Cryocanalization: a new approach for the immediate management of acute airway obstruction

Abstract

J Thorac Cardiovasc Surg 2004;127:1427–1431. Hetzel M, Hetzel J, Schumann C, Marx N, Babiak A. Study Summary: In this study, the authors examine the effectiveness of a newly developed cryoprobe in patients with airway stenosis as a result of exophytic tumors. The new probe has greater freezing power than the currently available probe. It is 78-cm long and has a 2.3-mm diameter and is designed for use with any therapeutic bronchoscope. The authors used this probe to treat airway stenosis in 60 patients. Of these, 23 had complete bronchial obstruction, 37 had high-grade stenosis, and 17 had segmental or lobar atelectasis. Underlying cause of stenosis was malignancy in all but 3 cases of granulation tissue over the tracheal stents. The procedure was performed under conscious sedation. The bronchoscope was introduced through an 8.5-mm endotracheal tube. The probe tip was placed 1 to 2 cm inside the tumor and was cooled for 5 to 20 seconds. The frozen tumor was extracted by pulling strongly on the probe. The bronchoscope and the cryoprobe with tumor attached to its tip were retrieved together. Immediate complete recanalization was achieved in 37 (61%) patients. Partial response was observed in 13 (22%) patients. In 10 (17%) patients, the procedure was unsuccessful. The procedure lasted for 41 ± 16 minutes. On average, 13 applications of cryoprobe were needed in each session. Minor bleeding was encountered in most cases. Six patients had moderate bleeding (100–300 mL) that was controlled with argon plasma coagulation. Fourteen patients developed restenosis during follow up. The authors call their technique cryocanalization and found it to be safe and effective for immediate relief of critical airway stenosis. Comments: Cryotherapy is an important treatment option for patients with endobronchial tumors. It is a safe technique without any risk of airway perforation, electrical accidents, or endobronchial fires (Chest 2001;120:3–5). There are no radiation issues. The instrument is relatively inexpensive and the technique is easy to learn. The main limitations are delayed results and need for ″clean up″ bronchoscopy 1- to 2-week after the procedure to remove the necrotic tissue and debris (Chest 1996;110:718). In many patients, multiple sessions of cryotherapy are needed before desired results are achieved (Journal of Bronchology 1995;2:145–153). As a result of delayed results, acute life-threatening airway stenosis that requires immediate measures to restore airway patency is considered a contraindication for cryotherapy (Chest 2003;123:1693–1717). In these situations, laser photoresection and bronchoscopic electrosurgery with or without airway stents are preferred (Clin Chest Med 2002;23:241–256). The use of a new probe in this study allowed a rapid relief of airway stenosis in majority of patients. The impressive results were mostly the result of a more effective cryoprobe. The other important factor was the different cryotherapy technique that authors used. Usually, the tumor is initially frozen to induce necrotic changes and coagulation and the cryoprobe tip is retrieved after the tumor thaws. The necrotic and devitalized tissue is then removed using biopsy forceps (Chest 1996;110:718). In comparison, the authors firmly pulled the cryoprobe while it was still attached to the frozen tumor. This allowed a larger amount of tumor to be avulsed from the airways. Because most of the tumor was removed during the cryocanalization procedure; there was no need for follow-up bronchoscopy. Some limitations of the study should be noted. Although patients had high-grade stenosis, no patient was critically hypoxic, on ventilatory support, or at immediate risk of asphyxiation. The results, therefore, cannot be applied to patients in extreme distress. This is especially important because the procedure was unsuccessful in 17% of patients. Also, although no major adverse outcome was noted, significant bleeding was noted in 10% of patients. This is higher than that previously reported with cryotherapy (Chest 1986;90:159–164). Lastly, like with any new technique, more studies are needed to independently confirm these findings. The preliminary findings are clearly encouraging and, if confirmed, this technique represents a significant advance in bronchoscopic cryotherapy.