October 23, 2020, 2:46 pm Michael Devitt -- Results from a special report in the Journal of the American Heart Association suggest that e-cigarette or vaping product use-associated lung injury may not be caused by substances such as tetrahydrocannabinol or nicotine, but rather by use of higher power settings and the types of heating elements in these devices.
The findings, published online Sept. 8 and in the Sept. 15 issue of the journal, serve as a reminder of the harms associated with e-cigarette use. Considering recent research that has shown an association between e-cigarette use and COVID-19 risk, the findings could also provide another avenue for family physicians to counsel patients on the use of both e-cigarettes and traditional cigarettes.
“We are reporting these initial findings now, even though our studies are continuing, because of their public health significance in light of the life-threatening potential of the EVALI epidemic as well as concern over vaping in the coronavirus disease 2019 era,” the authors wrote.
Cases of severe lung illness associated with vaping products were first reported in Illinois and Wisconsin in April 2019. At that time, many of the individuals who developed EVALI reported using e-cigarette products that contained THC, nicotine or both.
In August 2019 the CDC’s Health Alert Network issued a health advisory on severe pulmonary disease associated with e-cigarette use. The CDC then published updated guidance for health care professionals in November 2019. According to the agency, more than 2,800 hospitalized cases of EVALI, including 68 deaths, occurred in the United States by Feb. 18, 2020, the latest date for which data are available.
The report’s findings were part of a larger ongoing study designed to compare the effects of e-cigarette vapor (with and without nicotine), tobacco smoke and air on the cardiovascular system. The study was conducted in a laboratory setting using rats as test subjects.
Prior to September 2019, the researchers studied e-cigarette vapor generated from propylene glycol and vegetable glycerin, tobacco flavoring and nicotine using an e-cigarette device that contained a stainless-steel atomizing heating element. Test subjects were exposed to the vapor at the lowest dose available. None of the rats in this phase of the research developed respiratory distress.
The e-cigarette device the researchers were using subsequently went off the market. In its place, they were offered a substitute device with a nickel-chromium alloy heating element.
The researchers resumed their experiment using the same combination of propylene glycol and vegetable glycerin plus tobacco flavoring, but without nicotine. In this phase, test subjects received a single, nose-only, acute exposure lasting two hours, and were categorized into three groups:
None of the rats that were exposed to normal air or to e-cigarette vapor using stainless-steel heating elements developed respiratory distress.
In comparison, 14 of the 18 rats exposed to e-cigarette vapor with nickel-chromium heating elements quickly developed acute respiratory distress, which was characterized by labored breathing, audible wheezing and inactivity. All 14 rats had been exposed to the 70-watt power setting; one had to be euthanized.
Following the exposure, lung tissue samples were obtained from 19 rats. Of five rats exposed to normal air, all samples showed normal bronchial and alveolar structure. One out of five rats in the stainless-steel groups showed a less than 10% area of inflammation of the lung and bronchi, while tissue samples from eight out of nine rats in the nickel-chromium groups showed equal – and in most cases, higher – degrees of lung damage.
“After analyzing lung tissue from subjects in the study, we found them to be severely compromised and observed other serious changes, such as lung lesions, red blood cell congestion, obliteration of alveolar spaces and pneumonitis in some cases,” Michael Kleinman, Ph.D., a professor of occupational and environmental medicine in the Department of Medicine at the University of California, Irvine, School of Medicine and coauthor of the report, said in a press release.
Although the findings were based on experimental research, the authors recommended that health care professionals advise patients about the potential risks of using e-cigarettes that contain certain types of heating elements and of operating these devices at power levels higher than recommended.
“While further research is needed, these results indicate that specific devices and power settings may play a key role in the development of EVALI as much as the additives do,” Robert Kloner, M.D., Ph.D., chief science officer and scientific director of cardiovascular research at Huntington Medical Research Institutes in Pasadena, Calif., and the report’s corresponding author, said in the press release. “The harms associated with e-cigarettes and vaping simply cannot be overstated.”
Lynn Fisher, M.D., an assistant professor in the Department of Family and Community Medicine at the University of Kansas School of Medicine-Wichita, said FPs could use the findings to ask patients additional questions, leading to better care.
“This research helps us to better understand more regarding the relationship between the use of e-cigarettes and lung damage,” Fisher said. “While I would have focused counseling more on the additives and nicotine prior, now I know that the type of heating element used and the power settings may also play an important role. I will need to ask questions about that as well.”
When discussing tobacco use with patients, Fisher told AAFP News he always asks about their readiness to quit and what he can do to help them achieve that goal. He also tries to explain to patients how tobacco use may be contributing to any current health issues they’re experiencing, and provides education on the long-term consequences as well.
“I let patients know that while I won’t harass them about tobacco use, I will bring it up at future office visits because I care about them,” Fisher added. “Some patients may be ready the first time and some patients may not be ready for years, but the seed is planted.”
Fisher said he often relies on the AAFP’s patient care tools and physician resources on the use of e-cigarettes and tobacco products, as well as American Family Physician, which has an extensive collection on the topic. He also recommended UpToDate, which has published several articles on vaping and e-cigarettes, smoking cessation and related issues.
Fisher also suggested that as influenza season approaches, now may be a good opportunity to talk with patients about ways to quit using tobacco or e-cigarettes and to encourage them to receive the influenza vaccine.
“I think right now with the COVID-19 pandemic and the start of influenza season soon to come, patients are aware of the need to make changes that will decrease the chances for additional lung injuries and may be more open to cessation counseling and medications,” said Fisher. “I also take every opportunity to encourage vaccinations, namely influenza and pneumococcal (vaccinations), for patients using traditional cigarettes and e-cigarettes as a way to hopefully prevent a hospitalization or death.”