These come from Joe Ravera - creator of great podcast PEM GEMS - the U in BRUE stands for unexplained. So if it's explainable, it's not a BRUE. For example, if the baby vomited after eating and then choked on that vomit a bit, Joe says, "It's not a BRUE, it's a spew." And if the baby was defecating and strained and grunted and turned red in the face, "It's not a BRUE, it's a poo." Another important part of defining a low-risk BRUE is that it lasted < 1 minute. But terrified parents often report much longer times than the actual event. Some ways to better define the timing: 1) start a stopwatch (e.g. on your phone) and ask the parent to say Stop when they reach about how long it was, 2) ask the parent what he/she did - "I patted his back and he started crying" = < 1 minute, whereas "I ran to the neighbor's house, got a washcloth and put cold water on his face, then called 911, and then he started crying" is > 1 minute.