[Features of the course of non-ST elevation myocardial infarction in patients with a history of COVID-19].

Aim      To study the clinical course of non-ST segment elevation myocardial infarction (NSTEMI) in hospitalized patients after COVID-19 and to evaluate the effect of baseline characteristics of patients on the risk of complications.Material and methods  The study included 209 patients with NSTEMI; 104 of them had had COVID-19. The course of myocardial infarction (MI) was analyzed at the hospital stage, including evaluation of the incidence rate of complications (fatal outcome, recurrent MI, life-threatening arrhythmias and conduction disorders, pulmonary edema, cardiogenic shock, ischemic stroke, gastrointestinal bleeding).Results Mean age of patients after COVID-19 was 61.8±12.2 years vs. 69.0±13.0 in the comparison group (p<0.0001). The groups were comparable by risk factors, clinical data, and severity of coronary damage. Among those who have had СOVID-19, there were fewer patients of the GRACE high risk group (55.8 % vs. 74.3 %; p<0.05). Convalescent COVID-19 patients had higher levels of C-reactive protein and troponin I (p<0.05). The groups did not significantly differ in the incidence of unfavorable NSTEMI course (p>0.05). However, effects of individual factors (postinfarction cardiosclerosis, atrial fibrillation, decreased SpO2, red blood cell concentration, increased plasma glucose) on the risk of complications were significantly greater for patients after COVID-19 than for the control group (p<0.05).Conclusion      Patients with NSTEMI, despite differences in clinical history and laboratory data, are characterized by a similar risk of death at the hospital stage, regardless of the past COVID-19. Despite the absence of statistically significant differences in the incidence of in-hospital complications, in general, post-COVID-19 patients showed a higher risk of complicated course of NSTEMI compared to patients who had not have COVID-19. In addition, for this category of patients, new factors were identified that previously did not exert a clinically significant effect on the incidence of complications: female gender, concentration of IgG to SARS-CoV-2 ≥200.0 U/l, concentration of С-reactive protein ≥40.0 mg/l, total protein <65 g/l. These results can be used for additional stratification of risk for cardiovascular complications in patients with MI and also for development of individual protocols for evaluation and management of NSTEMI patients with a history of COVID-19.

[The determination of cardiac output by the dilution of ultrasonic blood density]. / Opredelenie serdechnogo vybrosa metodom razvedeniia ul'trazvukovoi plotnosti krovi.

The authors propose assessing cardiac output (CO) by diluting the blood ultrasonic properties. For measuring CO, the peripheral artery and vein were connected with a catheter, and ultrasonic flowmetric pickup was attached to the shunt. Indicator (0.9% sodium chloride) was injected into the central vein. Changes in the blood ultrasonic characteristics during the indicator flow were recorded by ultrasonic flowmeter. Dilution curves were computer processed. The method was tried in 7 experimental dogs and clinically in 11 patients and compared with the thermodilution method. The coefficient of correlation was 0.98 in experiment and 0.97 in clinical trials. Dilution of ultrasonic density of the blood helps accurately assess the CO and is highly informative, which is confirmed by a strong correlation with the results of thermodilution. The method is simple, little invasive, realized using available equipment, the indicators are cheap and available, and repeated studies can be performed within short periods of time.

[Effects of ventilation of the lungs in prone position on the pulmonary oxygenation function and hemodynamic parameters of heart surgery patients with respiratory insufficiency in the postoperative period]. / Vliianie ventiliatsii legkikh v polozhenii patsienta na zhivote na oksigeniruiushchuiu funktsiiu legkikh i pokazateli gemodinamiki u kardiokhirurgicheskikh bol'nykh s dykhatel'noi nedostatochnost'iu v posleoperatsionnom periode.

