Human rectal temperature is normally around 37-37.5 ° C and tends to increase in relation to the depth at which it is measured. It is therefore advisable to take the rectal temperature at a standard depth (about 5 cm in the adult), especially in the case of repeated tests.
Once inserted, the thermometer should be kept in place for at least two or three minutes. Before proceeding with the measurement, however, it is a good rule that the subject is kept in rest conditions for at least half an hour.
Among all, the rectal temperature is the best representative of the central or basal temperature, while the values measured in the oral and axillary areas are respectively lower by about 0.5 / 1 ° C. The rectal temperature is in fact less susceptible to variations due to external factors (such as the ambient temperature), although it is still subject to the typical circadian fluctuations (higher in the late afternoon), muscle activity, emotional stress and the phase of the menstrual cycle ( increases by half a degree in the period between ovulation and the onset of menstruation).
To relate the rectal temperature to the axillary one, it is necessary to subtract 5-10 dashes (half a degree / one degree) and vice versa. In practice, therefore, a rectal value of 38 ° C corresponds to about 37-37.5 ° C of axillary temperature.
Rectal temperature measurement techniques
How to measure the rectal temperature in the baby
- Clean the thermometer with soap and water, then wipe it with an alcohol or disinfectant wipe and rinse it.
- The thermometer (for small ones for children) must be held firmly between the index and middle fingers. If an old mercury model is used (not recommended), it must be shaken vigorously until the column has dropped below 34 ° C.
If you are using the digital thermometer, it will need to be turned on before using it. - Lay the baby on his back (belly up) on a rigid surface (changing table or bed). With your left hand, grasp the baby's ankles and lift his legs, as shown in the first figure on the left.
- With your right hand, dip the bulb of the thermometer into the oil or vaseline, then gently introduce only the bulb into the child's rectum (no more than 1.5 / 2 cm).
- Tighten the baby's buttocks by holding them firmly and wait two or three minutes.
- After the necessary time, read the measured rectal temperature on the thermometer.
Among all the possible detection sites, the measurement of the rectal temperature - by virtue of the greater degree of adherence to the basal temperature - is the most reliable, especially in infants and young children. Measuring the temperature below the armpit gives more reliable results from the age of four or five. Furthermore, in children, the use of digital thermometers is strongly recommended to replace older models made of glass, containing mercury and as such rather dangerous in case of accidental breakage.
The rectal temperature measurement should be performed with the baby lying on its side and with the thighs flexed at right angles (central figure), although other positions are possible. The thermometer must be inserted into the anus gently, avoiding the maneuver in the presence of bleeding or other contraindications indicated by the pediatrician. alcohol or disinfectant and rinsed again, the same operation will be repeated at the end of the measurement. Before insertion, the bulb should be sprinkled with a special lubricant available in pharmacies (vaseline). The maneuver must be performed with particular delicacy, making it penetrate for no more than a couple of centimeters and without ever forcing the maneuver in case of resistance.
As for the correct interpretation of the rectal temperature in the child, it is good to rely on what is reported by the pediatrician. In general, however:
a rectal temperature above 38 ° C can be considered febrile.
When to contact the pediatrician
Observe the following characteristics in advance: - Is the child pale? - Is he lively? do you have an appetite or do you not want to eat? do you want to play? are you crying all the time? is much calmer than usual? Are you breathing hard? Do you have a stuffy nose, cough, ear pain and / or difficulty moving your head? Do you have vomiting or diarrhea? What is your rectal temperature?
Warning signs: the child is very irritable, cries constantly and is difficult to console; he is very sleepy and it is difficult to wake him up; moves the head and neck with difficulty; violently shakes the arms or legs, remaining rigid or withdrawn (convulsions); have red or dark spots on the skin; has more than 50 breaths per minute (between 3 and 12 months of age) or more than 40 breaths per minute (after 13 months of life); have severe pain in the belly.
In the first three months of life, temperatures even slightly above normal deserve a careful medical evaluation, as they could be associated with a severe infection. From three months to three years of life, all cases of temperature should be submitted to the pediatrician's attention. rectal above 39 ° C. In these cases, the level of temperature (ie a more or less high fever) is not sufficient to make people understand the extent of the problem. In itself, in fact, fever is not a disease, but a reaction of the body to the " attack of bacteria or viruses. For this reason it is first of all necessary to observe the child and realize how he is; in addition to the rectal temperature, characteristics such as the appearance, the agitation, the suffering state, the type of rest he can have and the presence of breathing difficulties will therefore be evaluated. These signs will help the pediatrician to better interpret the condition and decide to schedule the visit at the most appropriate time.
