Chemical characterization of human breath

In the present work analysis of exhaled breath has been proposed as a novel way to detect disease, to monitor disease progression, and to monitor clinical intervention. An analytical method of analysis based upon two stages thermal desorption capillary gas chromatography and mass spectrometry was developed for the analysis of breath samples. All the steps of the analytical procedure were evaluated, trying to identify the critical aspects in order to optimize the entire procedure. A novel breath collection media has been developed that is cheap, disposable and readily available. This material allows breath samples to be collected in a novel manner. After validation the procedure was applied to real samples and preliminary experiments were performed aimed at estimating the variability of the composition of breath as a function of time of day and the inter-subject variability. In particular the trend in time of the two principal compounds in breath, acetone and isoprene was observed. The data showed a wide inter-variability between different people and also confirmed that a meal can influence breath composition. For this reason if possible, it was better to collect a breath sample in the morning before eating. Single substances or sets and patterns of exhaled markers were also investigated in order to establish correlations between the chemical composition of breath and patients’ clinical conditions. Preliminary studies were performed on patients with end-stage renal disease. The results underlined the capacity of the analytical procedure to appreciate small variation in breath composition. In particularly in people under dialysis treatment two compounds were found to show significant differences in breath concentration between patients and healthy people before the dialysis and no important differences after. These two compounds should become an additional and important parameter to determine the end of the dialysis treatment. In parallel a breath collection system prototype has been designed that enables samples of dead space air to be separated from end tidal breath and be collected independently. This device is also novel and has a great potential in breath analysis field

Determination of sevoflurane and isopropyl alcohol in exhaled breath by thermal desorption gas chromatography-mass spectrometry for exposure assessment of hospital staff

Volatile anaesthetics and disinfection chemicals pose ubiquitous inhalation and dermal exposure risks in hospital and clinic environments. This work demonstrates specific non-invasive breath biomonitoring methodology for assessing staff exposures to sevoflurane (SEV) anaesthetic, documenting its metabolite hexafluoroisopropanol (HFIP) and measuring exposures to isopropanol (IPA) dermal disinfection fluid. Methods are based on breath sample collection in Nalophan bags, followed by an aliquot transfer to adsorption tube, and subsequent analysis by thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Ambient levels of IPA were also monitored. These methods could be generalized to other common volatile chemicals found in medical environments. Calibration curves were linear (r2=0.999) in the investigated ranges: 0.01-1000ppbv for SEV, 0.02-1700ppbv for IPA, and 0.001-0.1ppbv for HFIP. The instrumental detection limit was 10pptv for IPA and 5pptv for SEV, both estimated by extracted ion-TIC chromatograms, whereas the HFIP minimum detectable concentration was 0.5pptv as estimated in SIM acquisition mode. The methods were applied to hospital staff working in operating rooms and clinics for blood draws. SEV and HFIP were present in all subjects at concentrations in the range of 0.7-18, and 0.002-0.024ppbv for SEV and HFIP respectively. Correlation between IPA ambient air and breath concentration confirmed the inhalation pathway of exposure (r=0.95, p<0.001) and breath-borne IPA was measured as high as 1500ppbv. The methodology is easy to implement and valuable for screening exposures to common hospital chemicals. Although the overall exposures documented were generally below levels of health concern in this limited study, outliers were observed that indicate potential for acute exposures

NUOVI MARKERS DI DANNO MIOCARDICO: DOLORE TORACICO E COPEPTINA

ABSTRACT Chest pain is one of the most common cause for Emergency Department (ED) visits. Nowadays the diagnostic gold standard for acute myocardial infarction (AMI) is Troponin T but its delayed release reduces the diagnostic sensibility in the early ischemic time. Copeptin, a biomarker associated with endovascular stress regulation, has been studied in various cardiovascular events. The aim of this study is to analyse the diagnostic/prognostic value of copeptin in myocardial infarction patients admitted to ED for chest pain to obtain a careful rule out of AMI. 90 consecutive patients admitted for chest pain were studied. Inclusions criteria were Chest Pain Score > 4 and negative electrocardiography for acute coronary syndrome (ACS) according to the European Society of Cardiology Guidelines 2009. Copeptin was evaluated at the ED presentation. 50 patients were discharged after AMI exclusion with negative copeptin and troponin. 40 patients were admitted, 18 of them had myocardial infarction, 12 had positive copeptin with negative troponin and myoglobin values. The overall copeptin sensibility in the infarcted patients was 69,4%, increasing to 77,7% adding troponin T, with a negative predictive value of 78%. Upon multiple regression frame copeptin appears to be an independent predictor factor of number of vessels involved in ACS (p<0,006). Copeptin blood level risen early in infarcted patients has a good sensibility; the combination with troponin T improved the diagnostic performance of these two biomarkers in AMI patients. Copeptin could be used also as a prognostic factor of myocardial damage because of its correlation with coronary involvement