Interpreting "Hemodialysis Output" and "Ultrafiltrate Output" Items

[whiskey0504]

Hi, I was wondering if anyone has any thoughts on how to interpret each charted value in "Hemodialysis Output" (226499) and "Ultrafiltrate Output" (226457) given their unit in mL and that each charted value has only one associated timestamp (charttime), not a range (starttime and endtime). Would each charted value be the total observed output in the last hour? or the set output in the next hour? or the observed output since the last charting (but then how to interpret the first observation in chronological order -- would that be the total amount since RTT started?)