Aanesthetic Agents for Day Surgery - NIHR Health Technology ...

6
Introduction
willingness to pay for autologous blood donation. 35
The willingness to pay of respondents informed
about actual risks far outweighed the cost of the
service. The interventions studied in this report
offer virtually no health benefits, but evidently
offer substantial intangible benefits in the form
of ‘peace of mind’. The CV method is increasingly
being applied to elicit preferences regarding the
use of pharmaceuticals (e.g. in hypertension, lipidlowering
and depression). 36–38 The CV method has
also been used to elicit preferences for side-effect
avoidance. O’Brien and co-workers 38 elicited
willingness-to-pay values for the seven principal
side-effects of antidepressants, and identified
those “most troublesome” to patients.
The CV method was therefore considered an
appropriate method to elicit preferences in daysurgery
anaesthesia. Prior to this study, a CV
method tool was developed and tested to identify
and quantify women’s preferences for alternative
anaesthetic agents in day surgery. 33 In this study,
this tool provided ‘net benefit’ valuations (see
page 44) from a randomised sample to be
incorporated in a cost–benefit analysis.
The rationale for a randomised
controlled trial design
This study examined the clinical, patient
preference and cost differences between the
main day-surgery general anaesthesia models of
practice in the UK, using a pragmatic randomised
controlled trial (RCT) design. RCTs are regarded
as the gold-standard design in scientific medical
research because the effects of bias are minimised
through accepted methodological and design
features. However, generalisability to normal
practice can be reduced if the protocol is too
rigid and does not reflect normal practice patterns.
The treatment protocol for this trial reflected
routine practice to ensure that the results are
applicable to NHS practice.
The alternative methods of anaesthesia under
investigation and the treatment protocol were
selected on the basis of the literature review and
the pilot phase of the paediatric national survey,
as well as ratification by a scientific advisory
group convened specifically for this study.
Aims and objectives of the study
The aim of this study was to assess the relative costeffectiveness
of alternative anaesthetic agents in
adult and paediatric day surgery using a
naturalistic RCT design.
The principal objectives relating to the principal
anaesthetic methods used in adult and paediatric
day surgery, were:
• to assess the relative clinical outcomes
• to identify resource use and the associated costs
incurred by the NHS during the anaesthetic
and postanaesthetic periods
• to determine the acceptability to patients of
the principal anaesthetic methods used
• to use the clinical, economic and patient-based
outcomes data collected in this study to assess
the relative cost-effectiveness of the different
anaesthetic regimens.
Furthermore, the methods used and the size of the
study ensured that the results are credible, relevant
and accessible to anaesthetists and surgeons, and
to healthcare decision-makers at both local and
national level. An evaluation of the safety of the
different anaesthetic techniques was not part of
this study.