Video-assisted instruction improves the success rate for tracheal intubation by novices.

BACKGROUND: Tracheal intubation via laryngoscopy is a fundamental skill, particularly for anaesthesiologists. However, teaching this skill is difficult since direct laryngoscopy allows only one individual to view the larynx during the procedure. The purpose of this study was to determine if video-assisted laryngoscopy improves the effectiveness of tracheal intubation training. METHODS: In this prospective, randomized, crossover study, 37 novices with less than six prior intubation attempts were randomized into two groups, video-assisted followed by traditional instruction (Group V/T) and traditional instruction followed by video-assisted instruction (Group T/V). Novices performed intubations on three patients, switched groups, and performed three more intubations. All trainees received feedback during the procedure from an attending anaesthesiologist based on standard cues. Additionally, during the video-assisted part of the study, the supervising anaesthesiologist incorporated feedback based on the video images obtained from the fibreoptic camera located in the laryngoscope. RESULTS: During video-assisted instruction, novices were successful at 69% of their intubation attempts whereas those trained during the non-video-assisted portion were successful in 55% of their attempts (P=0.04). Oesophageal intubations occurred in 3% of video-assisted intubation attempts and in 17% of traditional attempts (P<0.01). CONCLUSIONS: The improved rate of successful intubation and the decreased rate of oesophageal intubation support the use of video laryngoscopy for tracheal intubation training.

[Some microcirculatory and metabolic changes of rat myocardium following coronary artery occlusion]. / Nekotorye mikrotsikuliatornye i metabolicheskie izmeneniia miokarda krysy pri okkliuzii venechnoi arterii.

The experiments conducted on 50 albino male rats have shown that the increase of capillary metabolic surface area and capillary bed capacity detected 1-15 days after the coronary artery occlusion in the zones distant from necrotic focus, and resulting mainly from capillary dilation, correlated with the progressive reduction of lipid peroxidation intensity, decline in the necrotic focus area and in the activity of necrotic marker enzymes in blood serum. These changes were accompanied by a gradual increase in the activity of some enzymes and substrate content that characterize the myocardial energy supply. The changes detected could be regarded as a result of improvement of microcirculatory blood supply to the myocardium. while a prolonged (lasting for 15 days) increase of myocardial lipid peroxide content could reflect the natural reoxygenation arising from a collateral circulation development.

[The capillary system of the rat heart in occlusion of the coronary artery]. / Sistema kapilliarov serdtsa krys pri okkliuzii venechnoi arterii.

In 74 white rats by means of non-injection++ method morphofunctional state of the myocardial capillary bed has been studied in dynamics at occlusion of descending branch of the left coronary artery. During the first week after the operation blood supply of the areas, adjoining the necrosis, increases at the expense of dilatation and some increase in number of functioning capillaries, that results in enlargement of the exchanging surface and capacity of the capillary bed. Beginning from the 12th day, the value of all these parameters decreases, however, they do not reach their initial level. By the end of the experiment (45 days) the number of the functioning capillaries somewhat decreases, but the capillary diameters remain increased. By that time in the myocardial areas, adjoining the necrosis a parviansiform capillary network without a definite orientation, concerning muscle fibers, has been formed.

[Effect of preliminary administration of alpha-tocopherol and intal on the course of experimental myocardial necrosis]. / Vliianie predvaritel'nogo vvedeniia alpha-tokoferola i intala na techenie eksperimental'nogo nekroza miokarda.

Morphofunctional state of myocardial capillary bed and serum creatine kinase were measured in 70 white rats with coronary arterial occlusion. Four-day pretreatment with alpha-tocopherol and, particularly, intal, was conductive to the improvement of micro-circulation in the ischemized myocardium via an increase in the number, exchange surface area and capacity of functional capillaries. This effect became manifest since day 1 after coronary arterial occlusion and was accompanied by a stabilization of the creatine kinase level. The fact that the effect of intal was of basically the same type, but more pronounced, as compared to that of alpha-tocopherol, might be due to both the similarity of the drugs in terms of nonspecific antioxidant effect and specific properties of intal which has a membrane-protective effect on the mast cell, normalizing its stress-induced activation.

The effect of alpha-tocopherol and Intal on heart capillary bed and lipid peroxide oxidation in experimental necrosis of the rat myocardium.

The effect of Intal and alpha-tocopherol on the morphofunctional state of myocardial capillary bed and peroxide oxidation of lipids (POL) was studied in 160 albino rats with coronary artery occlusion. The vascular effect of Intal consisted in increasing the number of functioning capillaries and enlargement of their exchange surface. alpha-tocopherol proved to be less effective in this respect. The authors assume that besides its influence on myocardial microcirculation through POL reduction, Intal supports the increase in the number of functioning capillaries.

