RNC-LRN study materials
RNC-LRN study resources

RNC-LRN: Assessment and Physiologic Adaptation of the Newborn

RNC-LRN · Work through your exam, one topic at a time.

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Assessment and Physiologic Adaptation of the Newborn

Transition and vital signs

The first 6–8 hours divide into a first reactivity period (heart rate briefly to 160–180, respiratory rate to 80, acrocyanosis, transient crackles) and a period of decreased responsiveness, stabilizing by about 8 hours. Know the ranges: axillary temperature 36.5–37.5 °C, heart rate 110–160, respiratory rate 40–60, systolic blood pressure roughly 60–80 mmHg at term, lowest in the first hours.

Assessment tools

Apgar is a descriptive score at 1 and 5 minutes (then every 5 minutes to 20 while below 7). It does not drive resuscitation, and a low 1-minute score is not a diagnosis of asphyxia. Heart rate is the single most important element assessed. The full exam includes gestational age assessment (Ballard), anthropometrics plotted on growth curves, dysmorphology, hips and red reflex, and tone with reflexes (Moro, rooting, suck, palmar and plantar grasp).

Traps

Expect items that test whether you treat Apgar as a resuscitation trigger (it is not - heart rate under 100, apnea, or gasping is), distinguish caput and molding from cephalohematoma and subgaleal hemorrhage, and separate normal findings (erythema toxicum, milia, salmon patches, acrocyanosis) from petechiae or pallor. A common distractor: labeling a respiratory rate of 70 with retractions as normal newborn tachypnea.

Worked example

At 30 seconds of life a term newborn has heart rate 90, apnea, and central cyanosis. The correct action is to begin positive pressure ventilation - not to assign an Apgar score and reassess. Reassess heart rate in 15 seconds after corrective steps and use preductal SpO2 targets.