Convex probe endobronchial ultrasound (CP-EBUS) has probably been one of the most significant advances in the field of bronchology in the last decade. The curvilinear electronic transducer attached to the tip of the flexible bronchoscope allows real-time endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA).1 EBUS-TBNA has access to all the mediastinal lymph nodes accessible by mediastinoscopy and also the hilar and lobar lymph nodes. EBUS-TBNA was first developed for lymph node staging of lung cancer,2 but is now being applied for the diagnosis of mediastinal and hilar adenopathy such as sarcoidosis.3–5 The high diagnostic accuracy of EBUS-TBNA for diagnosis and lymph node staging of lung cancer has been well documented by recent systematic reviews and meta-analyses,6–9 and it is becoming a popular procedure performed mainly in specialized centers.
With the increasing number of EBUS-TBNA being performed, one may raise the question of the safety of the procedure. Potential complications related to EBUS-TBNA are similar to those of conventional TBNA, including bleeding from major vessels, pneumomediastinum, mediastinitis, pneumothorax, bronchospasm, and laryngospasm. The systematic reviews report only 1 incidence of morbidity in a patient with pneumothorax after the procedure (0.07% morbidity)7 with only minor issues of agitation, cough, and presence of blood at the puncture site being reported.8 There are case reports of infection after EBUS-TBNA, which may suggest prophylactic use of antibiotics in selected cases.10–12 From my experience in over 2000 cases, I have not yet encountered complications related to EBUS-TBNA. The only complication or problem related to EBUS-TBNA has been the damage to CP-EBUS. EBUS-TBNA is indeed a very safe modality with a high yield.
In the July 2010 issue of the Journal of Bronchology & Interventional Pulmonology, Hergott et al13 reported on the ongoing maintenance and repair costs associated with EBUS-TBNA in an Interventional Pulmonology Program in Canada. During a 4-year period, the number of procedures and the maintenance and repair costs for both EBUS-TBNA and regular flexible bronchoscopes were recorded and analyzed. A total of 949 EBUS-TBNA procedures and 2767 flexible bronchoscopies were performed. They reported 13 separate repair issues encountered with CP-EBUS or the ultrasound processor. On the basis of the calculation, the average repair cost per procedure for EBUS-TBNA and flexible bronchoscopy was $102.80 and $21.42, respectively. As they show in this study, the cost of EBUS repair per procedure was significant even in the hands of experienced interventional pulmonologists, which warrants the importance of understanding the nature of the delicate pieces of medical equipment included in CP-EBUS. The majority of the damage to the bronchoscope was related to moisture invasion in the insertion tube. This may result from a puncture by the needle in the biopsy channel, scope handling, and reprocessing. Although channel leaks and damaged insertion tubes are usual problems also seen in regular flexible bronchoscopes, the complexity of the EBUS-TBNA scope seems to have made the cost for repair extremely high. It is interesting to note that the increased experience and familiarity of the operators with the equipment had no effect in the reduction of the damage or the repair cost. General wear and tear may have had a major role in their experience. Nevertheless, it is important to understand the ongoing maintenance issues with CP-EBUS.
It will be extremely difficult to prevent wear and tear of the bronchoscope, but damage to the bronchoscope based on human error should be and can be avoided. Every bronchoscopist and the team assisting the procedure should fully understand the instrument, including the dedicated needle, before performing EBUS-TBNA. During the procedure, the endoscopic image should be clear at all times. Owing to the nature of the working channel and the suction port, it may be a challenge to suck out all of the secretions within the airway. One should start with the regular bronchoscope before insertion of CP-EBUS and try to clear the airway as much as possible. Fogging of the camera can be cleared by gently rubbing the camera against the main bronchus or the membranous portion. Before proceeding with CP-EBUS, the assistant and the operator should confirm that the needle is retracted inside the sheath and that the safety lock is secured. The authors use 2 monitors during EBUS-TBNA: 1 for the endoscopic image and 1 for the ultrasound image. After visualization of the lymph node or the lesion of interest, the endoscopic landmarks should be identified so that one has an idea of where to place the needle. During ultrasound visualization, the tip of the CP-EBUS is usually flexed. When the dedicated needle is introduced into the working channel, the bronchoscope should be repositioned back into the neutral position. This means that one should not try to maintain the ultrasound image of the lesion of interest when advancing the sheath. The sheath should also be advanced outside the working channel in a neutral position. After confirming that the sheath is outside the working channel on the endoscopic image, one may proceed with EBUS-TBNA. After the aspiration, the needle should be retracted back into the sheath. The tip of the bronchoscope should be repositioned back into the neutral position again, before the whole needle is taken out from the bronchoscope. By following these simple rules, one can avoid damaging the bronchoscope.14
The cost of repair for CP-EBUS may be underestimated in the publication by Hergott et al, because this is their experience in a relatively high-volume center performing EBUS-TBNA. Centers with less experience may encounter more issues related to damage to the bronchoscope. Major complications of EBUS-TBNA are rare and damage to the CP-EBUS, which may be a serious complication for bronchoscopists, can be avoided by understanding the delicate structure of the CP-EBUS and following the rules during EBUS-TBNA.
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