After conducting a general survey, take the physiologic measurements essential for the data-collection portion of the physical assessment of your pediatric patient. Many clinicians begin by measuring height (or for infants, length), head circumference for children up to the age of 3 years, and a body mass index. (For more information about growth measurements, see the accepted practice section that covers this area of physical assessment.) In some healthcare settings, pain and oxygen saturation are also considered vital signs and may also be measured depending on the reason the child needs healthcare. (These parameters will also be covered in more depth in this and other skills modules.)
How you measure a child’s vital signs varies to some extent with the age of the child. For example, when your patient is an infant, it is best to count respirations first. If you take the infant’s temperature first, you have to “disturb” him, and, if he cries in response to that procedure, you won’t obtain an accurate baseline respiratory rate. If your patient is a preschooler, it is important to be as noninvasive as possible. At this stage, children fear intrusive procedures, so an axillary or a tympanic temperature measurement is usually a better choice than a rectal measurement.
It is essential to use critical thinking when evaluating vital sign numbers with normal ranges for age and correlating them with your general physical assessment of the health status of the patient. The normal ranges for heart or respiratory rate might not be appropriate for an acutely ill patient and vital signs within those ranges could actually reflect deterioration. For example, a 3-year-old child with asthma who has had a heart rate of 150 and a respiratory rate of 44 but on retake of vital signs has a normal heart rate of 100 and a respiratory rate of 20 may be “tiring out” and respiratory failure might be imminent. Vital sign numbers alone have little meaning; you must analyze them critically for individual patients. Findings such as a rapid heart rate may be related to pain, fever, or anxiety. An elevated skin temperature may be due to excessive bundling or overdressing of an infant. It is also important to compare your findings with measurements documented at previous assessments, as well as with the normal ranges of vital signs for the particular age group.
Body temperature is more variable in infants and children than it is in adults. It tends to be higher in infancy and early childhood, with rectal temperature rarely falling below 99° F (37.2° C). Within a single day, body temperature might fluctuate up to 3 F° (1.7° C), especially late in the day or after strenuous activities.
There is some controversy about the optimal method of measuring temperature in children. Core body temperature provides the most accurate and useful data, and the rectal route is most reflective of core temperature. It can be used for children of all ages (although it is no longer standard procedure for newborns), but it is not without risks. It is invasive, and therefore can be upsetting for many children, so you have to weigh the need for absolute accuracy against the potential for losing the child’s cooperation early in the exam. Also, there is the potential for injury, especially if the child “fights” the procedure. And, of course, it would be a poor choice for a child who has diarrhea or any rectal or anal irritation or disorder.
The oral route is convenient but often inaccurate, unless the child is old enough to understand the need to keep the device under the tongue with the lips sealed around it and has clear nasal passages. Tympanic temperatures are convenient and safe and are often the preferred route; however, researchers do not concur on the accuracy and advisability of this route when precise measurement and correlation with core body temperature are imperative. Likewise, axillary temperatures are convenient and safe, but are not necessarily the most useful when precise measurement of core body temperature is critical. Various skin sensors are also available, but again, their usefulness when a precise measurement is warranted is uncertain.
Infants. If you take an infant’s rectal temperature, you might want to make this the last step of your vital-signs assessment, since it is invasive. The technique, however, is relatively simple. With the infant lying prone and preferably on the parent’s lap, separate the buttocks with the thumb and index finger of one hand while inserting the tip of a well-lubricated rectal thermometer probe at a 20° angle to the lap no more than about 3/4 inch, or 2 centimeters, in depth. If it is an electronic thermometer, keep it in place until the device signals that the temperature is recorded. Otherwise, keep it in place at least 2 or 3 minutes. Some clinicians advise taking a rectal temperature only when absolutely necessary due to the discomfort and the risk of trauma. Axillary and tympanic routes are appropriate for this age group as well. The usual temperature range for infants up to 1 year of age is 99.4° F to 99.7° F (37.5° C to 37.7° C).
Toddlers/preschoolers. For this age group, use the method that makes the most sense considering the degree of precision of measurement the child’s condition warrants. If you measure axillary temperature, place the covered temperature probe under the child’s arm in the center of the axilla. Lower the patient’s arm over the probe and hold the child’s arm across the abdomen. Leave the thermometer probe in place, close to the skin, until the audible signal indicates that the temperature has been measured. The usual temperature range for children between the ages of 1 year and 5 years is 98.6° F to 99.7° F (37.0° C to 37.7° C).
