The ventilation tubes are used to drain fluid out of the middle ear space and ventilate the area with air. The eardrum normally vibrates with sound because the space behind it (the middle ear) is filled with air. If it is filled with fluid, the hearing is muffled. This happens with ear infections. Sometimes after the infection clears, the fluid remains. This occurs if the eustachian tube (which runs from the back of the nose to the middle ear) has become blocked and no longer allows air in and fluid out. Following an ear infection, approximately 30% of children still have fluid in the middle ear at 1 month, 20% at 2 months, and 5% at 4 months. The main concern about prolonged fluid in the middle ear is that the associated hearing deficit may have an impact on speech development. By 5 years of age, the eustachian tube is wider and fluid usually doesn't persist long after ear infections are treated.
Ventilation tubes allow secretions to drain out of the middle ear space and air to reenter. The risk of recurrent ear infections is greatly reduced. The hearing returns to normal with the tube in place and speech development can get back on track. Tubes also prevent the fluid from becoming thicker (a "glue ear") and damaging the middle ear. The ventilation tubes also buy time while the child matures and the eustachian tubes begin to function better.
First, approximately 10% of children with ventilation tubes continue to have ear infections with drainage and pain. These bouts of infection, which require antibiotics, probably would have occurred anyway. Second, complications may occur around the tubes falling out too early or too late. Normally the tubes come out and fall into the ear canal after about 1 year. Sometimes they come out too quickly and need to be replaced by another set. If they remain in the eardrum for over 2 years, the ear, nose, and throat specialist may need to remove them. Third, after they come out, some leave scarring of the eardrum or a small hole (perforation) that doesn't heal. These both can cause a small hearing loss. Because of these possible complications and the requirement for an anesthetic, physicians recommend ventilation tubes only for children who definitely need them.
As described earlier, most children with a hearing loss caused by fluid in their middle ear have it on just a temporary basis. During this time when you talk with your child, get close to him, get eye contact, get his full attention, and occasionally check that he understands what you have said. If not, speak in a louder voice than you normally use. A common mistake is to assume your child is ignoring you when actually he doesn't hear you. Reduce any background noise from radio or television while talking with your child. If your child goes to school, be sure he sits in front near the teacher. (Middle ear fluid interferes with the ability to hear in a crowd or classroom.) Keep in mind that most children's speech will catch up following a brief period of partial hearing.
The surgical placement of ventilation tubes is usually indicated if several of the following conditions are met:
Chronic ear fluid and recurrent ear infections are usually due to a blocked eustachian tube. If any of the following triggers are present, treat or eliminate them before considering ventilation tubes.
Instructions for Pediatric Patients, 2nd Edition, ©1999 by WB Saunders Company.
Written by Barton D. Schmitt, MD, pediatrician and author of Your Child’s Health, Bantam Books, a book for parents.