Metabolic acidosis – disorder of acid-base balance which is characterized by reduction of concentration of bicarbonates against the background of the normal or increased content of acids in plasma. The main signs – decrease in pH of arterial blood to level 7,35 below, deficiency of the alkaline bases more than-2 mmol/litre, the normal or increased partial pressure of carbon dioxide. It is clinically shown by oppression of a myocardium, the respiratory center, decrease in sensitivity to catecholamines. It is diagnosed on the basis of results of laboratory studying of indicators of KShchS. Specific treatment – infusion of buffer solutions.
The Metabolic Acidosis (MA) or atsidemiya – the state connected with change of activity of biologically significant proteins against the background of shift of KShchS in the sour party. Develops at the heavy course of somatic diseases, some poisonings, shocks of any origin. The moderate atsidemiya is not followed by clinical symptomatology. At elimination of the reason of failure the normal state of the internal environment is restored without medical intervention. Heavy acidosises demand treatment in ORIT because of high risk of respiratory and cardiovascular accidents. Patients need continuous hardware monitoring of the vital indicators, daily, and sometimes and hourly blood sampling on laboratory researches.
Reasons of metabolic acidosis
The atsidemiya reason – hyperproduction or the lowered ekskretion of acids, and also the strengthened removal of alkaline components of blood. Metabolic acidosis meets in all cases of shock, clinical death and a post-resuscitation disease. In addition, pathology can develop at a set of pathological processes of a therapeutic and surgical profile. Depending on the main violation the zakislivaniye can occur at the expense of a lactate or ketone bodies. Distinguish the following types of this state:
- Lactateacidosises. Arise when strengthening processes of anaerobic glycolysis in muscles. Severe forms occur at patients with the expressed fabric hypoxia, respiratory insufficiency, decrease systolic HELL is lower than the level of 70 mm of mercury. Are observed at sepsis, a gipovolemiya, synthesis of a large number of a D-lactate by intestinal microflora. The physiological reason of shifts of KShchS active physical activity, including occupations is considered weightlifting. Zakislivaniye does not demand correction and passes independently soon after relaxation of muscles.
- Ketoacidosises. Are a symptom of somatic diseases. Meet at diabetes, a chronic and sharp renal failure, an alcoholic poisoning, methyl alcohol, ethylene glycol, salycylates, violation of secretory function of a liver. Besides, concentration of ketone bodies increases at a terminal stage of shock, at development of polyorgan insufficiency.
- Loss of the bases. Takes place at a number of diseases of digestive tract: long diarrhea, intestinal fistulas, intestinal derivation of urine. The last becomes result of surgery during which removal of mochetochnik in intestines at insolvency of a bladder is carried out. Urine has a hydrogen indicator at the level of 5-7, that is is acidic environment. At hit in a gut it neutralizes the intestinal alkaline environment.
Metabolic acidosis leads to decrease in concentration of HCO3 and growth of number of Cl-. Potassium ions in cages are actively replaced with sodium and hydrogen, there is an increase in volume of K+ in plasma. In the absence of a renal failure excess of potassium is removed with urine. At the same time its level in blood remains close to norm, the intracellular gipokaliyemiya is formed. At OPN plasma contains the increased quantity of ions of K+. Small shifts are compensated for the account of buffer systems: bicarbonate, phosphatic, gemoglobinovy, proteinaceous. They reversibly connect protons, supporting a homeostasis, however actions of these systems it appears insufficiently at massive acidosis. There is a decrease in pH which affects conformation of amphoteric connections. Activity of hormones, neurotransmitters changes, functions of receptor devices are broken.
There are several classifications of an alkalemiya. One of the most widespread criteria of division the anion difference – distinction in indicators of concentration of K+, Na + and CL-, HCO3-is considered. Normal it makes 8-12 mmol/litre. If this indicator is kept, speak about an alkaloza with a normal anion hole, excess demonstrates reduction of concentration of not measured cations of Mg+, Ca + or increase in level of phosphates, albumine, organic acids. To clinical practice it is used classifications by the level of compensation of MA:
- Compensated. Proceeds asymptomatically, maintenance of a homeostasis happens due to active operation of compensatory mechanisms. pH is kept at the level of 7,4, deficiency of the bases zero, the partial pressure of CO2 is supported at the level of 40 mm of mercury. Comes to light during the long work of large volume of muscular tissue, and also at the initial stage of internal diseases. Medical correction is not required.
- Subcompensated. The hydrogen indicator keeps within norm or slightly decreases (7,35-7,29). Small deficiency of the bases is noted (to-9). pCO2 decreases at the expense of a compensatory hyperventilation, however does not overcome value in 28 mm of mercury. There is a nonspecific ill-defined clinical picture. In use of buffer liquids there is no need.
- Dekompensirovanny. pH decreases lower than 7,29, deficiency of BE overcomes a mark of-9 mmol/litre. It is not compensated for the account of a pulmonary hyperventilation. Partial pressure falls to 27 mm of mercury. or below. The developed symptomatology, sharp deterioration in health of the patient takes place. Emergency aid with use of buffer solutions is required.
