An 8-hour-old girl is being evaluated in the newborn nursery because her lips turned blue while breastfeeding 20 minutes ago. She has not stopped crying since then. She was born at 38 weeks' gestation. Apgar scores were 7 and 8 at 1 and 5 minutes, respectively. She is at the 50th percentile for length and below the 30th percentile for weight. She is alert and agitated. Physical examination shows perioral cyanosis and retractions of the lower ribs with respiration. Cardiac examination shows a harsh grade 2/6 systolic crescendo-decrescendo murmur at the left upper sternal border. Which of the following oxygen saturation percentages are most likely present during the cyanotic episode?

Question

An 8-hour-old girl is being evaluated in the newborn nursery because her lips turned blue while breastfeeding 20 minutes ago. She has not stopped crying since then. She was born at 38 weeks' gestation. Apgar scores were 7 and 8 at 1 and 5 minutes, respectively.  She is at the 50th percentile for length and below the 30th percentile for weight. She is alert and agitated. Physical examination shows perioral cyanosis and retractions of the lower ribs with respiration. Cardiac examination shows a harsh grade 2/6 systolic crescendo-decrescendo murmur at the left upper sternal border. Which of the following oxygen saturation percentages are most likely present during the cyanotic episode?

Quizplus · Accepted Answer

Eductional Objective: Tetralogy of Fallot involves right ventricular outflow tract (RVOT) obstruction and a ventricular septal defect (VSD).  Cyanotic ("tet") episodes are commonly precipitated by a dynamic increase in RVOT obstruction that increases right-to-left shunting through the VSD.  These episodes involve decreased blood flow through the RVOT, causing disappearance of the associated systolic murmur, and reduced oxygen saturation of the left ventricular blood being pumped into the systemic circulation.

An 8-Hour-Old Girl Is Being Evaluated in the Newborn Nursery