This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preoperative assessment and monitoring in anaesthesia, Subject name: Anaesthesia
Heavy smoker for elective hernia repair, Smoking should be stopped before how much period 
Select and explain. 
A. 4 days, B. 10 days, C. 3-4 week, D. 6-8 week
D: 6-8 week
Answer: D: 6-8 week 
Explanation: Cessation of smoking : 12hrs : reduces CO-Hb,hence increases oxygen carrying capacity 2days : CVS : aboloshes nicotine effect on sympathetic system stimulation, hence HR & BP normalises RS : Improves mucociliary function 2weeks : Sputum volume is reduced 2months : Relieves bronchospasm,decreases bronchial secretions,Chronic broncitis is reduced,Improves lung function,immune function returns to normal,hepatic enzymes returns to normal.