Effect of ventilation in the face-down position (VFDP) on the oxygenation function of the lungs and hemodynamics is studied in 32 patients (aged 22-64 years) subjected to open-heart surgery complicated by development of acute respiratory failure (RF). In 23 patients with grave respiratory distress syndrome, VFDP was performed with forced ventilation of the lungs (FVL) and in 9 with less grave RF, with noninvasive mask ventilation of the lung (NIMVL). Body position of patients on FVL was changed every 4-12 h, of nonintubated patients, 45-60 min. The oxygenation function of the lungs improved in the intubated patients as early as during the first hour of FVL in the face-down position: PaO2/FiO2 notably increased and a tendency to decrease of A-aDO2 and Qs/Qt was observed. The positive effect was maximal after at least 4-hour FVP in the face-down position: PaO2/FiO2 increased by 76.6%, intrapulmonary shunting fraction decreased by 43%, and the O2 alveolar-arterial difference decreased by 27% in comparison with the initial values. After body position of patients was changed, the above improvements did not disappear, despite a slight decrease of the effect attained. VFDP with NIMVL led to similar results: O2 alveolar-arterial gradient decreased, PaO2/FiO2 decreased by 24.2%, the mean values of this ratio approaching the norm. Positive effect somewhat decreased after catecholamines were discontinued, but the oxygenation function of the lungs remained better than initially.

[Anatomic orthotopic heart transplantation: the surgical characteristics and the advantages of the method]. / Anatomicheskaia ortotopicheskaia transplantatsiia serdtsa: khirurgicheskie osobennosti i dostoinstva metodiki.

Standard technique of establishment of interatrial anastomoses allows to carry out orthotopic transplantation of the heart quickly and reliably. However the accumulation of collective experience evidences about a number of unavoidable shortcomings of such operation: rhythm disturbances, worsening of hemodynamics in discordant atrial contractions of recipient and donor, atrio-ventricular valve insufficiency, thromboembolism, coronary fistulas. Since 1990 in RRCS 25 operations were carried out with the use of standard technique and we also met with the risk of developing the above complications. In experiment on 30 mongrel dogs the technique of anatomical, truly orthotopic transplantation of the heart with six anastomoses was developed: left pulmonary veins with a common cuff, separate anastomoses of the superior and inferior caval veins, anastomoses of aorta and pulmonary artery. Particular attention was paid to developing of original surgical modes for prophylaxis of stenoses in the area of anastomoses of pulmonary and caval veins. In 1997 the anatomical technique of heart transplantation was successfully introduced by us into clinical practice. Clinical electrophysiological, echocardiographic and functional examinations have confirmed the results of the experiments and have evidenced for substantial advantages of the anatomical technique of orthotopic transplantation of the heart. By reliability the new operation is not inferior to standard method of N. Shumway.

Simultaneous separate assessment of the cardiac and LVAD output.

The electroimpedance indicators' dilution (EIID) technique was used to study the possibility of a simultaneous separate assessment of the biological heart and LVAD performance in the position of LVB. The experimental part of the research was performed on 5 dogs; an artificial ventricle of the pulsing type (USA) with cusps was used as a pump. The clinical part of the work was conducted on 5 patients after open-heart surgery who had the clinical picture of postcardiotomy cardiogenic shock; a centrifugal pump "Biopump" (Medtronic, USA) was used. The authors have shown a principally important possibility of applying the EIID, technique for studying the performance curves which are the integral derivatives of the work of a specific hybrid system--"the biological heart-assist device". From the practical viewpoint the EIID technique permits in the read time mode to control continuously the part of the pumping function which is assumed by the patient's own heart. This information can serve as the basis for making the prognosis and determining the further tactics of treatment; the restoration of the heart performance or its replacement by transplantation.

[Reduced paired stimulation in patients in the early postoperative period after an open-heart surgery]. / Urezhaiushchaia parnaia stimuliatsiia u bol'nykh posle operatsii na otkrytom serdtse v rannem posleoperatsionnom periode.

The authors provide the technique of underdriving paired ventricular stimulation as a variant of treating drug-resistant tachycardias and a formula of calculating rhythm inhibition and the impulse delay. Basing on the stimulation pathophysiology and positive shifts in hemodynamics, the validity of this stimulation, its advantages and indications are inferred.

[Noninvasive mask ventilation of the lungs in the treatment of acute respiratory insufficiency in heart surgery patients in the postoperative period]. / Neinvazivnaia masochnaia ventiliatsiia legkikh pri lechenii ostroi dykhatel'noi nedostatochnosti v posleoperatsionnom periode u kardiokhirurgicheskikh bol'nykh.

