Development Of Respiratory Function Research Articles

Study of cardiac, respiratory, and motor activities in rat fetuses

Development of the cardiac, respiratory, and motor activity was studied in rat fetuses with preserved placenta circulation was studied at the 16th, 18th, and 20th gestation days. The presence of three main movement types has been found: complexes of generalization activity, local movements, and jerks. In development of respiratory function, there is observed a gradual transition from individual inspirations to series of respiratory movements and then to formation of periodic respiration episodes. At the studied period, the heart rate has been found to increase. The existence of the slow-wave modulations it the heart rate with a period of 20-40 s has been revealed. Analysis of interrelations between the respiratory and motor systems has shown that in the 16-day fetuses, each respiratory movement is accompanied by extensor jerk. By the 20th days of embryonic development (E20), uncoupling of the respiratory and motor activities occurs. Comparison of the activity observed in the cardiac and somatomotor systems has shown that at E16, the cardiac rhythm fluctuations do not depend on the motor excitation jerks. In the 18-day fetuses, brief slowing down (decelerations) of the cardiac rhythm appeared during the motor activity jerks, whereas at E20, on the contrary, an increase of frequency (accelerations) of the cardiac rhythm occurred.

Development of respiratory function in patients with chronic obstructive respiratory disease

Follow-up assessments were done in 18 patients with chronic obstructive airways disease, mainly chronic obstructive bronchitis, over a mean of 9.4 (6-18) years. Two hospital admissions were required for periods of three years. In addition, 5 of the patients had concomitant severe emphysema (chronic obstructive emphysematous bronchitis). During the observation period development of emphysema and airways resistance had not increased to any measurable degree. The patients' mean age by the end of the study was 63.6 years. Reversibility of the disease could not be influenced during clinical treatment. Patients with serious emphysema had neither worse airways resistances nor worse arterial blood gases than patients with obstructive airways disease without emphysema. As expression of increasing distribution disorder only arterial oxygen pressure decreased during the observation period when compared to normal age-related changes. The investigation demonstrates the great relevance of persistent treatment for prevention of exacerbations as well as for interval periods. This has decisively influenced the course of the disease: life expectancy of patients has clearly improved as respiratory function can be maintained constant over many years.

Gas Exchange and Mechanical Properties of the Lung in Miners with Severe Concomitant Injury

Objective: to study the specific features of pulmonary gas exchange and mechanical properties in various manifestations of respiratory failure in miners with severe concomitant injury, who have a service length of 10 years or more, in order to optimize respiratory support. Subjects and methods. Pulmonary gas exchange and mechanical properties were studied over time in the presence of respiratory failure (acute lung injury/acute respiratory distress syndrome) in 34 miners and 36 victims (a control group) with severe concomitant injury who had no underground service length. Both groups were matched in age, severity and nature of traumatic lesions and surgical interventions. Pulmonary gas exchange and mechanical properties were evaluated by the following indices: oxygen fraction in an inspired gas mixture; hemoglobin saturation and partial arterial blood oxygen and carbon dioxide tension with the alveolar-arterial gradient being calculated by the oxygen level; oxygenation index; intrapulmonary shunting; statistical compliance and airways resistance. Results. The studies demonstrated that the miners, as compared with the controls, had more pronounced gas exchange changes within 5—7 post-traumatic days; later on (days 7—9) the above differences were undetectable. Impaired pulmonary mechanical properties in the miners persisted throughout the study while in the control group, their recovery started just on day 3. The course of respiratory failure in the miners was attributable to the baseline external respiratory function. Their respiratory support was performed during 14.5±1.4 days versus 9.5±1.9 days in the controls. In the miners, the mean bed-days at an intensive care unit were 18.5±2.2 whereas in the controls those were 12.3±2.1. Conclusion. More significant impairments of pulmonary gas exchange and mechanical properties are seen in the miners due to the background changes in external respiratory function in the development of respiratory function after severe concomitant traumatic lesions than in the victims without underground service length, which causes an increase in the duration of respiratory support and intensive care.

Development of respiratory function in perinatal ontogenesis

In development of respiratory function in rats, mice, and other representatives of placental animals there exists the general plan of formation of rhythm: from single contraction of respiratory musculature to formation of bursts and complexes alternating periodically with pauses and apnea intervals and subsequent rhythm stabilization. These peculiarities are closely connected with the states of sleep and consciousness. A concept is put forward about a certain sequence of functional maturation and ways of regulation of activity of the respiratory rhythm central pacemaker. At the first stage the autogenic rhythmical activity is determined by pacemaker properties of a part of neurons of the medulla rostral ventrolateral part. It is not ruled out that the first respiratory discharges in spinal cord ventral roots might have been a manifestation of the nervous network rhythmogenic properties. The direct sensitivity of central neurons to chemical composition if the medium and to some neutomodulators serves as the first regulatory mechanism. Somewhat later, inhibitory control is established from supramedullary structures, with an increase of role of peripheral receptors in regulation of respiration.

Acculturation and the Growth of Lung Function: Three Cross-Sectional Surveys of an Inuit Community

The influence of acculturation to a sedentary lifestyle upon the growth and development of lung volumes has been studied in Inuit children aged 9-19 years. Surveys were conducted in the circumpolar community of Igloolik (69 degrees 40'N, 81 degrees W) in 1969/70, 1979/80 and 1989/90. Over this period, the children showed little change of height or body mass at any given age, but a progressive loss of what initially had been a high level of health-related fitness. The sample for each survey comprised about 70% of children in the chosen age range: in the most recent study 87 males and 65 females. Respiratory data included forced vital capacity, one-second forced expiratory volume, maximal mid-expiratory flow rate (second and third surveys only), smoking habits and respiratory health. In each of the 3 surveys, many of the older children in the community were regular smokers. The average cigarette consumption currently rises progressively to 13 +/- 8 cigarettes/day in 87% of males and 11 +/- 7 cigarettes/day in 95% of females over 17 years of age. Nevertheless, lung volumes show the anticipated increase as a logarithmic function of stature. Furthermore, statistically fitted curves show only minor inter-survey differences in volumes for a given standing height. We thus conclude that the deterioration in other aspects of health-related fitness has not yet influenced the growth and development of respiratory function within this Inuit population.