[Cerebral metabolism in carotid endarterectomy (oxygenation, electrolytic balance, glucose consumption)].

The purpose of this study was to evaluate regional oxygenation, glucose metabolism and electrolytic balance of the brain in patients with an atherosclerotic lesion of the carotid arteries in the perioperative period. A total of 42 patients presenting with various combinations and degree of manifestation of occlusive-and-stenotic damages to the brachiocephalic arteries were examined. Regional oxygenation of the brain (rS02) was assessed using the unit INVOS 3100 (Somanetics Corp., USA) at rest, with the patient lying upon the back and breathing atmospheric air and oxygen, and while changing the assumed body position. The acid-base state, gases, electrolytic composition and the level of glucose in the arterial blood and blood outflowing from the brain were analysed with the help of the unit STAT profile 5 Analyzer (NOVA Biomedical, USA). Four variants of perioperative alterations in oxygenation of the brain were determined, with the respective comparative characteristics thereof given. The authors have shown that the rS02 at rest prior to surgery was determined in unilateral stenosis of the internal carotid artery on the side of the lesion, while in bilateral stenosis - on the side of the greater lesion of the internal carotid artery. A decrease in the rS02 value in patients with the internal carotid artery narrowed by 70% and more during the orthostatic test is characteristic of subcompensation of the cerebral blood flow. Decompensation thereof manifests itself by a positive reaction of rS02 to oxygen inhalation. Patients with the initially low values of rS02 during reperfusion of the brain were found to have diminished glucose utilization, while in the normal rS02, glucose metabolism was noted to increase.

[Clinical-and-pathophysiological prerequisites of impaired breathing and ensuring of safety in drug-induced depression of consciousness]. / Kliniko-patofiziologicheskie predposylki dlia narusheniia vneshnego dykhaniia i vozmozhnye puti dostizheniia bezopasnosti pri medikamentoznoi depressii soznaniia.

Seventy-three patients operated on under anesthesia based on regional blocks were examined. Thiopental-sodium (T; n = 29), myadozalam (M; n = 10) and propofol (P; n = 24) were used for sedation. The conditions of breathing and of gas exchange were evaluated by the findings of pneumotachography: V(peak insp), P(peak insp), P(100) Raw, breathing pattern, SpO2, PEtCO2 and EMG from mouth-diagram muscles. The obtained results were made use of to draw up a rating scale for impaired breathing, which is based on the respiratory volume and respiration rate of gas exchange as well as on different variations of respiratory support. Irrespective of a sedation type and of a degree of consciousness suppression, the impaired breathing was registered in 90-100% of cases: obstruction of the respiratory tracts was predominant in T (higher Raw); in M--depression of the respiratory center (lower P(100); in P--a pronouncedly lower of EMG, and, respectively, a weakened contraction of diaphragm (lower P(peak insp)). Depression of the respiratory center was found to occur irrespectively of a drug used in sedation, however, the mechanisms of obstruction were different: in T--impaired breathing; in M--impaired phase muscle activity. Sedation by P was not accompanied by any clinically valuable obstructive signs.

[Hemodynamic parameters and saturation of the cerebral cortex blood with oxygen during extracorporeal circulation in heart surgery]. / Vliianie parametrov gemodinamiki na nasyshchenie kislorodom krovi kory golovnogo mozga vo vremia iskusstvennogo krovoobrashcheniia pri operatsiiakh na serdtse.

Sixty-three patients were intraoperatively examined during heart surgery with extracorporeal circulation (AEC). They were operated on for an affected heart-valve apparatus (AHVA) and ischemic heart disease (IHD). There was a perioperative monitoring of central hemodynamics, pressure in the bulb of superior jugular vein (BSJV) and electroencephalography (EEG). Regional oxygenation of the brain was made in real time by a INVOS3100 oximeter (SOMANETICS, USA). A maximal saturation of the cortex blood with oxygen at AEC was registered in patients with AHVA at an average pressure below 70 mm Hg, and in patients with IHD--at 85 mm Hg. An increased pressure in BSJV at a constant mean arterial pressure and at AEC is related with blood outflow from the venous collector of the brain.

[Cerebral oximetry in the perioperative evaluation of the reserve of cerebral circulation in patients with brachiocephalic artery lesions]. / Tserebral'naia oksimetriia v otsenke rezervov krovoobrashcheniia golovnogo mozga v perioperatsionnom periode u bol'nykh s porazheniem brakhiotsefal'nykh arterii.

The reactivity of cerebral vessels and the reserve of collateral compensation of cerebral flow were studied in 71 patients with perioperative carotid stenosis of different degrees. Cerebral oximetry was made at rest and during hypercapnic and compression loads. The method's efficiency was demonstrated for the preoperative evaluation of the cerebrovascular reserve in patients with atherosclerotic affection of vessels in the brachiocephalic stem. A comparison of the preoperative and intraoperative dynamics of rSO2 at compression points at the feasibility of using the cerebral oximetry in predicting the degree of reduced regional oxygenation of the brain in the basin of an intraoperatively pinched artery.

