The endotracheal tube (ETT) leak test (LT), or audible leak test is a widely performed assessment to verify appropriate tube size in neonates, infants and children. However, many factors are known to influence the audible leak test. Even though the test is widely performed, the accuracy has not been evaluated.

The endotracheal tube (ETT) leak test (LT), or audible leak when the peak airway pressures reach 15-30 cmH2O, is a commonly performed assessment to confirm that an endotracheal tube size is appropriate for a child in order to minimize the risk of airway injury and adverse events after removal of ETT. Many factors are known to affect the results of the leak test and variation in results among experienced anesthesiologists may be as great as 38%, but the accuracy of the audible leak test by directly observing the presence of a leak around the ETT has not been evaluated. This study will attempt to use direct visualization of the air leak to correlate to and assess the accuracy of the audible air leak test.

Inclusion Criteria:

• Children aged between 1 month (post-natal) and 8 years scheduled for ENT surgery requiring general anesthesia with an endotracheal tube.

Exclusion Criteria:

• Known history of subglottic stenosis
• Known history of recurrent croup
• Known history of endolaryngeal or subglottic lesions
• Parents refusal of participation in study

Children aged between 1 month (post-natal) and 8 years scheduled for ENT surgery requiring general anesthesia with an endotracheal tube.