The narrowest part of larynx in infants is at the cricoid level. In administering anaesthesia this may lead to all except –
Subglottic region (cricoid region) is the narrowest part of larynx in infants. Mucosal trauma to force a tube can cause post-operative edema, stridor, croup and airway obstruction.
The size of tube is very important, both oversize and undersize tube are dangerous :-


Oversize tube will increase the chance of trauma and post intubation edema, croup & stridor.
Undersize tube will increase the chance of aspiration (because uncuffed tubes are used in children and the best way to prevent aspiration is to use appropriate size tube).
Choosing a smaller size endotracheal tube
Trauma to the subglottic region
Post operative stridor
Laryngeal oedema