They were bumping the Na to 200mOsm/L, which is insanely high compared to our plasma. Hypertonicity like this causes the cell to shrink, which spoils the delic

They were bumping the Na to 200mOsm/L, which is insanely high compared to our plasma. Hypertonicity like this causes the cell to shrink, which spoils the delicate relationships and ionic bonds between molecules in the cell. This causes a litany of issues, but one thing is an increase in production of reactive oxygen species, a byproduct of normal metabolism. ROS, otherwise known as free radicals, is what they use to measure cell stress.