BNA Bronchial needle aspiration
Bronchial needle aspirations (BNA) through rigid bronchoscopes were first reported in the literature in 1949. However, the procedure was not widely used until the advent of flexible bronchoscopy. Since 1978, flexible bronchoscopy with BNA has become a standard tool of the bronchoscopist. The technique is documented to be safe and effective, 1,2 as well as cost effective. 3,4
The method for this procedure is uncomplicated. A specially designed needle is passed though the bronchoscope. Under direct visualization the needle is introduced through the bronchial wall into the tissues beneath the bronchial wall. The needle is agitated to separate some of this tissue, and biopsy material is aspirated into a syringe under continuous suction.
Despite being a safe and effective procedure, BNA is not commonly used and is not adequately stressed during fellowship training. A recent review by Dasgupta and Mehta 5 reported that for a variety of reasons current fellowship programs do not provide enough training in BNA. Furthermore, Haponik and Shure 6 concluded that major modifications of fellow experiences are necessary if BNA is to impact optimally on patient management. They showed that many fellows rarely perform BNA and many of them believe BNA is not useful.
Haponik et al. showed that bronchial needle aspiration performance improves with education and experience. 7 Over a three year period, 6 bronchoscopists performed 185 BNA procedures. This was 13.7% of bronchoscopies done by them. Their diagnostic yield improved from 21.4 to 47.6% over the study period. Their review was complicated by the fact that there were changes in technique, equipment, and cytological processing throughout the study period. Perhaps fellows' lack of interest in BNA is due in part to a perception that it requires more practice and experience than fellowship can afford.
De Castro et al. 8 took another step in quantifying the effect of training in BNA. They compared the diagnostic yield of BNA by a bronchoscopist experienced in the procedure with the yield by a bronchoscopist before, during, and after training in BNA. They reported increased accuracy with increasing experience, and determined that at least 50 BNA procedures would be necessary for one to become proficient with the technique. 8 Those authors report the use of BNA in less than 10% of bronchoscopic procedures; therefore, one should not be proficient in BNA until after performing more than 500 bronchoscopies. Pulmonary fellows perform a mean of 77.7 bronchoscopies per year 9 —insufficient opportunity to provide that level of education and experience in BNA. This may explain, or even legitimate, the lack of interest that fellows have for this procedure. This study was conducted to measure the diagnostic yield and adequacy of biopsy procedures by a group of pulmonary fellows at a single institution during standard pulmonary fellowship training.
We retrospectively reviewed all bronchoscopies performed at our institution by the four most recently graduated pulmonary fellows. All fellows were naive to the procedure at the start of fellowship and were supervised in performing between ten and 17 BNA procedures during a two year pulmonary medicine fellowship. They were supervised by attending physicians who had board certification in pulmonary medicine but no extraordinary expertise in BNA. The procedure was done in the classic approach as described by Wang 10 with 19 gauge needles. Chest x-ray and computed tomography (CT) were available during BNA attempts. Standard fluoroscopy, but not CT fluoroscopy, is available at the institution, but is not used during bronchial needle aspirations. This study is limited, because it is a retrospective review of a database of procedures done by fellows and corresponding pathology reports. This database did not record the station of the nodes biopsied. There is no record of the number of passes at each BNA attempt.
The results of all BNA procedures were reviewed. Data were collected on specimens that were diagnostic of specific disease as well as specimens that were not diagnostic but contained lymphoid tissue indicating that they were adequate specimens. 10 These data were tabulated and graphs were produced comparing the cumulative diagnostic yield and adequacy of specimens to the number of procedures performed. This graph was used to display an effect of experience and training.
No fellow was successful at making a diagnosis or even collecting an adequate specimen on his first attempt. However, within the first ten attempts, each fellow had adequately sampled lymph nodes at least 40% of the time. During a three year period, the four fellows performed 61 BNA procedures (Table 1). Twenty-eight procedures (46%) were satisfactory and 13 (21%) yielded a specific diagnosis (Tables 1–4).
