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Biomedical subjects

R Ramoino

Publications and source records attributed to R Ramoino.

7 recordsLinked to original sources
PubMed1980

Identification and parameter estimation of the mechanical ventilatory system.

Oesophageal pressure and mouth volume were measured by oesophageal balloon and pneumotachography, respectively, in 10 men (both normal and diseases) under different experimental conditions, i.e. spontaneous ventilation, quasi-static manoeuvres and respiration at high frequencies. The recorded data were then analyzed by an identification and parameter estimation computer programme, to determine a mathematical model for the process. Contrary to other recently published papers dealing with frequency analysis, we studied a time-dependent model, represented by a linear time-invariant differential equation. The results were quite satisfactory since a relatively second-order model seems to be adequate for describing the process. Differences in the parameter values between normal and diseased subjects were characterized by increases in the patients' lung viscous component. In conclusion, our identification test results in the mechanical ventilatory system seem to indicate that a simple second-order mathematical model is consistent with the experimental data.

Adult↗
PubMed1980

Analysis of nitrogen multibreath washout curves through a statistical approach.

A new method for analyzing nitrogen multibreath washout curves, founded on a statistical multicompartment model is presented. This method consists of two phases: (i) the preliminary conversion by mathematical means of the nitrogen end-tidal concentration curves - as usually available in routine practice - into the corresponding lung nitrogen decay curves normalized for ventilation rate and function al residual capacity and (ii) the determination of distribution function G(k) in the Laplace integral y(t) = integral of infinity,G(k)e-ktdk (where y(t) represents the experimental curve, k is the compartmental rate constant and the random variable of the statistical set). G(k) values are approximated by an accurate calculation of the distribution moments and the use of Edgeworth-Cramér series expansion. The clinical usefulness of the method was verified in normal subjects and in patients with chronic obstructive pulmonary disease. An excellent separation of the two groups was achieved by calculating the following parameters: the first moment (m1), the standard deviation (sigma) and the coefficient of dispersion (sigma/m). Besides, further information about the lung ventilation pattern could be obtained by a skillful inspection of the approximated distribution function curves of the rate constant k.

Adult↗
PubMed1978

Dose-response study of a new oral bronchodilator, NAB 365 (clenbuterol).

A new oral bronchodilator, NAB 365 (clenbuterol), at doses of 10, 20, 30 and 40 microgram, was studied in a double-blind placebo-controlled incomplete cross-over study in 10 patients suffering from chronic bronchitis who had reversible airway obstruction. The ventilatory response was assessed by measurement of the forced expiratory volume in 1 sec (FEV1), total airway resistance (Raw) and specific airway conductance (sGaw) before and 30, 60, 120, 180, 240, 360 and 480 min after administration. With the 30 and 40 microgram doses, a significant bronchodilating effect was seen between 30 and 360 min after administration, with peak effects between 120 and 240 min. The maximal effects in ventilatory response after 30 microg were only slightly less than after 40 microgram; the bronchodilating effect of 20 microgram was statistically less marked than those of 30 of 30 and 40 microgram on FEV1, but not statistically different on Raw and sGaw. These findings have been briefly discussed. The effects of 10 microgram and of the placebo were always statistically lower than those of 20 microgram. No significant cardiovascular effects and no subjective side effects were observed. In conclusion, the results suggest that 30 microgram of NAB 365 (clenbuterol) are the suitable acute dose.

Adult↗
PubMed1975

[Modifications in the closing volume due to the inhalation of tobacco smoke].

Two methods, the one making use of nitrogen and the other of body plethysmography were applied to a group of normal young subjects in order to value the effects of the inhalation of tobacco smoke on the "closing volume". The results obtained with the two methods are different; according to authors, this phenomenon may be explained on the base of the physiopathologic meanings of the closing volume, under the condition to admit that tobacco smoke may promote an early closure and before all disorders in the distribution of the residual volume.

Humans↗