Fires and operating room pollution may occur when anesthesia gases leak into the oropharynx during airway surgery. Investigators sought to measure the concentrations of anesthetic gases that leak into the mouth of children undergoing adenotonsillectomy using cuffed and uncuffed tracheal tubes during spontaneous and controlled ventilation.

For the past 6 decades, uncuffed tubes have been used for the children less than 8 years of age out of a fear that cuffed tubes would cause damage to the subglottic region. The correct size uncuffed tube creates a seal in the subglottis that has minimal pressure on the mucosa. However, cuffed tubes have become more widely used in children recently without causing damage to the mucosa. There is very little literature comparing the magnitude of the gas leaks with cuffed and uncuffed tracheal tubes particularly in children. Several authors suggest that the leak of nitrous oxide and sevoflurane with uncuffed tubes was much greater than with cuffed tubes. One important but poorly studied issue is the risk of an airway fire when cautery is used for tonsillectomy because a large leak of oxygen in the mouth could ignite a fire. It also remains unclear whether the mode of ventilation, spontaneous or controlled, affects the leak of gases into the mouth. One might expect that the gas leak with spontaneous ventilation is less than with controlled ventilation, but it may not matter in the context of the small concentrations of oxygen and sevoflurane that investigators use. To address all of these concerns, investigators designed this study to compare the concentrations of gases (oxygen, carbon dioxide, nitrous oxide and sevoflurane) in the oral cavity of children undergoing T&A with either cuffed or uncuffed tubes, during spontaneous and controlled ventilation.

Inclusion Criteria:

1. American society of anesthesiologists physical status 1 and 2;
2. fasted
3. scheduled for elective adenotonsillectomy

Exclusion Criteria:

1. refusal of consent by parents
2. difficult tracheal intubation
3. craniofacial anomalies
4. gastroesophageal reflux
5. malignant hyperthermia
6. randomization to a tracheal tube is unacceptable.