Vaping disrupts ventilation-perfusion matching in asymptomatic users

Patterns of Use of e-Cigarettes and Their Respiratory Effects: A Critical Umbrella Review

E-cigarettes (ECs) are a well-established consumer product. To study their respiratory health effects, there is the issue of heterogenous patterns of use: concurrently with cigarette smoking (dual use), exclusive use after smoking cessation (exclusive use), or use initiated without any prior or current use of cigarettes (naïve use). Our primary goal was to synthesize the evidence on the respiratory effects of ECs use in adults, categorized by their pattern of use. Additionally, we identified the highest quality systematic reviews and critically evaluated the current literature on this topic. The review was developed with published umbrella review guidelines. The database searches were Medline, Scopus, Cochrane, Epistemonikos, LILACS, and grey literature databases. The criterion for inclusion of systematic reviews was analyses of respiratory tests from randomized controlled trials or cohort studies. Quality assessments were performed with AMSTAR2 and a checklist of reporting biases. A narrative analysis was synthesized by test method: spirometry, impulse oscillometry, breath gasses, biomarkers, and clinical serious adverse events. Twelve systematic reviews were included. The findings on respiratory functioning were statistically non-significant across all patterns of use. Reporting bias was frequently observed. Based on the current research, there is no evidence of significant change in the short or medium term in respiratory function with any pattern of ECs use. We attribute the null findings to the weaknesses of acute studies, the participants' smoking history masking testing, and the inclusion of participants with a low frequency of use.

Association between e-cigarette exposure and ventilation homogeneity in young adults: a cross-sectional study

BACKGROUND

The number of young people who use e-cigarettes is rising. It remains unclear whether e-cigarette use impairs lung function. We aimed to compare ventilation distribution between young adults exposed to e-cigarettes and an unexposed group.

METHODS

Study participants included otherwise healthy young adults (18-24 years) who self-reported e-cigarette use and unexposed participants who had no history of e-cigarette, tobacco or cannabis exposure. Exposure to e-cigarettes was defined using three measures: 1) ever-exposed, 2) daily use and 3) puff frequency, which includes none (unexposed), minimal (<2 puffs·h-1), moderate (3-4 puffs·h-1) and heavy (≥5 puffs·h-1). Ventilation distribution was measured using the multiple-breath washout test and reported as lung clearance index (LCI).

RESULTS

A total of 93 participants were recruited; 38 unexposed and 41 exposed participants had LCI measures. The exposed group consisted predominately of participants who used flavoured e-liquids (94.5%) that contained nicotine (93.5%). The magnitude and direction of the difference in LCI across the exposure definitions was similar. Compared with the unexposed group, in the unadjusted models LCI was higher in those with any e-cigarette use (mean difference 0.15, 95% CI -0.004-0.31), daily users (mean difference 0.10, 95% CI -0.08-0.28) and heavy users (mean difference 0.22, 95% CI 0.03-0.41).

CONCLUSION

This preliminary work suggests that LCI may be a useful biomarker to measure the effects of e-cigarette use on ventilation distribution and to track early functional impairment of the small airways.

Vaping causes an acute BMI-dependent change in pulmonary blood flow

Vaping use has skyrocketed especially among young adults, however there is no consensus on how vaping impacts the lungs. We aimed to determine whether there were changes in lung function acutely after a standard vaping session or if there were differences in lung function metrics between a healthy never-vaping cohort (N = 6; 27.3 ± 3.0 years) and a young asymptomatic vaping cohort (N = 14; 26.4 ± 8.0 years) indicating chronic changes. Pulmonary function measurements and impulse oscillometry were obtained on all participants. Oxygen-enhanced and Arterial Spin Labelling MRI were used to measure specific ventilation and perfusion, respectively, before and after vaping, and in the control cohort at baseline. MRI metrics did not show any significant differences in specific ventilation or perfusion after vaping. Heart rate increased post-vaping (68.1 ± 10.5 to 71.3 ± 8.7, p = 0.020); however, this and other metrics did not show a nicotine dose-dependent effect. There was a significant negative correlation between BMI and change in mean perfusion post-vaping (p = 0.003); those with normal/low BMI showing an increase in perfusion and vice versa for high BMI. This may be due to subjects lying supine during vaping inhalation. Pulmonary function metrics indicative of airways resistance showed significant differences between the vaping and control cohorts indicating early airway changes.