Noninvasive ventilation of the lungs using a mask (NIVLM) was used in 54 patients with hypercapnic (n = 14) and hypoxemic (n = 40) respiratory failure. Respironics (USA) nasal and facial masks were applied. Ventilation regimens were selected individually. Trigger monitored ventilation, intermittent forced ventilation of the lungs, and assisted ventilation with positive expiratory pressure, biphasic positive pressure in the airways, and constant positive pressure in the respiratory contour were used. The efficacy of NIVLM in patients with hypercapnic respiratory failure was 100%. The pCO2 and ETCO2 normalized in all patients both during and after discontinuation of NIVLM. Despite a relatively long period of ventilation (229 +/- 72 min), the patients did not complain of discomfort during the procedure; no complications or individual intolerance of nasal or facial masks were observed. In patients with hypoxemic respiratory failure NIVLM resulted in a decrease of dyspnea, increase of respiratory volume, etc. The detected changes did not disappear after NIVLM was discontinued. Individual tolerance of nasal and facial masks was somewhat worse in this group: patients complained of stuffiness, lack of air, difficult respiration. Six patients (18.2%) developed episodes of psychomotor excitation which required sedative and analgesic therapy. In general, the efficacy of NIVLM was 91%, but resolution of respiratory failure without repeated intubation of the trachea was attained in only 33 patients (87%) with the hypoxemic condition. The mean duration of NIVLM in this group was 464 +/- 47 min. Hence, NIVLM is an effective method for respiratory support in patients with both hypoxemic and hypercapnic respiratory failure, which helps decrease the duration of forced ventilation of the lungs or do without repeated intubation of the trachea.

[Use of software "Aggregate state of the blood" in staged diagnosis and correction of disorders of blood coagulation and rheology]. / Ispol'zovanie algoritma "Agregatnoe sostoianie krovi" v poétapnoi diagnostike i korrektsii naryshenii svertovaniia i reologii krovi.

The "Aggregate State of the Blood" software was created at the National Research Center of Surgery in 1994. The software is intended for comprehensive assessment of the blood fluidity under different conditions of clotting, rheology, and acid-base balance and shows deviations of the detected values from the norm, predicting the risk of thrombotic and/or hemorrhagic complications. From 1994 to 1996, the program was used in more than 1000 patients subjected to cardiopulmonary bypass surgery with complicated and uneventful peri- and postoperative period. The operations were as follows: heart and liver transplantations (19 and 7 cases), intraaortic balloon counterpulsation (16), extracorporeal detoxication (10), acute myocardial infarction (9), etc. The results were compared with the data recorded in case histories of 255 patients who underwent similar operations in 1991-1994. The results of diagnosis and prediction were commented in the protocol for each case. The conclusions were used for therapy or prevention. The incidence of thrombotic and hemorrhagic complications and the DIC syndrome in 1995-1996, when the new software started to be used, was significantly lower than before. The best clinical results were attained in the patients examined before surgery (n = 92). In this group application of the program (and subsequent preventive treatment) helped improve the adaptive potential of the physiological systems maintaining the blood fluidity. This resulted in a lower postoperative blood loss and a lesser incidence of thrombotic and hemorrhagic complications and the DIC syndrome as against the reference group.

Validation of a new method to measure cardiac output during extracorporeal detoxification.

Cardiac output was measured in 11 patients during extra-corporeal detoxification after open heart surgery. All patients were mechanically ventilated and had pulmonary artery catheters for cardiac output (COT) measured by thermodilution. A sensor on the arterial side of the extracorporeal circulation measured flow and sound velocity transients. Injections of 2-5 ml 0.9% saline at 37 degrees C into the arterial line upstream of the sensor permitted its calibration; 10-20 ml of the same solution was injected intravenously or into the venous dialysis injection port, and cardiac output (COUD) was calculated by the ultrasound velocity dilution technique. COT was measured within 5 min of the ultrasound dilution measurement. CO was in the range of 2-8 L/m. The regression equation was COUD = 1.09 x COT-0.32 (r = 0.97, n = 31). These data suggest agreement between the ultrasound dilution technique and thermodilution. Ultrasound dilution is preferable in patients undergoing extracorporeal detoxification when pulmonary artery catheterization is not required or dangerous.

