Effect of Food Intake on Exhaled Volatile Organic Compounds Profile Analyzed by an Electronic Nose.

Exhaled breath analysis using an e-nose is a groundbreaking tool for exhaled volatile organic compound (VOC) analysis, which has already shown its applicability in several respiratory and systemic diseases. It is still unclear whether food intake can be considered a confounder when analyzing the VOC-profile. We aimed to assess whether an e-nose can discriminate exhaled breath before and after predefined food intake at different time periods. We enrolled 28 healthy non-smoking adults and collected their exhaled breath as follows: (a) before food intake, (b) within 5 min after food consumption, (c) within 1 h after eating, and (d) within 2 h after eating. Exhaled breath was collected by a formerly validated method and analyzed by an e-nose (Cyranose 320). By principal component analysis, significant variations in the exhaled VOC-profile were shown for principal component 1 (capturing 63.4% of total variance) when comparing baseline vs. 5 min and vs. 1 h after food intake (both p < 0.05). No significance was shown in the comparison between baseline and 2 h after food intake. Therefore, the exhaled VOC-profile seems to be influenced by very recent food intake. Interestingly, two hours might be sufficient to avoid food induced alterations of exhaled VOC-spectrum when sampling for research protocols.

Short-Term Effect of Cigarette Smoke on Exhaled Volatile Organic Compounds Profile Analyzed by an Electronic Nose.

Breath analysis using an electronic nose (e-nose) is an innovative tool for exhaled volatile organic compound (VOC) analysis, which has shown potential in several respiratory and systemic diseases. It is still unclear whether cigarette smoking can be considered a confounder when analyzing the VOC-profile. We aimed to assess whether an e-nose can discriminate exhaled breath before and after smoking at different time periods. We enrolled 24 healthy smokers and collected their exhaled breath as follows: (a) before smoking, (b) within 5 min after smoking, (c) within 30 min after smoking, and (d) within 60 min after smoking. Exhaled breath was collected by a previously validated method and analyzed by an e-nose (Cyranose 320). By principal component analysis, significant variations in the exhaled VOC profile were shown for principal component 1 and 2 before and after smoking. Significance was higher 30 and 60 min after smoking than 5 min after (p < 0.01 and <0.05, respectively). Canonical discriminant analysis confirmed the above findings (cross-validated values: baseline vs. 5 min = 64.6%, AUC = 0.833; baseline vs. 30 min = 83.6%, AUC = 0.927; baseline vs. 60 min = 89.6%, AUC = 0.933). Thus, the exhaled VOC profile is influenced by very recent smoking. Interestingly, the effect seems to be more closely linked to post-cigarette inflammation than the tobacco-related odorants.

Relationships between Obstructive Sleep Apnea Syndrome and cardiovascular risk in a naïve population of southern Italy.

BACKGROUND: Obstructive sleep apnea (OSA) is a worldwide increasing syndrome, which, by promoting endothelial dysfunction, contributes to extend the cardiovascular risk. We evaluated the cardiovascular risk in a group of OSA patients. METHODS: A total of 185 OSA subjects (19 normal weight, 57 overweight, 109 obese), who entered the Ambulatory of Sleep Disorders of the Institute of Respiratory Diseases of the University of Bari, during 1 year, were enrolled in the study. We assessed anthropometric features, polysomnographic findings, cardiovascular risk factors, smoking habit, Pulmonary Function Test, Arterial Blood Gas Analysis, Epworth Questionnaire, and Charlson Co-morbidities Index (CCI). Subjects were divided into three groups, according to their BMI: individuals with BMI ≥30 kg/m2 (Group 1 n = 109, mean age 61 ± 1; 74.3% men), individuals with BMI ranging from 25.0 to 29.9 kg/m2 defined as overweight subjects (Group 2 n = 57, mean age 58.8 ± 1.4; 77% men), and subjects with a BMI ranging from 18.5 to 24.9 kg/m2 defined as normal weight subjects (Group 3 n = 19, mean age 54.2 ± 2.3; 64,2% men). RESULTS: In the whole population, the percentage cardiovascular risk was weakly related with BMI (r = 0.33; P < .001), but not with AHI. The cardiovascular risk was strictly related to the obesity (P < .00002), while the Epworth Questionnaire score and the Charlson Co-morbidity Index were respectively statistically higher in the group of obese individuals (P = .004, P = .0002) than in the other two sub-groups. When AHI values were stratified in tertiles, the percentage cardiovascular risk did not vary with increasing AHI values (Figure 2). CONCLUSIONS: Further studies are required to investigate the pivotal role of inflammation resulting from obesity, and underlying increased cardiovascular risk in OSA patients.

Criteria of prescription of antibiotics and systemic corticosteroids among pulmonologists and general practictioners during asthma and COPD exacerbations: a southern Italian survey.

