MS-0192
You are on the ward and notice that an elderly patient lying supine in a monitored bed is hypotensive, with a blood pressure of 90/70 mmHg and tachycardic, with a heart rate of 120 beats/minute.
You adjust the bed to raise the patient’s legs by 45 degrees and after 1 minute you measure the blood pressure again. The blood pressure increases to 100/75 and you prescribe a 500mL bag of normal saline to be given IV over 15 minutes.
What physiological association explains the increase in the elderly patient’s blood pressure?