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Infant Vital Signs Assessment

Jul 23, 2025

Overview

This lecture demonstrates the correct procedure for assessing vital signs and growth measurements in infants, emphasizing order, technique, and normal ranges.

Sequence of Infant Vital Sign Assessment

  • Start with the most non-invasive measurements while the infant is calm: respirations, heart rate, temperature, weight, length, head circumference, and chest circumference.
  • Gather all supplies beforehand: infant stethoscope, measuring tape, thermometer, scale, and a watch.
  • Sanitize all equipment and perform hand hygiene before and after the assessment.

Respiratory Assessment

  • Count respirations first while the infant is calm, for a full one minute.
  • Normal infant respiratory rate is 30–60 breaths per minute.
  • Watch for signs of respiratory distress: nasal flaring, chest retractions, and cyanosis (bluish skin color).
  • Infants may have irregular ("periodic") breathing patterns; always count for a full minute.

Heart Rate Assessment

  • Use an infant-sized stethoscope to assess the apical pulse, not the radial pulse.
  • For infants <1 month: normal heart rate is 100–190 bpm; for >1 month: 90–180 bpm.
  • Locate the apical pulse at the fourth intercostal space, lateral to the midclavicular line.
  • Heart rhythm may be irregular (sinus arrhythmia); count for a full minute.

Temperature Measurement

  • Take temperature via the axillary (armpit) route.
  • Normal axillary temperature range in infants: 97.5–99.3°F (36.4–37.4°C).
  • Place the thermometer tip deep in the armpit, lower the arm, and record the reading once it beeps.

Infant Weight Measurement

  • Remove clothing and any soiled diaper for accurate measurement; a dry diaper may be used.
  • Place the infant on the scale and document the weight in pounds and ounces.
  • Compare with birth weight to assess growth.

Length, Head, and Chest Circumference Measurement

  • Measure length from head to heel with the infant lying flat, head midline, and leg extended; normal length is 18–22 inches.
  • Measure head circumference above eyebrows and around the largest part at the back; normal is 33–38 centimeters.
  • Measure chest circumference at the nipple line; it should be 1–2 cm less than head circumference.

Key Terms & Definitions

  • Respiratory Distress — difficulty breathing indicated by nasal flaring, chest retractions, or cyanosis.
  • Periodic Breathing — irregular breathing pattern seen in infants.
  • Apical Pulse — heartbeat heard at the chest over the heart's apex, used for accurate heart rate in infants.
  • Sinus Arrhythmia — normal variability in heart rate with breathing.
  • Cyanosis — bluish discoloration of the skin due to low oxygen.

Action Items / Next Steps

  • Review other videos in the Pediatrics series for more infant assessment skills.
  • Practice proper hand hygiene and equipment sanitation before and after assessments.