Background

Objective

To assess the effectiveness and cost-effectiveness of ODM, in comparison with conventional clinical assessment and other methods of monitoring cardiovascular function.

Methods

A systematic review of studies of effectiveness and cost-effectiveness was conducted.

Results

Costs

No studies reporting costs were identified. The addition of ODM would incur the cost of a monitor (approximately £10,000) which will last several years and typically a single disposable probe per patient (approximately £60–£120). In addition, maintenance contracts might be necessary (approximately £550). Apart from the few minutes required to insert the probe there are few other additional costs. Any changes in length of stay, complications and mortality would also affect total costs.

Cost-effectiveness

No economic evaluations that met inclusion criteria were identified from the existing literature and a series of balance sheets were constructed to highlight the choices and trade-offs that may exist. For ODM plus CVP monitoring plus conventional assessment versus CVP monitoring plus conventional assessment during surgery, the ODM strategy is likely to be more effective and the costs of ODM are likely to be offset by reductions in length of stay and complications. However, the cost of interventions prompted by monitoring (intravenous fluids and vasoactive drugs, etc.) is not known. For ODM plus conventional assessment versus conventional assessment during surgery, it is likely that the costs of ODM will be offset by the reductions in length of stay, but the overall differences in costs and effectiveness are unclear as there is insufficient evidence on mortality and complications. For ODM plus conventional assessment versus CVP monitoring plus conventional assessment during surgery, there is insufficient evidence available and where data are available the confidence intervals are sufficiently wide to cover clinically and economically important differences favouring either intervention. In critically ill patients the cost of ODM appeared to be compensated for by differences in length of stay and its use may reduce complications, but the effect on mortality and on the cost of interventions prompted by monitoring is unclear.

A partial economic modelling exercise was conducted for ODM plus CVP monitoring plus conventional clinical assessment versus CVP monitoring plus conventional clinical assessment and ODM plus conventional clinical assessment versus conventional clinical assessment for high-risk surgical patients, as well as for ODM plus CVP monitoring plus conventional clinical assessment versus CVP monitoring plus conventional clinical assessment comparison for critically ill hospitalised patients. Results show that ODM strategies are likely to be considered cost-effective. More specifically, the threshold value for the extra cost per additional survivor that would need to be incurred before ODM would no longer be considered cost-effective was estimated. The required magnitude of these costs ranged from £581 to £11,600. However, these results are heavily dependent on the underlying assumptions of the analyses (e.g. pairwise comparisons rather than comparisons of all relevant methods of monitoring, limited number of studies, limited or non-existent data on relevant outcomes, small sample sizes and different underlying conditions).

Recommendations for research

Although some modest data are available and consideration can be given to the balance of costs and benefits using the data from the balance sheets, more formal economic evaluation would be desirable to make better use of the data available and to make valuations implicit in any decision more explicit. Furthermore, well-designed, multicentre RCTs are required among high-risk surgical patients to address the following question: Does ODM-guided fluid therapy plus conventional clinical assessment improve outcome with and without CVP monitoring compared with conventional clinical assessment with and without CVP monitoring?

All the identified studies were conducted in unconscious patients. Newer ODM probes that may be tolerated by awake patients are now manufactured and further research is needed to evaluate these.

Further research is required to assess the benefits of ODM-guided fluid administration during surgery and continuing into the early postoperative period versus the benefits of ODM-guided fluid administration during surgery alone. Further research is also required to determine the optimal number of hours for ODM-guided fluid administration to continue after surgery once the patient has been admitted to a critical care facility.

Given the paucity of the existing economic evidence base any further primary research should include an economic evaluation or should provide data suitable for use in an economic model.

Publication

• Mowatt G, Houston G, Hernández R, de Verteuil R, Fraser C, Cuthbertson B, et al. Systematic review of the clinical effectiveness and cost-effectiveness of oesophageal Doppler monitoring in critically ill and high-risk surgical patients. Health Technol Assess 2009;13(7). [PubMed: 19200414]

NIHR Health Technology Assessment Programme

The Health Technology Assessment (HTA) Programme, part of the National Institute for Health Research (NIHR), was set up in 1993. It produces high-quality research information on the effectiveness, costs and broader impact of health technologies for those who use, manage and provide care in the NHS. 'Health technologies' are broadly defined as all interventions used to promote health, prevent and treat disease, and improve rehabilitation and long-term care.

The research findings from the HTA Programme directly influence decision-making bodies such as the National Institute for Health and Clinical Excellence (NICE) and the National Screening Committee (NSC). HTA findings also help to improve the quality of clinical practice in the NHS indirectly in that they form a key component of the 'National Knowledge Service'.

The HTA Programme is needs led in that it fills gaps in the evidence needed by the NHS. There are three routes to the start of projects.

First is the commissioned route. Suggestions for research are actively sought from people working in the NHS, from the public and consumer groups and from professional bodies such as royal colleges and NHS trusts. These suggestions are carefully prioritised by panels of independent experts (including NHS service users). The HTA Programme then commissions the research by competitive tender.

Second, the HTA Programme provides grants for clinical trials for researchers who identify research questions. These are assessed for importance to patients and the NHS, and scientific rigour.

Third, through its Technology Assessment Report (TAR) call-off contract, the HTA Programme commissions bespoke reports, principally for NICE, but also for other policy-makers. TARs bring together evidence on the value of specific technologies.

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Criteria for inclusion in the HTA journal series

Reports are published in the HTA journal series if (1) they have resulted from work for the HTA Programme, and (2) they are of a sufficiently high scientific quality as assessed by the referees and editors.

Reviews in Health Technology Assessment are termed 'systematic' when the account of the search, appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.

The research reported in this issue of the journal was commissioned by the HTA Programme as project number 07/20/01. The contractual start date was in April 2007. The draft report began editorial review in August 2007 and was accepted for publication in June 2008. As the funder, by devising a commissioning brief, the HTA Programme specified the research question and study design. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors' report and would like to thank the referees for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.

The views expressed in this publication are those of the authors and not necessarily those of the HTA Programme or the Department of Health.

Editor-in-Chief: Professor Tom Walley

Series Editors: Dr Aileen Clarke, Dr Peter Davidson, Dr Chris Hyde, Dr John Powell, Dr Rob Riemsma and Professor Ken Stein