The Boarding Patient: Effects of ICU and Hospital Occupancy Surges on Patient Flow

Abstract

Patients admitted to a hospital’s intensive care unit (ICU) often endure prolonged boarding within the ICU following receipt of care, unnecessarily occupying a critical care bed, and thereby delaying admission for other incoming patients due to bed shortage. Using patient-level data over two years at two major academic medical centers, we estimate the impact of ICU and ward occupancy levels on ICU length of stay (LOS), and test whether simultaneous “surge occupancy” in both areas impacts overall ICU length of stay. In contrast to prior studies that only measure total LOS, we split LOS into two individual periods based on physician requests for bed transfers. We find that “service time” (when critically ill patients are stabilized and treated) is unaffected by occupancy levels. However, the less essential “boarding time” (when patients wait to exit the ICU) is accelerated during periods of high ICU occupancy and, conversely, prolonged when hospital ward occupancy levels are high. When the ICU and wards simultaneously encounter bed occupancies in the top quartile of historical levels—which occurs 5% of the time—ICU boarding increases by 22% compared to when both areas experience their lowest utilization, suggesting that ward bed availability dominates efforts to accelerate ICU discharges to free up ICU beds. We find no adverse effects of high occupancy levels on ICU bouncebacks, in-hospital deaths, or 30-day hospital readmissions, which supports our finding that the largely discretionary boarding period fluctuates with changing bed occupancy levels.

The mortality of critically ill patients was not associated with inter-hospital transfer due to a shortage of ICU beds - a single-centre retrospective analysis

“…Apart from the interest in avoiding excess mortality that comes with refusal of ICU admittance [ 16 ], availability is expected for the next critically ill patient in need of specialized care. Efficient use of resources in such a tertiary ICU does not allow final mobilization or boarding of patients who can be cared for in other ICUs [ 17 ]. Indeed, patients not in need of tertiary care are not necessarily kept for longer time in our CICU.…”

Evaluating intensive care unit admission and discharge policies using a discrete event simulation model

“…Due to large number of comparisons for multiple factors, we only report the single factor results, shown in Table 9. For the multiple factors and interaction terms, we found that interactions of p:w, p:d, w:d, and p:w:d contained 48 120 , 57 66 , 48 66 , and 820 1128 significantly different means, respectively. Table 10 presents a summary of the results obtained by averaging across all four patient mix combinations, for discharge windows and wait thresholds.…”

“…An empirical study of similar chain of incidences was carried out by Long and Mathews. 48 They also suggested prioritizing ICU patients for discharge when floor occupancy exceeds a certain threshold, for example, 80%. In fact, patients who complete their ICU service during the day shift (from 7:00 to 19:00), experience significant discharge delays due to bed shortage in downstream units.…”

“…In fact, patients who complete their ICU service during the day shift (from 7:00 to 19:00), experience significant discharge delays due to bed shortage in downstream units. 48 In addition, out-of-hour (from 20:00 to 7:00) discharge from the ICU is strongly associated with both in-hospital mortality and ICU readmission. 49 While these results might be due to patient differences, differences in care, or both, 49 extending the ICU discharge in practice will need to account for such risks.…”

Load Effect on Service Times

“…(D) Workload smoothing: Completing the discharge of customers whose processing is complete earlier, in anticipation of incoming demand. Long & Mathews (2017) observed that ICU patients often board while awaiting transfer to other hospital units. By decomposing ICU LOS into care time and boarding time, they found that the shorter LOS during higher ICU occupancy is not related to early discharge decisions (in contrast to findings by other researchers about early discharge, which we cited under the task reduction mechanism) but is instead caused by decreased boarding times of patients that are discharged in order to free ICU capacity.…”