keepgoing
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Which of following is most likely to occur in salt water drowning rather than fresh water?
A. volume overload
B. faster death
C. hemolytic anemia
D. hypervolemia
E. hyponatremia
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| new_n_lost
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B. faster death >> Saltish water which is hyperosmotic results in fluid entering the alveoli and further causing damage, which leads to hypoxemia and acidosis faster.
Hyponatremia, Volume overload, Hemolytic anemia and Hypervolumia will all occur upon ingestion and not aspiration of water which has to be in a quite large amount around a 1-2 L.
Again Moi 2 Cents.
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| Tiff
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A. Volume overload
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| yarab99
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B- Agree with NNL,,,,faster death
but whats the diffrence b/w hypervolemia and voloum overload?????
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| Tiff
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"but whats the diffrence b/w hypervolemia and voloum overload?????"
Your right yarab99. Seems like the same thing. Drowning is faster in freshwater. Salt water drowning causes hypernatremia. So the only other one that makes sense to me is C - hemolytic anemia.
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| keepgoing
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new_n_lost wrote:
B. faster death >> Saltish water which is hyperosmotic results in fluid entering the alveoli and further causing damage, which leads to hypoxemia and acidosis faster.
Salt water drowning -->salt water in alveolar space--->causes osmotic shift of water into alveolar space-->impaired oxygenation/ventilation-->death usually within 6-7 minutes,so patient would have hypovolemia from this osmotic movement of fluid and hemolysis is not a signifcant feature.
Fresh water drowning-->water in alveolar space-->destroys SURFACTANT activity-->alveolar collapse and intrapulmonanry shunting(perfusion w/o ventilation).Water is reabsorbed into the vascular system.producing VOlume overlaod w/ subsequent hyponatremia,and hemolysis of red blood cells.
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| Tiff
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 Having a little trouble with this. Maybe you guys can help. Now I've always understood that drowning is more rapid in fresh water than salt water. I thought I might have this misunderstood, so I looked it up. This is what I got. Please correct me if you disagree. If anyone has more definitive information it's gladly welcomed. This is what I understand - Both types of drowning will cause hypoxemia but the pathogenesis is different. Fresh water drowning causes hypervolemia & pulmonary edema. Salt water causes hypovolemia & pulmonary edema. Freshwater is hypotonic and diffuses into vascular space increasing blood plasma volume. Surfactant is destroyed and alveolar walls become thick and hemorrhagic pneumonitis occurs. Salt water is hypertonic. Alveoli accumulates water from circulation leading to pulmonary edema and hypoxemia. Now the question is what happens faster.
"Freshwater contains less salt than blood and will therefore be absorbed into the blood stream by osmosis. In animal experiments this was shown to change the blood chemistry and led to cardiac arrest in 2 to 3 minutes. Sea water is much saltier than blood. Through osmosis water will leave the blood stream and enter the lungs thickening the blood. In animal experiments the thicker blood requires more work from the heart leading to cardiac arrest in 8 to 10 minutes." http://en.wikibooks.org/wiki/Transwiki
"In addition haemolysis occasionally occurs after fresh water near drowning. Fresh water drowning can be much faster than salt water drowning. Salt water has a higher osmolarity than plasma and tends to draw water out of the erythrocytes. Fresh water is hypotonic, water is drawn into erythrocytes that swell and burst releasing potassium. This induces hyperkalaemia that can stop the heart." http://www.patient.co.uk/showdoc/40001333/
Therefore I'm left a bit puzzled.....
Also, Keepgoing, Can you supply the source of this question. Thank you.
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| keepgoing
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source is BSS
and also check emedicine for this topic,it states,
In salt water near drowning, surfactant washout occurs, and protein-rich fluid exudates rapidly into the alveoli and pulmonary interstitium. Compliance is reduced, alveolar-capillary basement membrane is damaged directly, and shunting occurs. This results in rapid induction of serious hypoxia than seen in fresh water drowning.
