Bronchoscopy and bronchoalveolar lavage have been key tools in the clinical and diagnostic workup of patients with lung injuries related to vaping.

The Centers for Disease Control and Prevention recently reported that, based on data collected through mid-October, 86 percent of 867 patients reporting trouble breathing and other symptoms said they used tetrahydrocannabinol (THC)-containing products in the three months before their symptoms emerged. Officials are calling the disease EVALI, short for e-cigarette, or vaping, product use associated lung injury.

The CDC, the Food and Drug Administration, and state and local health departments have been investigating a national outbreak of EVALI cases since August 2019, when the outbreak started. Public health officials reported 2,172 lung injury cases linked to e-cigarette or vape products in mid-November, up 121 cases from the week prior. The illness has killed 42 people in 24 states and Washington, D.C.

Public health officials are zeroing in on THC-containing products and have identified possibly harmful additives therein, particularly Vitamin E acetate, used in the production of vaping products.

The harmful effects on lung function were isolated via bronchoscopy and bronchoalveolar lavage, or BAL, with fluid specimens collected by clinical teams caring for hospitalized EVALI patients. Public health laboratories and health departments from 10 states (California, Connecticut, Hawaii, Illinois, Maryland, Michigan, Minnesota, Texas, Utah, and Wisconsin) coordinated the submission of residual BAL fluid specimens from 29 patients to CDC. All 29 samples had extremely high levels of Vitamin E acetate.

The first finding of a “toxin of concern”—which is generally considered harmless in foods, supplements and lotions—doesn’t mean the culprit behind this crisis has been discovered. The CDC is continuing to evaluate a wide range of chemicals and possible causes.

Researchers have compared the lung injuries seen with EVALI to chemical burns suffered by soldiers attacked with mustard gas in World War I.

The CDC issued guidance for health care providers and recommended, on a case-by-case basis, using bronchoscopy and bronchoalveolar lavage to rule out alternative diagnoses such as pulmonary infection. The value of staining BAL cells or fresh lung biopsy tissue for lipid-laden macrophages (e.g., using oil red O or Sudan Black) in the evaluation of EVALI remains unknown, according to CDC.

Physicians complete nearly 500,000 bronchoscopies each year in the United States, with the number and complexity of procedures on the rise. That complexity has led to challenges in reprocessing bronchoscopes—while rare, cases of cross-contamination during bronchoscopy do happen. Single-use bronchoscopes greatly reduce any risk of cross-contamination.