Ed Rivers, a 3rd year medical student, was alone in the hospitalER one night. It was unusually quiet that night, and the residentwas getting some much needed sleep. A patient, Mrs. X, was broughtin showing signs of serious dehydration. Ed tried to give herewater, but she vomited this back up. Feeling he must try something,and not wanting to wake the resident, Ed administered 1 liter ofsterile distilled water IV. Assume for simplicity that the redblood cells contain only solutes to which the rbc membrane isimpermeable, and that the rbcs and plasma are in osmoticequilibrium when the patient is brought in. The osmolarity of therbc is 300 mOsm/L.
Mrs.X got much worse after Ed's treatment so the resident wascalled and she drew some blood from the patient and centrifuged it.The supernatant above the packed red blood cells was pink. Theresident then decided to infuse a sucrose solution into the patient(the red blood cell membrane is impermeable to sucrose).Had Edgiven Mrs. X a sucrose solution instead of water, he might havehelped her.
What concentration of sucrose solution should he haveadministered to leave her red blood cell volume unaffected. Showcalculations.
Ed Rivers, a 3rd year medical student, was alone in the hospitalER one night. It was unusually quiet that night, and the residentwas getting some much needed sleep. A patient, Mrs. X, was broughtin showing signs of serious dehydration. Ed tried to give herewater, but she vomited this back up. Feeling he must try something,and not wanting to wake the resident, Ed administered 1 liter ofsterile distilled water IV. Assume for simplicity that the redblood cells contain only solutes to which the rbc membrane isimpermeable, and that the rbcs and plasma are in osmoticequilibrium when the patient is brought in. The osmolarity of therbc is 300 mOsm/L.
Mrs.X got much worse after Ed's treatment so the resident wascalled and she drew some blood from the patient and centrifuged it.The supernatant above the packed red blood cells was pink. Theresident then decided to infuse a sucrose solution into the patient(the red blood cell membrane is impermeable to sucrose).Had Edgiven Mrs. X a sucrose solution instead of water, he might havehelped her.
What concentration of sucrose solution should he haveadministered to leave her red blood cell volume unaffected. Showcalculations.
