عملکرد و تخصیص بستر انعطاف پذیر در واحد مراقبت های ویژه

The beds of an intensive care unit (ICU) are a scarce resource. Stochastic patient demands for these beds and stochastic service times in their utilization make managing that resource a complex problem lacking an easy solution. The current practice in one Hong Kong hospital is for the ICU administrator to exploit the fact that there are some patients whose admission to the unit can be postponed. These are patients scheduled for an elective surgery that can be cancelled. One way to minimize the number of cancelled surgeries is to reserve some of the unit's beds for the exclusive use of the elective-surgery patients. We evaluate various bed-reservation schemes via a simulation model that is based on this ICU's historical data, and demonstrate the tradeoffs that each requires among various relevant system-performance measures. We further show how this information can be summarized in a classic efficient frontier. This frontier provides a useful medium through which the ICU administrator can communicate the rationale behind the chosen bed-allocation system to the surgeons and the ICU physicians, in an attempt to resolve the potential conflicts between them.

Operations managers make repetitive decisions subject to capacity constraints that are not readily relaxed. Thus, utilizing the extant capacity optimally is an operational imperative. Nowhere is this imperative better exemplified than in a hospital's intensive care unit (ICU) where the lives of the hospital's most critically ill patients are at stake. We focus on the ICU in a not atypical Hong Kong public hospital whose administrator, acting as a triage officer, determines admissions priorities so as to enhance the number of surviving patients. Expanding capacity, the number of beds in the unit, is not an option, as ICU care is an unusually expensive therapy. Reducing capacity is not an option either, as this would risk deserving patients being denied admission to the unit or released prematurely. Thus, the ICU administrator's problem is how to better utilize the existing capacity so as to relieve what upon occasion is a bed shortage and better serve the patients without incurring additional cost. Patients, however, are only one of several constituencies to which the administrator is accountable, and the preferences of those constituencies in the prioritization process often conflict. One especially prominent conflict in our sample hospital is between the operating surgeons and the ICU physicians. This is a potential conflict in any hospital that has an ICU.

Managing the beds in an ICU is a difficult problem that lacks a single solution to please everybody. New demands for ICU care and the service times required by its current residents are stochastic, which makes it impossible to guarantee admission to all deserving patients. When no beds are unoccupied, the administrator takes the path of least resistance. That path exploits the fact that there are some patients whose admission can be postponed. The latter patients are those scheduled for elective surgery. In their case the surgery is cancelled, which inconveniences the surgeon and the attending staff, to say nothing of the patient. It is therefore incumbent upon the administrator to make the most effective use of the extant bed capacity. One suggestion for achieving this goal at minimal cost is to reserve some beds for the exclusive use of the elective-surgery patients. In dealing with this suggestion, the administrator faces two major issues. First, it is necessary to evaluate the various proffered bed-reservation schemes on any number of performance criteria, which creates a multiple-objective decision-making problem. Second, it is necessary to communicate the results, and the reasons for either rejecting those schemes or for putting one in place, to those higher up in the managerial hierarchy, as well as to the operating surgeons and the ICU physicians.