School-age children. Again, use the method that makes the most sense considering the degree of precision of measurement the child’s condition warrants. When you use a tympanic thermometer, remember the principles for inserting eye drops or an otoscope into a child’s ear: Straighten the ear canal by pulling the pinna up and back for children 3 years of age and older (as in this age group) and down and back for children younger than 3 years of age. Place the covered tip at the external opening of the ear canal and wait 2 to 5 seconds after you press the scan button for the temperature display. To obtain an accurate reading from a tympanic thermometer, it is important to place the probe at the proper angle for sealing the ear canal. Do not use the tympanic site if the child has ear pain or has excessive earwax, drainage from the ear, or sores or injuries in or around the ear. The usual temperature range for children between the ages of 5 years and 11 years is 98.0° F to 98.6° F (36.7° C to 37.0° C).
Adolescents. Likewise, use the method that makes the most sense considering the degree of precision of measurement the child’s condition warrants. If you measure an adolescent’s temperature orally, place the covered temperature probe under his tongue in the posterior sublingual pocket. Instruct him to close his lips gently around the probe and to keep his mouth closed until the temperature has been measured. Remind him not to bite down on the temperature probe. Leave it in place until you hear the signal that indicates that the temperature has been measured. Remember not to measure temperature orally right after the adolescent has just had food or fluids. The usual temperature range for children between the ages of 11 years and above is 97.8° F to 98.0° F (36.6° C to 37.0° C).
Assessing the rhythm, strength, and rate of a child’s pulse is an important part of a pediatric physical assessment, as it provides essential information about cardiovascular function. Before 6 months of age, infants cannot stretch their myocardial fibers to increase cardiac output and are totally heart-rate dependent. Thus, higher heart rates are normal for this age group. Bradycardia in infants is most often due to hypoxia, secondarily to hypothermia. In older infants, elevated heart rate can reflect fever, pain, anxiety, dysrhythmias, congestive heart failure, and medication effects. A slow heart rate suggests hypoxia (most often), hypothermia (particularly in infants younger than 6 months), or congenital heart problems or is medication-related, (digoxin toxicity, effects of opioids or sedatives).
Infants. Heart rate varies quite a bit in infants and is especially sensitive to the effects of illness and activity. For infants and children under the age of 2 years, the most reliable way to measure pulse is to auscultate the apical impulse. Place the warmed bell or diaphragm of your stethoscope over the child’s chest at the apex of the heart. It is best to count for 1 full minute because of the possibility of irregular rhythms. If you have established that the rhythm is regular and you must measure pulse repeatedly, count for 30 seconds and multiple by 2. Keep in mind that you will obtain the most accurate measurement while the child is asleep. Over the first year, the heart rate slows, with a range of 90 to 100 beats per minute up to 2 months of age, 80 to 180 up to 6 months, and 75 to 155 up to 12 months.
Toddlers/preschoolers. For this age group, radial pulse measurement is appropriate. The radial pulse point is easily accessible and easy to locate. Just apply light pressure with the pads of the fingers in the groove along the radial or thumb side of the child’s inner wrist. The usual pulse rate for children between the ages of 2 and 5 years ranges from 70 to 110 beats per minute while awake and 60 to 90 while asleep.
School-age children. For this age group, radial pulse measurement is also appropriate. The usual pulse rate doesn’t change much during this stage; it remains 70 to 110 beats per minute while awake and 60 to 90 while asleep.
Adolescents. Measuring the pulse rate of children in this age range doesn’t vary much from measuring an adult’s pulse. Using the radial site is typical, but remember, if the child has any identified or suspected cardiovascular problems, check the apical rate as well. The usual pulse rate for children above the age of 10 years ranges from 55 to 90 beats per minute while awake and 50 to 90 while asleep.
Accurate assessment of respiration is another important component of your physiologic measurements. It involves observing the rate, depth, and rhythm of chest-wall movement during inspiration and expiration. Tachypnea and increased respiratory effort, particularly in infants, are signs of pneumonia. Extremely rapid and shallow respirations can reflect cyanotic heart disease. And these are just a couple of examples that highlight the importance of assessing respiration in children.
Infants. Measure respiratory rate early in your assessment; it will not be accurate if the infant is crying, in fact, a sleeping rate is best. Infants’ respirations are primarily diaphragmatic, so, when counting their respirations, observe abdominal movements. Infants typically breathe irregularly, so be sure to count for a full minute. Also, keep in mind that fever raises infants’ respiratory rates up to 10 breaths per minute for each degree (centigrade) of fever. The usual range for respiratory rates of infants up to 1 year of age is 30 to 35 breaths per minute.
