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
Tracheostomy reduces dead space by ? 
Select and explain. 
A. By-passing upper airway, B. Increasing V/Q ratio, C. Reducing airflow resistance, D. By all of the above mechanisms
A: By-passing upper airway
Answer: A: By-passing upper airway 
Explanation: Ans. is'a'i.e., By-passing upper airway (Ref: Morgan 4tu/e p. 553) Impoant effects of tracheostomy on respiratory physiologyTracheostomy decreases dead space as upper airways and nasal cavity are bypassed.Tracheostomy decreases ventilation/perfusion (V/Q) ratio.Tracheostomy reduces the airflow resistance.