Skip to 0 minutes and 8 secondsWhen I am observing the cardiac status of the baby, again, I'm observing at rest, and I need to listen to the baby's heart. Now, when you listen to a heart rate of a newborn, the sounds you're going to hear are a first sound, which is quite loud, and the second sound is going to be split into two. So you'll hear a sound and then a sound that is split very quickly. The reason for that split second sound that you hear-- and this is entirely normal-- is because of the aortic valve and the pulmonary valve closing. We do become concerned if in that second split sound there's a delay between the split sound. We call this a murmur.

Skip to 0 minutes and 53 secondsAnd we're thinking then about the baby still being in a state of foetal circulation, if you like, as they make that transition. Because what happens when a baby is born-- and this is really interesting-- is that when a baby is still in utero, so it's still inside its mother, the blood actually pumps in the opposite direction to the blood flow when you are delivered. So the baby needs to make this transition. And during this transition, which can happen over a few hours after the baby's born, it's not unusual to hear a murmur. What's important is that the baby stays uniformly pink, may remain a bit dusky and blue on the hands and the feet during this period of transition.

Skip to 1 minute and 40 secondsWe call this acrocyanosis. It's an entirely normal finding and nothing for you to be concerned about, but this transition does happen over a few hours. Placement of the stethoscope when you're listening to the baby's heart rate, and the normal heart rate is between about 120 and 160 beats per minute. So, it's quite high. If we have a baby with a heart rate less than 100, we're going to be very concerned about that. So being able to listen and take a heart rate accurately is really important. And again, listening for a whole minute. So with the placement of the stethoscope, I'm looking for the second intercostal space on the left hand side of the chest.

Skip to 2 minutes and 21 secondsSo the intercostal space are those areas between the ribs. So I'm looking for the collar bone (the clavicle), which is this bone up here, going to the mid clavicle, the mid clavicular line here on the baby, and going down to that second space between the lungs, placing my stethoscope there, and that is where I'm going to listen to the heart. That's probably the most important location to listen to the heart. So I'm looking for that first sound, that second split sound, and with a fast heart rate of between 120 and 160. You're going to have to get a lot of practise to be able to read that really accurately.

Assessing newborn cardiac status

Time to assess the baby’s heart beat.

After you’ve assessed the chest and respiratory status of the newborn, auscultate for heart sounds. These are best heard along the left sternal border (left side of the chest bone). Physiological murmurs may be heard in the first few days of life as the newborn adapts to extra uterine life.

The normal heart rate for a newborn is 100–160 bpm and the rate should be regular.

If you have experience, you can also palpate for pulses. Palpation of femoral (groin) pulses should be part of routine assessment of the newborn. Pulses should be present bilaterally (both sides), with a regular rhythm (Kain & Mannix, 2018). Take note of and report weak or absent pulses, as these are of concern (Queensland Clinical Guideline, 2014).

Your task

Listen to these audio file examples of a normal newborn heart rate. Note: you will need to click back to return to this course window.

Next, if you have questions or comments about assessing cardiac status, please post them using the link below.

References

Kain. V. & Mannix, T. (2018). Neonatal Nursing in Australia and New Zealand, 1st Edition. Australia: Elsevier.

Queensland Clinical Guideline (2014). Routine newborn assessment.

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This video is from the free online course:

Assessment of the Newborn

Griffith University