Teoría de la Calidad Total de William Edwards Deming

This section explains the structure of the model and is divided into two sub-sections. The first sub-section elaborates on the four types of flexibility configurations used. The second sub-section explains the timeline for decision making that are used to make capacity and staffing decisions for each flexibility configuration. We consider two non-homogeneous hospital units, one being a complex unit with high patient acuity and the other being a simple unit with lower patient acuity. Patients in the simple unit, in some configurations, can be upgraded to complex unit but not vice-versa. For notation purposes, we assume unit 1 to be a complex unit and unit 2 to be a simple unit. For example, assume unit 1 to be the intensive care unit in the pre-natal floor while unit 2 is the medical/surgical unit in the same pre-natal floor. Both the units are under the same clinical grouping (pre-natal) so if there is not enough capacity to admit a newborn in the med/surg unit, the new born is upgraded to ICU. These two units can be staffed with three types of nursing staff, depending on availability. The in-house regular nurses are assigned to their home unit (hereafter referred to as dedicated nurses) while the in-house flexible nurses (hereafter referred to as flexible nurses) are assigned to either of the two units based on demand. The dedicated nurses and flexible nurses are called total staff in the notation and formulation. If patient demand is still not met, then travel/contract nurses from an outside agency (hereafter referred to as contract nurses) are hired (at higher cost than either unit). The two non-homogenous units have different capacities, measured in

FIGURE 3.1: Four Configurations

terms of number of bed spaces. We assume that one patient needs only one bed space for his/her treatment and that one nurse treats one patient.

3.3.1

Configurations

This section describes the model using two types of flexibility under four configurations. Figure 3.1 shows the network representation of the four configurations. Nursing staff (number of dedicated and flexible nurses) and capacity (number of bed spaces) for each unit are the decision variables in our model. Configuration 1 : Base case No flexi- bility

When both bed space and nursing staff are available, the patient is admitted and treat- ment proceeds. In this configuration nursing staff consists of only dedicated nurses; no

nurses have been cross-trained. If bed space is available when a patient arrives but nurs- ing staff is not available, contract nurses are hired at a costsi for unit i. If a bed space is

not available, the patient is directed to another hospital and the system incurs a penalty cost of pi for unit i.

Configuration 2 : Demand Upgrades

When both capacity and nursing staff are available, the patient for unit i is admitted to uniti. Here again, there are no flexible nurses. Nursing staff consists of dedicated nurses and contract nurses.

Unlike configuration 1, in this configuration, when capacity is not available in unit 2, patient is admitted to unit 1 provided unused capacity is available in unit 1. Such upgrades to unit 1 are allowed only when demand in unit 1 is first met. The dedicated nurses in unit 1 are not trained to handle patients from unit 2 and so contract nurses are hired to treat patients upgraded to unit 1. Since unit 1 is a complex/sophiticated unit, the equipment is sufficient to treat patients from unit 2 but the staff are not trained in that skill. Therefore, contract nurses are hired at a higher cost to treat the upgraded patients in unit 1. Patients for unit 2 are turned away at a cost of p2 if capacity is not available in unit 2 and if upgrade to unit 1 is not possible. If enough capacity in unit 1 is not available, patients for unit 1 are turned away at a cost ofp1.

If capacity is available in unit i but dedicated staff is not available in unit i then contact nurses are hired for unit i.

Configuration 3 : Staffing Flexibility

nurses). Dedicated nurses are trained to work only in their home unit. Cost of wages for them is hi for uniti. Flexible nurses are cross-trained to work in both unit 1 and unit 2.

These cross-trained nurses, also called float nurses, can work in either unit 1 or unit 2. Cost of wages for flexible nurses is t. We assume flexible nurses are equally productive in both unit 1 and unit 2. The third type of nursing staff are the contract nurses who are hired at an additional cost of si for unit i.

Unlike configuration 2, in this configuration we do not have demand upgrades. If both capacity and nursing staff are available, patient is admitted for treatment at the appropriate unit. If capacity is not available, patients are turned away, incurring a penalty cost of pi.

In each unit, at first dedicated nurses are assigned. If demand exceeds the number of dedicated nurses, flexible nurses are used. Flexible nurses are first assigned to unit 1 because unit 1 is the complex unit and hiring contract nurses for unit 1 is more expensive. Any remaining flexible nurses are assigned to unit 2. If dedicated and flexible nurses are still not able to meet demand, contract nurses are hired as needed.

Configuration 4 : Demand Upgrades and Staffing Flexibility

This configuration is highly flexible. Both types of flexibility, demand upgrades and staffing flexibility, are used in this model. If capacity is not available in both units, patients are turned away incurring a penalty cost ofpi. When capacity is not enough in

unit 2 patients are upgraded to unit 1, provided there are beds not being used by unit 1 patients.

nurses are assigned first to meet the demand in unit i, followed by assigning flexible nurses to unit 1. Any excess flexible nurses are assigned to unit 2, as needed. Finally, contract nurses are hired to meet the remaining demand in each unit.

3.3.2

Timeline for decision making

This section motivates and explains the framework for the timing of decision making. In all cases, the actual allocation of nursing staff and beds are made after demand is realized. The timing issues we discuss here relate to decisions regarding capacity (number of beds) and nurse staffing levels (both dedicated and flexible). As indicated in Figure 2, we consider two types of sequential decision making and simultaneous decision making The south-east academic, medical center, for example, had decided on capacity and total staffing levels initially when the units were created. Now, in order to reduce labor costs, they are planning to implement cross-training programs. The cross-training program chooses some dedicated nurses and trains them to float to other units. This motivated us to study the impact of decision timing on system performance. We model sequential decision making that closely represents the process followed by the south-east academic, medical center. Ideally, both capacity and staffing decisions has to be made at the same point of time. So, in our paper we also model simultaneous decision making.

We consider two cases of sequential decision making. In sequential decision making case 1, capacity and total staffing decisions are made initially. Given capacity and total staff, we later determine number of flexible nurses to train in order to minimize total expected cost. This type of decision making is applicable only in configuration 3 and

FIGURE 3.2: Timeline for Configurations

configuration 4, where staffing flexibility is modeled.

In sequential decision making case 2, the capacity decisions are made originally and all staffing decisions (including dedicated and flexible staff) are made later. This type of decision making is applicable in all four configurations.

With simultaneous decision making, both capacity and staffing (both dedicated and flexible staff) decisions are made at the same time.