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Communications to the Editor |

Underwater Photography in the Human Airway: Use of Saline Solution to Visualize Peripheral Tumors and Evaluate Airway Rigidity FREE TO VIEW

Andrew M. Jones, MD; Ronan O’Driscoll, MD
Author and Funding Information

Hope Hospital, Salford, UK

Correspondence to: Ronan O’Driscoll, MD, Consultant Chest Physician, Department of Cardio-Respiratory Medicine, H3 Teaching Block, Hope Hospital, Stott Lane, Salford M6 8HD, United Kingdom; e-mail: Rodriscoll@hope.srht.nwest.nhs.uk



Chest. 2002;122(1):384-385. doi:10.1378/chest.122.1.384
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Published online

To the Editor:

Bronchoscopy is the most commonly used modality for establishing the diagnosis of lung cancer. The small size of peripheral human airways limits the scope of the flexible bronchoscope. When using flexible bronchoscopy, we use a technique of attempted saline distension to assess narrow segmental and subsegmental bronchi. The technique is used if a medium-sized airway appears abnormal or if a chest radiograph suggests a peripheral lesion in a particular segment, but no lesion is seen during the initial bronchoscopic inspection.

The technique of saline distension involves rapidly instilling 10 to 20 mL of 0.9% saline solution via the suction channel of a flexible bronchoscope that is wedged in a segmental or subsegmental bronchus. This saline distension often allows a more distal view of the bronchus and may indicate the nature of any narrowing, if present.

Saline distension is a technique that can reveal hidden peripheral tumors, and it can provide the operator with an immediate indication, at the time of flexible bronchoscopy, as to whether an area of narrowing in a segmental or subsegmental bronchus may be true or apparent. This, in turn, may help guide the physician in arranging the priority and urgency of future investigations. It may also help the bronchoscopist in deciding the type and amount of specimens to be taken from that area.

In a recent audit of a total of 319 flexible bronchoscopy procedures, carried out in our unit to investigate possible lung cancers during a 12-month period, the technique of saline distension was used in 47 cases. It was not associated with any significant complications. The technique of saline distension revealed hidden tumors in approximately 1% of all patients undergoing flexible bronchoscopy procedures, although the yield was much higher if used in a selected group of patients where a plain chest radiograph suggested a possible tumor in a medium-sized airway. The operator had made use of the technique in nine cases in which, on initial inspection, no lesion had been seen, despite a plain chest radiograph suggesting a likely tumor in a segmental or subsegmental bronchus. This technique revealed the presence of hidden tumors (not visible at routine bronchoscopy because of peripheral location; Fig 1) in three of these patients (one submucosal and two endobronchial tumors). All had positive brush cytology findings.

If the bronchoscope is wedged in a small bronchus, the saline solution will remain static, giving a clear view for a minute or more. This can allow “underwater” photographs and brush and biopsy samples to be taken. The technique can also provide a clear view in bronchi that are partially occluded by blood or mucus that cannot be aspirated due to the small size of the airways.

During inspection with a flexible bronchoscope, the operator may discover apparent narrowing of a segmental bronchus. Use of the technique of saline solution distension in this circumstance can help the bronchoscopist in the assessment of the underlying nature of the narrowing, although sensitivity will be low. If the bronchus distends easily when saline solution is instilled, this indicates that fixed narrowing due to peribronchial tumor is less likely. There were 21 cases in our study in which a narrowed bronchus had easily distended with saline solution, revealing a macroscopically normal distal airway. All subjects had negative cytology findings, although 3 of 13 subjects did have CT-scan findings suggestive of peribronchial tumor. If the narrowed bronchus is nondistendable, the chances of an underlying tumor in the airway are much greater. In our study, 15 of 17 patients (88.2%) with a fixed narrow bronchus had evidence of a peribronchial tumor by cytology and/or histology results, or CT-scan findings. Only one patient had an apparently fixed narrow bronchus at flexible bronchoscopy but no evidence of tumor on a CT scan or from cytology/histology.

There is a strong correlation between an abnormal result during saline distension (ie, failure of bronchus to distend or distension revealing an endobronchial tumor) and the chances of either positive cytology/histology or abnormal CT-scan findings. The information is immediately available to the physician. The physician must remain aware that the technique should be used to give an indication, but it is not diagnostic of malignancy; other causes of airway rigidity, such as posttuberculous scarring, are possible in addition to malignant stenoses. This technique is both quick and easy to perform. It does not require any additional equipment by the bronchoscopy unit. In our own experience, it is not associated with any significant complications. We conclude that the technique of saline distension is a useful tool in the bronchoscopist’s armory.

Figure Jump LinkFigure 1. Photographs taken from the same subsegmental bronchus before (top, A) and during (bottom, B) saline distension. Use of the technique revealed a previously invisible endobronchial tumor. Brush cytology taken from the tumor showed large-cell undifferentiated cancer.Grahic Jump Location

Figures

Figure Jump LinkFigure 1. Photographs taken from the same subsegmental bronchus before (top, A) and during (bottom, B) saline distension. Use of the technique revealed a previously invisible endobronchial tumor. Brush cytology taken from the tumor showed large-cell undifferentiated cancer.Grahic Jump Location

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