[Cerebral oximetry during cardiac surgery under extracorporeal circulation]. / Opyt ispol'zovaniia tserebral'noi oksimetrii pri operatsiiakh na serdtse v usloviiakh iskusstvennogo krovoobrashcheniia.

The time course of changes in rSO2 were studied in 58 patients during the uncomplicated course of cardiac operations under extracorporeal circulation (EC) and moderate hypothermia. rSO2 was also compared with central hemodynamic parameters, bioelectrical cerebral activity, and hemoglobin oxygen saturation of the bulb of the internal jugular vein (jbSO2). In the pre- and postperfusion period there was a significant correlation of rSO2 and jbSO2 (p = 0.01), yet with a low correlation coefficient (r = 0.348). During EC, no correlation was found between rSO2 and jbSO2 (p = 0.09, r = 0.386). Changes in rSO2, blood pressure, EEC, body temperature were analyzed in 2 groups of patients at the stages of an operation under EC. Group 1 comprised patients with cardiac valvular apparatus lesions and Group 2 included those with coronary heart disease who differed not only in age, but also in the history of mainly cerebrovascular atherosclerotic lesions, hypertensive disease, myocardial infarction, etc. In patients from both groups, a reduction in rSO2 occurred at the beginning of EC and at the maximum of cooling. But if in Group 1 patients, the significant reductions in rSO2 at the beginning of EC coincided both with that in mean blood pressure (BPmean), as compared to the baseline values (from 75.55 +/- 10.68 to 66.5 +/- 11.73 mm Hg, p = 0.01), and with the change in the frequency spectrum of EEC (a decrease in the frequency of the right edge, as compared to the baseline values, from 20.77 +/- 1.44 to 19.58 +/- 1.14 Hz, p = 0.01), in Group 2 patients, all significant decreases in rSO2 were accompanied only by a significant reduction in BPmean, but without changes in the frequency spectrum of EEG. It should be noted that over the uncomplicated course of an operation all changes in rSO2 were in the normal range of age-related values.

[The perioperative diagnosis of cerebral ischemia during reconstructive operations on the carotid arteries (initial experience in using transcranial oximetry)]. / Perioperatsionnaia diagnostika tserebral'noi ishemii pri rekonstruktivnykh operatsiiakh na sonnykh arteriiakh (pervyi opyt primeneniia transkranial'noi oksimetrii).

Intraoperative monitoring of cerebral ischemia during surgery on the brachiocephalic arteries is carried out by several methods: transcranial dopplerography, electroencephalography, recording of the somatosensory evoked potentials, puncture measurement of intravascular pressure, etc. However, not all these methods are sufficiently informative, reliable, and safe. One of the methods meeting these requirements is noninvasive cerebral oximetry. The study was carried out by the Invos-3100 device (Somanetics, USA). The method of cerebral oximetry is based on optic spectroscopy using infrared light in the 650-1100 nm waveband. Monitoring was carried out in 34 patients with involvement of the brachiocephalic arteries. The results persuasively prove high informative value and safety of the method.

[Significance of the energetic value of respiration in the assessment of the degree of strain of compensatory mechanisms in respiratory insufficiency]. / Znachenie énergeticheskoi stoimosti dykhaniia pri otsenke stepeni napriazheniia kompensatornykh mekhanizmov pri dykhatel'noi nedostatochnosti.

A total of 170 examinations of the external respiration function were carried out in 114 patients with postoperative respiratory insufficiency (RI). The patients were examined during air respiration (FiO2 0.21). Pulmonary function was computer monitored. Thirty-four parameters were analyzed, which characterize pulmonary ventilation, gas exchange, respiratory mechanics, and metabolism. Three groups of patients were distinguished: with moderate, expressed, and maximal stages of energy compensation of RI. Augmentation of RI in the course of the postoperative period was found to be characterized by reduction of lung compliance and increase of aerodynamic resistance of the airways and specific and minute Decompensation of RI develops due to fatigue of the respiratory muscles under conditions of increased energy value of respiration, which is proved by the appearance of a reliable inverse correlation between the minute respiratory volume and increased inhalation and exhalation resistance and between respiratory volume and increased inhalation resistance and of a direct correlation between respiratory volume and lung compliance in patients during the maximal energy compensation of respiratory insufficiency. Hence, the energy value of respiration objectively reflects the strain of the compensatory mechanisms during respiratory insufficiency.

[Methodological approaches to studies of the functional state of lungs under conditions of intensive care]. / Metodicheskie podkhody k issledovaniiu funktsional'nogo sostoianiia legkikh v usloviiakh intensivnoi terapii.

