Frustration of the acid-base state (ABS) often meet at patients of intensive care units. The doctors dealing with these patients for ensuring effective treatment have to have a clear idea of a pathophysiology of frustration of KShchR. Diagnostics of these frustration is made on the basis of a research of tests of arterial, venous or capillary blood by means of special gas analyzers. After carrying out such analysis the doctor receives a number of certain indicators, on the basis which is drawn a conclusion about existence of these or those disturbances.
It is necessary to remember that the combined disturbances of KShchS can meet at the patient that does diagnostics even more difficult as it is necessary to reveal both primary disturbance, and compensatory. Further we will consider main types of disturbances of an acid-base state.
The metabolic acidosis is rather frequent disturbance accompanying critical states. This type of disturbance of BRAIDS means accumulation of organic acids in fabrics and change rn blood in the acid party. The state which develops at receipt in an organism of acids from the outside is considered also metabolic acidosis, but it is more correct to call this pathology after all the induced or exogenous acidosis. The organism can compensate significant changes in concentration of acids by means of buffer systems: bicarbonate, pulmonary and renal. The main buffer substance of blood — bicarbonate which enters interaction many acids (hydrogen ions) and forms carbon dioxide that reduces influence of acids on rn blood. The main sign of a metabolic acidosis — decrease in concentration of bicarbonate. The bicarbonate buffer system joins very first, then lungs and — kidneys come into effect already only then. Treatment of a metabolic acidosis includes first of all elimination of its reason and also administration of alkalizing drugs: hydrosodium carbonate and Trisaminum.
Estimating the patient with a metabolic acidosis, it is necessary to define its type and the reason. For classification of a metabolic acidosis it is expedient to calculate anion and osmolyarny intervals. The anion interval is the difference between concentration of the main cations (positively charged ions) and anions (negatively charged ions) of plasma. Normal this indicator is 12–18 mmol/l. This difference is caused by availability of negatively charged proteins, phosphates, sulfates and a small amount of organic acids which are not measured at routine blood test. The AI normal value demonstrates that acidosis is initially caused by bicarbonate loss. Increase in AI demonstrates accumulation of the fixed acids or presence of exogenous organic acids.
Respiratory acidosis is a frustration of KShchS at which PaCO2 increases to the level which goes beyond its physiological values. At respiratory acidosis of pH it can be reduced (acute acidosis), to be within norm (chronic acidosis) or it is increased (the mixed frustration of KShchS).
Respiratory acidosis represents increase in content of carbonic acid in blood (over PaCO2> 45 mm Hg.), but at the same time it is necessary to understand that respiratory acidosis is not always connected with a hypercapnia. Allocate two types of respiratory acidosis: acute and chronic. Acute respiratory acidosis develops prior to renal compensation, and chronic respiratory acidosis the sign has existence of full renal compensation.
As opposed to changes of KShchS in the acid party, in an organism also development of the return morbid conditions when rn Wednesdays changes in the alkaline party, that is an alkalosis which represents both accumulation of certain products, and change first of all of gas composition of blood is possible.
The metabolic alkalosis represents frustration of KShchS at which there is an increase in concentration of bicarbonate. The second in frequency reason of a metabolic alkalosis loss of nonvolatile acids (for example, hydrochloric acid of a stomach considers at repeated vomiting). Among patients of OITR the metabolic alkalosis is quite frequent pathology which reason is use of diuretics and nazogastralny probes. In both cases there will be a loss of ions of hydrogen, increase in amount of bicarbonate in blood and shift of its reaction in the alkaline party.
The respiratory alkalosis is the result of a hyperventilation which leads to decrease in content of carbon dioxide in blood. The respiratory alkalosis can be acute or chronic. The type of a respiratory alkalosis depends on at the expense of what systems it is compensated rn to blood. At a chronic respiratory alkalosis of PaCO2 is below normal level, but PH value is in normal limits thanks to renal compensation. Among patients of intensive care unit the respiratory alkalosis is the most frequent disturbance of an acid-base state.