This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
[{'content': 'The narrowest pa of larynx in infants is at the cricoid level. In administering anesthesia this may lead to all except. \nSelect and explain. \nA. Choosing a smaller size endotracheal tube, B. Trauma to the subglottic region, C. Post operative stridor, D. Laryngeal oedema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Choosing a smaller size endotracheal tubeEndotracheal tube that passes through the glottis may still impinge upon the cricoid cailage; the cricoid cailage is the narrowest point of the airway in children younger than 5 years of ageQMucosal trama can cause post operative edema, stridor, croup & airway obstruction() in subglottic & glotic regionThe appropiate size of tube is estimated by an age based formula, which provides only a rough guide line however. Exceptions include premature neonates (2.5 to 3 mm tube) and full term neonates (3-3.5 mm tube)Correct tube size is confirmed by easy passage into the larynx and the development of gas leak at 15-20 cm H20 pressure. So the size of ETT depends on age, easy passage & gasleak at 15-20 cm H20 pressure.', 'role': 'assistant'}]