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| Tiff
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Can you provide that link. I'm having trouble finding it. Thank you.
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| sergey1987apr
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I think for fresh water drowning, the shift of water into the body is so fast than it causes hemodilution quickly, and the electrolyte disturbances then kill the host.
But that's for animal experiments.
http://en.allexperts.com/q/Pathology-1640/drownin...
In fresh water and brackish water (approximately 0.5% salinity) drowning the aspirated water is rapidly absorbed from the alveoli into the circulation producing an expansion of blood volume, haemodilution and haemolysis. Within three minutes of submersion haemodilution was up to 72%. Circulatory overload, hyponatraemia and sodium/potassium imbalance together with myocardial hypoxia resulted in a dramatic collapse of systolic pressure quickly followed in the majority of cases by ventricular fibrillation.
...
...
These experiments have been extrapolated to man but have been criticised because (a) the animals were always completely submerged and (b) the main intracellular cation in the dog erythrocyte is not potassium but sodium. The biochemical findings in humans surviving drowning are less distinct.
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| 1.ammara
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As far i know, fresh water drowning causes volume overload and hemolysis,reulting in several effects, including hyperkalemia because of exccesive release of K+ from the RBCs> cardiac standstill and death in 4-5 mintues. ventricullar fibrillation may set in.
about salt water drowning,there is basically fulminant pulmonary oedema, you already know why, progessing to cardiac failure and arrest, but this usually takes 8-12 mintues. so, i go with what Tiff has already posted above.
keepgoing, serious hypoxia than seen in fresh water drowning, agreed but it doesnt mean at all that death will occur faster as this statment isnt saying it to be logical.okay
still confusion is there, either we are getting something wrong or this MCQ isnt correct
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| keepgoing
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Guyz,you all are right to your concepts,even i think so but death in fresh water is not due to asphyxia,its secondary(complications,not the primary reason,water aspiration) consequence which take place due to hypotonic solution(water),like hypervolemia,hemolysis and most impt ventricular fibrilation,BUT in salt water asphyxia is the reason for death, you know why,b/c water is sucked up into alveolar space due to osmotic pull(salt) and no proper O2/ventilation -->hypoxia-->death and is faster.
i do not have any reference to support my answer but, i will search and post,meanwhile if you find please share.
thanks.
Edited by keepgoing on 03/14/08 - 10:48 AM
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| new_n_lost
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In patients who survive an initial episode of freshwater submersion or are resuscitated, substantial changes in serum electrolyte concentrations are rarely seen by the time blood is analyzed, and such changes are documented in only approximately 15 percent of those who are retrieved from the water and cannot be resuscitated. This suggests either that a small amount of water was aspirated or that rapid redistribution of fluid occurred. In either case, treatment of severe electrolyte disturbance is rarely required. Aspiration of a large quantity of sea water causes hypovolemia, with concentration of the extracellular electrolytes. Aspiration of a substantial quantity of fresh water leads to acute hypervolemia, with dilution of extracellular electrolytes. If enough water is aspirated to make the plasma hypotonic and the patient has hypoxemia, red-cell membranes rupture, and plasma hemoglobin and serum potassium concentrations increase substantially. With rapid redistribution of fluid and the development of pulmonary edema, however, even patients who have been submerged in fresh water frequently have hypovolemia by the time they reach the hospital.
http://content.nejm.org/cgi/content/full/328/4/25...
Both result in Hypoxemia and V/Q mismatch. You can argue with the timings of it but a severe pulmonary edema and pulmonary shunting is more evident in sea water drowning.
All the above citations have not argued one essential point that which caused a faster death and whether if these findings are applicable on human subjects. So far everyone sort of backs away from making such conclusion. But what everyone has agreed to is that Sea water causes a massive pulmonary edema in terms of comparison with fresh water. Now unless we can prove a massive pulmonary edema patient lived long enough to prove that it was the hemolysis and the overloading volume that killed him this is going to remain as a mystery to be solved.
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