The authors have been studying the system-scientific modeling of the inpatient flow in an acute-care hospital using the recorded order log data for the movement of patients over a finite observation period. We have thus far published the study results for the patient flows of obstetric and neonatal patients in a hospital. The order log in the University of Tsukuba Hospital during the two fiscal years 2010-2011 was used as a data source.
In the present study, we deal with pediatric patients who are transferred over several wards from their admission until their discharge. We calculate the number of admissions, ward transfers, and discharges during the two years of observation. Special attention is paid to the numbers of patients who are hospitalized before and after the finite observation periods. We consider the total number of days on which patients stay in each ward over the observation period, which is called the patient-days (PD) as a measure of clinical load brought by patients on the hospital. We count the numbers of patients who arrive to, depart from, and stay in each ward over the observation period and show that these numbers satisfy the conservation law for the patient flow in a hospital. We also confirm an identity relation among the mean number of patients staying in each ward per day, mean number of patients who arrive to that ward per day, and mean number of days a patient stays in that ward, called the mean length-of-stay (LoS), which may be thought of as a discrete-time, finite-horizon version of Little's law in queueing theory. We propose a patient residence chart to visualize the movement of each patient during their hospitalization. We present a method to classify the paths of patients, i.e., a sequence of pairs (ward number, length-of-stay on that ward), from which we calculate a variety of measures of patient movement.