Review of quantitative and functional lung imaging evidence of vaping-related lung injury

Introduction

The pulmonary effects of e-cigarette use (or vaping) became a healthcare concern in 2019, following the rapid increase of e-cigarette-related or vaping-associated lung injury (EVALI) in young people, which resulted in the critical care admission of thousands of teenagers and young adults. Pulmonary functional imaging is well-positioned to provide information about the acute and chronic effects of vaping. We generated a systematic review to retrieve relevant imaging studies that describe the acute and chronic imaging findings that underly vaping-related lung structure-function abnormalities.

Methods

A systematic review was undertaken on June 13th, 2023 using PubMed to search for published manuscripts using the following criteria: [("Vaping" OR "e-cigarette" OR "EVALI") AND ("MRI" OR "CT" OR "Imaging")]. We included only studies involving human participants, vaping/e-cigarette use, and MRI, CT and/or PET.

Results

The search identified 445 manuscripts, of which 110 (668 unique participants) specifically mentioned MRI, PET or CT imaging in cases or retrospective case series of patients who vaped. This included 105 manuscripts specific to CT (626 participants), three manuscripts which mainly used MRI (23 participants), and two manuscripts which described PET findings (20 participants). Most studies were conducted in North America (n = 90), with the remaining studies conducted in Europe (n = 15), Asia (n = 4) and South America (n = 1). The vast majority of publications described case studies (n = 93) and a few described larger retrospective or prospective studies (n = 17). In e-cigarette users and patients with EVALI, key CT findings included ground-glass opacities, consolidations and subpleural sparing, MRI revealed abnormal ventilation, perfusion and ventilation/perfusion matching, while PET showed evidence of pulmonary inflammation.

Discussion and conclusion

Pulmonary structural and functional imaging abnormalities were common in patients with EVALI and in e-cigarette users with or without respiratory symptoms, which suggests that functional MRI may be helpful in the investigation of the pulmonary health effects associated with e-cigarette use.

A Single 10-Minute E-cigarette Vapor Exposure Reduces Tidal Volume and Minute Ventilation in Normoxia and Normobaric Hypoxia in Adult Rats

The present study investigated the effects of a single 10-minute exposure to e-cigarette vapor on ventilation in adult male Long-Evans rats. Ventilation was recorded using awake, unrestrained whole-body plethysmography. Baseline recordings were taken the day before full-body exposure to either room air (n = 9; air control group) or e-cigarette vapor (n = 9; treatment group). Post-exposure recordings were taken immediately after the 10-minute room air or vapor exposure. As part of the ventilation protocol, in addition to recording the subject's ventilation in room air, the subjects were also exposed to 10% oxygen (balanced with nitrogen) to assess the effects of e-cigarette vapor on an increased drive to breathe. Ventilation data were analyzed using a 2x2x2 mixed-model ANOVA measuring treatment (vape vs. air) x time (baseline vs. post-treatment) x condition (normoxia vs. hypoxia) for breathing frequency, tidal volume, and minute ventilation. Breathing frequency increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), with no effect of time (baseline vs. post-treatment) for either group. Tidal volume increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), and an effect of time (baseline vs. post-treatment) was observed (p = 0.010) for the vape group. Minute ventilation increased in both treatment groups (air and vape) with exposure to normobaric hypoxia (p < 0.001), and an effect of time (baseline vs. post-treatment) was observed (p < 0.001) for the vape group. In conclusion, immediately following a single 10-minute e-cigarette vapor exposure, both tidal volume and minute ventilation were reduced during normoxia and normobaric hypoxia, indicating a decrease in ventilation after a single 10-minute e-cigarette vapor exposure. Furthermore, this exposure also blunted the physiological response to acute hypoxia exposure. Subjects in the vape group, while breathing more rapidly as expected, experienced shallower breathing than the air group during hypoxia. The findings in this study confirm that vaping could result in reduced lung function.

A systematic review of the effects of e-cigarette use on lung function

Given the increasing use of e-cigarettes and uncertainty surrounding their safety, we conducted a systematic review to determine the effects of e-cigarettes on measures of lung function. We systematically searched EMBASE, MEDLINE, and PsycINFO databases via Ovid, the Cochrane CENTRAL database, and the Web of Science Core from 2004 until July 2021, identifying 8856 potentially eligible studies. A total of eight studies (seven studying immediate effects and one long-term effects, 273 total participants) were included. The risk of bias was assessed using the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) and Cochrane risk of bias tools. These studies suggest that vaping increases airway resistance but does not appear to impact forced expiratory volume in one second (FEV₁₎, forced vital capacity (FVC), or FEV₁/FVC ratio. However, given the limited size and follow-up duration of these studies, larger, long-term studies are required to further determine the effects of e-cigarettes on lung function.

