[The contribution of military aviation and space medicine to the biomedical support of the first flight into space].

April 12, 2011 Humanity celebrated 50 years of one of the greatest achievements of the twentieth century--the legendary flight of Y. Gagarin into space. In this study are highlighted the role and importance of military aviation and space medicine, and in particular, the State Scientific Research Testing Institute of Aviation and Space Medicine, Ministry of Defence of the USSR (now--the State Scientific Research Testing Institute of Military Medicine, Military Medical Academy named after S.M. Kirov) in the preparation and conduct of flight of Yu.A.Gagarin.

[On-board medical support system (MSS) of flights of promising aerospace sets (design)].

It was suggested as the main compositive fractions MSS to consider the base system of automated evaluation of blood redistribution (BR) in body means of crew members protection and prophylaxis (CMPP) of unfavourable effects of flight factors to organism and also the automated circuit of CMPP' control. The advanced MSS includes 4 original measuring channels for registration of the base physiologic indices (electrocardiogram, venous-arterial pulsegram of neck vessels, reogram of head, earlap vessels pulsegram) the dynamic of which allows to determine with the help of computer the BR-integral parameter. The CMPP automated control circuit unites the separate protecting means in common system and executes the individual selection of regimes and CM PP-composition in accord with, first of all, body reactions manifestation and, secondly, individual physiologic status of spaceman. As CMPP was selected the negative pressure production around lower body part. Approlation of constructed active laboratory engineering mock-up MSS has performed investigations with participation of 29 subjects (Volunteers) under the modeling of hemodynamic shifts, developing in human body in short-term antiorthostatic hypokinesia (-10 degrees), as well as, in combined effect of antiorthostatic hypokinesia (-10 degrees), Coriolis acceleration and optokinetic stimulation. Results of investigations have showed, that the use of advanced MSS gives the indices of operator professional activity on the average of 17-32% under the decrease of hemodynamic stressful.

[Academician O.G. Gazenko and aviation medicine].

The paper analyzes the contribution of O.G. Gazenko to the theory and practice of aviation medicine in the period of his service at the State Test and Research Institute of Aviation and Space Medicine under the USSR Ministry of Defense (1947-1969). O.G. Gazenko took the leadership and participated in personally in the broad investigations of the altitude effects on human organism, medical care of the staff of AF units and troops based in the Arctic, improvement of life and duty conditions for pilots and technicians in hot climate, ejection seat testing, development of methods modeling erroneous pilot's actions in order to understand their triggers.

[Mathematical modeling of passive mechanisms of the human vascular regulation in orthostatic position]. / Matematicheskoe modelirovanie passivnykh mekhanizmov reguliatsii sostoianiia sosudistoi sistemy organizma cheloveka v ortostatike.

Formalized description of the vascular component of the human circulation system taking in the effects of gravity on the human organism during the standing test is presented. The structure proposed in the model by R.D. Grigorian has been used as basic to describe the vascular system. The neuroreflex and humoral regulators of circulation have been counted as constant. Organs and elements of the vascular system were represented as a network of sequential and parallel separate elastic reservoirs with distributed parameters. The pressure-volume ratio was represented by piecewise linear approximation with 3 fragments imitating main forms of the vascular cross section. Primary focus was put on investigation of circulation in the leg and the head which is of interest for evaluating body reactions to postural changes. Result of modeling have been displayed as curves of volumetric velocity, and blood volume and pressure in different fragments of cranial and crus vessels.

[Simulation models of thermal-humidity parameters of the space suit]. / Imitatsionnaia model' temperaturno-vlazhnostnogo rezhima vykhodnogo kosmicheskogo skafandra.

The paper describes a mathematical model of and methods of calculating thermal-humidity fields in a spacewalking suit. The authors made an integral calculation of thermal and mass transfer in the spacesuit. A system of equations is solved analytically and numerically with the use of a combined method. As a result of model calculations, determined were integral spacesuit characteristics including total amount of rejected heat, heat rejected by the WC suit, humidity rejected by ventilation, and humidity accumulated in different spacesuit layers. Comparison of calculation and experimental data for spacesuit Orlan showed that maximal differences in temperature, humidity, thermal and humidity flows, and other system parameters did not exceed 13%.

[Flight personnel rehabilitation]. / Meditsinskaia reabilitatsiia letnogo sostava.

Presented are results of the body functional evaluation on a background of the most common syndrome of neurocirculatory dystonia and spinal osteochondrosis in flying personnel. Execution of tone-strength stimulating physical exercises for 10 to 12 days noticeably improved professional health.

[The development of the syndrome of congestive parenchymatous organs under conditions of short-term hypokinesia]. / Razvitie sindroma zastoinykh parenkhimatoznykh organov v usloviiakh kratkovremennoi gipokinezii.

