Availability and Performance of Health IT

Section 6.1 introduced the concept of dependable computing and the notion that availability and reliability are two of its key characteristics. A HIT system which is relied on clinically for the delivery of care can quickly result in a hazardous scenario when it becomes unavailable to users. This is particularly the case for systems that deliver data which is consumed quickly by its users and influences clinical decisions in a short timeframe. One study reported that for each minute of system downtime it took approximately 4.5 min for staff to complete the equivalent work had the system been operational [1]. 

The potential unavailability of a HIT system should always be anticipated. Whilst its timing may be unpredictable the fact that at some point access to the system will not be possible is virtually inevitable in view of the number of typical dependencies. Architectural and procedural measures can be employed to minimise the risk of unavailability but this should in no way translate into a guarantee of continuous operation. Healthcare organisations need to plan from the very start of a project how they will manage and cope without access to the system for short, medium and long periods. 

Note that in discussing availability and performance one needs to make reference to the stakeholders responsible for hosting the system. In practice this could be the healthcare organisation, software manufacturer or a third party. The principles of fault tolerance and resilience remain the same irrespective of which party takes commercial responsibility. However the stakeholder responsible for implementing controls will vary as will the information available to safety case developers. In this 

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The client has specific duties under the CDM Regulations, one of which is to appoint a planning supervisor and a principal contractor. The client must be reasonably satisfied with the competence of these appointees and with the adequacy of resources allocated by the appointees to perform their duties. The client must provide health and safety information about the project, not permit construction work to start until an adequate construction health and safety plan is available, and hold the health and safety file and make it available to others. The client must also issue a notification of the project using Form FIO. 

Section 1 of the guidelines establishes the context of the submission. It asks for a description of the drug, its use on the PBS and the therapies that wiU be co-administered or substituted. Section 2 asks for the best available evidence on the clinical performance of the drug, including the scientific and statistical rigour of randomised trials, and a preliminary economic evaluation based on evidence from the randomised trials. Section 3 describes when extrapolation beyond the preliminary economic evaluation maybe made and how adjustments can be made in a modelled economic evaluation. Section 4 requests a financial analysis from the perspective of the PBS and government health budgets. 

There are also practical limitations to the selection and use of biomarkers in human studies. The biomarker should be measurable in a relatively available tissue or fluid for example, urine and breath. Sampling blood is an invasive process and so is more difficult to perform although it is done routinely. However, sampling liver tissues from humans for DNA adducts is much too invasive and would not be performed except at the time of autopsy. In addition, the assays for the marker of interest should not be so expensive that the cost of a study using the marker is prohibitive. Finally, the marker must be validated for its accuracy in quantitatively reflecting either exposure or health outcome. Otherwise, the results of the biomarker assays cannot be interpreted. 

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