Thank you for your inquiry on CMS819v2: Hospital Harm - Opioid Related Adverse Events and CMS871v4: Hospital Harm - Severe Hyperglycemia. In the narrative Definition sections of these measures, inpatient hospitalizations are defined as including time spent in the emergency department (ED) or observation when these encounters are within an hour of the inpatient admission. In other words, if the transition time between when an ED visit ended and an inpatient admission started is one hour or less, then the inpatient hospitalization period would begin at the start of the ED or OBS visit. If the transition time between when an ED visit ended and an inpatient admission started is more than one hour, then the inpatient hospitalization period would begin at the start of the inpatient admission. In the following example, the start of the ED visit would be used as the start of the inpatient hospitalization period: 12/1 at 8:00AM – ED visit start 12/1 at 8:45AM – ED visit end 12/1 at 8:59 AM – Inpatient admission start 12/1 at 08:00 AM- Start of Inpatient Encounter (as the ‘ED Encounter or Observation [OBS] has coalesced with the inpatient encounter). Conversely, in the following example, the start of the inpatient admission would be used as the start of the inpatient hospitalization period as the delay between ED/ OBS discharge and admission is greater than 1 hour: 12/1 at 8:00AM – ED visit start 12/1 at 8:45AM – ED visit end 12/1 at 10:30 AM – Inpatient admission start 12/1 at 10:30 AM- Start of Inpatient Encounter (as the ‘ED Encounter has NOT coalesced with the inpatient encounter).