A 4-month-old child is at the clinic for a well-baby checkup and immunizations. Which of these actions is most appropriate when the nurse is assessing an infant's vital signs?

A) The infant's radial pulse should be palpated, and the nurse should notice any fluctuations resulting from activity or exercise.
B) The nurse should auscultate an apical rate for 1 minute and then assess for any normal irregularities, such as sinus dysrhythmia.
C) The infant's blood pressure should be assessed by using a stethoscope with a large diaphragm piece to hear the soft muffled Korotkoff sounds.
D) The infant's chest should be observed and the respiratory rate counted for 1 minute; the respiratory pattern may vary significantly.

The nurse auscultates an apical rate, not a radial pulse, with infants and toddlers. The pulse should be counted by listening to the heart for 1 full minute to account for normal irregularities, such as sinus dysrhythmia. Children younger than 3 years of age have such small arm vessels; consequently, hearing Korotkoff sounds with a stethoscope is difficult. The nurse should use either an electronic blood pressure device that uses oscillometry or a Doppler ultrasound device to amplify the sounds. An infant's respiratory rate should be assessed by observing the infant's abdomen, not chest, because an infant's respirations are normally more diaphragmatic than thoracic. The nurse should auscultate an apical heart rate, not palpate a radial pulse, with infants and toddlers.