As for infants, rectal temperature-taking is the most favored method by pediatricians. Because taking rectal temperature can also be painful, even if done by trained practitioners, rectal digital thermometers are preferable. Additionally, a lubricant like petroleum jelly should be used when taking the temperature.
Rectal thermometry is a general term used to cover a wide range of methods for taking rectal temperature, in most cases used only in pediatrics. Rectal thermometry is also sometimes used in animal testing, veterinary, research, and forensics. In any case, rectal thermometry, when done in humans, should be undertaken with extreme care. If done by a person who is not trained in medicine, the process can be painful and can cause damage in the rectum or anus.
Many medical practitioners regard rectal thermometry as an 'invasive' medical procedure, and for good reason. Therefore, the practice is generally used only in children. On certain occasions, when taking temperature in any other way is not possible, rectal thermometry is used with older patients. Emergency rooms may use one of many ways to take the temperature of a patient. In emergency rooms, because of its open space and somewhat public location, rectal thermometry is summarily avoided. However, if there is no other alternative, that understandable choice is completely disregarded.
Rectal thermometry is fairly easy to learn; but it is not advisable to be practiced for medical purposes by anyone other than a doctor. Ordinary mercury-based thermometers are more difficult to use, and involves making the patient lie still for a few minutes. Furthermore, the reading cannot be accurate until after the thermometer is cleaned using a tissue. Rectal digital thermometers are quite the opposite. The digital ones are also used with lubricants, such as petroleum jelly, but are considerably easier to clean. The following are steps on how to clean a digital rectal thermometer:
First, wipe off the lubricant, be it petroleum jelly or water-based lubricant, using a thick tissue paper or a disposable paper towel. Create a mixture of liquid soap and warm water in a small disposable glass. The glass doesn't always have to be disposable, but, for obvious reasons, should never be a drinking glass. Dip the tip of the digital thermometer, not the whole thermometer itself, into the soapy water and swirl it until the water bubbles.