Five series of head-down (-10 degrees to -30 degrees, up to 18 hr) tilt tests were performed with participation of 65 healthy male subjects. The ultrasonic technique was used to investigate the liver, spleen, pancreas, kidney, and the main abdominal vessels, i.e. aorta in the abdomen and superior mesenteric artery, interior caval, portal, and splenic veins. A few hours of HDT already brought about a complex of load-deprivation reflexes (the syndrome of stagnant parenchymal organs) characterized by a prolonged venous congestion in the abdominal organs-vessels system, increases in sizes and blood filling of the liver, spleen, pancreas, kidney, and the main arteries and veins in this hemodynamic region. This was the first time when increases in pancreas including its head, body and tail, and the abdominal blood vessels were quantified at the beginning of adaptation to HDT. The load-deprivation reflexes arising in this period were hemodynamic by nature. Considering the significant functional strain of the abdominal organs and vessels and particularly the limited control of excessive blood flow towards the pancreas and kidneys, there is a good reason to look into the ways to improve the existing countermeasures against the consequences of immobilization for humans both in general clinic and preventive medicine, and in short- and long-term space missions.

[Need to correct indicators of "physiological norm" in pilots]. / O neobkhodimosti korrektsii pokazatelei "fiziologicheskoi normy" u lits letnogo sostava.

Examination including echocardiography and Doppler-cardiography covered 222 pilots and revealed that 27-64% of pilots had reliable cardiodynamic peculiarities, if compared with healthy individuals not involved into piloting. The authors necessitate introducing a concept of "pilot's heart" into medical expert examination for piloting. This concept should be considered a variant of functional adaptational "stress-norm".

Ultrasound techniques in space medicine.

Ultrasound examinations have been performed on 15 cosmonauts who have remained in orbit for flights ranging from 2.5 to 8 months in duration. Soviet researchers have combined hemodynamic assessments with parallel attempts to develop improved ultrasound techniques and equipment for use onboard space stations. These techniques and equipment are reviewed, as are findings relative to exercise effects on hemodynamic changes. In general, longitudinal echocardiographic studies have suggested that 1) few differences exist between resting preflight and on-orbit cardiac contractility measures; 2) declines in orthostatic stability after long-term flights are not due to deterioration of the myocardial functional state; and 3) lower stroke volumes and heart rate increases occurring during exertion may be considered compensatory hemodynamic resettings rather than indications of disturbed left ventricular contractility.

[Cumulative effect of Coriolis acceleration on coronary hemodynamics]. / Vliianie kumuliativnogo vozdeistviia uskorenii Koriolisa na koronarnuiu gemodinamiku.

Time-course variations in coronary circulation and cardiac output were measured in 29 healthy test subjects who performed tests with a continuous cumulation of Coriolis accelerations and in 12 healthy test subjects who were exposed to Coriolis accelerations combined with acute hypoxia. Adaptive changes in coronary circulation were seen. It is recommended to monitor coronary circulation during vestibulometric tests as part of medical expertise of the flying personnel.

[Effect of acute hypoxia on coronary and systemic hemodynamics]. / Vliianie ostroi gipoksii na koronarnuiu i sistemnuiu gemodinamiku.

Variations in coronary circulation, cardiac output and heart rate were examined by dopplerography in 14 test subjects kept in an altitude chamber. It was found that during acute hypoxia the effective coronary blood flow decreased distinctly prior to general circulatory disorders. It is recommended to monitor coronary circulation during altitude exposures.

[Coronary blood flow function in patients with chronic postembolic pulmonary hypertension]. / Sostoianie koronarnogo krovotoka u bol'nykh s khronicheskoi postémbolicheskoi legochnoi gipertenziei.

Variations in coronary blood flow and cardiac output were studied using dopplerography throughout rationed exercise in 16 patients with chronic postembolic pulmonary hypertension. All patients showed reduced coronary flow during exercise, an evidence of early signs of coronary insufficiency. A correlation was demonstrated between coronary flow disorders and the severity of pulmonary hypertension, the extent of pulmonary vascular bed lesion and right-ventricular hypertrophy.

[Evaluation of the hemodynamic indices of a pilot in flight]. / Otsenka nekotorykh pokazatelei gemodinamiki u letchika v polete.

Coronary circulation and systolic and diastolic time intervals were measured in one-seat high-manoeuvrability aircraft pilots during 22 flights. The effective coronary blood flow values varied significantly and reached maximum during landing. In some cases these changes were very large, suggesting a low level of conditioning and physiological reserves. It is recommended to monitor coronary circulation inflight.

[Reliability of the ultrasonic study of the heart]. / K voprosu o nadezhnosti ul'trazvukovogo issledovaniia serdtsa.

Based on a study of echograms from the heart structures the probabilities of receiving echosignals have been calculated. The probability to detect signals from the endocardium has been shown to be markedly higher than that from the pericardium. Because of great diffusive component of a scattered signal from the endocardium echosignals are reliably received during ultrasonic heart examination.