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Caution to use bronchoscopic CO2 cryotherapy for foreign body removal in children

We share the opinion that the article published by Zhang et al. calls for a strong note of caution. We would like to warn against introducing the potentially unsafe and dangerous technique of bronchoscopic cryoextraction of foreign bodies into clinical practice in children. Children are the most vulnerable subjects for serious complications of foreign body aspiration due to their small airway size and limited cardiorespiratory reserve. There is basically uniform agreement among pediatric airway experts, including the American Thoracic Society and the European Respiratory Society, that the safest technique for foreign body removal in children is using the rigid bronchoscope. In trained hands, foreign body removal using the flexible bronchoscope with forceps, baskets or loops is feasible in children, but for safety reasons conversion to rigid bronchoscopy should be immediately available. The study population described by Zhang et al. is very small (N1⁄4 12) and the authors report successful removal without complications in only 8 of 12 children (66%). Bleeding requiring local administration of adrenaline or hemocoagulase occurred in 3 of 12 (25%) children, and even more importantly, cryotherapy resulted in partial airway obstruction by causing granulation tissue in 2 of 12 (17%) children. The authors’ conclusion that this technique is safe, easy, and effective is based on data demonstrating a 33% failure rate in a potentially life-threatening situation! A recent retrospective study on bronchoscopic cryoextraction described a limited success rate for foreign body extraction in adults too. Other authors have cautioned that objects should be tested for cryoadherence before the technique is used in patients because cryoadhesive properties of most inorganic and several organic objects are unpredictable. Cryotherapy can induce bronchospasm and coagulation necrosis of tissue in the bronchial tree. The relatively small airways of children are potentially more vulnerable to the local application of extreme cold ( 908C) than those of adults. The cold conductance variability of foreign bodies and the inconsistent duration of the freezing cycle add an unpredictable dimension for potential tissue injury to this technique. In addition, the study also raises significant ethical concerns because the children were exposed to unnecessary radiation by multislice spiral CT scanning preand post-operatively for a problem that often does not even require any imaging, if history and clinical signs demand an endoscopy. While we do not dispute the accuracy of CT imaging in detecting foreign bodies in the airway, the amount of radiation involved is prohibitive and other imaging techniques yield similar results. It is unclear whether parents consented specifically to the additional radiation exposure of their children. We are all open-minded and usually very fascinated by new technologies, but the motivation to exchange a safe and validated technique against a new technique should be based on a comprehensible benefit to the patient. This may include a decrease in complications or procedural risks, an improvement of success rate, a reduction in procedure or recovery time, or at least a reduction in costs. The main reasons why rigid bronchoscopy has remained the gold standard for foreign body extraction in small children are the excellent control of the compromised airway, the much brighter and magnified view by the telescope, and the possibility to use comparatively large instruments. Unsurprisingly, it has a much higher success rate than flexible bronchoscopy, even in skilled hands. Nevertheless, foreign body extraction is feasible by use of the flexible bronchoscope with instruments that are specifically designed to extract foreign bodies such as forceps, baskets, and slings. For safety reasons, the rigid bronchoscope should always be immediately available to intervene in the case of a life-threatening obstruction during flexible foreign body removal. The complication and failure rates of foreign body extraction by rigid bronchoscopy are very low and nearly negligible in experienced centers. It is a rare exception that foreign bodies cannot be grasped with current instruments. Crushing or peripheral dislocation of foreign bodies is