To date, there is still a lack of unanimity regarding the definition of exacerbation of asthma and COPD and about objective measurements in the currently used criteria. The aim of our study was to conduct a survey among general practitioners (GPs) and pulmonologists regarding the clinical criteria arbitrarily considered as important to start a course of systemic corticoids and/or antibiotics in asthma and COPD. We conducted a survey enrolling 50 general practitioners (GPs) and 50 pulmonologists, that evaluated the clinical criteria arbitrated as essential to start a course of systemic corticosteroids or antibiotics during asthma and/or COPD exacerbations. Our results demonstrated incongruities between GPs and pulmonologist and within the same professional category concerning systemic corticosteroids. Conversely, we showed higher consensus between and within the groups about criteria to prescribe antibiotics.

Breathing Rhythm Variations during Wash-In Do Not Influence Exhaled Volatile Organic Compound Profile Analyzed by an Electronic Nose.

E-noses are innovative tools used for exhaled volatile organic compound (VOC) analysis, which have shown their potential in several diseases. Before obtaining a full validation of these instruments in clinical settings, a number of methodological issues still have to be established. We aimed to assess whether variations in breathing rhythm during wash-in with VOC-filtered air before exhaled air collection reflect changes in the exhaled VOC profile when analyzed by an e-nose (Cyranose 320). We enrolled 20 normal subjects and randomly collected their exhaled breath at three different breathing rhythms during wash-in: (a) normal rhythm (respiratory rate (RR) between 12 and 18/min), (b) fast rhythm (RR > 25/min) and (c) slow rhythm (RR < 10/min). Exhaled breath was collected by a previously validated method (Dragonieri et al., J. Bras. Pneumol. 2016) and analyzed by the e-nose. Using principal component analysis (PCA), no significant variations in the exhaled VOC profile were shown among the three breathing rhythms. Subsequent linear discriminant analysis (LDA) confirmed the above findings, with a cross-validated accuracy of 45% (p = ns). We concluded that the exhaled VOC profile, analyzed by an e-nose, is not influenced by variations in breathing rhythm during wash-in.

Nocturnal Hypoventilation May Have a Protective Effect on Ischemic Heart Disease in Patients with Obesity Hypoventilation Syndrome.

The importance of nocturnal hypoventilation (nHyp) in the development of cardiovascular comorbidity (CVM) in patients with obesity hypoventilation syndrome (OHS) is controversial. We recently hypothesized that nHyp may have a protective effect on CVM in OHS. The aim of this study was to evaluate the link between nHyp and CVM in patients with OHS. We performed a retrospective analysis of the clinical records of 60 patients with OHS. The initial population was divided into two groups: (1) 31 subjects with OHS and nHyp (nhOHS); (2) 29 individuals with OHS without nHyp (wnhOHS). All patients had also obstructive sleep apnea. Anthropometric data, medical history, electrocardiogram, pulmonary function testing, arterial blood gas test, and sleep recordings were collected. Patients with nhOHS, compared with those wnhOHS, showed higher values of PaCO2 (48.75 ± 3.78 vs. 46.91 ± 2.09 mmHg; p = 0.023), lower percentage of ischemic heart disease (3.2% vs. 20.7%; p = 0.042), higher oxygen desaturation index (ODI; 55.10/h ± 28.76 vs. 38.51/h ± 23.21; p = 0.017), and higher total sleep time (TST90) with SpO2 <90% (53.58% ± 26.90 vs. 25.64% ± 21.67; p = 0.000). Moreover, individuals in the nhOHS group showed a significantly different (p = 0.031) distribution of the three ODI tertiles 0-32/h, 33-72/h, >72/h compared with those in wnhOHS group (19.4% vs. 37%, 41.9% vs. 51.7%, 38.7% vs. 10.3%, respectively). Subsequent discriminant analysis correctly classified nhOHS and wnhOHS in 66.7% of the cases. Ours is the first study analyzing the correlation between nHyp and CVM in patients with OHS. We showed that nHyp in OHS may have a protective effect on cardiovascular morbidity, in particular on ischemic cardiac disease.

Exhaled breath profiling by electronic nose enabled discrimination of allergic rhinitis and extrinsic asthma.

