Departments: Interventional Pulmonology in Other Journals
A New Method for Detection of Postpneumonectomy Broncho-Pleural Fistulas
Ann Thorac Surg. 2003;75: 1662–1664. Alifano M, Sepulveda S, Mulot A, Schussler O, Regnard JF. Unite de Chirurgie Thoracique, Hotel-Dieu, Paris.
The authors describe a new technique to identify bronchopleural fistula (BPF) that occurred as a complication of pneumonectomy. The technique measured the concentrations of O2 and N2O in the pneumonectomy cavity at baseline and after allowing patients to breathe gas mixtures enriched with O2, N2O, or both. Because sampling of gas from the postpneumonectomy cavity is required for this technique to work, the test is preferably performed in patients with a chest drainage tube. In the absence of a chest tube, the authors inserted a small 12-Ch pleuro-catheter in the second intercostal space 1 cm lateral to the midclavicular line. The chest tube or the pleuro-catheter was connected with a chest drainage unit through a Y-shaped connector. The free end of the Y-tube was connected to an anesthetic gas analyzer. Concentrations of O2 and N2O were monitored while the patient breathed room air (O2 concentration was <21%, and N2O was not detected). Then the patient was instructed to breathe through a high-concentration O2 mask (fraction of inspired O2 = 90%). In the absence of BPF, no increase in O2 concentration was registered during the next 2 minutes. If a BPF was present, O2 concentration quickly rose; levels of approximately 40% were reached within 30 seconds. The rapidity of changes in O2 concentration was related to the size of the fistula. The results of the O2 test were subsequently confirmed by an N2O test. The patient breathed a mixture of N2O (50%) and O2 (50%). If no BPF was present, N2O was absent. In the presence of a BPF, N2O concentration quickly increased, reaching levels of 30% to 40% after approximately 30 seconds. The rapidity of changes in N2O concentrations was related to the size of the fistula. The entire test required less than 5 minutes. In ventilated patients, the O2 test was performed while the patient was breathing less than 60% oxygen. The O2 concentration was subsequently increased to 100%, and increases in O2 levels in the postpneumonectomy space were recorded. The N2O test was performed similarly by the addition of N2O to the gas mixture of the mechanical ventilation system. This technique was used in 22 patients as well as in 20 control patients 48 hours after pneumonectomy, immediately before chest tube removal. Both the O2 and the N2O tests were negative in all except 2 patients with BPF. In these 2 patients, both the O2 and the N2O tests were positive. In one of them, bronchoscopy showed a BPF on the 12th postoperative day. In the other patient, both the O2 and the N2O tests were positive on the third postoperative day and bronchoscopy showed no BPF. Both the bronchoscopy and the breath test were repeated on the fourth postoperative day, and both were positive; bronchoscopy showed a small fistula involving one third of the bronchial stump suture. Although relatively uncommon (2–6% incidence), BPF can be a life-threatening complication of pneumonectomy and can lead to prolonged morbidity. Early detection and appropriate therapy is important to prevent mortality and morbidity. Flexible bronchoscopy is helpful and diagnostic of BPF when a notable defect can be observed in the area of pneumonectomy stump. However, flexible bronchoscopy can be nondiagnostic when the fistula is small. We have used small metallic wire probed (<1.0 mm) through the working channel of the flexible bronchoscope to detect tiny BPF. Other techniques used have included instillation of diluted methylene blue through the stump area and observation of chest tube drainage for bluish-green discoloration of the drained fluid (Journal of Bronchology. 2000;7:54–57). Others have used ventilation scans to identify postpneumonectomy BPF. The technique described by Alifano and coworkers appears easy to perform and rapid in providing results. Ability to complete the test at the bedside is a major advantage. The 2 patients described in the present report makes it difficult declare it a dependable technique. As the authors indicate, studies on larger series of patients to confirm the usefulness of this technique are necessary.