True statements regarding the respiratory disease is

(All of the above) (188-B &L 25th)RESPIRATORY DISEASE* Blood gases and pulmonary function test are needed to assess severity of problems* Stop smoking, continue inhalers at least 4 weeks before surgery* Involve physiotherapists and anaesthetics post-operately* Avoid respiratory suppressants such as narcotics* Mobilise early* Give oxygen* COPD of any cause, asthma, chest infection or bronchietasis causes increased post operative morbidity* A careful history - taking of exercise tolerance, triggering factors and medications will determine the severity* Arterial blood gas measurement should be performed prior to major surgery to obtain a baseline and to measure any respiratory failure* Pulmonary function tests, peak expiratory flow rate (PEFR), vital capacity, and forced expiratory volume in 1 second provide an objective measurements of obstructive restrictive ventilatory defects along with reversibility of the former when treated with bronchodilators.* The use of post-operative epidural analgesia is useful