SPOILER: Low systemic blood pressure & high localized blood pressure

[Int'lEng]

(Confusion brought up by a U World question) The patient was said to have low systemic blood pressure, low blood oxygen and excess fluid in the lungs, and the question asked about the reason for the fluid in the lungs, to which the answer was [spoiler starts] (increased hydrostatic pressure within pulmonary capillaries) [spoiler ends]. I was just wondering if these two are contradictory to each other.

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[GreenDuck12]

Not it’s not contradictory. It’s helpful to think of pulmonary capillaries as separate from systemic capillaries so yes you can have increased hydrostatic pressure in pulmonary capillaries and have a low systemic bp (Common in left heart failure).

 

[Blueprint Med School]

Pretty common, actually. Anything like mentioned above like heart failure that is going to cause backflow of blood will reduce the amount of blood moving forward to lower the systemic pressure and increase the amount of blood going backwards increasing the pulmonary pressure. Pulmonary embolism (blood clot in the lungs) and cardiac tamponade (cardiac sack filling up with fluid) can both cause right heart failure due to the large amounts of pressure being sent backwards that at the same time doesn't let blood go forward so you get systemic low blood pressure.

David D, MD - USMLE and MCAT Tutor
Med School Tutors