Grade 1: 1-2 episodes (separated by 5 minutes) in 24 hrs
Grade 2: 3-5 episodes (separated by 5 minutes) in 24 hrs
Grade 3: ≥ 6 episodes (separated by 5 minutes) in 24 hrs; tube feeding, TPN or hospitalization indicated
Grade 4 - Life threatening consequences; urgent intervention indicated
Grade 5 - Death