Veterinary Technician

Answer: E - It is common to select endotracheal tube sizes based on the internal diameter (I.D.) as well as the length of the ET tube. The internal diameter should be sufficient to reduce resistance to ventilation while the length allows proper placement of the distal end of the ET tube to be located at the mid-cervical trachea while the proximal end of the ET tube with the breathing circuit adapter is located at the patient's incisors. A tube too short may slip out and creates excessive dead space and a tube too long may enter a bronchus creating partial inflation of the lungs and transfer of oxygen and inhalant.