Quote from leslie :-d
it *sounds* like they could be used as a volume expander (r/t dehydration), in addition to raising his k+ level by bringing it back into cells.
it should only used short term.
i agree with leslie. lr is slightly hypotonic and converts to bicarbonate when metabolized. d5ns is slightly hypertonic and causes the push/pull effect that will effect the k move form extracellular to intracellular. the removal of copious amounts of gastric contents will cause acidosis and dehydration. i have seen this technique used in the effect that one is the cc/cc fluid replacement for gastric content and the other is fluid replacement/maintenance.
this needs to be used with great caution in a compromised elderly patient. large amounts of volume will be difficult for this population to deal with and the potential for heart failure/volume overload is almost assured if not monitored closely. be careful this time of year when the med students are fresh on their rotations.
there's no one ideal fluid for every situation. for resuscitation, crystalloids allow rapid repletion of volume. 0.9% sodium chloride is slightly hypertonic compared to plasma (308 mosm/l vs 290). lactated ringer's is slightly hypotonic (273 vs 290). since they are both so close to plasma, they are considered the isotonic fluids. you can get a hyperchloremic metabolic acidosis from large volumes of 0.9% nacl (typically 5+liters). you can get hyponatremic from large volumes of lr. either are acceptable for volume resuscitation.
for maintenance, sodium content and tonicity matters. if you use 0.9% nacl for an extended amount of time, the plasma sodium content will increase and you may get hypernatremic. to avoid this, solutions like 0.45% or lower are used. if the patient is not eating, and you are concerned about providing calories to prevent protein breakdown, dextrose is added to the fluid. 3 liters of a 5% dextrose solution provides 500 kcal a day enough to be protein sparing. adding d5 to ns results in a hypertonic solution (560 mosm/l). if the patient's glucose metabolism is impaired, you could cause cellular dehydration from the hypertonic solution. d5 0.45% nacl avoid this.
i don't care about the med student but i do care about you......this charts may help you.....they were made by a great nurse here daytonite
(rip). table of commonly used iv solutions.doc chart of commonly transfused blood products.doc