AIM: To assess whether an e-nose could discriminate between subjects affected by allergic rhinitis with and without concomitant extrinsic asthma, as well as from healthy controls, in terms of exhaled VOC-profile. METHODS: Fourteen patients with Extrinsic Asthma and Allergic Rhinitis (AAR), 14 patients with Allergic Rhinitis without asthma (AR) and 14 healthy controls (HC) participated in a cross-sectional study. Exhaled breath was collected by a standardized method and sampled by an e-nose (Cyranose 320). Raw data were reduced by Principal component analysis and analyzed by canonical discriminant analysis. Cross-validation accuracy (CVA) and Receiver Operating Characteristic(ROC)-curves were calculated. External validation in newly recruited patients (7 AAR, 7 AR and 7 HC) was tested using the previous training model. RESULTS: Breathprints of patients with AR clustered from those with AAR (CVA = 85.7%), as well as HC (CVA = 82.1%). Breathprints from AAR were also separated from those of HC (CVA = 75.0%). External validation confirmed the above findings. CONCLUSIONS: An e-nose can discriminate exhaled breath from subjects with allergic rhinitis with and without extrinsic asthma, which represent two different diseases with partly overlapping features. This supports the view of using breath profiling to diagnose asthma also in patients with allergic rhinitis.

The ovarian cycle may influence the exhaled volatile organic compound profile analyzed by an electronic nose.

INTRODUCTION: We aimed to investigate whether the sex hormone profile during the ovarian cycle in healthy women could affect the volatile organic compound (VOC) profile analyzed by an electronic nose (e-nose). METHODS: We enrolled 21 healthy, never-smoking, regularly menstruating women who were not taking any medications. A series of exhaled breath measurements were performed on all subjects at predefined intervals (days 1-6, 7-12, 13-19, 20-25 and 26-31; day 1 was the first day of menstruation) during their ovarian cycle and analyzed by an e-nose (Cyranose 320). RESULTS: By principal component analysis, significant modifications of the exhaled VOC profile were observed over the cycle for principal component 1 (PC1; p = 0.001). In particular, the PC1 value was significantly higher during the premenstrual period and during menstruation compared with the first third of estrogen phase, mid-cycle and the first third of progestational phase (for all parameters p < 0.05 and p < 0.01, respectively). Subsequent linear discriminant analysis confirmed the above findings. CONCLUSIONS: The ovarian cycle may alter the exhaled VOC pattern and this should be taken into account during serial measurements of these markers in the female population.

Exhaled breath profiling in patients with COPD and OSA overlap syndrome: a pilot study.

The analysis of volatile organic compounds (VOCs) by an electronic nose (e-nose) is a groundbreaking method that provides distinct exhaled molecular patterns in several respiratory and systemic diseases. It has been shown that an e-nose can detect obstructive sleep apnea (OSA) as well as chronic obstructive pulmonary disease (COPD). OSA and COPD are sometimes associated into the so-called overlap syndrome (OVS). In this pilot study we hypothesized that an e-nose could discriminate the exhaled breath of patients with OVS from that of subjects with OSA and COPD alone. Thirteen patients with OSA, 15 patients with COPD and 13 with OVS participated in a cross-sectional study. Exhaled breath was collected by a formerly validated method and sampled by using an electronic nose (Cyranose 320). Raw data were analyzed by canonical discriminant analysis on principal component reduction. Cross-validation accuracy (CVA) and ROC-curves were calculated. External validation in newly recruited patients (6 OSA, 6 OVS and 6 COPD) was tested using the previous training set. Breathprints of patients with OSA clustered distinctly from those with OVS (CVA = 96.2%) as well as those with COPD (CVA = 82.1%). Breathprints from OVS were not significantly separated from those of COPD (CVA = 67.9%). External validation confirmed the above findings. The e-nose can distinguish with high accuracy the exhaled VOC-profile of patients with OSA from those with OVS as well as those with COPD. This warrants future studies to confirm the potential of this technique in the non-invasive detection of sleep apnea.

An electronic nose may sniff out amyotrophic lateral sclerosis.

Amyothrophic lateral Sclerosis (ALS) is a neurodegenerative disease characterized by a progressive degeneration of the cortical and spinal motor neuron. Exhaled molecular profiles that have potential in the diagnosis of several respiratory and systemic diseases can be obtained by analyzing human breath with an electronic nose. We hypothesized that exhaled molecular profiling may discriminate well-characterized patients with ALS from controls. 20 ALS patients (age: 63.5±12.3), and 20 healthy controls (age: 58.1±4.4) participated in a cross-sectional study. A Tedlar bag was used to collect exhaled breath by using a validated method. Bags were then sampled by an electronic nose (Cyranose 320). Statistical analysis on sensor responses was performed off-line by principal component analysis, linear discriminant analysis and ROC curves. Breathprints from patients with ALS were discriminated from healthy controls (CVA: 75.0%; p=0.003; AUC 0.795). Based on our results, patients with ALS can be discriminated from healthy controls. This suggests that exhaled breath analysis has potential for screening and/or diagnosis of this neuromuscular disease.

Influence of age and gender on the profile of exhaled volatile organic compounds analyzed by an electronic nose.