[Right ventricular insufficiency in patients in the early periods after orthotopic transplantation of donor heart]. / Pravozheludochkovaia nedostatochnost' u patsientov v rannie sroki posle ortotopicheskoi transplantatsii donorskogo serdtsa.

The function of transplanted heart in the early postoperative period is analyzed in 20 patients operated on at the Research Center of Surgery of the Russian Academy of Medical Sciences. Cardiac function was assessed by a complex of hemodynamic parameters, among which were the ratio between the ventricular stroke index and end diastolic pressure in the ventricle. Right-ventricular dysfunction of varying severity was detected in all the patients in the immediate postoperative period. Three variants of right-ventricular insufficiency were singled out: isolated right-ventricular insufficiency with increased (20%) and normal (45%) total vascular resistance and right-ventricular insufficiency combined with left-ventricular insufficiency (35%). Isolated right-ventricular insufficiency could be, as a rule, treated by combined intensive care including sympathomimetics and vasodilators. A combination of right-ventricular and left-ventricular insufficiency, which may be caused by incompatability between the sizes of the donor and recipient, as well as hypoxic and metabolic cardiac injury in donor body, is prognostically infavorable, for it requires intensive inotropic therapy and is associated with a high mortality.

[Clinical aspects of the use of nubain, tramal and moradol in patients in the early postoperative period]. / Klinicheskie aspekty primeneniia nubaina, tramala, moradola u bol'nykh v rannem posleoperatsionnom periode.

Opioid analgesics were used in 282 patients on the first-third day after heart, lung and abdominal surgery. The main indication for their use was pain syndrome. Adequate analgesia with tramal, nubain and moradol was noted in 73, 76 and 81% of cases. In marked pain syndrome after thoracotomy the most effective agents were moradol and morphine. Computer monitoring of the respiratory function in tramal analgesia has shown a decrease in lung ventilation, esophageal pressure, inhalation volume, O2 production. Tramal, nubain and moradol in analgesic doses did not inhibit respiration. In adequate analgesia there was a decrease in lung ventilation which was not accompanied by shifts in acid-base balance of the arterial blood. The above analgesics had no considerable effect on systemic hemodynamics, though the use of tramal decreased systemic blood pressure and the use of moradol decreased systemic blood pressure and total peripheral vascular resistance. Tramal was most effective for synchronization of spontaneous respiration with a lung ventilation device in prolonged ventilation, as well as for the arrest of muscular tremor in the postoperative period. Tramal was effective in 95% of patients in the early post-anesthesia and postoperative period.

[Possibilities of the method of dilution of electro-impedance indicators in the assessment of volume dynamics of extravascular lung fluid in intensive care and resuscitation units]. / Vozmozhnosti metoda razvedeniia élektroimpedansnykh indikatorov dlia otsenki dinamiki ob"ema vnesosudistoi zhidkosti legkikh v praktike otdeleniia intensivnoi terapii i reanimatsii.

The possibility of using impedance plethysmography to assess changes in the volume of the extravascular lung fluid in intensive therapy and resuscitation patients is discussed. Changes in the volume of the fluid during extracorporeal detoxication are analysed. A correlation was found between these changes and lung distensibility (r = -0.7). A significant diminution of the fluid volume was observed in response to therapeutic doses of Lasix and Nitroglycerin. Data are cited on the increasing (85 percent) volumes of the fluid in preclinical pulmonary edema in patients with left ventricular insufficiency.

[Current methods of assessing hemodynamics in the intensive care unit (comparative aspects)]. / Sovremennye metody otsenki gemodinamiki v usloviiakh otdeleniia intensivnoi terapii (sravnitel'nyi aspekt).

The paper deals with comparative characterization of validity shown by current techniques for assessing hemodynamic parameters such as radiocardiography, echocardiography, Doppler cardiography, electroimpedance indicator separation, alveolar gas carbon dioxide concentration change technique, tetrapolar chest rheography and their potential role in the practice of intensive care and resuscitation units.