Electronic cigarettes and lung toxicity

The use of electronic cigarettes (e-cigarettes) in the United States has steadily increasedsince their introduction into the market in 2007. These devices deliver nicotine through thevaporization of a liquid which contains a vehicle (propylene glycol or glycerin), artificialflavoring, and nicotine. The combustion of these liquids creates a vapor containing particulates,multiple chemicals, and nicotine. The long-term safety of these products is unknown. Studiesin healthy, non-smoking volunteers and smokers with no clinical pulmonary disease havedemonstrated that the inhalation of e-cigarette vapor has minimal short-term effects onpulmonary function. The exposure of cell cultures to e-cigarette liquid or aerosols has beenshown to reduce cell viability, induce cytokine production, and cause oxidative stress. Theexposure of animals (mice and rats) to e-cigarette aerosols induces inflammatory responsesin the lungs and delays the clearance of bacterial and viral challenges. There are a smallnumber of case reports of patients developing acute pulmonary toxicity following the use ofe-cigarettes. Two patients have developed lipoid pneumonia following the use of e-cigarettesfor 3 and 7 months. Finally, several studies suggest that patients with chronic lung diseasewho switch from tobacco cigarettes to e-cigarettes can have improvement in lung function(asthmatics) and a reduction in the number of exacerbations (chronic obstructive pulmonarydisease). Clearly, the public and the medical profession need more information about thelong-term complications associated with the use of e-cigarettes and their benefit in smokingcessation efforts.Keywords: electronic

Συγκριτική αξιολόγηση της ανάλυσης Fourier και της πολλαπλής γραμμικής παλινδρόμησης για τη μελέτη των χρονικών μεταβολών της πίεσης και της ροής κατά τη διάρκεια μηχανικής αναπνοής

Two linear methods for the analytical estimation of the respiratory system mechanicalparameters are compared the Multiple Linear Regression (MLR) and the Fourier Analysis(FA) This comparison refers to their competence and reliability during mechanical ventilationin 3 groups of patients a) without respiratory disorder b) with Chronic Obstructive PulmonaryDisease (COPD) and c) with acute respiratory distress syndrome (ARDS) Measurementswere applied in the usually applied range of ventilatory frequencies ((BF 0 17 0 33 Hz)externally applied positive end expiratory pressure (PEEP 0 10 hPa) Tidal volume (VT 300800 ml) before as well as after tracheotomy According to the results 1) The 2 methodsrevealed the differences of mechanical coefficients between the 3 studied groups of patientsElastance (Ers) Resistance (Rrs) Impedance (Zrs) Reactance (Xrs) phase angle betweenpressure and flow (Ors) time constant (Trs) and end expiratory pressure (EEP)) in allinstances accordingly 2) The two methods revealed clearly the influence of BF PEEP VTand tracheotomy on the mechanical parameters of the respiratory system 3) FA resultedgenerally to higher Ers Rrs Zrs Ors Trs and RMSD and to lower Xrs and EEP values thanMLR The higher differences between the 2 methods are noted in the ARDS & COPD groupsThis difference is influenced by the increase of BF PEEP and VTAlthough MLR depends on the total harmonic content of pressure & flow while FA is based onthe first harmonic term the two methods are equally reliable for revealing the underlyingpathophysiological respiratory disorder and the influence of BF PEEP VT and tracheotomyon the respiratory mechanics