In the article, we will consider the norm of blood acid-base ratio.
Analysis of the acid-base state of blood and its gases is of no small importance in the diagnosis of diseases in surgery, anesthesiology and resuscitation, and also plays an equally important role in treatment. Each modern laboratory has a special gas blood analyzer . If you want to control the main indicators in the blood, data on them allows you to get an electrolyte analyzer.
Any changes in the acid-base state of the blood indicate the development of a certain pathological process. Studies of the gas composition of the blood is used, as a rule, when there is a suspicion of a person having respiratory diseases or metabolic disorders. The results of repeated studies allow you to track the dynamics and evaluate the effectiveness of the prescribed treatment.
But for this you need to know the standard KShchS.
What does this study show?
Blood is one of the main substances of the human body. It constantly circulates through it, supplying oxygen to all tissues and cells. In addition, it is directly involved in the elimination of toxins and harmful compounds from the body. Blood renewal is also an ongoing process. It is important to understand that a blood test for KHS is such an analysis, based on the results of which a specialist can evaluate the work of the body as a whole.
The most clinically significant indicator is the pH level. This value must be stable. With its deviations to a greater or lesser extent, the specialist may suspect irregularities in the processes that are responsible for the formation of such an indicator.
The norm of KShchS at adults differs from such indicator at children.
In violation of acid-base balance in humans, very rapid aging is observed. Along with this, a significant weakening of the body's protective barriers occurs, as a result of which a variety of diseases develop. With untimely therapy, serious pathologies can occur that are often not treatable.
Indicators
In addition to pH, the main indicators of blood acid-base ratio are:
- pCO2 - this value characterizes the partial tension of carbon dioxide in the blood. It is determined in the absence of air access. Based on this indicator, we can talk about the degree of functioning of the respiratory organs.
- PaO2 is a value that characterizes the partial pressure of oxygen, which is present in a gaseous medium balanced with blood.
- PAO2 is the partial pressure of oxygen, which is present in the alveolar air.
- TCO2 is an indicator that characterizes the overall level of carbon dioxide, that is, all its forms and conditions.
- AB - is an indicator of true bicarbonate. Deviation of this value in one direction or another is observed with respiratory disorders.
- SB is an indicator of standard bicarbonate. Allows you to assess the severity of disorders in the metabolic processes.
- BE is an indicator of excess or deficiency of non-carboxylic acids. This value shows the volume of the strong base, which is necessary for the normalization of pH values.
- BE-ecf is the amount of excess or deficiency of bases, which is calculated for extracellular fluid.
- BB - is the total indicator of bicarbonate ions and protein anions.
- CaO2 is the level of oxygen capacity of the blood.
- CtO2 is a value reflecting the actual oxygen content in the blood.
- DA-aO2 - a value based on which it is possible to evaluate the diffusion capacity of the lungs and the volume of shunt blood flow.
- SpO2 is an indicator that characterizes the ratio of total and oxygenated hemoglobin fractions.
If you suspect the occurrence of certain pathological processes in the body, the doctor prescribes a laboratory analysis to study the acid-base balance.
Indications for study designation
The doctor should be consulted if certain disturbing symptoms appear that indicate a violation of the functioning of the digestive system, liver, kidneys and lungs, as well as with frequent exacerbation of existing chronic diseases. Especially if, at the same time, a person experiences rapid aging, which externally manifests itself in the form of the appearance of early wrinkles, sagging skin, this indicates a deviation from the norm of blood acid-base balance.
Analysis Objectives
The study of the gas composition is prescribed for the following purposes:
- Detection of various pathologies at the earliest stages of their development.
- Evaluation of the effectiveness of a previously established therapeutic regimen.
When evaluating the results of the study, a specialist can also judge the general condition of the patient’s body.
Study Preparation
When assigning the analysis of KShS, the specialist explains to the patient some rules that must be followed before the delivery of biological material. The doctor is obliged to inform the patient that during this analysis in most cases artery puncture is performed. The patient should be ready for the appearance of uncomfortable or painful sensations in the puncture site of a blood vessel. Before taking biomaterial, the patient is recommended to rest for 30 minutes. A stable physical condition is the key to obtaining the most informative results, especially for people suffering from severe respiratory failure. Correction of diet and diet before the study is not required.
Rules for the collection of biomaterial
Blood is needed to study the acid-base balance:
- Venous The norms of the acid-base compound of venous blood Ph 7.26-7.36.
- Lymph - 7.35-7.40.
- Arterial. The norms of the acid-base ratio of arterial blood Ph 7.35-7.45.
- Intercellular fluid - 7.26-7.38.
- Capillary. Norms of acid-base liquids of capillary blood Ph 7.35-7.44.
- Intra-articular fluid - 7.3.
Arterial blood is the most suitable biological material for the study of gas composition. This is because its study allows you to fully evaluate the degree of functioning of the respiratory system.
Types of receipt:
- Puncture of the radial artery. This technique is considered the simplest. After its implementation, the probability of hematoma formation is less than 2%. The puncture of the radial artery cannot be performed with severe atherosclerosis in this area, as well as with the receipt of a negative Allen test. The latter is done as follows: the patient needs to squeeze and unclench the brush several times until the skin becomes pale, after which the vessel is pinched. If normal skin color is restored in less than 5 seconds, this can be considered normal. A longer shade restoration process indicates blood flow disorders.
