This project is based on the implementation of a priority replacement index (RPI) that, although it is based on a careful analysis of the literature available on the subject, departs from it in relation to the needs of the Hospital. The model of inspiration is the RPI developed by Eng. Elena Milani at Humanitas Mirasole SpA, which is shown in Table 1. [14].
The index consists of 10 indicators and is characterized by both objective and subjective parameters, such as technical adequacy and clinical fitness [15].
Therefore, although there is no real conception of an RPI based on the opinion of users, the author entering these subjective parameters opens the way to strategies that integrate objective assessments with those of health professionals. It is arranged in a "fuzzy logic", a recent methodology which is part of the Multi Criteria Decision Analysis techniques and allows to expand the "yes/no" duality of the Fennigkoh model, allowing the use of intermediate scores [16].
From this theory, the subdivision of the values that the various parameters can assume has been resumed; in fact, each of it is worth 0, 0.5 or 1. The use of three ranges to evaluate the parameters makes mathematical processing easier and allows a robust analysis of the different levels of criticality that a device can show in a specific evaluation criterion [17].
Table 1
METRIC | PARAMETER DESCRIPTION | ASSUMED VALUE | NOTES |
X1 | AGE | 0; 0,5; 1 | ASSIGNED WRT AN AVERAGE THRESHOLD VALUE OF THE CLASS |
X2 | FUNCTIONAL STATUS | 0; 0,5; 1 | |
X3 | SPARE PARTS AVAILABILITY | 0; 1 | |
X4 | DEGREE OF USE | 0; 0,5; 1 | |
X5 | CRITICALITY | 0; 0,5; 1 | |
X6 | RELIABILITY | 0; 0,5; 1 | ASSIGNED WRT AN AVERAGE THRESHOLD VALUE OF THE CLASS |
X7 | AVAILABILITY | 0; 0,5; 1 | ASSIGNED WRT AN AVERAGE THRESHOLD VALUE OF THE CLASS |
X8 | CLINICAL FITNESS | 0; 0,5; 1 | |
X9 | TECHNICAL ADEQUACY | 0; 0,5; 1 | |
X10 | MAINTENANCE COST | 0; 0,5; 1 | ASSIGNED WRT AN AVERAGE THRESHOLD VALUE OF THE CLASS |
Thresholds have been attributed since the historical of the maintenance interventions and the strategic choices undertaken within the structure to create an ad hoc model.
Milani’s research already assigns different importance to each criterion in the calculation of the RPI, depending on the strategic choices of the management, making it possible to shift the focus to the indicators deemed most relevant.
The proposed index at Fatebenefratelli-Sacco consists of two distinct parts: first, an index has been created called internally "Technical" RPI, resulting from the weighted sum of technical parameters. This first construct serves as a filter for the identification of the equipment on which it is necessary to place an additional focus for the evaluation of the substitution. To implement an effective replacement plan and thus make proper use of the resources to purchase the necessary equipment, the second step of the work is focused on the direct involvement of users, namely medical and nursing professionals, to calculate the “Clinical” RPI. In this regard,a questionnaire was created to be submitted to employees to prioritize the urgency of renewal of equipment based on actual work activity and the perception of users constantly in contact with technology. The starting point for the analysis is the CosWin portal. It represents the Computerized Maintenance Management System (CMMS) at the Hospital, from which the necessary information about the equipment has been extracted. It has been provided by the Global Service, the external company that provides the service of management and maintenance of electromedical equipment and collects data about the medical devices in dowry to the hospital. In addition, another feature of CosWin is the ability to store inside the historical maintenance carried out on the fleet. All the data of interest, related to the equipment registry and maintenance carried out in the last year, have been extrapolated and unified on an Excel spreadsheet. This calculation tool allowed to determine at first the Technical IPS, which was then implemented on the company CMMS, as the call for the award of the service for the management and maintenance of medical equipment places the obligation on the part of the Global Service to make available to the institution such a tool.
Table 2 shows the parameters included in the calculation of the Technical IPS and the respective weights. The age of the equipment and the possible unavailability of spare parts or technical assistance by the manufacturer in case of failure (EoS) were evaluated. Then, the number of annual corrective maintenance interventions and the resulting derived downtime were counted. As noted above, the acceptability threshold was defined on the average values of these criteria on the homogeneous cohort installed at the Hospital. A critical parameter has been inserted referring to what was defined in the call for the management and maintenance of electromedical equipment organized by ARIA S.p.A., which establishes a specific first intervention time per type of equipment according to the criticality threshold assigned during the award of the tender. A first step is implemented by calculating an IPS for each equipment considering these indicators. At this point, the algorithm inserts a sixth parameter. It evaluates the number of devices of the same type working in a department. In fact, the number of equipment needed for each department of the hospital has been defined through comparison with the departments and the creation of "standard equipment" for the type of service offered. Therefore, the amount of equipment with IPS below the threshold defined as the necessary replacement alert is considered and, based on the comparison with the number set as standard, the technical IPS is recalculated [18].
Table 2
TECHNICAL IPS CRITERIA | WEIGHT 1° STEP | WEIGHT 2° STEP |
AGE | 0.17 | 0.13 |
END OF SUPPORT (EoS) | 0.19 | 0.15 |
CRITICALITY | 0.23 | 0.20 |
AFFIDABILITY | 0.20 | 0.16 |
UPTIME | 0.21 | 0.17 |
PRESENCE OF OTHER EQUIPMENT OPERATING IN THE SAME DEPARTMENT | / | 0.19 |
Once the technical IPS has been calculated, the focus is only on equipment with an above-threshold value. For these, the Clinical IPS is calculated, consisting of the parameters in Table 3; parameters chosen on the basis of the result of the administration of an ad hoc questionnaire to healthcare professionals [19].
Table 3
CLINICAL IPS CRITERIA | WEIGHT |
DEGREE OF RISK DERIVED ON THE PATIENT/OPERATOR | 0.19 |
FREQUENCY OF USE | 0.10 |
FUNCTIONAL STATUS | 0.08 |
CLINICAL ADEQUACY | 0.23 |
FAILURE CAUSED BY THE ABSENCE OF THE DEVICE | 0.10 |
LEVEL OF TRAINING BY OPERATORS | 0.06 |
DEGREE OF TECHNOLOGICAL INNOVATION | 0.11 |
AVAILABILITY OF OTHER ALTERNATIVE EQUIPMENT | 0.13 |
The weights are assigned to obtain criteria of relative importance that fully reflect the structure.
Definition of these weights was implemented following the operating mode adopted by the Lombardy Region for the Regional Health Technology Assessment model, collecting expert opinion on the relative importance of the various criteria [20].
The definition of acceptability thresholds for RPI was also fundamental, inspired by Armisi’s model [16].
This is the adopted RPI scale:
\(\text{R}\text{P}\text{I} <\) 0.5: the equipment does not need intervention.
0.5 \(\le \text{R}\text{P}\text{I} \le\)0.7: the equipment must be monitored in the short.
\(\text{R}\text{P}\text{I} >\) 0.7: the equipment needs urgent replacement.It was decided to outline the final ranking as the weighted sum of the two indices, assigning a slightly greater coefficient to the Technical IPS. In this way, it is possible to reduce any biases due to the willingness of clinicians to replace equipment even if not strictly necessary [21].
$$IPS=\text{0,55}*{IPS}_{T}+ \text{0,45}*{IPS}_{C}$$