RAHK
Forum Junior
Topics: 7
Posts: 34
|
In Error, a patient is infused with large volumes of solution that causes lysis of his RBCs, the solution was most likely :
a- Isotonic Saline
b- Isotonic mannitol
c- Hypertonic mannitol
d- Hypotonic urea
e- Hypertonic urea
Need help please ! 
|
| Peace
Forum Newbie
Topics: 0
Posts: 4
|
I think the answer is C.
b/c Hypertonic solution will cause the cell to lyse and hypotonic will cause it to swell and no changes with Isotonic solution. Urea will distribute itself and mannitol will stay in the ecf and cause the cell to lyse. pls correct me if wrong.
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
I guess lysis means that Cells swell, which has to be by the effect of hypotonic solution, and hypertonic will cause the cells to shrink. but I agree with you, about the mannitol, cuz as far as I know that urea does not contribute to the osmolality, and will have no effect on the cells. but the answer I have in the book is D !!! 
|
| lnb6des
Forum Newbie
Topics: 0
Posts: 5
|
i think that the right answer is DD, iagree with rahk
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
Can you give us an explanation please ?
|
| Peace
Forum Newbie
Topics: 0
Posts: 4
|
RAHK, you are right the answer is D. I read the question again and by process of elimination the only correct choice has to be D. as you mentioned above the Hyper will cause it to shrink by increasing the Ecf osmolarity and causing a shift of fluid from ICF to ECF. Isotonic gain will not affect ECF Osmolarity and therefore no movement of fluid from ICF to ECF. Hypotonic infusion will lower ECF osmolarity and causes an increase in both ECF and ICF volume and therefore causes the cell to swell and lyse.
|
| muzammil
Forum Guru
Topics: 16
Posts: 664
|
the answer is d
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
Ok ... but I'm sure I won't figure it out in the exam ! simply by saying urea has no role in effective osmolarity, according to kaplan !
but I guess there is no other answer that is more right than this one !
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
A 50kg, 32-year-old man has sustained a stab wound to the right axilla with laceration of the axillary artery. The first response team notes a blood pressure of 80/20 mm Hg and rapidly infuses one liter of water instead of normal saline. The new condition of the body fluid compartments, as compared to the condition prior to infusion, is
a- expanded ECF volume and no change in body fluid osmolality
b- expanded ECF and ICF and decreased body fluid osmolality
c- expanded ECF and an increase in body fluid osmolality
d- expanded ICF and no change in body fluid osmolality
e- contracted ICF and expanded ECF with higher body
|
| doc179
Forum Guru
Topics: 67
Posts: 1,217
|
1.D
2.B
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
I agree !!
|
| jole
Forum Elite
Topics: 14
Posts: 300
|
1,D 2,B
About urea not cotributing to osmolarity-i don't agree to that cos u need urea for the establishment of the corticopapillary gradient which is needed to concentrate urine in water deprivation.
Any explantions please.I think urea is definitely osmotically active.
___________________
Never underestimate the power of prayer.
|
| muzammil
Forum Guru
Topics: 16
Posts: 664
|
2nd answer is b
|
| RAHK
Forum Junior
Topics: 7
Posts: 34
|
the effective osmolirity of the solution is determined by the non penetrating solutes. A penetrating substance such as urea will diffuse across the membrane and equalize it's concentration in the two compartments. therefore it will not contribute to effective osmolirity. so here in this case it will be like pure water, so the effective osmolirty will be zero and therefore the cells will swell and lyse !!! 
|
| me007
Forum Guru
Topics: 72
Posts: 799
|
in this setting, there is not any difference between hypertonic and hypotonic urea, both will equalize their concentration inside and outside cell and result in cell swelling.
Is it right?
But there is a choice d and a choice e in the question.
?
|
|
| |
| | | | | | | | | | | | | | | |
