Degree Name

Doctor of Philosophy


Faculty of Engineering and Information Sciences


This study investigates the relationship between the reliability of Critical Medical Equipment (CME) and the maintenance management strategies influencing patient outcomes in Australian Public Hospitals in the state of NSW. The work examined the effectiveness of CME maintenance strategies used in this large public hospital system. The conceptual framework was designed to examine the significance of the relationships between five variables: (1) types of maintenance management strategies (2) maintenance practices (3) medical equipment reliability (4) maintenance costs and (5) patient outcomes.

The study initially focused on 14 types of CME where failure or non-availability posed a high level of risk to patients. The evaluation of the performance of CME was carried out by using qualitative and quantitative investigations in order to examine failure rates and their effects. The parameters used for measuring performance were CME availability, failure rate, MTBF (Mean Time Between failures) and MTTR. (Mean Time to Repair). The quantitative conclusions of this work have resulted from 84 valid responses to a survey consisting of 54 detailed questions. Respondents indicated that they use and/or are responsible for 5769 individual items of CME. This provides a substantial and likely statistically reliable sample from which data has been gathered. Due to difficulties in handling very large amounts of data, the 6 most representative of the 14 CME types on which data was obtained were examined. These were kidney dialysis, anesthesia, defibrillator, ECG, infusion pumps and ventilator machines. The study targeted a variety of departments in hospitals: biomedical engineering, surgical and theatre operations, kidney dialysis and renal and cardiac catheterisation. The breakdown of respondents comprised hospital staff from the following units: 3% biomedical engineering, 29% surgical, 25% theatre operations, 22% kidney dialysis, 9% cardiac catheterisation, 3% intensive care units and 9% hospital administration.

Results showed that there is significant correlation between current maintenance management strategies and the reliability of critical medical equipment affecting patient outcomes. The results also provide interesting insight into the effectiveness of the maintenance strategies being used. For example, there appears to be a significant probability of failure of anesthesia equipment when treating patients with resulting potential risks. The survey results also provide some findings to indicate that most CME types surveyed fail while in service and there are some cases where patients have been exposed to harm due to breakdowns. Two hospitals reported cases of injury and one hospital reported a case of patient death due to the failure of anesthesia machines. One hospital reported a case of patient death due to the failure of a defibrillator machine, another hospital reported cases of patient death when using cardiac catheterisation machines and two hospitals reported cases of patient death due to the failure of diathermy machines. There are also some findings in relation to outsourcing maintenance strategies that point to further questions in relation to the cost of those services. For each of the variables listed results were reported in relation to the various types of maintenance management strategies in use.

Decision-makers may be able to use these results to adopt more effective maintenance strategies for CME which can lead to improved patient outcomes. The study goes on to propose a maintenance model for critical hospital equipment with greater emphasis on Reliability-Centred Maintenance (RCM), Condition Based Maintenance (CBM) and Total Productive Maintenance (TPM), which are advanced asset management and equipment maintenance strategies that have been developed and are now common in aviation and manufacturing industries. This work highlights the economic life cycle operations and patient outcome priorities that are connected with critical medical equipment. While it must be acknowledged that the case for adopting a Reliability Centred Maintenance regime is not proven, it is interesting to note that, in line with RCM type philosophies, there is the possibility that some hospital equipment may be “over maintained” resulting in decreased reliability and increased costs. Certainly in the interests of patient safety and economic operation of CME, this work provides evidence that there is a need to reconsider and update current maintenance practices. The study paves the way for an in-depth enquiry and presents a proposal for a program of further work.

FoR codes (2008)

0903 BIOMEDICAL ENGINEERING, 0910 MANUFACTURING ENGINEERING, 1503 BUSINESS AND MANAGEMENT, 150307 Innovation and Technology Management, 150313 Quality Management



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.