[Evaluation of functional reserves of the oxygen transport system in cardiac surgery patients]. / Otsenka funktsional'nykh rezervov sistemy transporta kisloroda u kardiokhirurgicheskikh bol'nykh.

The informative value of determination of the restoration rate of spiroergometric parameters was examined in cardiosurgical patients who had undergone exercise testing. All the patients were divided into 3 homogeneous groups: (1) those without disorders; (2) those with moderate restoration; and (3) pronounced restoration. There was a moderate relationship between the restoration rate and the function of the oxygen transport system (OTS) and a high relationship between the rate and exercise tolerance in decompensated metabolic acidosis and left ventricular function. Analysis of the restoration of spiroergometric parameters provided a final assessment of the functional reserves of OTS in cardiosurgical patients and serves as a non-invasive technique to study left ventricular function in the patients.

[Physical exercise tolerance in heart surgery patients during decompensated metabolic acidosis]. / Perenosimost' fizicheskoi nagruzki v usloviiakh dekompensirovannogo metabolicheskogo atsidoza kardiokhirurgicheskimi bol'nymi.

Spiroergometric findings obtained before and in different periods (1 month to 8 years) after surgical correction were analyzed in 373 patients with congenital and acquired heart diseases. This allowed the patients to be divided into two groups in terms of their exercise tolerance in decompensated metabolic acidosis. The division should be used to assess the function of the oxygen transport system in cardiac surgical patients who have failed to achieve the "plateau" of oxygen uptake.

[The spiroergometric assessment of the level of exercise hyperventilation in patients with heart defects before and after their surgical correction]. / Spiroérgometricheskaia otsenka urovnia nagruzochnoi giperventiliatsii u bol'nykh s porokami serdtsa do i posle khirurgicheskoi korrektsii.

The paper is concerned with elaboration of criteria for spiroergometric assessment of the level of load hyperventilation (LHV) in patients with heart diseases before and after surgical correction. Study of the dynamics of the correlation between CO2 production and ventilation underlies the method suggested. Four grades of LHV are distinguished: mild, moderate, pronounced and dramatic. It is shown that the pronounced and dramatic grades of LHV may provide indirect evidence for high pulmonary hypertension (stage II or III).

[Use of anaerobic threshold for determining the level of exercise capacity in rehabilitation of patients operated on for heart defects]. / Ispol'zovanie anaérobnogo poroga dlia naznacheniia treniruiushchego urovnia nagruzki pri reabilitatsii bol'nykh, operirovannykh po povodu porokov serdtsa.

An analysis of results of spiroergometry and radionuclide ventriculography in the mixed group of cardiosurgical patients allowed to reveal a reliable accretion of fraction of expulsion of the left ventricle during transition from the state of rest to work at the level of anaerobic threshold and absence of accretion of this index in further increase of exercise. The results obtained allowed to propose the use of anaerobic threshold equal to 60% of the threshold uptake of oxygen as an indicator in choosing the optimum intensity of the training exercise of patients operated on for heart diseases.

[Maximal oxygen consumption and decompensated metabolic acidosis threshold in the assessment of functional reserves of oxygen transport in cardiosurgical patients]. / Maksimal'noe potreblenie kisloroda i porog dekompensirovannogo metabolicheskogo atsidoza v otsenke funktsional'nykh rezervov sistemy transporta kisloroda u kardiokhirurgicheskikh bol'nykh.

Possibilities of assessing the functional reserves in the oxygen transport system (OTS) were studied in cardiosurgical patients by spiro-ergometrically determining the maximal oxygen consumption (VO2 max) and decompensated metabolic acidotic threshold (DMAT). Seventy seven patients (53 males and 24 females) with various cardiac diseases were examined. A low incidence of an oxygen consumption "plateau" was found, which limited the determination of VO2 max in the cardiosurgical setting. DMAT occurred at a level of 76.0 +/- 11.6% of VO2 max and closely correlated (r = 0.86; p less than 0.05). It was concluded that it was advisable to additionally study the prospects for applying DMAT to the assessment of OTS functional reserves in cardiosurgical patients.

Comparative analysis of various types of exercise tests in evaluating the functional reserves of the oxygen transport system in cardiac surgery patients.

