The Lasix sandwich is when you give 25 g albumin and 20 minutes later give 20 mg IV Lasix. It is often used by surgeons after abdominal surgery to theoretically pull water into the intravascular space and then have the pt pee it out.
In the MICU, the Lasix sandwich is postulated to be helpful in pts with ARDS/ALI who have water-logged lungs (See Martin, Crit Care Med). However, this theory doesn’t hold up in large randomized trials, and one could argue that in really sick patients, the endothelial barrier is often damaged—this means that as soon as you give the albumin, it leaks across the endothelium.
Albumin in third space + Lasix in the intravascular space= a patient who has a lot of third-spacing but is more intravascularly depleted. Not good.