Algorithms for automated processing of curves reflecting respiratory function of the lungs (pneumotachygram, psyrogram, transthoracic pressure) in grave patients were developed. A system of monitoring the parameters characterizing real time pulmonary ventilation, gas exchange, respiratory mechanics and aerodynamics was created. The described algorithms for calculating the curves of respiratory functions permit examination of pulmonary function during spontaneous respiration of a patient.

[Relationship between pulmonary circulation and respiratory mechanics in patients artificial pulmonary ventilation]. / Vzaimosviaz' legochnogo krovoobrashcheniia s mekhanikoi dykhaniia u bol'nykh na IBL.

Thirty-four patients in the early postoperative period after surgery on the lungs and mediastinum and 23 patients after cardiopulmonary bypass surgery have been examined. 187 studies of central hemodynamics and pulmonary function during cardiopulmonary bypass have been performed to investigate the correlation between pulmonary hemodynamics and parameters of respiratory mechanics in the early postoperative period after thoracic surgery. The studies have revealed reverse dependence of lung and chest compliance (C) on pulmonary artery diastolic pressure (PAPdiast) (r = -0.61, p < 0.05) in patients after thoracic surgery with clinical signs of cardiopulmonary failure. When analogous studies were performed in patients with intact lungs after aortocoronary bypass, C/PAPdiast correlation was more close (r = 0.880, p < 0.05). At the same time there is a correlation between C and extracellular fluid volume (r = -0.7). The above correlations to a great extent predetermine the pathogenesis of respiratory failure in the postoperative period.

[Computerized monitoring of patients in the intensive care and resuscitation unit]. / Komp'iuternyi monitoring u bol'nykh v otdelenii intensivnoi terapii i reanimatsii.

Monitoring-computed systems were used during the therapeutic-diagnostic process at the resuscitation department of the All-Union Surgery Research Center in more than 1,000 patients who underwent operations on the heart, coronary arteries, bronchi, trachea, and esophagus. The main importance is attached to examination of the cardiorespiratory system. More than 90 derived parameters characterizing intracardiac hemodynamics, ventricular contractility, and oxygen transport are calculated according to special programs. For evaluation of the function of the lungs in an automated regimen, 32 parameters characterizing lung ventilation, gas exchange in the lungs, mechanism of respiration, and metabolism are calculated. Monitoring-computed care makes it possible to appraise the patient's condition in a given situation, the transient nature of changes in the physiological systems of the organism under the effect of therapy, and helps in choice of the optimal regimens of artificial lung ventilation and the methods of treatment. Computed appraisal of hemodynamics by means of the algorithm of the nearest point was found to be correct in 93% of cases. Storage of the results in the computer memory ensures an operative approach to information on any of the patients.

[The effect of bronchofibroscopy on the mechanics of breathing during disorders of bronchial patency in the postoperative period]. / Vliianie bronkhofibroskopii na mekhaniku dykhaniia pri narusheniiakh bronkhial'noi prokhodimosti v posleoperatsionnom periode.

Changes in lung ventilation and pulmonary mechanics have been studied after bronchoscopy (BS) performed in 22 patients with early postoperative bronchial patency disturbances. All in all the results of 27 BS procedures have been assessed. It has been found that according to the nature of respiratory changes the patients could be divided into 2 groups. In one group pulmonary mechanics improved right after the procedure. While in the other group BS was associated with an increase in aerodynamic bronchial resistance to inhalation, respiratory work and energy waste. The parameters returned to normal values within an hour. It was noticed that the second type of the reaction was characteristic of patients over 50 with low respiratory reserve, heart failure and hypoxemia. In such patients BS is recommended together with high frequency jet ventilation through a nasotracheal catheter.

[Clinical use of tramal in patients in the early postoperative period]. / Klinicheskoe primenenie tramala u bol'nykh v rannem posleoperatsionnom periode.

Tramal was given to 204 patients who were operated on the lung, heart, abdomen. During pain therapy, good and satisfactory results were on average obtained in 75% patients operated on the lung, in 77%, on the heart, in 89%, on the abdomen, in 70%, on the great vessels. The absence of the inhibitory effect of the drug on the respiratory center and its slightly marked sedative effect allow one to recommend the agent for application in the early period following the surgery when narcotic analgesics still retain their effect and a real risk of their overdosage exists. During prolonged artificial pulmonary ventilation in the early postoperative period and in impaired adaptation of the patients to a respirator, tramal aids normalization of lung mechanics and hemodynamic parameters without eliminating and suppressing the patients' consciousness and results in cessation of muscular shivering. Adverse effects of tramal are of no decisive clinical significance and occur mainly when the drug is rapidly injected into the vein.

[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.