Using bronchoscopy to examine the airways and the surrounding tissues of people with cystic fibrosis, coupled with the collecting of lung fluid through bronchoalveolar lavage (BAL), is safe and a reasonable alternative when sputum samples are not possible, a study reports.
Adult patients participating in research reported mild side effects to bronchoscopy with BAL, its scientists wrote, with the most frequent adverse events similar to healthy adults given the same procedure.
The study, “Safety of research bronchoscopy with BAL in stable adult patients with cystic fibrosis,” was published in the journal PLOS One.
In bronchoscopy, a thin tube (bronchoscope) through is inserted though the nose or mouth, then down the throat and into the lungs. It is used in CF research to identify immune cells and microorganisms in alveoli (air sacs of the lungs) to study airway inflammation.
BAL consists of injecting a sterile saline solution through the bronchoscope into alveoli, and then collecting the fluid — along with cells — for analysis. It has been shown to be useful in helping predict pulmonary exacerbations in children with CF, and in microbiologic sampling of patients whose sputum is scarce due to the use of newer CF modulator therapies.
“Chronic lung inflammation remains a problem in CF … To identify novel therapeutic targets to combat CF lung inflammation, the use of primary immune cells is critical. Therefore, research bronchoscopy with BAL is a highly useful tool to facilitate the development of improved therapies to target inflammation,” the researchers wrote.
Bronchoscopy with BAL, while considered safe overall and minimally invasive, is not routinely performed by doctors in clinical practice.
“To justify an elective invasive procedure for research with no direct clinical benefit the risks need to be minimal,” the researchers wrote.
Their study noted, however, that throat swaps that might be used when a sputum sample cannot be collected lack sensitivity in detecting Pseudomonas aeruginosa, a known bacterial source of chronic lung infections in CF, and other potentially harmful bacteria.
This procedure is also more frequently given when examining pediatric CF patients who cannot produce sputum than adults, so that safety data on older patients are lacking.
Researchers at Dartmouth-Hitchcock Medical Center in New Hampshire investigated the safety of adult bronchoscopy in a study of two groups: 32 CF patients (mean age, 28 ) with mild or moderate obstructive lung disease, and 82 healthy nonsmokers (mean age, 29) serving as controls.
All underwent a research bronchoscopy with BAL, with scientists isolating lung macrophages (a type of immune cell) from both groups and bacteria from patients.
No major safety differences, in terms of adverse events, were reported between patients and controls.
Sore throat and cough were the most common side effect among the CF patients (22% and 25%, respectively), and occurred at a rate similar to healthy controls (26% and 23%, respectively).
But fever, reported in 16% of CF patients, was significantly higher compared with controls (4.8%). Headaches, reported in 13% patients and 3.7% of healthy adults (3.7%), were also significantly higher.
Headaches resolved within 48 hours with patients given over-the-counter medications and oral hydration, and no patient with a fever required an antibiotic or higher CF treatment dose, the study noted. Most patients with a fever (80%) and headaches (75%) also had poorer lung function, with predicted FEV1 values lower than 65%.
Forced expiratory volume or FEV1 measures the amount of air a person can forcibly exhale in one second, and is a standard measure of lung health. Values greater than 80% of the predicted average value are considered normal.
“We found a similar rate of side effects between CF and non-CF subjects, with more side effects occurring in CF subjects with worse lung function,” the researchers wrote.
Low FEV1 values have been linked to increased inflammation, suggesting that patients who experienced fever may have more lung inflammation.
“We hypothesize that the mobilization of bacteria and inflammatory cells may cause the release of cytokines [small proteins released by immune cells] and LPS [lipopolysaccharide, the most abundant component of the cell wall of certain bacteria], resulting in fevers,” the researchers wrote.
In follow-up phone calls, the majority of CF patients reported no overall negative health effects following a research bronchoscopy. In fact, more 50% of them choose to participate in the protocol multiple times.
These “data demonstrate that research bronchoscopy with BAL is safe in CF subjects and that safety profile is improved if bronchoscopies are limited to subjects with an FEV1 [higher than] 65% predicted,” the team concluded.
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