Fluid shifts due to the law of osmosis.

We read the paper by Ljunggren et al[1] with great interest as it addresses the use of mannitol in cardiopulmonary bypass(CPB) prime. In our paper "Cardiopulmonary bypass prime composition: beyond crystalloids versus colloids"[2] we could show significant changes in osmolality when a hyperosmolar prime containing mannitol was used for CPB. More important than confirming that adding osmoles will temporarily change the osmolality was our discussion regarding possible negative outcomes. [Extracted from the article]