The nurse is reading the results of non-stress test (NST) strips completed that day. Which of the following strips meets the criteria for a reactive NST? Select one:
A.
A fetal heart rate baseline of 140 with one acceleration to 155 for 15 seconds within 30 minutes.
B.
A fetal heart rate baseline of 140 with two accelerations to 160 for 15 seconds within 20 minutes.
C.
A fetal heart rate baseline of 130 with two accelerations to 135 for 15 seconds within 20 minutes.
D.
A fetal heart rate baseline of 150 with two accelerations to 160 for 10 seconds within 20 minutes.
The correct answer and Explanation is :
The correct answer is B: A fetal heart rate baseline of 140 with two accelerations to 160 for 15 seconds within 20 minutes.
Explanation:
A reactive non-stress test (NST) is a key tool used in prenatal care to assess fetal well-being by monitoring the fetal heart rate (FHR) in response to fetal movements. A reactive result indicates that the fetus is receiving adequate oxygenation and has a healthy autonomic nervous system response.
Criteria for a Reactive NST:
- Baseline FHR: The baseline fetal heart rate should fall within the normal range of 110 to 160 beats per minute.
- Accelerations: A reactive NST requires two or more accelerations within a 20-minute period. Each acceleration must meet the following:
- Duration: Last at least 15 seconds.
- Increase in heart rate: The fetal heart rate must increase by 15 beats per minute (bpm) or more above the baseline.
Review of Each Option:
- Option A: This strip only shows one acceleration, whereas two accelerations are required for a reactive NST.
- Option B: This strip meets all the criteria for a reactive NST:
- The baseline FHR is 140, which is within the normal range.
- There are two accelerations, both lasting 15 seconds.
- The accelerations show an increase of 20 bpm (from 140 to 160), which meets the criteria for a reactive result.
- Option C: While there are two accelerations, they only increase by 5 bpm, which is below the required 15 bpm threshold for a reactive NST.
- Option D: Although there are two accelerations, they last only 10 seconds, which is below the required 15 seconds duration.
Thus, Option B best fits the criteria for a reactive NST and indicates fetal well-being.