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

The structure and content of this discussion
follows the revised Consolidated Standards
for Reporting of Trials (CONSORT) statement
for reporting randomised trials. 262
The overall aim of the CESA project was to assess
the relative cost-effectiveness of different anaesthetic
agents in adult and paediatric day surgery.
The rationale for this was a perceived need to
provide the NHS with new and reliable information
about the relative value for money of
alternative methods of anaesthesia. The CESA
project is based on the premise that that there are
no differences in the long-term clinical outcomes,
such as death, respiratory and cardiac sequelae or
long-term cognitive differences, associated with the
use of different anaesthetic agents and techniques.
The optimal choice of anaesthetic agent for daysurgery
anaesthesia depends on the profile of
short-term, transient effects, patient preferences
and the costs of the alternatives.
The CESA project comprised three interrelated
studies to assess these short-term clinical, patient
and cost outcomes. The first of these studies was a
literature review of the clinical, patient outcome
and economic literature to assess the evidence
currently available. Secondly, a survey of current
practice in anaesthesia for day surgery was undertaken.
Both the literature review and the national
survey were used to inform the design of an RCT
of alternative anaesthetic agents, which was the
third component of the project (CESA RCT).
This chapter summarises the findings of each of
these components of the CESA project. Practical
problems encountered in the implementation of
the CESA RCT are presented, followed by a
discussion of the internal and external validity
of the CESA RCT. Finally, key conclusions are
drawn for health policy, clinical practice and
the need for future research.
Findings of the study
Literature review
The literature review of clinical papers identified
a large number of high-quality RCTs (grade I) of
methods of anaesthesia and anaesthetic agents used
in adult and paediatric day surgery. However, the
© Queen’s Printer and Controller of HMSO 2002. All rights reserved.
Chapter 7
Discussion
Health Technology Assessment 2002; Vol. 6: No. 30
comparability of the studies was low, owing
to a wide variation in the patient groups, anaesthetic
agents and treatment protocols, surgical
procedures and primary clinical outcomes used.
PONV was the most commonly used measure,
but varied in how and when it was measured.
Therefore, few firm conclusions could be drawn
about the relative effectiveness of frequently used
alternative agents. The review of patient-based
outcomes identified mainly descriptive studies,
with very few comparative evaluations. The review
of the cost and economic literature yielded a
small number of low-quality evaluations.
The overall findings of the literature review
were that:
• the available evidence on short-term outcomes
concentrated on predischarge PONV and
discharge times
• there was no clinical, patient-based outcome
or economic evidence to indicate the optimal
agent for anaesthesia in day surgery
• there was no clinical, patient-based outcome
or economic evidence to indicate the optimal
method of induction (inhalational or
intravenous) anaesthesia in day surgery
• TIVA is not yet standard practice in anaesthesia
for day surgery in paediatric patients
• desflurane is not used in British practice and
is not an appropriate comparator
• the tools used to measure outcomes were
varied and mostly unvalidated
• patients may not consider PONV, mode of
anaesthesia or cognitive function to be
important outcomes.
National survey of anaesthetic practice
for paediatric and adult day surgery
For adult day surgery, current practice is one of no
premedication, a preference for induction with propofol
and maintenance with isoflurane. One-tenth
of respondents reported use of propofol for maintenance
and one-fifth reported use of sevoflurane.
A very small minority of respondents reported using
desflurane. After induction, fresh gas flow rates are
restricted to around 3 1/min, reflecting moderate
but not ultra-low flow anaesthesia. Laryngeal masks
are used in virtually all patients. Prophylactic antiemetics
were used by approximately half of the
81