Application of multivariate linear discriminant analysis to lung sounds in some pulmonary diseases.

In the past 15 yrs, a number of investigators have applied spectral analysis to respiratory sounds recorded from the chest wall or the trachea in order to objectively characterize them and to relate them with different pulmonary diseases. In the present study, we have applied multivariate linear discriminant analysis to the spectral features of respiratory sounds. Lung sounds and the airflow velocity were recorded from 15 normal adults and 37 patients falling into three different disease categories: chronic obstructive lung disease, bronchial asthma and bronchiectasis. All patients had prominent adventitious lung sounds (i.e. either wheezes or crackles). Amplitude spectra of five selected inspiratory and expiratory sound segments of each subject were calculated using the Fast Fourier Transform algorithm. Multi-variate linear discriminant analysis was then applied to the normalized and averaged spectral area values calculated for 10 unequal and arbitrarily selected frequency bands for each patient in the frequency range between 80 Hz and 1 kHz. Inspiratory and expiratory sounds were treated separately. Discriminant functions were computed from the spectral area values and plotted on graphs to classify the subjects into one of the disease categories or as normal (training set). While some separation was achieved among the different disease groups, a clearer separation was evident between normals and patients as a whole on the basis both of inspiratory and expiratory sounds. Inspiratory and expiratory sound frequency bands having the largest weights in classification were determined. Admittedly, the specific results of this study are preliminary or even tentative in view of the inadequacies of sound recording and signal conditioning techniques that were available to us at the time of recording. However, we believe that the investigation serves to illustrate the potential of multivariate discriminant analysis in the diagnostic classification of patients on the basis of their lung sound patterns. We suggest that this technique be considered by investigators involved in lung sound research, because it also allows other patient variables to be combined with the selected parameters of lung sounds.

Age related differences in plasma theophylline levels.

Because of its special pharmacokinetic properties, plasma levels of theophylline show significant differences between individuals and also its therapeutic index is very low. So, plasma theophylline concentration measurements are essential for an effective and safe treatment. In the present study, age related differences in plasma theophylline levels were evaluated in patients from different age groups. Patients were divided randomly into two groups. Group I included patients under the age of 50 years, group II included patients over 50 years of age. Plasma theophylline levels were measured before and 3, 7, 12 and 19 h after a single dose given orally. The results show that 3, 7 and 19 h post dose, levels of theophylline were significantly higher in group II than in group I (P < 0.001).

Pulmonary aspiration of a two-unit bridge during a deep sleep.

Aspiration of teeth and dental restorations is a recognized, yet an infrequent happening in the literature. Main reasons of aspiration are maxillofacial trauma, dental treatment procedures or ethanol intoxication and dementia. The present case of a 2-unit bridge aspiration is however, not related with any trauma, dental procedure or systemic disease. A 37-year-old male patient had aspirated his bridge while sleeping and the bridge remained unidentified for 1 year despite the radiographic controls. He was then referred to the Chest Diseases Department of School of Medicine, Ege University and the radio-opaque object in the right intermediate bronchus was diagnosed to be an aspirated dental prosthesis. Subsequent to the failure of the rigid bronchoscopy, the patient was referred to the Thoracic Surgery Department and had to be operated for retrieval of the foreign body.

The European Organization for Research and Treatment of Cancer QLQ-C30: an examination into the cultural validity and reliability of the Turkish version of the EORTC QLQ-C30.

The Turkish version of the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire version 2.0 (EORTC QLQ-C30 v.2.0) has started to be used in clinical trials recently. The objective of the study was to evaluate the validity and reliability of the Turkish version of the EORTC QLQ-C30 v.2.0 and the correlation between the Karnofsky Performance Scale (KPS) and the EORTC QLQ-C30. Two hundred and two lung cancer patients were included in the study between January and March 2000. All the subscales met the minimal standards of reliability (Cronbach's alpha > or = 0.70). Only the role functioning scale differed among the three disease stages of patients (local, locoregional and metastatic). There was no statistically significant difference among therapy types. All interscale correlations were statistically significant (P < 0.01). The strongest correlations were found among the physical functioning, role functioning and fatigue scales. Social functioning was closely related with physical, role, emotional and cognitive functioning. The weakest correlations were between nausea/vomiting and the other scales. Global quality of life (QOL) was substantially correlated with most of the scales except cognitive functioning. The coefficients for the correlation between the items differed between 0.12 and 0.97 and all the subscales were strongly correlated with the scales which they formed. The highest correlation between the EORTC QLQ-C30 and KPS was for physical functioning (r = 0.62, P < 0.05). The Turkish version of the EORTC QLQ-C30 is a valid (by means of interscales validity) and reliable instrument for Turkish lung cancer patients and can be used in clinical studies but needs supporting by the reference data on the QOL of the Turkish population.