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Biomedical subjects

V Bellia

Publications and source records attributed to V Bellia.

83 records · Page 5Linked to original sources
PubMedDate not supplied

Obesity as a possible cause of respiratory failure in bilateral diaphragmatic paralysis. Case report.

An obese woman with respiratory failure and bilateral diaphragmatic paralysis, was studied in order to investigate the effects of weight loss on respiratory function during wakefulness and sleep. The patient was studied on 5 different occasions during which diurnal blood gas analysis, spirometry, CO2 rebreathing test, nitrogen wash-out test and a nocturnal polysomnographic study were performed. The follow-up period lasted 9 months, during which the patient progressively lost 19 kg. Progressive improvement in awake blood gas tensions (PaO2 + 21 mmHg, PaCO2 - 16 mmHg) as well as in nocturnal oxyhemoglobin saturation and transcutaneous PCO2 were observed; at the same time only minor changes in responsiveness to CO2 and in lung volumes were found. Conversely alveolar efficiency for CO2, obtained with the nitrogen wash-out test, in the supine posture increased from 81.7 to 90.5%, indicating an improvement in ventilation/perfusion ratio as a possible determinant of blood gas tension improvement during wakefulness and, as a consequence, also during sleep. We conclude that obesity is one possible cause of the occurrence of respiratory failure in bilateral diaphragmatic paralysis.

Adult↗
PubMedDate not supplied

Limitations of applicability of current calibration procedures for respiratory inductive plethysmography.

Repeatability of calibration of the respiratory inductive plethysmograph and its stability with time were investigated in young healthy subjects. Eight were submitted to sequential runs of calibration-validation by simultaneous equation (SEM) and least squares methods (LSM) (30 in all): in five subjects, after an initial acceptable calibration, accuracy and precision were repeatedly checked over three hours (a total of 50 trials). Although mean errors for the whole sample seemed acceptably low (7.6%, SD 7.0 for SEM; 7.3%, SD 7.3 for LSM), a marked inconsistency of apparently comparable calibrations and a wide variability of results along but independently of the time in steady conditions (ranging up to 30%) were discovered. An analysis of factors interfering with the response of the equipment was made. The unreliability of the current calibration procedure was related to the fact that in most cases the calibration line derived by the change-in-posture technique, as currently applied, may not be adequately representative of the full range of relationships between the participant variables, as they occur in the selected posture. To overcome this difficulty, two suggestions are made: a) prolong the calibration procedure so as to use more data points, and b) investigate alternative procedures of calibration in any one position.

Adult↗
PubMedDate not supplied

Theophylline pharmacokinetics in patients with mild or severe airway obstruction.

A standard loading dose of aminophylline, followed by constant rate infusion for 3 h was used to study theophylline pharmacokinetics in 36 patients (age range 27-73 years) admitted to hospital during an exacerbation of chronic airway obstruction. The severity of the disease was assessed by peak expiratory flow rate and blood gas analysis. It was assumed that the severity of the disease and the patients' age, sex and smoking habits were relevant in predicting individual kinetics and hence in establishing individual theophylline dosage. Multiple regression analysis of the results failed to confirm this hypothesis and showed no significant relationship between the severity of the disease and pharmacokinetics even when other biological variables were taken into account. The results confirm the importance of careful monitoring of blood levels of theophylline since they cannot be predicted from functional indices of the severity of obstructive lung disease.

Acidosis, Respiratory↗
PubMedDate not supplied

Evaluation of a test of density-dependence of the expiratory flows in the screening of peripheral airways obstruction.

A test of density-dependence of flow at 50% of vital capacity has been investigated in two groups of subjects (86 in total) in order to evaluate respectively: a) influences that on it may be exerted by altered mechanical properties of the lung in chronic airflow obstruction; b) accuracy and precision of the test in latent and clinical asthma. Lung elastic recoil pressure does not seem to be related to the intensity of density-dependence. Relationships between MEF50 on air and on He-O2, expressed as means of groups allow distinguish between each other, whereas a definite overlap between groups is patent; absolute flows, either on air or on He-O2 are quite satisfactorily reproducible, both in health and disease. Delta% MEF50 shows a good specificity but a poor sensitivity; reproducibility is unacceptable, unless when using on a qualitative scale of figure of 20% as borderline to distinguish subjects responders from non responders.

Airway Obstruction↗