Discussion about this post

User's avatar
Alexander Rodarte's avatar

In 2009, I had a handout that compared the solutions for use in the OR. I had to fight the Pharmacy and Therapeutics Committee to allow me to use Plasmalyte outside the heart room because it was a few cents more expensive than NS. Of note was that fact that at the time, it was the common misconception that only NS was compatible with blood or blood products. So at the bottom of my excel spreadsheet that was very similar to yours, I noted the following. "Package insert for Plasmalyte-A injection pH 7.4: The indications and usage section of the package insert of Plasmalyte-A injection pH 7.4 states that the solution is equally compatible to normal saline with blood and components. Plasmalyte-A injection pH 7.4 can be used as a priming solution for blood components, and may be added to or used with blood components through the same line, and may be used as a diluent for blood components."

Expand full comment
Andrew Davidson's avatar

"Poisonous for children!". That was the label, in large red letters, that started appearing next to bags of "half normal saline" on some Australian children's wards 10 years ago. Since then hypotonic fluids have disappeared from our wards. It has been a slow journey since the 1950's Halliday paper mentioned by Myron. The journey has been controversial and tragic for those children that died due to well-meaning staff prescribing a "poisonous fluid". From the beginning there was doubt that 0.2% saline was the right fluid for children. Some suggested isotonic fluid would be better. Others feared this would lead to hypernatremia. A compromise was reached. We feared going all the way, so we went half-way and half normal saline was born. Alas, children still died from iatrogenic hyponatremia. The medical community couldn't agree on isotonic fluid. The evidence was not quite there yet.

As a researcher we start thinking we will make great discoveries and change the way we care for children; spectacularly improving outcomes. Alas you soon realize that you are lucky if you make one discovery in your lifetime that has any impact - let alone spectacular impact. If you're really lucky you may make two. For me it was the PIMS trial published in the Lancet in 2015 (McNab S, Duke T, South M, et al. 140 mmol/L of sodium versus 77 mmol/L of sodium in maintenance intravenous fluid therapy for children in hospital (PIMS): a randomized controlled double-blind trial. Lancet. 2015;385(9974):1190–1197), though even then "discovery" may be an overstatement. We randomized hundreds of children across the hospital to maintenance with isotonic or half normal saline. The hospital was full of fluid bags wrapped in black plastic. Every ward, every nurse and every junior staff member was involved in the trial. In those days such trials were actually feasible! Sure enough, those with isotonic fluid got less hyponatremia and perhaps fewer nasty complications. Doh... Virtually overnight practice changed across Australia. Trials change practice when we are at the cusp of evidence; just enough to flip things. This was such a trial. We alone didn't change practice, we just gave the final nudge. A couple of years afterwards the American Academy of Pediatrics published the guideline recommending isotonic fluid. (Feld et al Pediatrics (2018) 142 (6): e20183083. https://doi.org/10.1542/peds.2018-3083). Hopefully the "poison" labels are no longer needed anywhere and half saline has gone for good.

One last part of the story. Switching to isotonic fluid didn't completely eliminate iatrogenic hyponatremia. Sick children have elevated levels of ADH, and are at risk of hyponatremia, more so than adults. The 4:2:1 rule is fine for well children but too much water for sick children. We may have got rid of half normal saline but the 4:2:1 error persists; and is still harming children.

Expand full comment

No posts