Case Study 3: Blanche Devereaux is a 78-year-old widow who was brought to the em
ID: 51307 • Letter: C
Question
Case Study 3:
Blanche Devereaux is a 78-year-old widow who was brought to the emergency room one evening by her sister. Earlier in the day, she had seen bright red blood in her stool. She continued with her daily activities. However, the bleeding continued all day. By dinnertime, she could no longer ignore it. Blanche takes aspirin, as needed, for arthritis, sometimes up to 12 tablets daily. In the emergency room, she was light-headed and her skin was pale and cool to the touch. Her hematocrit was 26% (normal for women, 35%-45%). The ER doctor ordered orthostatic vital signs. Below are the results of the test:
Measurement
Supine
Standing
Blood Pressure
88/60
74/464.
Heart Rate
106 bpm
130 bpm
Q. What was the compensatory mechanism that leads to her heart rate being fast in both positions?
Measurement
Supine
Standing
Blood Pressure
88/60
74/464.
Heart Rate
106 bpm
130 bpm
Explanation / Answer
Compensatory mechanism which was used to restore blood pressure to normal was Baroreceptor reflex. In Baroreceptor reflex the sympathetic outflow to heart and blood vessels increase due to which heart rate increases.
Her heart rate was more elevated in standing position because in standing position the arterial blood pressure was higher than supine position so the Baroreceptor reflex mechanism was stimulated at a much higher rate which caused the increase in heart rate as well as stimulation of blood vessels