Main Category :Medicine Sub Category :Medicine Dr.Shantha Jayathilake Bandara Lenadora During the surgical procedure, as the anesthetic effect fades away with time, the muscle tone of the tissues will increase gradually there by exerting agradually increasing forceon the air column. The compression of the air due to the increased tissue action gives a movement to the retractor bars. This movement provides avaluable indication to the surgical team to enhance the anesthetic dose.