NMR cryoporometry with octamethylcyclotetrasiloxane as a probe liquid. Accessing large pores.

Octamethylcyclotetrasiloxane is presented and investigated as probe liquid for NMR cryoporometry or DSC-based thermoporometry. This compound which may imbibe into both hydrophilic and hydrophobic pores is shown to exhibit a melting point depression that is larger than that for other cryoporometric probe materials such as cyclohexane. The transverse relaxation time differs by more than three orders of magnitude between the solid and liquid states, separated by a sharp phase transition. Hence, as demonstrated in controlled pore glasses, octamethylcyclotetrasiloxane can provide pore size distributions for materials with pore sizes up to the micrometer range.

[Blood oxygen-transporting function during different anesthesiological provision procedures in the surgery of the hepatopancreatoduodenal area].

A comparative analysis of blood oxygen-transportingfunction (BOTF) under 6 types of combined general anesthesia (low-flow inhalational anesthesia in combination with a narcotic analgesic or with continuous graded epidural infusion (CGEI) of local anesthetics) during high-traumatic and prolonged operations on the hepatopancreaoduodenal area has revealed no significant abnormalities of tissue oxygen transport and metabolism. At the same time when a procedure of anesthesia is chosen for this category of patients, preference should be given to a combination of CGEI and low-flow inhalational anesthesia with isoflurane in nitrous-oxide mixture, which provides a minimum drug load, optimal conditionsfor cardiovascular performance, and stability of BOTF parameters even in baseline endotoxicosis.

[Prediction of cardiac complications during operations on the brachiocephalic arteries].

The development of myocardial or brain ischemia is a major hazard to patients operated on the brachiocephalic arteries. The purpose of the present study was to reveal a risk factor or its group of factors whose correction would improve the prediction of surgical interventions as a whole. A preliminary study included 105 patients (among them there were males (80%), whose mean age was 60 +/- 0.77 years; females (20%) whose mean age was 64 +/- 1.38 years). It has shown that a significant individual impact on the occurrence of cardiac complications was produced by the following factors: the severity of angina pectoris (p = 0.01); diabetes mellitus (p = 0.01); transesophageal stimulation test (the presence of a low or moderate coronary circulatory reserve) (p = 0.02), hypertensive disease (p = 0.04). The likelihood of development of cardiological complications drastically increases with a rise in the number of significant risk factors of concomitant diseases. Their determining risk factors are hypertensive disease and postoperative arterial hypertension, which, in combination with other risk factors, provokes cardiac complications in the postoperative period. In the patients with the high predictable likelihood of cardiac complications during operations on the brachiocephalic arteries, the priority task is to stabilize blood pressure when the patients are prepared for surgery and to prevent unstable hemodynamics in the postoperative period.

[Prolonged epidural infusion of ropivacaine in the complex of anesthesiological protection at pancreatoduodenal surgery].

The purpose of this study was to examine the expediency and efficiency of use of an infusion administration of naropine into the epidural space for intraoperative anesthesia and to develop the optimum procedure for administering this anesthetic during operations on the upper abdomen. Studies were performed in 43 patients operated on for different pancreatic diseases. Anesthesia based on epidural naropine infusion versus ataralgesia was compared. This study indicated that epidural naropine infusion-based anesthesia provides stable hemodynamic parameters and reduces the use of narcotic analgesics by more than twice. Inclusion of prolonged epidural infusion of 0.3% naropine solution into the anesthesiological appliance scheme during this type of operations provides an adequate antinociceptive protection and contributes to the early activation of patients, which prevents the development of postoperative complications.

[Combined monitoring of the central and autonomic nervous system during operations on the liver and pancreas].

Thirty patients from 3 groups that differed only in the scope of monitoring were examined to study the efficiency of combined neurophysiological and autonomic nervous monitoring in the assess of the quality of anesthesiological protection during highly traumatic surgical interventions made in abdominal patients under combined general anesthesia based on long-term graded epidural naropine (3 mg/ml) infusion at the thoracic level Addition of the Harvard standard with monitoring the information saturation of EEG made it possible to maintain the depth of anesthesia, by reducing the dose of dormicum by 20% (p < 0.05). The use of combined monitoring of EEG information saturation and the tension index after R. M. Bayevsky could reduce the dose of fentanyl by 2.3-2.7 times (p < 0.05) and the incidence of critical cardiovascular incidents by 39% (p < 0.05).

[Information method of EEG analysis in anesthesiology]. / Informatsionnyi metod analiza EEG v anesteziologii.

An information concept of nociceptive impulses is proposed. The device for quantitative analysis of information coming to CNS has been constructed and approved. It is demonstrated that monitoring of informative loading of EEG may be used for evaluation of anesthesia adequacy. Level of this index from 40 to 50% corresponds to effective protection.

[Electroencephalogram, informational saturation of electroencephalogram, and bispectral index during xenon anesthesia for laparoscopic operations]. / Elektroéntsefalogramma, informatsionnaia nasyshchennost' élektroéntsefalogrammy i bispektral'nyi indeks pri anestezii ksenonom vo vremia laparoskopicheskikh operatsii.