Chronic health effects associated with electronic cigarette use: A systematic review

Introduction

Over the last decade, e-cigarette use has been on the rise but with growing health concerns. The objective of this systematic review was to update findings for chronic health outcomes associated with e-cigarette use from the 2018 National Academies of Sciences, Engineering, and Medicine (NASEM) report.

Methods

Three bibliographic databases were searched to identify studies comparing the chronic health effects of e-cigarette users (ECU) to non-smokers (NS), smokers, and/or dual users indexed between 31 August 2017 and 29 January 2021. Two independent reviewers screened abstracts and full texts. Data were extracted by one reviewer and verified by a second one. Outcomes were synthesized in a narrative manner using counts and based on statistical significance and direction of the association stratified by study design and exposure type. Risk of bias and certainty of evidence was assessed. The protocol was prospectively registered on Open Science Framework https://osf.io/u9btp.

Results

A total of 180 articles were eligible. This review focused on 93 studies for the 11 most frequently reported outcomes and from which 59 reported on daily e-cigarette use. The certainty of evidence for all outcomes was very low because of study design (84% cross-sectional) and exposure type (27% reported on exclusive ECU, i.e., never smoked traditional cigarettes). Overall, the summary of results for nearly all outcomes, including inflammation, immune response, periodontal and peri-implant clinical parameters, lung function, respiratory symptoms, and cardiovascular disease, suggested either non-significant or mixed results when daily ECU was compared to NS. This was also observed when comparing exclusive ECU to NS. The only notable exception was related to oral health where most (11/14) studies reported significantly higher inflammation among daily ECU vs. NS. Compared to the smokers, the exclusive-ECUs had no statistically significant differences in inflammation orperiodontal clinical parameters but had mixed findings for peri-implant clinical parameters.

Conclusions

This review provides an update to the 2018 NASEM report on chronic health effects of e-cigarette use. While the number of studies has grown, the certainty of evidence remains very low largely because of cross-sectional designs and lack of reporting on exclusive e-cigarette exposure. There remains a need for higher quality intervention and prospective studies to assess causality, with a focus on exclusive e-cigarette use.

E-Cigarettes Reexamined: Product Toxicity

The introduction of e-cigarettes, or electronic nicotine delivery systems (ENDS), has been accompanied by controversy regarding their safety and effectiveness as a cessation aid and by an explosion in their use by youth. Their use does not involve the combustion of tobacco and the creation of harmful combustion products; they have been seen as a "harm reduction" tool that may be of assistance in promoting smoking cessation. Recognition that ENDS can deliver an array of chemicals and materials with known adverse consequences has spurred more careful examination of these products. Nicotine, nitrosamines, carbonyl compounds, heavy metals, free radicals, reactive oxygen species, particulate matter, and "emerging chemicals of concern" are among the constituents of the heated chemical aerosol that is inhaled when ENDS are used. They raise concerns for cardiovascular and respiratory health that merit the attention of clinicians and regulatory agencies. Frequently cited concerns include evidence of disordered respiratory function, altered hemodynamics, endothelial dysfunction, vascular reactivity, and enhanced thrombogenesis. The absence of evidence of the consequences of their long-term use is of additional concern. Their effectiveness as cessation aids and beneficial impact on health outcomes continue to be examined. It is important to ensure that their production and availability are thoughtfully regulated to optimise their safety and permit their use as harm reduction devices and potentially as smoking-cessation aids. It is equally vital to effectively prevent them from becoming ubiquitous consumer products with the potential to rapidly induce nicotine addiction among large numbers of youth. Clinicians should understand the nature of these products and the implications of their use.

Impact of vaping on respiratory health

Widespread uptake of vaping has signaled a sea change in the future of nicotine consumption. Vaping has grown in popularity over the past decade, in part propelled by innovations in vape pen design and nicotine flavoring. Teens and young adults have seen the biggest uptake in use of vape pens, which have superseded conventional cigarettes as the preferred modality of nicotine consumption. Relatively little is known, however, about the potential effects of chronic vaping on the respiratory system. Further, the role of vaping as a tool of smoking cessation and tobacco harm reduction remains controversial. The 2019 E-cigarette or Vaping Use-Associated Lung Injury (EVALI) outbreak highlighted the potential harms of vaping, and the consequences of long term use remain unknown. Here, we review the growing body of literature investigating the impacts of vaping on respiratory health. We review the clinical manifestations of vaping related lung injury, including the EVALI outbreak, as well as the effects of chronic vaping on respiratory health and covid-19 outcomes. We conclude that vaping is not without risk, and that further investigation is required to establish clear public policy guidance and regulation.

