Biomedical subjects

I Yanev

Publications and source records attributed to I Yanev.

16 recordsLinked to original sources

PubMed1993

Screening of the respiratory functions of workers engaged in bearing manufacture.

The lung functions of 285 workers were investigated. It was found that the ventilatory functions of 20.5% of the female and 23.5% of the male testes were impaired. Prevalence of mild obstructions was established which can be attributed to both cigarette smoking and the length of service. Maximal expiratory flows are worth a special attention in mild airflow obstructions as they could be decreased when forced expiratory volume in the first second (FEV1) remains unchanged.

Adult↗

PubMed1993

Relationships between blood oxygen parameters in patients with chronic obstructive lung disease.

The hemoglobin-oxygen dissociation curve and the relationships between the parameters of tension, saturation, capacity, affinity and concentration of oxygen in the course of respiratory failure in chronic obstructive lung diseases (COLD) were studied. The study included 141 patients divided into four basic groups according to the value of pO2 (a): patients with normoxia, mild, moderate and severe arterial hypoxia. The blood-gas status was determined using the ABL-330 and OSM-3 analyzers (Radiometer A/S, Denmark). It is concluded that: 1. Presence of normoxia (pO2 and sO2 in norm) in COLD patients does not exclude abnormalities in their arterial blood oxygen transport and increased risk of tissue hypoxia. 2. Total oxygen concentration in respiratory failure is relatively stable and "independent" from the stepwise decrease of the arterial pO2, which results from the compensatory increase of the total and effective hemoglobin. 3. There are phase fluctuations of the ctO2/pO2 dissociation curve in the reference interval, expressed in the "lowering" of P50 and p90 in mild hypoxia and the "centering" or "raising" of their values in severe hypoxia. Such fluctuations are more pronounced in the p90 than in the p50. 4. The oxygen extraction tension lowers progressively (without reaching the anaerobic threshold) and the oxygen compensation factor elevates with the pO2 (a) reduction and the arising of hypercapnia and acidemia. 5. The calculated 2,3-diphosphoglycerate (2,3-DPG) concentration values are significantly higher in hypercapnics with COHb > 1% than in those with COHb < 1%. The relationships between hypoxia, oxygen affinity, hemoglobinemia and oxygen affinity as well as the dissociation curve properties in chronic respiratory failure are discussed.

Acid-Base Equilibrium↗

PubMed1992

Importance of nasal clipping in screening investigations of flow volume curve.

Comparative analysis of some basic lung indices obtained from a screening investigation of the flow volume curve by using two techniques, with a nose clip and without a nose clip, was made on a cohort of 86 workers in a factory shop for the production of bearings. We found no statistically significant differences between the indices obtained by the two techniques. Our study showed that the FVC and FEV1 obtained in workers without using nose clips were equal to or better than those obtained using nose clips in 60% of the workers. The reproducibility of the two methods was similar. The analysis of the data has shown that the flow volume curve investigation gives better results when performed without a nose clip, especially in industrial conditions.

Adult↗

PubMed1992

Comparative analysis of some methods for standardizing the maximal expiratory flows.

Maximal expiratory flows were obtained in 40 patients with chronic non-specific pulmonary diseases displaying mild obstruction of air flows and in 35 clinically healthy subjects with normal ventilatory functions and similar anthropometric characteristics. The flows for the two groups and their standardized values by referring to FVC, TLC, H and H3 were compared. The u-criterion and V% were used as measures for the diagnostic value of the flows and their standardized values. In the patients with mild airflow obstruction the highest u-criterion and the lowest V% were obtained by standardizing the maximal expiratory flows through referring to H3. This is an indication that this method of standardization is to be preferred to other methods in the functional diagnostics of mild obstructive disorders.

Adult↗

PubMed1992

Importance of the breathing manoeuvre in detecting mild air flow obstructions in a lung function screening.

Maximal expiratory flow-volume curves (MEFVC) were recorded in 610 workers using two different breathing manoeuvres. Inspiration in one was forced and maximal, while in the other, it was slow and maximal. In both manoeuvres, the ventilatory function was defined according to the diagnostic classification proposed by I. Kirin. Two groups of workers with mild obstructive changes were found. In one group, we diagnosed a condition defined as transitional state to obstructive ventilatory disorder (Tr.OVD) using both manoeuvres. In the second group, we detected normal lung functions using one of the breathing manoeuvres while the other manoeuvre disclosed Tr.OVD. In the second group, the relative share of workers scoring below the lower limits on the test of Tiffeneau was significantly lower than in the first group. Instantaneous flows also were significantly lower in the second group. Also, the FEV1, FEV1/FVC and MEF25-75% were significantly higher in the second group. The results showed that obstructions were milder in the second group than in the first. A new approach is suggested to detect obstructions milder than Tr.OVD. This approach would be practical for use in mass epidemiological screening studies because its performance does not require complicated equipment.

Adult↗

PubMed1992

Relationships between some oxygen and carbon dioxide indices in patients with chronic lung and cardiovascular diseases.

A total of 281 patients were divided into groups according to their clinical diagnosis and were examined using capnography, spirometry and blood-gas analysis. The highest percentage of patients with arterial hypoxemia was found in the group with chronic bronchitis and emphysema. The same group had the highest number of patients with moderate hypoxemia and was the only group containing patients with severe hypoxemia. Alveolar hypoventilation and increased ventilation-perfusion ratio were most pronounced in patients with chronic bronchitis and emphysema. The greatest negative correlation between PaO2 and PaCO2 was found, again, in this group. We also found the greatest direct correlation between the oxygen and carbon dioxide gradients in this group. These results suggest that the relationships between the partial pressures of O2 and CO2 depend on the type of the pulmonary and cardiovascular diseases. The relationships between the partial pressures of O2 and CO2 as well as between their gradients, become stronger with the increase of the ventilation-perfusion ratio. The relationships between the expired alveolar gases are approximately the same as those of these gases in blood.

Adult↗

PubMed1991