The depth of xenon anesthesia was never evaluated by modern methods of EEG monitoring, and hence, we studied changes in EEG, INEEG, and BIS during different stages of xenon narcosis and evaluated the possibility of using these values as criteria of xenon anesthesia adequacy. The study was carried out in 60 patients during laparoscopic operations on abdominal organs. The patients were divided into 2 groups receiving different gas anesthetics (xenon or nitric oxide). The results indicate that xenon monoanesthesia caused dose-dependent changes in the native and treated EEG; xenon is a good inhalation anesthetic providing adequate anesthesia for little traumatic operations even in case of mononarcosis; INEEG and BIS monitoring during xenon anesthesia allows an objective evaluation of its depth.

[Bispectral index (BIS)--a new ideology in solving an old problem]. / Bispectral index (BIS)--novaia ideologiia v reshenii staroi problemy.

A new method of electroencephalogram (EEG) processing is discussed: bispectral index (BIS), used for monitoring the depth of total anesthesia. The technology of BIS estimation is a principally novel approach to EEG processing, which can be denoted as an expert conclusion. EEG monitor Aspect A-100 (Aspect Medical System, USA) has been used for 3 years in the operation room during narcoses with barbiturates, propofol, midasolam, fentanyl, calypsol, isoflurane, and nitric oxide. BIS is a convenient and reliable method for evaluating the depth of total anesthesia with anesthetics with pronounced hypnotic effects at all stages of surgery. The disadvantages of the method are enumerated. The authors claim that monitors designed for expert evaluations hold good promise.

[Monitoring of the informative saturation of EEG: a new method for intraoperative assessment of antinociceptive defense of the organism]. / Monitoring informatsionnoii nasyshchennosti EEG-novyi intraoperatsionnyi metod otsenki antinotsitseptivnoi zashchity organizma.

EEG is the result of brain activity aimed at processing the external and internal information. Intraoperative pain (as a specific type of information) developing because of inadequate anesthesia increases the total amount of information on the EEG. A new original method is proposed for assessing the efficacy of analgesia, based on computer monitoring of information saturation of EEG in the on-line regimen during an operative intervention under combined total anesthesia. Physiological and clinical significance of the detected phenomena is discussed.

[Study of mechanisms of the antihypotensive effects of antishock suits in injured with traumatic shock]. / Izuchenie mekhanizmov antigipotenzivnogo deistviia protivoshokovogo kostiuma u postradavshikh s travmaticheskim shokom.

The mechanisms of antihypotensive action of antishock overalls (ASO) were studied on the basis of comparison of 30 patients with traumatic shock at the prehospital stage of medical care; in 15 of these ASO was used, in the other 15 traditional antishock intensive care. Use of a portable device for noninvasive measurement of cardiac stroke volume at the prehospital stage permitted us detect the principal mechanisms of liquidation of shock-induced arterial hypotension with the use of ASO: increase of cardiac output at the expense of autohemotransfusion from the lower part of the body to the upper vital organs with increase in the volume of venous blood restitution to the heart, the increase of total peripheral vascular resistance being negligible. Use of ASO in a complex of intensive care measures for the treatment of traumatic shock at the prehospital stage is physiological and conducive to optimization of medical care rendered to victims at the early stages of treatment.

[Electrophysiology of the central nervous system in effective anesthesia]. / Elektrofiziologiia tsentral'noi nervnoi sistemy pri éffektivnoi anestezii.

In authors' opinion, the more precise methods for controlling the depth and efficiency of general anesthesia are those which are based on the direct control over the intraoperative status of the central nervous system which reflects the time course of the status in question. Whether monitoring of the early components of somatosensory evoked potentials could be used for multimodality anesthesia was analysed. As high as 50% or lower decreases in the amplitude of the complex N19-P23 were typical of adequate defense, irrespective of anesthesias. The authors provide evidence for the efficiency of their procedure for controlling the depth and efficiency of general anesthesia. Some electroencephalographic phenomena of anesthesia were analysed with computed monitoring. The authors showed that there was a relative value of such signs of inadequate anesthesia as interhemispheric asymmetry by the leading spectral frequency and the power index of deep rhythms. Despite the procedure used (neuroleptic analgesia, ataralgesia, inhalation anesthesia, etc.), the effective anesthesia exhibited pronounced power peaks, otherwise there was a chaotic activity of the central nervous system. The physiological and clinical values of the phenomena detected are discussed in the paper.

[The possibility of predicting the antinociceptive effect of dalargin in the preoperative period]. / Vozmozhnost' prognozirovaniia antinotsitseptivnogo éffekta dalargina vpredoperatsionnom periode.

The antinociceptive effect of dalargin was studied by its influence on the amplitude of somatosensory induced potentials (IP) and by changes in the threshold pain sensitivity to heat stimulation. It was shown that it was necessary to taken into account the patients' individual sensitivity to the drug. The influence of dalargin on IP in the pre-operative period was compared with the quality of its analgetic defence in surgical interventions. The defence quality was determined according to the reduction in the consumption of the narcotic analgesic phentanyl during anesthesia. The studied parameters were found to be directly related to the correlation coefficient 0.75 (p less than 0.05). The findings allow for a reliable prediction of the antinociceptive effect of dalargin in its application in anaesthesiological practice.