Checking an infant’s pulse is substantially different from checking an adult’s pulse. An infant, defined as a child under one year of age, possesses smaller blood vessels and a unique physiological makeup that necessitates a specific approach for accurate assessment. Knowing the correct location to check is paramount because an incorrect site or technique can lead to a misleading reading or a dangerous delay in treatment during an emergency.
The Primary Pulse Site for Infants
The standard and most accessible location for checking a pulse on an infant is the brachial artery. This artery is situated on the inside of the upper arm, running between the elbow and the shoulder. To locate it, gently extend the infant’s arm with the palm facing upward.
The pulse is typically found midway along the upper arm, nestled in the soft groove between the biceps and triceps muscles. The brachial artery is chosen because it is a relatively large vessel that lies close to the surface, making it easily compressible against the underlying humerus bone. This ease of palpation makes it the preferred site for quick and reliable circulation checks.
Technique and Safety for Accurate Counting
Once the location is identified, the technique involves using the pads of two fingers, typically the index and middle fingers. Avoid using the thumb, as it has its own detectable pulse, which can lead to a false count. Apply gentle but firm pressure to the artery in the inner upper arm, just enough to feel the pulse against the bone.
Applying excessive pressure must be avoided because it can accidentally compress the artery shut, making the pulse undetectable. Once the pulse is felt, the standard practice is to count the beats for a full 60 seconds for a resting rate. For a quick estimate, count for 15 seconds and multiply that number by four to calculate the beats per minute (BPM).
Interpreting the Rate and Recognizing Emergencies
The normal resting heart rate range for an infant is significantly higher than that for an adult. This rate often varies between 80 to 160 beats per minute (BPM), depending on the infant’s age. For example, a newborn may have a resting rate between 70 to 190 BPM, while an older infant typically falls between 80 and 160 BPM. The rate naturally fluctuates based on activity level, increasing during crying and decreasing during sleep.
The threshold for immediate intervention is a pulse rate significantly slow, generally below 60 BPM. A very slow pulse, especially when combined with signs of poor circulation such as pale or bluish skin discoloration, signals a severe emergency. In this situation, a caregiver should immediately activate emergency medical services (911 or the local equivalent) and be prepared to follow instructions for infant cardiopulmonary resuscitation (CPR).
Why Adult Pulse Sites Are Not Used
Pulse sites commonly used for adults and older children are inappropriate for infants due to anatomical and safety concerns. The radial artery, located at the wrist, is often too deep or too faint to be reliably palpated due to the small size of the vessel and the layer of subcutaneous fat. Trying to find a pulse at this site wastes valuable time in an emergency.
Checking the carotid artery in the neck, a common site for adults, carries a higher risk of accidental compression in a small infant. The infant’s neck is short, and applying pressure can potentially compress the airway or the carotid artery itself, which is dangerous. The brachial site offers the most accessible and reliable reading without posing these risks.