Dasgupta and Mehta reviewed the published data on the diagnostic yield of BNA. They found reports ranging from 0 to 100%. BNA can stage 80% or more of patients with a known diagnosis of bronchogenic carcinoma. 5 There is, however, insufficient literature on the diagnostic yield in patients without a previously known malignancy. This study measured the diagnostic yield in all patients presenting for BNA, not just those with a known carcinoma. BNA is an important tool for diagnosing mediastinal adenopathy as well as staging malignant disease. The overall yield of 21% is less than the published yield when BNA is used as a cancer staging procedure, but reasonable for an initial diagnostic test of mediastinal adenopathy.
This study attempts to assess the effect of experience and training in the BNA procedure during pulmonary fellowship. Positive and negative predictive values are not very helpful in this setting. In this study, as in others, the positive predictive value of BNA is 100%, because a diagnostic pathologic specimen is accepted to be a true positive. The negative predictive value of BNA is low in this study, (12.5%) because all patients without a diagnostic BNA and no definitive surgical exploration are defined as false negatives. The adequacy of the cytological specimens, is a gauge of the bronchopists' technical competence. Unlike diagnostic yield, the adequacy of specimens is not dependent on the disease state of the patient. Fig. 1 illustrates that despite universal failures on initial attempts, performance improved quickly with just a little experience. Within 10 trials each fellow had adequate specimens on at least 40% of his trials. Overall 28 (46%) specimens were adequate, showing that it is possible for pulmonary fellows to reach this level of proficiency without any extraordinary training.
This retrospective review is limited. It measured only the adequacy and diagnostic yield of the procedure as a function of the number of procedures attempted. Unfortunately, there is no record of some important details such as the number of passes at each attempt. Furthermore, these fellows had no specific syllabus in BNA, but trainees observed others performing the procedure and had opportunity to attend lectures, meetings, and review courses where bronchoscopic procedures were discussed. This study does not measure these events.
In conclusion, BNA is an indispensable part of the pulmonologists' armamentarium. It allows one to diagnose benign and malignant disease without resorting to surgical biopsy. Not all pulmonary fellows appreciate the importance of this procedure to their education, and not all training programs stress this essential part of graduate medical education in pulmonology. Part of this may be due to suggestions in the literature that extraordinary training is necessary to be competent. As with most skills in medicine, true expertise requires many years of experience, but it is possible to gain some proficiency during a standard pulmonary fellowship.
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2. Mehta AC, Dasgupta A, Wang K. Transbronchial needle aspiration. In: Beamis JF, Mathur PN, ed. Interventional pulmonary. New York: McGraw-Hill, 1999:241–254.
3. Crocket JA, Wong EY, Lien DC, et al. Cost effectiveness of transbronchial needle aspiration. Can Respir J 1999; 6 (4):332–5.
4. Jain P, Arroliga A, Mehta AC. Cost-effectiveness of transbronchial needle aspiration in the staging of lung cancer. Chest
5. Dasgupta AD, Mehta AC. Transbronchial needle aspiration: an underused diagnostic technique. Clin Chest Med 1999; 201:39–51.
6. Haponik EF, Shure D. Underutilization of transbronchial needle aspiration: experiences of current pulmonary fellows. Chest 1997; 112 (1):251–3.
7. Haponik E, Cappellari JO, Chin R, et al. Education
and experience improve transbronchial needle aspiration performance. Am J Respir Crit Care Med 1995; 151:1998–2002.
8. de Castro RF, Lopez FD, Serda GJ, et al. Relevance of training
in transbronchial fine-needle aspiration technique. Chest 1997; 111: 103–5.
9. Baker JJ, Solanki PH, Schenk DA, et al. Transbronchial fine needle aspiration of the mediastinum importance of lymphocytes as an indicator of specimen adequacy. Acta Cytol 1990; 34:517–23.
10. Wang KP: Transbronchial needle aspiration. J Bronchol
Dasgupta AD, Mehta AC. Transbronchial needle aspiration an underused diagnostic technique. Clin Chest Med 1999; 20 (1):39–51.
Keywords:© 2002 Lippincott Williams & Wilkins, Inc.
Bronchial needle aspiration; Bronchoscopy; Training; Education; Fellowship