In 373 cardiac surgery patients and in 33 healthy persons, the authors compared the results of two (continuous and discontinuous) types of exercise tests designed to assess maximal (VO2max) and peak (VO2peak) oxygen uptake, anaerobic threshold (AT), threshold of decompensated metabolic acidosis (TDMA) and oxygen cost of exercise. The authors found that use of continuous tests is associated very rarely with "plateau" oxygen uptake (in less than 1%); it is present in 20.6% during discontinuous tests. Nevertheless, the values of VO2peak obtained in continuous tests and VO2max did not differ significantly. This makes VO2peak a fairly accurate indicator of VO2max if sufficiently exact criteria of maximal exertion have been defined. Both types of exercise tests provide close values of oxygen uptake at AT, TDMA and oxygen cost of physical exercise (up to 100 W). Therefore, both types of exercise tests can be employed in evaluating the functional state of the oxygen transport system in cardiac surgery patients.

Comparison of various approaches used to assess the functional state of the cardiac and respiratory system in patients undergoing rehabilitation following cardiac surgery.

A total of 338 patients aged 10 to 56 years, who had undergone various cardiac operations, were divided, on the basis of a spiroergometric examination, performed together with the determination of maximal oxygen intake (MOI), into 4 functional classes. Determination of functional aerobic impairment, i.e. the magnitude of deviation of the established MOI value from that theoretically anticipated in view of the patient's age and sex, made it possible to determine the degree of decrease in the reserve capacity of the patient's cardiac and respiratory system (CRS). Comprehensive assessment of the functional state of the CRS, while taking into account the patient's individual characteristics, is a prerequisite for a differentiated quantitative approach to the design of rehabilitation programmes.

[Spiroergometric assessment of the reserves of the heart pumping function at different times following closed mitral commissurotomy]. / Spiroérgometricheskaia otsenka rezervov nasosnoi funktsii serdtsa v razlichnye sroki posle zakrytoi mitral'noi komissurotomii.

The paper is concerned with the results of a spiroergometric study of cardiac pumping function reserves (an ability of the heart to increase its output in response to physical load of maximum intensity) and physical working capacity in 35 patients after closed mitral commissurotomy during a dynamic follow-up in the first year after operation. Altogether 30 healthy subjects were entered into a control group. The data obtained made it possible to reveal residual hemodynamic disorders retained for the entire follow-up period and noted with physical load (a decrease in cardiac pumping function reserves) among the examined patients. The disorders determined lowered physical working capacity. The time course of cardiac pumping function reserves and physical working capacity was studied during the first half year after operation. There was no significant change of the studied values in the second half year.

[Maximal oxygen consumption as the basis for functional classification of patients subjected to surgery for a mitral defect]. / Maksimal'noe potreblenie kisloroda kak osnova funktsional'noi klassifikatsii bol'nykh, operirovannykh po povodu mitral'nogo poroka.

A functional classification of the physical condition of patients operated on for heart diseases is proposed on the basis of exercise testing results. It is based on the assessment of maximum individual capacity to increase oxygen consumption over the resting level. The identification of 4 functional classes is supported by hemodynamic, ventilation and pulmonary gas exchange data obtained at the peak of exercise. The proposed classification meets the requirements of an objective and quantitative assessment of the patients' functional capacity as may be needed in the assessment of the efficiency of cardiosurgical correction of the defect, the rationing of therapeutic and domestic activity, working capacity prognosis and occupational recommendations.

[Dynamics of the functional state of the oxygen transport system following surgical correction of mitral valve stenosis]. / Dinamika funktsional'nogo sostoianiia sistemy transporta kisloroda posle khirurgicheskoi korrektsii mitral'nogo stenoza.

Twenty-one male and 32 female patients were examined, using spiroergometry with simultaneous measurement of maximum oxygen consumption, in a study of natural adaptation after surgical correction of mitral stenosis. It was demonstrated that the transformation in the oxygen transport system after closed mitral commissurotomy continued throughout the first post-operative year and resulted in considerably improved physical working capacity; two phases can apparently be distinguished here: during the first phase, working capacity mostly expands at the expense of improved pump function of the heart, and in the second phase, due to better peripheral circulation in working muscles.

[Noninvasive diagnosis of mitral regurgitation by impedance cardiography]. / Neinvazivnaia diagnostika mitral'noi regurgitatsii metodom impedanskardiografii.

A total of 46 patients with mitral regurgitation (MR) of varying degrees of manifestation and 84 subjects with no MR were investigated. The possibilities were elucidated of the MR diagnosis by the impedance index (IMR): the ratio of the primary diastolic wave O amplitude to the primary systolic wave amplitude (dz/dt)min of the impedance cardiogram. A significant increase of the IMR was recorded in the MR presence. The degree of such increase depended on the MR manifestation and not on the impairment of the left or right ventricle function. The high specificity and sensitivity of the method, the value of the negative and positive tests as well as their reproducibility evidence that impedance cardiography is a perspective method for the noninvasive diagnosis of MR.