Symptoms of metabolic acidosis
The compensated or subcompensated versions proceed asymptomatically. At deficiency of hydrocarbonates more than-10, a hydrogen indicator lower than 7,2 there is a compensatory hyperventilation. It is shown in the form of deep slow breath. In process of a state decompensation at the patient Kussmaul's breath develops. Chronic acidosises at children lead to growth inhibitions and development. Other clinical signs depend on the main pathology. Diarrhea, a skin itch, a polyuria, visual violations, dizziness can be noted. At the anamnesis there is a long starvation, reception of high doses of salycylates, ethylene glycol, methanol or ethanol, existence of diabetes, intestinal frustration, a renal failure of chronic type.
Heavy metabolic violations exponentiate hypotonia. Reaction to introduction of pressor amines is reduced or is absent. Decrease in sokratitelny ability of a myocardium, a compensatory takhiaritmiya comes to light. The plasma giperkaliyemiya against the background of a renal failure becomes the reason of fibrillation of auricles (vibrating arrhythmia). There are signs of violation of atrioventricular conductivity. Patients complain of breast pain, heartbeat, shortage of air. At objective survey skin pale or tsianotichny, cold to the touch, pulse arrhythmic, weak filling and tension, breath deep, heavy, noisy. Development of encephalopathy is possible.
Hard proceeding metabolic acidosis at a terminal stage causes oppression of the respiratory center. The hyperventilation is succeeded by weak superficial breath. The brain hypoxia leading to loss of consciousness and a coma develops. Activity of kidneys, a liver is broken, there is a polyorgan insufficiency. Violation of neuromuscular conductivity progresses that becomes the reason of disorder of activity of all systems of an organism. Initially predserdny arrhythmias extend to ventricles. Fibrillation of the last is observed, clinical death is diagnosed.
Diagnostics of MA at patients of ORIT is carried out by the doctor the intensivist. In the presence of chronic somatic diseases consultation of narrow experts is necessary: endocrinologist, surgeon, nephrologist, hepatologist. Chronic metabolic acidosis can be revealed by the general practitioner on outpatient appointment. The diagnosis is established on the basis of these next researches:
- Fizikalnoye. Does not allow to define precisely existence of changes as violation signs are too not specific and can meet at a set of other pathological processes. However the corresponding clinical picture gives the grounds for purpose of the analysis of KShchS and electrolytes of plasma.
- Laboratory. Is a basis of diagnostic search. Atsidemiya is diagnosed at moderate or considerable decrease in pH, deficiency of hydrocarbonates, decrease in partial pressure of carbon dioxide. Like acidosis make assessment of an anion difference for definition. For specification of the mechanism of loss of the bases studying of an anion hole not only in plasma, but also in urine can be required.
- Hardware. It is carried out for detection of the main disease, and also for the purpose of diagnostics of the arising changes. On the ECG T tooth point, expansion of the QRS complex, disappearance of a tooth of P, krupnovolnovy or melkovolnovy fibrillation of auricles, uneven intervals between ventricular complexes is noted. At emergence of stagnation in a big circle an ultrasonography signs of increase in a liver, spleen, a liquid congestion in an abdominal cavity can be noted.
Treatment of metabolic acidosis
Therapy of MA without elimination of its reasons is inexpedient, detection and treatment of the main disease is the cornerstone. At diabetic ketoacidosises correction of level of sugar in blood is necessary, at lactateacidosis – knocking over of fabric ischemia and hypoxia. At shock states the relevant resuscitation activities are shown to the patient. Treatment of the prime cause of an atsidemiya is carried out in parallel with normalization of acid-base structure of the internal environment. For this purpose apply the following methods:
- Medicamentous. At dekompensirovanny forms of a disease correction is carried out by infusional intravenous administration of sodium of a hydrocarbonate. In other cases buffer solutions do not use. Transfusion of a laktasol who is metabolized in a liver with formation of HCO3 is possible. Restoration of electrolytic balance with injection is carried out disalting, , . At a gipoproteinemiya the transfusion of proteins is shown. Normalization of oxidizing processes in fabrics is made by purpose of polyvitaminic complexes, pantothenic and pangamovy acid.
- Equipment rooms. Are necessary at the complicated course of process for correction of the vital functions. Respiratory insufficiency is the indication for transfer of the patient to artificial ventilation of lungs, decrease in function of kidneys demands carrying out a hemodialysis. At decrease HELL is carried out hardware (through ) injection of vazopressor. At fibrillation of ventricles apply electropulse treatment, indirect massage of heart.
Forecast and prevention
The course of frustration directly depends on the main pathological process and a possibility of its full elimination. After elimination of the reasons of an atsidemiya of violation of KShchS corrections even at a decompensation stage easily give in. Medicamentous completion of deficiency of hydrocarbonates at preservation of an etiologichesky factor of a zakislivaniye does not allow to achieve permanent normalization of a hydrogen indicator and BE (an indicator of a surplus/lack of HCO3). Prevention consists in timely treatment of the processes capable to become the reason of acidosis, regulation of level of sugar of blood, passing of the procedure of a hemodialysis at HPN. In the conditions of ORIT metabolic acidosis is found and corrected at an early stage at daily studying of indicators of acid-base balance.