The preoperative use of large doses of cholinesterase inhibitors will activate muscarinic receptors, accelerate the destruction of postsynaptic acetylcholine receptors (AChRs) at the neuromuscular junction, decrease the ability of patients to cough up sputum due to postoperative pain, cause excessive respiratory secretions after the operation, increase the risk of respiratory tract infection, and increase the risk of crisis. This evidence concerns the gene BCHE and Respiratory tract infection.