We aimed to investigate the effects of age and gender on the profile of exhaled volatile organic compounds. We evaluated 68 healthy adult never-smokers, comparing them by age and by gender. Exhaled breath samples were analyzed by an electronic nose (e-nose), resulting in "breathprints". Principal component analysis and canonical discriminant analysis showed that older subjects (≥ 50 years of age) could not be distinguished from younger subjects on the basis of their breathprints, as well as that the breathprints of males could not distinguished from those of females (cross-validated accuracy, 60.3% and 57.4%, respectively).Therefore, age and gender do not seem to affect the overall profile of exhaled volatile organic compounds measured by an e-nose.

A new approach for the assessment of sleepiness and predictivity of obstructive sleep apnea in drivers: A pilot study.

BACKGROUND: Falling asleep behind the wheel is one of the most relevant consequences of obstructive sleep apnea (OSA). We created a new screening questionnaire, named the Driver Sleepiness Score (DSS), aiming to assess sleepiness in drivers with suspected OSA. The primary aim of our study was to evaluate sleepiness in drivers with a suspicion of OSA by the DSS in order to assess its correlation with the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and total sleep time with oxyhemoglobin saturation below 90% (TST90). We also aimed to assess the diagnostic accuracy of DSS for three different cutoffs of AHI (AHI = 5, AHI = 15, AHI = 30), which allow stratification of the severity of OSA. MATERIALS AND METHODS: Seventy-three driving patients at risk for OSA participated in the study. DSS and the Epworth Sleepiness Scale (ESS) were both administered in operator-dependent modality and in randomized sequence. RESULTS: The DSS showed higher accuracy in screening patients with mild OSA [area under curve (AUC): 0.88 vs 0.74] and moderate OSA (AUC: 0.88 vs 0.79), whereas ESS showed higher accuracy in screening patients with severe OSA (AUC: 0.91 vs 0.78). A DSS score ≥ 7 is the optimal cutoff for distinguishing true positives from false positives for the presence of OSA and for its different severity levels. The administration of both questionnaires increases the accuracy for the detection of all OSA severity levels. CONCLUSIONS: If validated, DSS may qualify as a new screening tool specifically for drivers with the suspicion of having OSA, in combination with the ESS.

Titration effectiveness of two autoadjustable continuous positive airway pressure devices driven by different algorithms in patients with obstructive sleep apnoea.

BACKGROUND AND OBJECTIVE: Nocturnal application of continuous positive airway pressure (CPAP) is the standard treatment for patients with obstructive sleep apnoea (OSA). Determination of the therapeutic pressure (CPAP titration) is usually performed by a technician in the sleep laboratory during attended polysomnography. One possible alternative to manual titration is automated titration. Indeed, during the last 15 years, devices have been developed that deliver autoadjustable CPAP (A-CPAP). The aim of the present study was to compare the titration effectiveness of two A-CPAP devices using different flow-based algorithms in patients with OSA. METHODS: This is a randomized study; 79 subjects underwent two consecutive unattended home A-CPAP titration nights with two different devices (Autoset Resmed; Remstar Auto Respironics); during the third and the fourth night, patients underwent portable monitoring in the sleep laboratory during fixed CPAP at the A-CPAP recommended pressure. RESULTS: Bland Altman plots showed good agreement between the recommended median and maximal pressure levels obtained with the two devices. A significant improvement was observed in all the sleep parameters by both A-CPAP machines to a similar degree. CONCLUSIONS: It was observed that the two A-CPAP devices using different algorithms are equally effective in initial titration of CPAP.

The Epworth Sleepiness Scale: conventional self vs physician administration.

BACKGROUND: The Epworth Sleepiness Scale (ESS) is a simple, self-administered questionnaire that provides a measurement of the subject's level of daytime sleepiness, and is widely used for patients with obstructive sleep apnea (OSA). Some works undermined its accuracy. The aim of this study was to compare self-administered ESS scores to physician-administered scores in a sample of patients with suspicion of OSA. METHODS: Patients were randomly divided into two groups: group 1, or the self-administered group (n = 113); and group 2, or the physician-administered group (n = 112). Patients in group 1 were asked to complete the ESS in the traditional way; in group 2, the ESS was administered by a sleep-medicine physician. Subjects in both groups underwent diagnostic in-laboratory portable monitoring (PM) within 1 week's time. RESULTS: The percentage of questionnaires properly completed was significantly different between groups: 77% (87 of 113) in the group 1 vs 100% (112 of 112) in the group 2 (P = .00). Scores obtained when a physician administered the questionnaire (ESSp) were higher than those when the ESS was self administered (ESSs) (ESSp:12.09 ± 4.1 vs ESSs:10.37 ± 5.49; P = .01). The ESSp was more highly correlated with apnea-hypopnea index and oxygen desaturation index than the ESSs. CONCLUSIONS: Our results lead us to consider the physician-administered ESS to be more accurate than the traditional ESS; thus, our suggestion is to validate this new method of administration.