Isotonic Solutions (Nursing)

00:00 So, isotonic osmolarity falls within or close to the normal range of your serum. Normal was 270-300 and if we give it in appropriate amounts, yeah, that was intentional silence there because I want you to really hear that if we give isotonic in appropriate amounts for that patient. Find a little tiny 95-year-old grandma. She can't handle as much someone my age and my size, okay? So, in appropriate amounts for that patient's age and body and ability of their heart to pump and function should not cause fluid volume to shift. The volume we put in should stay in the intravascular space and it should be about equal of what stays in the cells. Isotonic solutions, we used to expand the intravascular compartment. That just means because the fluid stays in the intravascular department we use it to fill that tank back up. Watch the patient for fluid volume overload.

01:03 Once you give too much isotonic fluids for that patient, you can throw them into at least elevated blood pressure or even congestive heart failure depending on how fragile they are. So look back at our picture there. We've got 60% of fluid, is extracellular, it's outside of the cells, it's either in the interstitial or the intravascular. With an isotonic solution, we're putting the solution directly into the intravascular space and it's likely going to stay there. Not cause too much problems as long as we don't overload the patient. If we overload the patient and hang way too much isotonic solution, it's going to start functioning like another one of our solutions, we're going to be in big trouble. Here's a listing again. Each solution on this slide is an isotonic solution that if hang in an appropriate amount should not cause fluid shifting. Normal saline is what you're going to see most often in your practice, 0.9% normal saline. Sometimes you see just written as NS.

02:09 We use it if the patient needs extra volume, they're a little low, they're a little dehydrated but keep in mind these are crystalloids. Crystalloids mean they don't have the ability to carry oxygen, they don't have any protein, they're just a crystalloid. C-r-y-s-t-a-l-l-o-i-d. Now colloids are proteins. That's spelled c-o-l-l-o-i-d-s. These are crystalloids. So we give this to people who are in shock, who are in diabetic ketoacidosis. We give normal saline with blood transfusions, if they have a little bit of low sodium, that's what hyponatremia is. We give it for metabolic alkalosis or for elevated calcium, hypercalcemia. Okay so this is a pretty generic solution. No solution is harmless but this is the one that's least risky as long as we give it in the appropriate amount.

03:05 Watch them for fluid volume overload, watch them to see if their sodium is going so high it's causing their potassium to be lower and if they have renal disease or they're on the right kind of glucocorticoid make sure that you watch your sodium levels because normal saline will be adding additional sodium to your patient. Lactated Ringer's is our next solution. Now, Lactated Now, Lactated Ringer's is a little bit different because the liver takes that lactate and converts it to bicarbonate. So the name of this solution is Lactated Ringer's and the liver once it takes in that lactate it will change it to bicarbonate, which is a base. So, patients with liver disease, this is a problem. Lactated Ringer's in liver disease, they can't metabolize that lactate well.

03:56 So it's not good for them and it's really not good if someone's already in alkalosis. Their pH is already too basic and so they're already too basic and we turn this into more of a carbonate, we're going to have an even bigger pH problem. So we give this as a fluid and electrolyte replenisher. You just want to be careful with people who have liver problems or who are in alkalosis, that's a pH that's greater than 7.45. Now, D5W. This one has got like a double life. It's isotonic in the bag but once that dextrose is metabolized, it becomes hypotonic. So in the bag it's an isotonic solution but once you put it in the body and the body eats to that dextrose, it's metabolized, happens pretty quick then it becomes hypotonic. So, remember hypotonic solutions cause fluid to go into the cells. Right? Because you hang a hypotonic solution, I'm more concentrated in my cell so you're into the cell. So it's not good for people with elevated ICP, I don't want swollen souls there. It's not good for people with CHF or who are early postop. Surgical stress might cause this increase in their ADH so this isn't a great choice for them. Now we can use it for fluid loss in dehydration or hypernatremia because it will help dilute that extra sodium and their extracellular fluid. So D5W is a little different, isotonic in the bag, hypotonic after the body metabolizes that. Hetastarch to Normosol, you may or may not see, they're a little bit unusual but it depends on what type of unit you're on but they function just like in isotonic solution.