title: Spray cryotherapy (SCT): institutional evolution of techniques and clinical practice from early experience in the treatment of malignant airway disease.
abstract: BACKGROUND
  Spray cryotherapy (SCT) was initially developed for gastroenterology (GI) endoscopic use in the esophagus. In some institutions where a device has been utilized by GI, transition to use in the airways by pulmonologists and thoracic surgeons occurred. Significant differences exist, however, in the techniques for safely using SCT in the airways.
  
  
  METHODS
  We describe the early experience at Walter Reed National Military Medical Center from 2011 to 2013 using SCT in patients with malignant airway disease and the evolution of our current techniques and clinical practice patterns for SCT use in patients. In November 2013 enrollment began in a multi-institutional prospective SCT registry in which we are still enrolling and will be reported on separately.
  
  
  RESULTS
  Twenty-seven patients that underwent 80 procedures (2.96 procedures/patient). The average age was 63 years with a range of 20 to 87 years old. The average Eastern Cooperative Oncology Group (ECOG) status was 1.26. All malignancies were advanced stage disease. All procedures were performed in the central airways. Other modalities were used in combination with SCT in 31 (39%) of procedures. Additionally 45 of the 80 (56%) procedures were performed in proximity to a silicone, hybrid, or metal stent. Three complications occurred out of the 80 procedures. All three were transient hypoxia that limited continued SCT treatments. These patients were all discharged from the bronchoscopy recovery room to their pre-surgical state.
  
  
  CONCLUSIONS
  SCT can be safely used for treatment of malignant airway tumor (MAT) in the airways. Understanding passive venting of the nitrogen gas produced as the liquid nitrogen changes to gas is important for safe use of the device. Complications can be minimized by adopting strict protocols to maximize passive venting and to allow for adequate oxygenation in between sprays.
authors.affiliation: 1 Division of Interventional Pulmonology, Walter Reed National Military Medical Center, Bethesda, MD, USA ; 2 Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Browning
authors.affiliation: 1 Division of Interventional Pulmonology, Walter Reed National Military Medical Center, Bethesda, MD, USA ; 2 Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.
authors.forename: J Francis
authors.initials: JF
authors.lastname: Turner
authors.affiliation: 1 Division of Interventional Pulmonology, Walter Reed National Military Medical Center, Bethesda, MD, USA ; 2 Department of Medicine, Division of Pulmonary & Critical Care Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Parrish
keywords: Cryotherapy; bronchoscopy; malignant airway tumor (MAT); spray cryotherapy (SCT)