Short-term Pulmonary Effects of Using an Electronic Cigarette

Impact on Respiratory Flow Resistance, Impedance, and Exhaled Nitric Oxide

Constantine I. Vardavas, MD, MPH, PhD; Nektarios Anagnostopoulos, MD; Marios Kougias, MD; Vassiliki Evangelopoulou, MD; Gregory N. Connolly, DMD, MPH; Panagiotis K. Behrakis, MD, PhD, FCCP


CHEST. 2012;141(6):1400-1406. 

In This Article

Abstract and Introduction


Background: Debate exists over the scientific evidence for claims that electronic cigarettes (e-cigarettes) have no health-related ramifications. This study aimed to assess whether using an e-cigarette for 5 min has an impact on the pulmonary function tests and fraction of exhaled nitric oxide (Feno) of healthy adult smokers.
Methods: Thirty healthy smokers (aged 19–56 years, 14 men) participated in this laboratory-based experimental vs control group study. Ab lib use of an e-cigarette for 5 min with the cartridge included (experimental group, n = 30) or removed from the device (control group, n = 10) was assessed.
Results: Using an e-cigarette for 5 min led to an immediate decrease in Feno within the experimental group by 2.14 ppb (P = .005) but not in the control group (P = .859). Total respiratory impedance at 5 Hz in the experimental group was found to also increase by 0.033 kPa/(L/s) (P < .001), and flow respiratory resistance at 5 Hz, 10 Hz, and 20 Hz also statistically increased. Regression analyses controlling for baseline measurements indicated a statistically significant decrease in Feno and an increase in impedance by 0.04 kPa/(L/s) (P = .003), respiratory resistance at 5 Hz by 0.04 kPa/(L/s) (P = .003), at 10 Hz by 0.034 kPa/(L/s) (P = .008), at 20 Hz by 0.043 kPa/(L/s) (P = .007), and overall peripheral airway resistance (β, 0.042 kPa/[L/s]; P = .024), after using an e-cigarette.
Conclusions: e-Cigarettes assessed in the context of this study were found to have immediate adverse physiologic effects after short-term use that are similar to some of the effects seen with tobacco smoking; however, the long-term health effects of e-cigarette use are unknown but potentially adverse and worthy of further investigation.


Electronic cigarettes (e-cigarettes) are marketed as potentially reduced tobacco exposure products. The product resembles, but is not, a cigarette in design or function and is marketed as "safer" than a conventional cigarette. However, debate exists over the scientific evidence for the claims that the products have no health-related ramifications. Because e-cigarettes do not contain or burn tobacco, they do not appear to deliver the known toxins found in conventional cigarette smoke.[1–4] Conversely, US Food and Drug Administration (FDA) analyses have indicated that e-cigarettes contain a number of toxins and carcinogens, including tobacco-specific nitrosamines, diethylene glycol, and other components suspected of being harmful to humans.[5]

Because of the increase in interest regarding e-cigarettes and they claims that they are potentially reduced-exposure product, a nicotine-delivery device, or a smoking-cessation tool, it is imperative to assess the risks related to alternative nicotine delivery systems to protect public and consumer health.[6–10] Previous research has indicated that smokers have significantly higher lung resistances at 5 Hz and 20 Hz and lower concentrations of fraction of exhaled nitric oxide (Feno)—a noninvasive marker of bronchial inflammation—compared with nonsmokers.[11,12] To date, there is no published evidence of any direct health-related effect of acute physiologic response to using an e-cigarette; thus, the aim of the current study was to investigate whether using an e-cigarette ab lib for 5 min could affect respiratory mechanics and Feno within the context of an experimental vs control group study design.


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