title: Effects of thrombolytic agents on tympanostomy tubes occluded by blood clots.
abstract: OBJECTIVE
  To investigate the efficacy of various topical applications in opening a clotted tympanostomy tube (TT) using an in vitro model.
  
  
  METHODS
  In vitro clinical trial.
  
  
  METHODS
  Fresh human blood was allowed to clot in the lumen of TTs. Seven agents were tested: 0.9% saline (control), 1-mg/mL alteplase, 100-U/mL unfractionated heparin, 3% hydrogen peroxide (H(2)O(2)), 3% acetic acid, 5% acetic acid, and a mixture of 3% H(2)O(2) and 3% acetic acid. Each agent was added twice a day for 14 days to TTs that were incubated and humidified to simulate ear canal conditions. The tubes were analyzed with binocular microscopy to determine the status of the obstruction.
  
  
  RESULTS
  A total of 16 trials per agent, including a saline control, were performed. The saline control, alteplase, and heparin failed to open any TTs in any of the trials. Compared with the control, H(2)O(2) also was not effective (P = .23). Acetic acid was increasingly effective, with a 3% concentration completely clearing 5 of 16 tubes and a 5% concentration completely clearing 11 of 16 tubes (P = .006). The addition of 3% H(2)O(2) to 3% acetic acid did not significantly increase clearance (P = .21).
  
  
  CONCLUSIONS
  Thrombolytic agents and H(2)O(2) were not effective in resolving TTs that were clotted with blood in an in vitro environment simulating the ear canal. Increasing concentrations of acetic acid are increasingly effective in this capacity.
authors.affiliation: Department of Otolaryngology, Walter Reed Army Medical Center, Washington, DC 20307, USA.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Orestes
authors.forename: Bader
authors.initials: B
authors.lastname: Fileta
authors.forename: Snezana
authors.initials: S
authors.lastname: Haymes
authors.forename: Scott E
authors.initials: SE
authors.lastname: Brietzke
mesh_terms: D019342:Acetic Acid / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004868:Equipment Failure; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006493:Heparin / Q000008:administration & dosage; D006861:Hydrogen Peroxide / Q000008:administration & dosage; D066298:In Vitro Techniques; D008876:Middle Ear Ventilation; D011183:Postoperative Complications / Q000188:drug therapy*; D012965:Sodium Chloride / Q000008:administration & dosage; D013927:Thrombosis / Q000188:drug therapy*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; D005343:Fibrinolytic Agents; D012965:Sodium Chloride; D006493:Heparin; D006861:Hydrogen Peroxide; D010959:Tissue Plasminogen Activator; D019342:Acetic Acid