When do we have to sta antibiotics to prevent post-operative infections

Prophylactic Antibiotics Antibiotics should be used when local wound defences are not established (the decisive period) Ideally, maximal blood and tissue levels should be present at the time at which the first incision is made and before contamination occurs IV administration at induction of anaesthesia is optimal If induction is not mentioned in the option go for 30 minutes to 1 hour before surgery In long operations, those involving the inseion of a prosthesis, when there is excessive blood loss or when unexpected contamination occurs, Antibiotics may be repeated 8 to 16 hours later The use of the newer, broad spectrum antibiotics for prophylaxis should be avoided Benzyl penicillin should be used if clostridium gas gangrene infection is a possibility Patients with hea valve disease or a prosthesis should be protected from bacteraemia caused by dental work, urethral instrumentation or visceral surgery Ref: Sabiston 20th edition Pgno :224,251