[Effect of calcium blockers on the morphofunctional state of the capillary system of the cerebral cortex]. / Vliianie blokatorov kal'tsiia na morfofunktsional'noe sostoianie kapilliarnoi sistemy kory golovnogo mozga.

The use of the non-injection method for determination of the intraorgan microcirculatory bed in cats has shown that calcium channels play an important role in the functioning of precapillary sphincters, whose activity depends to a greater extent on the activity of alpha-adrenoreceptors, particularly alpha 1-receptors. The so-called "gaiting mechanism" of calcium channels plays a more essential part in the changes in the basal tone of precapillary sphincters influenced by calcium antagonists, whereas voltage-controlled and receptor-operated calcium channels are responsible for variations in the adrenergic tone of precapillary sphincters.

[Role of endogenous prostaglandins in the mechanism of action of CO2 and O2 on the morphofunctional state of the capillary system in the cat cerebral cortex]. / Rol' éndogennykh prostaglandinov v mekhanizmakh deistviia CO2 i O2 na morfofunktsional'noe sostoianie kapilliarnoi sistemy kory bol'shogo mozga koshek.

In acute experiments on cats hypocapnia produces an appreciable diminution in the mean diameter of the capillaries and an increase in the number of the non-functioning capillaries of the brain cortex. Hypercapnia and hypoxia raise the mean diameter of the capillaries. The former leads to the opening of the non-functioning capillaries whereas the latter one does not affect this indicator. Despite the fact that the indomethacin-induced inhibition of prostaglandin biosynthesis produces no effect on the morphofunctional shifts in brain microcirculation during hypocapnia it averts the effects of hypercapnia and hypoxia on the capillary diameter. An assumption is made about the heterogeneity of receptor formations in the smooth muscles of the arterioles and precapillary sphincters responding to CO2.

Capillary system of rat myocardium in experimental hypertrophy and physical exercise.

The authors investigated in 90 albino rats, by means of a new non-injection method, the morpho-functional state of the capillary system in various parts of the myocardium in a normal state, in hypertrophy of varying degree and during physical exercise. It was found that the density, the surface are (CSA) and the capacity of the capillary bed of the right ventricle are larger than in the left ventricle. The increase in capillary blood supply in a hypertrophic myocardium occurs in parallel with the development of the hypertrophy and at rest fully corresponds to the increased myocardial mass. However, at maximal physical load the capillary segment of blood supply to the myocardium functions insufficiently, which is evidenced by a decrease in the working capacity of the experimental animals.

[Changes in the morphofunctional status of the capillary system of the cerebral cortex in cats exposed to adrenergic stimulation while prostaglandin biosynthesis is inhibited]. / Izmeneniia morfofunktsional'nogo sostoianiia kapilliarnoi sistemy kory golovnogo mozga koshek pod vliianiem adrenergicheskikh vozdeistvii v usloviiakh tormozheniia biosinteza prostaglandinov.

Experiments were made in cats to study the morphological and functional state of the capillary system of the brain in response to adrenaline administration and stimulation of the sympathetic cervical nerve under conditions of prostaglandin biosynthesis inhibition. In the presence of indomethacin administration there occurs potentiation of the vasoconstrictor effect of noradrenaline as well as of stimulation of the sympathetic nerve although to a less extent. It is assumed that the effect of exo- and endogenous noradrenaline on cerebral microcirculation is related to a definite measure to prostaglandin endogenous biosynthesis whose inhibition may lead to potentiation of the adrenergic effects thereby creating a risk of cerebrovascular spasms. Evidence for adrenergic control at the level of the capillary system of the cerebral cortex is discussed.

[State of the capillary network of rat myocardium in the presence of hypertrophy and physical loading]. / O sostoianii kapilliarnoi seti miokarda krys pri ego gipertrofii i pri fizicheskoi nagruzke.

Morphofunctional state of the capillary network in various myocardial parts was studied in white rats under normal conditions, myocardial hypertrophy of different degree and under physical loading. It was demonstrated that density, metabolic surface and capacity of the capillary bed is larger in the right ventricle than in the left one. The capillary blood supply in hypertrophied myocardium, increasing simultaneously with hypertrophy, at the state of rest corresponds to its increasing mass. On the contrary, under maximal physical loading functioning of the capillary part in the myocardium becomes unadequate that is evident from a decreasing activity of the test animals.