Nursing fundamentals textbooks provide comprehensive discussions of measurement of vital signs. Only significant pediatric variations in the measurement of body temperature, pulse, and respirations are presented here.
Measurement of Body Temperature
Rationale
Environmental factors and relatively minor infections can produce a much higher temperature in infants and young children than would be expected in older children and adults. In most cases, an elevated temperature is the result of fever and is one of the most common manifestations of illness in young children. In very young infants, fever might be one of the few signs of an underlying disorder. In toddlers, febrile convulsions can parallel fever and are of particular concern. Ascertaining the absence or presence of fever and determining the cause of fever are important in planning nursing care. Body temperature should be measured on admission to the health care facility, before and after surgery or invasive diagnostic procedures, during the course of an unidentified infection, after fever-reduction measures have been taken, and any time that an infant or child looks flushed, feels warm, is lethargic, looks “glassy-eyed,” or has increased pulse and respirations.
Anatomy and Physiology
Temperature is regulated from within the hypothalamus. During an infection, the body’s normal set point is elevated, and the hypothalamus increases heat production until the body’s core temperature is consistent with this new set point. Shivering and vasoconstriction during the chill phase help the body reach the new set point by conserving and generating heat.
The control of body heat loss improves with age. The ability of muscles to shiver increases with maturity, and the child accumulates greater amounts of adipose tissue necessary for insulation against heat loss. Heat production decreases with age. The infant produces relatively more heat per unit of body weight than older children do, as reflected by the infant’s higher average body temperature (Table 8-1). A variety of other factors also affect the body temperature of the child (Table 8-2).
| Temperature in Degrees | ||
|---|---|---|
| Age | Celsius | Fahrenheit |
| 3 mo | 37.4 | 99.4 |
| 1 yr | 37.6 | 99.7 |
| 3 yr | 37.2 | 99.0 |
| 5 yr | 37.0 | 98.6 |
| 7 yr | 36.8 | 98.3 |
| 9 yr | 36.7 | 98.1 |
| 13 yr | 36.6 | 97.8 |
| Factor | Effect |
|---|---|
| Active exercise | Might temporarily raise temperature |
| Stress, crying | Raises body temperature |
| Diurnal variation | Body temperature is lowest between 0100 and 0400 hours (1:00 and 4:00 AM), highest between 1600 and 1800 hours (4:00 and 6:00 PM) |
| Environment, including clothing, swaddling, and nesting | Body temperature can vary with room temperature, amount and type of clothing |
| Pharmacologic agents (antipyretics, muscle relaxants, vasodilating anesthetic agents) | Decrease body temperature |
Preparation
Ask the parent or child if the child has been febrile, and if so, when the fever began. Inquire whether the onset was abrupt or gradual and whether other symptoms or localizing signs accompany the fever. Most diseases have no particular fever pattern. However, although the rapidity of temperature elevation and response to antipyretics are not indicative of the severity of the disease, knowing the pattern of the fever (onset, magnitude, frequency, recurrence, defervescence or decrease) can be helpful, especially if there are no localizing signs with the fever (Table 8-3).
| Fever Pattern | Associated Etiologies | Additional Characteristics of Fever |
|---|---|---|
| Single spike: refers to a single increase or spike, usually within a 12-hour period or less | Transfusion of blood or blood products | |
| Double quotient: fever in which there are two distinct peaks in a day | Miliary tuberculosis | Fever with general symptoms such as weight loss, malaise, weakness, anemia, pallor, diminished breath sounds, crackles |
| Hectic: involves wide swings in fever, usually with chills and sweating | Bacterial pneumonia | Fever usually quite high, chills, abrupt onset, anorexia, headache, cough, meningeal symptoms |
| Intermittent: fever returns to normal at least once during the day | Bacterial (infective) endocarditis | Low-grade fever with nonspecific symptoms such as malaise, myalgia, headache, diaphoresis, weight loss |
| Hodgkin’s disease | Low-grade fever with enlargement of supraclavicular or cervical nodes, weight loss, night sweats, pruritus, anorexia, nausea | |
| Remittent: fever rises at least 0.6° C (1.0° F) in a 24-hour period and abates but does not return to normal | Viral upper respiratory tract infections | Fever with myalgia, malaise, headache, coryza; slow defervescence |
| Continuous or sustained: little or no variation in temperature | Roseola | Fever above 39° C (102° F) for 3 to 4 days without localizing signs |
| Scarlet fever | High fever with vomiting, headache, chills, malaise, abdominal pain in prodromal stage | |
| Urinary tract infection (children younger than 5 years) | Fever of 39° C (102° F) or higher for 2 days or more, with no respiratory symptoms | |
| Severe acute respiratory syndrome (SARS) | Diarrhea, vomiting, irritability, poor feeding, foul-smelling urine | |
| Fever at or above 38.5° C (101.5° F), cough, malaise, chills or rigor, coryza (younger than 12 years), headache, sputum, myalgia, sore throat, no crackles or wheezing | ||
| Relapsing: recurrent over days and weeks; fever occurs at various intervals after initial episode | Acute rheumatic fever | Low-grade fever with late afternoon spike, polyarthritis, chorea, subcutaneous nodules, erythema marginatum, carditis |
| Infectious mononucleosis | Fever with malaise, sore throat, lymphadenopathy, splenomegaly that can persist for months | |
| Extreme hyperthermia: fever above 41° C (106° F) | Noninfectious origin (neoplastic, trauma, heat stroke, drug fever) HIV |
Guidelines for Measurement of Body Temperature
▪ Select the site for temperature measurement based on the child’s age and condition (Table 8-4), institutional policy, and what might be least traumatic for the child. The tympanic route, for example, has a high level of acceptability by children.
| Site | Age Group | Special Considerations |
|---|---|---|
| Axilla | All age groups, but particularly preschoolers, who tend to fear invasive procedures. Can be used for children for whom the oral route is not possible and for those who would not tolerate the rectal route. |
Measures shell temperature.
Can be taken using standard glass (in rare use), electronic, digital, chemical dot, or infrared thermometers.
Although some sources recommend the monitor mode for electronic thermometers, some evidence also suggests that the predictive mode be used for full-term infants.
Wearable chemical dot thermometers enable continuous reading for as long as 48 hours (must be replaced after 48 hours). Reading might be increased for axillary route.
Might be contraindicated when accuracy is especially critical or in the early stages of a fever when the axilla might not be sensitive to early changes. Accuracy can be affected by increased peripheral circulation.
|
| Rectal | All age groups. Some sources recommend use in children older than 2 years because of risks of breakage and perforation. Some evidence suggests that the rectal route is the most reliable route for measurement of temperature in infants and children, although others recommend its use only when no other route is appropriate (e.g., children who are too young or too agitated to cooperate or follow directions, children who have had oral or axillary surgery). |
Measures core temperature.
Can be taken using standard glass (in rare use), electronic, or chemical dot devices.
Do not force insertion of thermometer.
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