MRI Shows Lung Perfusion Changes after Vaping and Smoking

Background Evidence regarding short-term effects of electronic nicotine delivery systems (ENDS) and tobacco smoke on lung ventilation and perfusion is limited. Purpose To examine the immediate effect of ENDS exposure and tobacco smoke on lung ventilation and perfusion by functional MRI and lung function tests. Materials and Methods This prospective observational pilot study was conducted from November 2019 to September 2021 (substudy of randomized controlled trial NCT03589989). Included were 44 healthy adult participants (10 control participants, nine former tobacco smokers, 13 ENDS users, and 12 active tobacco smokers; mean age, 41 years ± 12 [SD]; 28 men) who underwent noncontrast-enhanced matrix pencil MRI and lung function tests before and immediately after the exposure to ENDS products or tobacco smoke. Baseline measurements were acquired after 2 hours of substance abstinence. Postexposure measurements were performed immediately after the exposure. MRI showed semiquantitative measured impairment of lung perfusion (R_Q) and fractional ventilation (R_FV) impairment as percentages of affected lung volume. Lung clearance index (LCI) was assessed by nitrogen multiple-breath washout to capture ventilation inhomogeneity and spirometry to assess airflow limitation. Absolute differences were calculated with paired Wilcoxon signed-rank test and differences between groups with unpaired Mann-Whitney test. Healthy control participants underwent two consecutive MRI measurements to assess MRI reproducibility. Results MRI was performed and lung function measurement was acquired in tobacco smokers and ENDS users before and after exposure. MRI showed a decrease of perfusion after exposure (R_Q, 8.6% [IQR, 7.2%-10.0%] to 9.1% [IQR, 7.8%-10.7%]; P = .03) and no systematic change in R_FV (P = .31) among tobacco smokers. Perfusion increased in participants who used ENDS after exposure (R_Q, 9.7% [IQR, 7.1%-10.9%] to 9.0% [IQR, 6.9%-10.0%]; P = .01). R_FV did not change (P = .38). Only in tobacco smokers was LCI elevated after smoking (P = .02). Spirometry indexes did not change in any participants. Conclusion MRI showed a decrease of lung perfusion after exposure to tobacco smoke and an increase of lung perfusion after use of electronic nicotine delivery systems. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kligerman in this issue.

Vaping and E-Cigarette Use in Children and Adolescents: Implications on Perioperative Care From the American Society of Anesthesiologists Committee on Pediatric Anesthesia, Society for Pediatric Anesthesia, and American Academy of Pediatrics Section on Anesthesiology and Pain Medicine

Electronic cigarettes (e-cigarettes) or vaping use in adolescents has emerged as a public health crisis that impacts the perioperative care of this vulnerable population. E-cigarettes have become the most commonly used tobacco products among youth in the United States. Fruit and mint flavors and additives such as marijuana have enticed children and adolescents. E-cigarette, or vaping, product use-associated lung injury (EVALI) is a newly identified lung disease linked to vaping. Clinical presentation of EVALI can be varied, but most commonly includes the respiratory system, gastrointestinal (GI) tract, and constitutional symptoms. Clinical management of EVALI has consisted of vaping cessation and supportive therapy, including supplemental oxygen, noninvasive ventilation, mechanical ventilation, glucocorticoids, and empiric antibiotics, until infectious causes are eliminated, and in the most severe cases, extracorporeal membrane oxygenation (ECMO). Currently, although there is an insufficient evidence to determine the safety and the efficacy of e-cigarettes for perioperative smoking cessation, EVALI clearly places these patients at an increased risk of perioperative morbidity. Given the relatively recent introduction of e-cigarettes, the long-term impact on adolescent health is unknown. As a result, the paucity of postoperative outcomes in this potentially vulnerable population does not support evidence-based recommendations for the management of these patients. Clinicians should identify "at-risk" individuals during preanesthetic evaluations and adjust the risk stratification accordingly. Our societies encourage continued education of the public and health care providers of the risks associated with vaping and nicotine use and encourage regular preoperative screening and postoperative outcome studies of patients with regard to smoking and vaping use.