Hospitals operate 24 hours a day, and it is assumed that critical decisions occur continuously around the clock. However, many aspects of hospital operation occur at particular times of day, including medical team rounding and shift changes. It is unclear if this impacts patient care, as an empirical account of 24 h treatment patterns is lacking. We analyzed the daily distribution of ~120K doses of 12 separate drugs in 1,486 inpatients at a major childrens hospital in the U.S. Treatment orders and administration were strongly time-of-day-dependent, marked by distinct morning time surges and overnight lulls. These 24 h rhythms in treatment were remarkably consistent across drugs, diagnoses, and hospital units. In sum, nearly one-third of all 116,975 orders for treatment were placed between 8 AM and 12 PM. This rhythm in hospital medicine coincided with medical team rounding time, not necessarily immediate medical need. Lastly, we show that the clinical response to hydralazine, an acute antihypertensive, is dosing time-dependent and greatest at night, when the fewest doses were administered. The prevailing dogma is that hospital treatment is administered as needed regardless of time of day. Our findings challenge this notion and reveal a potential operational barrier to best clinical care.

A Large-scale Study Reveals 24 hour Operational Rhythms in Hospital Treatment