Toddlers/ preschoolers. For this age group, count the respiratory rate just as you would for an adult. It is always best to count respirations without the child knowing what you are doing. Just as for adults, when a patient knows you are counting breaths, that awareness of breathing often alters the rate and pattern. The usual range for respiratory rates of children between the ages of 2 and 5 years is 22 to 25 breaths per minute.
School-age children. Your technique in evaluating respiration won’t vary much for children past infancy. The usual range for respiratory rates of children between the ages of 5 and 12 years is 19 to 22 breaths per minute.
Adolescents. Assessing respiration in this age group is the same as for adults. The usual range for respiratory rates of children 12 years old and above is 16 to 19 breaths per minute.
Measuring blood pressure, the force that blood exerts against the vessel wall, is just as important for children as it is for adults. Hypertension in children is most often the result of renal disease, coarctation of the aorta, stress, or medication effects, but essential hypertension is also seen in children, with evidence indicating that both genetic and environmental factors play a role in its development. Hypotension can signal hemorrhage, sepsis, and septic shock. In infants, the most common causes of sustained hypertension are renal artery disease, congenital renal malformations, and coarctation of the aorta.
The most important factor in obtaining an accurate blood-pressure measurement is using a cuff of the appropriate size. The cuff’s bladder width should be about 40% of the child’s arm circumference, measured at a point halfway between the olecranon and the acromion. The cuff’s bladder length should cover 80% to 100% of the arm’s circumference. A cuff that is too small can yield falsely high blood-pressure readings; a cuff that is too large can yield falsely low blood-pressure readings.
When using an automatic blood-pressure device, use the correct setting (neonatal, pediatric, adult) so that the pressure generated to occlude the artery isn’t too high for a younger patient. The initial pressure on an adult setting may be much higher (200 mm Hg) than the pressure on a pediatric or neonatal setting. If this is a concern, use a manual pressure cuff for better control of maximal occlusion pressure.
In children 3 years of age and older, blood pressure should be measured annually, and more often for children with cardiovascular and other disorders. Blood pressure in the upper extremities should be compared at least once with blood pressure in the lower extremities to detect problems such as coarctation of the aorta. This disorder results in a lower-extremity blood pressure lower than that of the upper extremities.
Normal blood pressure readings for children vary not only with age, but with gender and height, as is illustrated in the tables accessible via this link: www.nhlbi.nih.gov/guidelines
Infants. Unless there are any special indications, blood pressure is not routinely measured for infants, although it should be measured at least once during the first year of life. To measure an infant’s blood pressure, it is probably best to use a Doppler device. It detects arterial blood-flow vibrations and converts them to systolic readings. Another electronic method is oscillometry, where pressure changes are transmitted through the arterial wall to the cuff. Average readings from the newborn period up to the age of 2 years via oscillometry range from 65/41 to 101/57.
Toddlers/preschoolers. It is especially important to prepare this age group for the procedure. The tightening of the cuff can be intimidating; to allay anxiety (which can increase blood pressure), explain that it will feel like an “arm hug.” When measuring blood pressure, position the limb at heart level, rapidly inflate the cuff to about 20 mm Hg above the point at which the radial pulse disappears, and release the cuff at the rate of about 2 to 3 mm Hg per second while using a pediatric stethoscope to listen to the Korotkoff sounds. For children in this age group, record the first Korotkoff sound as the systolic pressure and the fourth Korotkoff sound as the diastolic pressure.
School-age children. Measure blood pressure of school-age children as you would measure an adult’s blood pressure. Record the first Korotkoff sound as the systolic pressure and the fourth Korotkoff sound as the diastolic pressure. Talk to the child about blood pressure and the importance of eating healthfully and exercising to keep blood pressure at an appropriate range both to have a healthy heart and to prevent heart disease.
Adolescents. Measure adolescents’ blood pressure as you would measure an adult’s blood pressure. For children between the ages of 12 and 18, record the first Korotkoff sound as the systolic pressure and the fifth Korotkoff sound (the disappearance of sound) as the diastolic pressure.
Bickley, L. S., & Szilagyi, P. G. (2007). Bates’ guide to physical examination (9th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 697-698.
Hockenberry, M. J., Wilson, D., & Winkelstein, M. L. (2005). Wong’s essentials of pediatric nursing (7th ed.). St. Louis, MO: Elsevier Mosby. pp. 139-145, 930, inside back cover.
National Heart, Lung, and Blood Institute/National Institutes of Health. (2004.) Blood pressure tables for children and adolescents from the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Retrieved November 9, 2007, from http://www.nhlbi.nih.gov/guidelines/hypertension/child_tbl.htm
Nettina, S. M. (2006). Lippincott manual of nursing practice (8th ed.). Philadelphia: Lippincott Williams & Wilkins. p. 1326.
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