Expiratory flow rate, breath hold and anatomic dead space influence electronic nose ability to detect lung cancer.

BACKGROUND: Electronic noses are composites of nanosensor arrays. Numerous studies showed their potential to detect lung cancer from breath samples by analysing exhaled volatile compound pattern ("breathprint"). Expiratory flow rate, breath hold and inclusion of anatomic dead space may influence the exhaled levels of some volatile compounds; however it has not been fully addressed how these factors affect electronic nose data. Therefore, the aim of the study was to investigate these effects. METHODS: 37 healthy subjects (44 ± 14 years) and 27 patients with lung cancer (60 ± 10 years) participated in the study. After deep inhalation through a volatile organic compound filter, subjects exhaled at two different flow rates (50 ml/sec and 75 ml/sec) into Teflon-coated bags. The effect of breath hold was analysed after 10 seconds of deep inhalation. We also studied the effect of anatomic dead space by excluding this fraction and comparing alveolar air to mixed (alveolar + anatomic dead space) air samples. Exhaled air samples were processed with Cyranose 320 electronic nose. RESULTS: Expiratory flow rate, breath hold and the inclusion of anatomic dead space significantly altered "breathprints" in healthy individuals (p < 0.05), but not in lung cancer (p > 0.05). These factors also influenced the discrimination ability of the electronic nose to detect lung cancer significantly. CONCLUSIONS: We have shown that expiratory flow, breath hold and dead space influence exhaled volatile compound pattern assessed with electronic nose. These findings suggest critical methodological recommendations to standardise sample collections for electronic nose measurements.

Health Related Quality of Life of Children with Chronic Respiratory Conditions.

BACKGROUND: In the management of chronic diseases, treatment approaches have changed in recent decades. Not only are clinical outcomes assessed but also the patients' perception of their quality of life has become an important aspect. OBJECTIVES: The aim of our study was to compare the health-related quality of life (HRQoL) of children with cystic fibrosis (CF) to the HRQoL of asthmatic patients, to assess the level of agreement between parent proxy-report and child self-report and to measure the relationship between spirometry and HRQoL. MATERIAL AND METHODS: 172 children (mean age: 11.61±2.56 years) and their parents completed the questionnaire. The Hungarian version of the Pediatric Quality of Life InventoryTM 4.0 (PedsQLTM 4.0) Generic Core Scale was used to assess HRQoL. Lung function was assessed via spirometry. RESULTS: Significantly lower PedsQLTM scores were measured for CF patients on the psychosocial health (p<0.05), emotional functioning (p<0.005) and school functioning (p<0.01) subscales and the total scale (p<0.05) from the children's self-report. The level of child-parent agreement was fair and moderate in both patient populations [intra-class correlation coefficient range (ICC) asthma=0.29-0.37; ICCCF=0.39-0.59, p<0.001]. The relationship between forced expiratory volume in 1 second (FEV1) and the physical health subscale (r=0.49, p<0.01) was moderate in young (8-12 years) children and also teenagers (13-18 years), with CF (r=0.58, p<0.05) from self-report. We found weak, non-significant correlations between FEV1 and PedsQLTM subscales in children with asthma (8-12 years) (r=-0.01-0.18, ns.). CONCLUSIONS: Children suffering from CF perceive their HRQoL as poorer than children with asthma. In asthmatic patients, it is not sufficient to evaluate clinical outcomes (FEV1); subjective HRQoL should be also estimated in the course of patient care.