Dissolving the glue in glue ear: Assessment of the efficacy of the use of Dornase alfa as an adjunct therapy to ventilation tube insertion.

INTERVENTION: Children will act as their own internal control. Ears will be individually randomised for each child to receive a single application of 1 ml of Dornase alfa (Pulmozyme®, Genentech) immediately prior to ventilation tube insertion or 1 ml placebo (sterile saline). Intervention will be administered by the ear nose throat specialist performing the ventilation tube insertion surgery. Administration to the correct ear is recorded by the attending researcher and drug containers are returned to the clinical trials phramacy following the surgery to ensure adherance. Following ventilation tube insertion, Ciloxan® (topical ciprofloxacin) drops will be administered bilaterally as per normal procedure (5 drops twice daily for 5 days). CONDITION: Ear ‐ Other ear disorders otitis media; ; otitis media PRIMARY OUTCOME: Efficacy of a single application of Dornase alfa at time of ventilation tube insertion as assessed by need for repeat surgery due to the recurrence of chronic otitis media with effusion (cOME). cOME is determined using tympanometry and video otoscopy and defined as having an effusion present at 2 consecutive visits at least 3 months apart. ; [At time of repeat ventilation tube insertion or at 2 years post intervention; ] SECONDARY OUTCOME: Efficacy of a single application of Dornase alfa at the time of ventilation tube insertion as assessed by occurrence of blocked ventilation tubes using tympanometry and video otoscopy.[Any time until 2 years post intervention or until time of repeat ventilation tube insertion] Efficacy of a single application of Dornase alfa at the time of ventilation tube insertion as assessed by occurrence of otorrhoea as determined by parental report, medical records and/or video otoscopy at scheduled visits.[Any time until 2 years post intervention or until time of repeat ventilation tube insertion] Efficacy of a single application of Dornase alfa at the time of ventilation tube insertion as assessed by recurrence of otitis media indicated by parental report of acute otitis media episodes or consecutive type B tympanograms over 3 months[Any time until 2 years post intervention or until time of repeat ventilation tube insertion] Safety of a single direct application of Dornase alfa into the middle ear at time of first ventilation tube insertion as assessed by any change in hearing levels when measured by audiometry.[Audiometry conducted 2‐4 weeks post intervention] Safety of a single direct application of Dornase alfa into the middle ear at time of first ventilation tube insertion as assessed by no change in body temperature as measured using an axillary thermometer.[Temperature collected daily for 5 days post‐intervention] Tolerability of a single direct application of Dornase alfa into the middle ear at time of first ventilation tube insertion as assessed by any change in pain in the intervention ear according to parental scoring using a numerical scale developed for this trial. [Pain scores collected per ear and daily for 5 days post‐intervention] INCLUSION CRITERIA: 1. 6 months‐5years of age. 2. Undergoing surgery for ventilation tube insertion for recurrent Acute Otitis Media (rAOM) and/or otitis media with effusion (OME). 3. Have a bilateral effusion for 3 months or longer.