Fluid Overload Question

[WaveRunner123456]

Could a fluid overload event resulting from an intravenous infusion of 0.9% (normal) saline result in neuronal swelling? (As you would see during water intoxication)

If so, would this be hyposmotic swelling or isosmotic swelling of the cell?

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[typhoonegator]

Is this for a test?

 

[WaveRunner123456]

No, this is not for a test.

 

[typhoonegator]

Normal saline has 154mEq/L of sodium. So it will not cause neuronal swelling immediately from hyponatremia the way that water intoxication will. However, it will cause a hyperchloremic non-gap metabolic acidosis. This will cause activation of the Na+/H+ exchanger resulting in cellular swelling. Because this activity is pH dependent and not driven by passive diffusion or idiogenic osmoles, it is most consistent with an isosmotic cellular swelling.

It's probably pretty trivial though, unless the patient already has cerebral edema for another reason, and in that case the issue is more from acidosis-related changes in cerebral blood volume than cellular swelling.

 

[WaveRunner123456]

Thank you very much for the detailed reply. I asked in relation to this paper which I have been reading: http://www.ihrdni.org/306-112.pdf, with the primary interest being if such an event would be cytotoxic. This study: https://www.researchgate.net/public...oride_on_Serum_Osmolality_in_Human_Volunteers , which created this exact event, observed that the participants who sustained fluid overload from normal saline suffered from cognitive impairments. The study does not mention recovery, but I would like to presume that such an event does not cause permanent harm.

 

[typhoonegator]

Given how much normal saline over-resuscitation and volume overload occurs in EDs and ICUs throughout the world, I would hope that it doesn't have lasting neurologic sequelae.