- Puncture of the femoral artery. The disadvantages of this technique are a high risk of blood loss, thrombosis, occlusion of a blood vessel, ischemia of the hand, and various complications of an infectious nature. Taking biomaterial is not carried out in the presence of a vascular prosthesis in this area, taking anticoagulants, with aneurysms and local thrombosis. The complexity of this method of research is that on the first attempt it is not always possible to puncture the artery.
The level of carbon dioxide, which is the final product of metabolic processes in tissues, in the composition of venous blood is slightly higher than in arterial blood. The volume of oxygen, on the contrary, is lower. If you conduct a study of venereal venous blood coronary artery disease, it is possible to evaluate systemic metabolism. Biological material is rarely taken from peripheral vessels, since the result of such a study is not considered clinically significant.
In most cases, this analysis is performed by puncture of the pulmonary artery. When taking blood, if it is made from a limb vessel, the tourniquet, as a rule, is not superimposed. This is due to the fact that against the background of changes in local blood circulation, the results of the study are significantly distorted and become uninformative. If the biomaterial is taken by means of a catheter inserted into the central vein, the specialist should avoid the channel through which glucose and electrolytes are introduced. In this case, blood acid-base balance can also be considered uninformative due to falsely elevated rates.
In terms of gas content, capillary connective fluid tissue is close to arterial. However, her study is considered by clinicians to be the least informative. Capillary blood is taken, as a rule, in those cases when it is necessary to evaluate the main indicators of the acid-base balance of blood in newborn babies.
So, what is the standard of KHS?
Interpretation of Results
The norm of KShchS of blood interests many. First of all, experts analyze the pH level. This is because this value is the main among all clinically significant. Deciphering the norm of acid-base blood tests in adults is done by such doctors as a hematologist and therapist. A normal result is considered if this indicator is in the range of 7.37-7.44. With a slight deviation to a greater or lesser extent, it is customary to talk about certain violations in the functioning of the body. If such an indicator significantly increases or decreases, a person usually has a fatal outcome.
In children, a pediatrician and a hematologist are involved in the interpretation of KHS. The result of the norm for babies are values from 7.30 to 7.37.
Norms KShchS in newborns are presented in the table.
In addition, diagnostically important indicators are:
- The partial tension of carbon dioxide. In this case, arterial blood is most often taken. The norm KShchS for children can be considered from 27 to 39 mm RT. Art., for women - from 31 to 44 mm RT. Art., for men - from 34 to 49 mm RT. Art. If venous blood acted as biological material, such indicators will be 5-6 units higher, which is not a deviation.
- Standard bicarbonates. The norm of KHS for whole arterial blood is - from 17 to 24 mmol / l, venous plasma - from 21 to 30 mmol / l. With a decrease in these indicators, it is customary to talk about the development of acidosis, with an increase in alkalosis.
Now it’s clear what KShchS. The meaning of the norm is described above.
Factors adversely affecting the acid base
If a specialist detects certain deviations in the process of interpreting a blood test for KHS, he is obliged to clarify whether the patient passed the biological material in a calm state, and also determine what other factors could cause the distortion of the results.
A negative impact on the main indicators of this study may have:
- unbalanced diet, excessive consumption of fast food;
- living in areas with poor environmental conditions;
- frequent use of alcoholic beverages;
- prolonged state of stress;
- smoking;
- wrong daily routine.
In the presence of such factors, a specialist can prescribe a re-examination and determination of the blood acid-base ratio in children and adults.
Determination of acid-base state independently
It is extremely important to understand that the information content of a study in a specialized laboratory is as high as possible. It is carried out with the help of modern automated analyzers of blood gases, electrolytes, glucose and KHS. If, for certain reasons, the patient often needs to take biological material, he can acquire a special device and use it to regularly evaluate pH values.
The principle of operation of this device is as follows: the device has two electrodes that are placed in a drop of blood. In this case, an electromotive force arises. After analysis, the pH meter (within one minute) gives accurate results. Such a device may be digital or analog. Analog models are considered obsolete, so they are rarely used by patients in practice. Digital pH meters are the most modern devices with a convenient interface, built-in memory and a hint system, so there is no need to record the results of the study every time on paper.
In pharmacies and stores selling medical equipment, portable and stationary devices can be purchased. Thus, a person can set the pH meter at home. There are mobile options for this device.
Deciphering the blood acid-base acid ratio is simple.
Alkalosis and acidosis
It is customary to talk about such conditions in cases when the doctor detects deviations when deciphering the KHS. Alkalosis is a disease that is characterized by an increase in the levels of key indicators. This condition leads to the following consequences:
- violation of the digestion of food;
- mineral deficiency;
- the entry into the blood of a large volume of toxic compounds.
Over time, this pathological process begins to progress. The lack of treatment leads to pathologies of the digestive tract, severe allergic reactions, dermatological problems. In addition, if a person has chronic diseases, against the background of alkalosis, they begin to rapidly become complicated. The reasons for the increase in pH are:
- malfunctions of the heart and blood vessels;
- prolonged stressful situations;
- diseases in which frequent episodes of vomiting are observed;
- overweight;
- unbalanced diet.
If during the study of KShchS revealed a deviation of indicators to a smaller side, this indicates acidosis. This condition is considered very life-threatening, and this threat is that in the initial stages the disease is not accompanied by alarming symptoms. As you progress, the following phenomena occur:
- increased blood sugar;
- episodes of lack of air;
- nausea;
- shock state.
If the analysis is significantly reduced, the blood acidifies. With untimely treatment, a fatal outcome is inevitable.
We examined the interpretation and standards of blood acid-base ratio in children and adults.