate the symptoms of the disease by drinking a glass of water with soda.

How to normalize acidity

As a rule, if the Ph level in the blood is normal, then you need to monitor your diet and get tested regularly.

You can control your acid-base environment using the following rules:

• Adhere to the principles of proper nutrition. There are certain products that will help maintain normal levels of acids and alkalis. These are vegetables, fruits, some cereals, nuts, dried fruits, and mineral water.
• Garlic, potato juice and some types of medicinal herbs (chamomile, mint) help normalize Ph.
• It is necessary to give up fatty, fried and smoked foods, drink less caffeine- and alcohol-containing liquids, and stop smoking. All this leads to the accumulation of substances harmful to the body and their deposition on the walls of blood vessels.
• To eliminate the negative effects of these products, it is necessary to cleanse the body.

It is useful to drink special alkaline water, which enriches the body with ions, helps strengthen the immune system and removes waste and toxins from the body. You can make tea from this water or use it in preparing first courses. If medications are prescribed to increase the acid-base environment, then a break of several hours must be taken between taking them and drinking water.

In addition, it is worth leading a healthy lifestyle, normalizing physical activity, and not forgetting about adequate periods of sleep and rest.

Indicators of the acid-base state are determined by the Astrup equilibration micromethod, the basis of which is the physical relationship between the components on which the balance of acids and bases in the body depends.

Two indicators are determined directly in the blood: pH, pCO 2 - other values ​​of the acid-base state are calculated using the Sigaard-Andersen nomogram (modern microanalyzers determine all values ​​automatically). To assess the type of acid-base disorder in everyday practice, 4 indicators are of greatest importance: pH, pCO 2, pO 2, BE.

Indicators of the Siggaard-Andersen nomogram

Three golden rules of the US Heart Association

1. Change in blood pCO 2 by 10 mm Hg. causes a reciprocal decrease in pH by 0.08.
2. A change in pH of 0.15 results from a change in the concentration of buffer bases of 10 mmol/L.
3. Total base deficiency in the body (mmol/l) = BE, determined on the basis of the second rule (mmol/l)·1/4 body weight (kg).

ATTENTION! Information provided on the site website is for reference only. The site administration is not responsible for possible negative consequences if you take any medications or procedures without a doctor’s prescription!

Sarah Gehrke is a registered nurse from Texas. She received her Master of Science in Nursing from the University of Phoenix in 2013.

Number of sources used in this article: . You will find a list of them at the bottom of the page.

If you have symptoms of oxygen, carbon dioxide, or pH imbalances that include confusion or difficulty breathing, your doctor may do a blood gas test or arterial blood gas test (ABG). Thanks to a tiny blood sample, the doctor will be able to measure partial levels of these substances. From this information, your doctor can determine how well your lungs carry oxygen into your blood and remove carbon dioxide. It can also help detect the presence of certain diseases, such as kidney or heart failure, drug overdose or uncontrolled diabetes. It is up to your doctor to interpret the test results, but you can get some idea about them. To interpret the results of the analysis, you should study them carefully and be mindful of other information.

Steps

Carefully study the analysis results

Review the results with your doctor. The best way to interpret blood test results is to talk to your doctor. He has the best understanding of this information and analysis. Your assessment may lead to misdiagnosis or complications due to self-medication. Ask your doctor to answer any questions you have about individual and total levels and find out what they mean.

• Ask your doctor to explain each test to you, including why the test was done and what the specific results mean.
• Ask your doctor to compare past test results with new ones to better assess your health.

1. Check the pH level. This indicator measures the amount of hydrogen ions in the blood and can indicate diseases such as chronic obstructive pulmonary disease, asthma, pregnancy, diabetic ketoacidosis, lung or liver disease, or drug use. Normal pH levels are between 7.35 and 7.45.

   Check the bicarbonate or HCO 3 level. Your kidneys produce bicarbonate and help maintain healthy pH levels. Normal bicarbonate levels are 22 to 26 millimoles per liter (mmol/L). Discrepancies in bicarbonate levels may indicate conditions such as respiratory failure, anorexia, and liver failure.

   • An HCO 3 level below 24 mmol/L indicates metabolic acidosis. This can be the result of diseases such as diarrhea, as well as liver and kidney failure.
   • An HCO 3 level above 26 mmol/L indicates metabolic alkalosis. This may result from dehydration, vomiting or anorexia.

2. Check PaCO 2 level. The partial pressure of carbon dioxide, or PaCO 2 , is responsible for the level of carbon dioxide in the blood. The normal PaCO 2 level is 38–45 mmHg. Art. Deviations from this level may indicate shock, renal failure, or chronic vomiting.

   Check the PaO 2 level. Partial pressure of oxygen, or PaO 2 , is a measure of how well oxygen moves from the lungs into the blood. The normal level is 75–100 mmHg. Art. Higher or lower levels may indicate conditions such as anemia, carbon monoxide poisoning, or sickle cell disease.

   Pay attention to oxygen saturation. Oxygen saturation measures how well your hemoglobin carries oxygen to your red blood cells. The normal level is 94–100%. Lower readings may indicate the following diseases:

   • anemia;
   • asthma;
   • Congenital heart defect;
   • chronic obstructive pulmonary disease;
   • abdominal muscle stretch;
   • lung collapse;
   • pulmonary edema or embolism;
   • obstructive sleep apnea syndrome.

   Consider other factors

   1. Consider taking medications or drugs. Certain factors, such as your health, medications you take, and where you live, can affect your blood gas test results. If you are taking any of the following drugs or drugs, be aware that they may interfere with your test results:

      Consider your location. As altitude increases, the amount of oxygen in the air decreases, which can affect your test results. If you live at an altitude of 900 meters or above sea level, take this into account when checking your test results. Ask your doctor to adjust your oxygen partial pressure based on your location, or consider the fact that at altitudes of 3,000 to 4,500 meters, healthy blood saturation is 80 to 90 percent.

      Consider current illnesses. Illnesses ranging from colds to liver failure can affect blood gas test results. Keep this in mind when checking test results or discussing them with your doctor. The following diseases can affect normal blood gas levels: