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Biomedical subjects

A A Viljanen

Publications and source records attributed to A A Viljanen.

At least 19 recordsLinked to original sources
PubMed1987

Effect of lung autotransplantation on breathing regulation. Studies in dogs.

The effect of autotransplantation of the left lung on respiratory regulation was studied in four dogs in pentobarbital anaesthesia. In each dog the electrical and mechanical activity of the inspiratory muscles was studied before and 4-6 weeks, 3, 6 and 12 months after the transplantation. No or very little change was found in comparisons of spontaneous respiration or response to inhalation of carbon dioxide, hypoxia or combined hypercapnia and hypoxia. When the airways were closed after inflation with varying volumes of air, the increase in number and frequency of the electromyographic impulses in the intercostal muscles and the diaphragm (compared with the preceding unobstructed breaths) was greater before than after the lung autotransplantation. The duration of the first respiratory cycle after airway closure increased progressively with the volume of inflation in intact dogs and in dogs with autotransplanted left lung, though the increase was approximately halved following autotransplantation.

Animals↗
PubMed1986

The effect of inhaled carbon dioxide and hypoxia mixtures on the electrical and mechanical activities of respiratory muscles in dogs.

The effects of hypercapnia and hypoxia on the regulation of breathing was studied in six mongrel dogs during pentobarbital anaesthesia with special reference to their action on the respiratory muscles. Carbon dioxide (5.5% in air) inhalation produced an increase of minute volume due to augmentation of respiratory frequency and tidal volume. The number of electrical impulses per breath remained unaffected despite the increase tidal volume. Therefore the mechanical ventilation increased more than the electrical output to the respiratory muscles indicating that the efficiency of the muscles increased. The tidal volume increased more than the pressure impulse (mechanical work by the respiratory muscles) suggesting that the airway conductance was increased during hypercapnia. During hypoxic stimulus (11% oxygen in nitrogen) the increase of minute volume was due to increase in respiratory frequency. The ratio of tidal volume to the number of electrical impulses in the respiratory muscles remained unaltered. During combined carbon dioxide and hypoxia stimulus the responses were similar to those of carbon dioxide stimulus alone. However, the increase of minute volume and the increase in the ratio of tidal volume and pressure impulse to the number of electrical impulses in the respiratory muscles were more pronounced. These findings suggest that carbon dioxide affects the regulation of breathing above the respiratory muscles and in the muscles themselves. Hypoxic stimulus seems not to have any direct effect on the respiratory muscles in dogs during pentobarbital anaesthesia.

Animals↗
PubMed1983

Surgical treatment of chronic laryngeal stenosis secondary to vocal cord paralysis: pre and postoperative evaluation of ventilatory function.

Thirteen patients with chronic laryngeal stenosis were operated upon with total excision of stenotic scar tissue, enlargement of the lumen by sectioning the back and front wall of the larynx, and application of an indwelling Teflon prosthesis for 4 months. The stenosis was in many cases caused by long-standing recurrent paralysis complicated by attempted surgical correction of the stenosis. Following operation, the specific airway conductance increased in all patients (mean +/- SD pre and postoperative values 0.51 +/- 0.30 and 1.12 +/- 0.51 kPa-1.s-1, respectively). The FIV1/FVC ratio was determined in 9 patients and an increase was postoperatively noted in all of them (mean +/- SD pre and postoperative values 43 +/- 17 and 76 +/- 13%, respectively). The physiological findings confirmed the excellent clinical results of the treatment.

Adult↗
PubMed1982

Spirometric studies in non-smoking, healthy adults.

Reference spirometric values for vital capacity (VC), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory volume in one second as percentage of vital capacity or of forced vital capacity (FEV%), the highest flow during forced inspiration (Vmax insp), the highest forced expiratory flow at 50% vital capacity (Vmax 50%), the highest forced expiratory flow when 75% of vital capacity has been expired (Vmax 25%), Vmax insp/Vmax 50% and peak expiratory flow (PEF) were determined in a series of 296 males and 257 females, 18-65 years old, who have never smoked. Equations were derived using height and age as predictors. The reproducibility was tested.

Adolescent↗
PubMed1980

Management of severe bronchial asthma in an intensive care unit.

Seventy-nine patients suffering from severe bronchial asthma were treated in the intensive care unit (ICU) between 1970 and 1978. This was 0.8% of the total number of asthmatic patients treated in Meilahti hospital during the same period. The major indication for admission to the ICU was severe airway obstruction leading to respiratory failure. In 65% tracheal intubation and mechanical ventilation were needed besides the conventional treatment. In spite of intensive care 9% of the patients died.

Airway Obstruction↗
PubMed1977

A new ear oximeter for assessment of exercise-induced arterial desaturation in patients with pulmonary diseases.

Changes in arterial oxygen saturation during exercise were measured with a new eight-wavelength ear oximeter and calculated from blood gas measurements on simultaneously drawn arterial blood samples from 48 patients with pulmonary diseases. When the calculated oxygen saturation during exercise was more than 80% there change in oxygen saturation (SEE 1.0%). This non-invasive, simple and rapid method seems to be clinically useful for detecting the development of significant arterial hypoxaemia during exercise in patients with pulmonary diseases.

Ear, External↗
PubMed1975

Treatment of steroid-dependent asthma patients with beclomethasone dipropionate aerosol.

Fifty-two steroid-dependent adults with chronic perennial asthma were transferred to beclomethasone dipropionate aerosol. The tests demonstrated a significant improvement with beclomethasone in terms of the diary score, bronchodilator use, and PEF and FEV1.0 measurements, as compared with the previous period of prednisolone treatment. Before the transfer, 26 of the patients displayed one or more diseases or symptoms which were probably due to systemic steroid medication. Morning cortisol levels, along with the response to tetracosactrin had in all cases returned to normal when tests were carried out 41 days after transfer to beclomethasone dipropionate. In a group of 12 patients with the lowest 11-OHCS basal values, the mean of their 11-OHCS values during prednisolone treatment was as low as 0.14 plus or minus 0.06 mumol/l, but tetracosactrin challenge induced an elevation to a normal level, 0.33 plus or minus 0.13 mumol/l. After 41 days of beclomethasone treatment, the corresponding values were 0.56 plus or minus 0.90 plus or minus 0.28 mumol/l. Thirty-seven patients experienced one or more disturbing symptoms after transfer to beclomethasone. In many cases, the symptoms of allergic rhinitis were troublesome and persistent leading to a sixfold increase in the use of antihistaminic tablets. When the patients had learned to exhale through the nose following beclomethasone inhalation, the use of antihistaminic tablets again diminished to some extent. Moreover, two cases of ulcerative colitis were encountered during the beclomethasone treatment. During a follow-up period of one year, 14 patients were again receiving prednisolone; most often, this was due to worsening of the asthma because of respiratory infections. During the beclomethasone treatment, a continuous significant improvement in PEF was noted after isoprenaline inhalation, suggesting that further benefit may be obtained by the employment of bronchodilator aerosols as an essential part of the treatment.

11-Hydroxycorticosteroids↗
PubMed1975

Arterial to end-tidal CO2 difference in respiratory disease.

The difference in CO2 tension between arterial blood and end-tidal alveolar gas (a-end-tidal)DCO2 was found to correlate fairly well with the VD/VT ratio in 13 healthy subjects and 50 patients with pulmonary diseases (r = 0.74), and to discriminate between healthy subjects and patient groups at least as effectively as did the VD/VT ratio. An increase in breathing frequency from 8 to 32/min, without simultaneous change in alveolar ventilation, was associated with a mean increase in (a-end-tidal) DCO2 of several mmHg in both the healthy subjects and the patient groups. It is concluded that measurement of (a-end-tidal)DCO2 seems to be a clinically useful alternative to measurement of VD/VT ratio for evaluation of the wasted ventilation component, provided that the effect of the breathing frequency on (a-end-tidal) DCO2 is taken into account.

Adult↗