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

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Results of the paediatric economic evaluation
agent dominates sevoflurane/sevoflurane. It
can be seen that substituting halothane with
sevoflurane has a larger effect on costs, such
that this arm is now more costly as well as more
effective. The ICER derived for propofol/
sevoflurane compared with sevoflurane/
sevoflurane is £3.10 for each extra PONV
episode avoided.
Use of the Dion algebraic approximation
Variable costs for patients who received sevoflurane
were recalculated using the same methods used
in the analysis in the adult study, using inflation
factors of 6% (anaesthetic room) and 14%
(operating theatre) (see appendix 18). The mean
(SD) variable cost per patient increased from
£12.40 (5.90) to £13.40 (6.50). However, the rank
order of the alternatives does not change, so the
conclusions regarding cost-effectiveness do
not change from those in the base case.
Net benefit
The net benefit was calculated in the same way
as in the adult study (see chapter 4). Net benefit
(called ‘net cost’) was calculated only for those
parents who had given a valid CV for both
scenarios (n = 217). Table 64 summarises
the net cost by anaesthetic regimen for:
• mean net cost (induction only, Net[I])
• mean net cost (maintenance only, Net[M])
• mean net cost (induction and maintenance,
Net[I + M]).
No significant difference in net cost (Net[I +
M]) was found between anaesthetic regimens
(p = 0.1007) (Figure 26). The net benefit for both
propofol/halothane and sevoflurane/sevoflurane
was positive. This result apparently contradicts the
net savings and higher effectiveness of propofol/
halothane in the cost-effectiveness analysis. The
direction and magnitude of parents’ preferences
TABLE 64 Net cost by randomisation (excluding invalid answers) (paediatric study)
for their child to have an inhalational induction
are responsible for this disagreement in results
between the two economic evaluations. This
suggests that parents do not consider the clinical
outcome measure (PONV) to be as important as
the method of administration of anaesthetic.
Figure 27 shows the cumulative percentage of the
net cost for each anaesthetic regimen. The net
benefit was positive for over 90% of patients in
both groups.
Net cost Anaesthetic regimen Total
(n = 217)
Propofol/halothane Sevoflurane/sevoflurane
(n = 112) (n = 105)
Mean (SD) total cost (£) 85.1 (24.3) 97.3 (25.8) 91.0 (25.7)
Mean (SD) net cost (induction only, Net[I]) –62.3 (194.1) –129.4 (285.1) –94.8 (244.2)
Mean (SD) net cost (maintenance only, Net[M]) –486.7 (388.6) –573.3 (652.7) –525.5 (524.1)
Mean (SD) net cost (induction and
maintenance, Net[I + M])
–638.8 (505.1) –812.1 (927.3) –716.9 (729.5)
200
100
0
–100
–200
–300
–400
–500
–600
–700
–800
–900
Net cost (£)
Propofol/
halothane
Sevoflurane/
sevoflurane
FIGURE 26 The net cost for each anaesthetic regimen
(limit 5% and 95% percentiles) in the paediatric study