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

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Discussion
In addition, it was not possible to screen all
patients who attended for day surgery to determine
if they were eligible and willing to enter the trial.
This meant that the sample of patients screened
was not randomly drawn from the population
treated. However, as discussed above, the reasons
for this were logistical and there is no evidence
to suggest that the patients screened were
different to those not screened.
Treatment settings
The CESA RCT was conducted in two hospitals.
One is a university teaching hospital NHS trust
and the other a non-teaching hospital NHS
trust. There was evidence of differences between
the sites in terms of staffing, organisation and
costs of services. However, these differences did
not affect the estimates of total or variable cost.
There was no evidence that the hospital was a
factor that predicted the incidence of PONV.
The overall unexpected admission rate was
1.2%. This and the average length of stay were
lower than anticipated. There were differences
between the two hospitals in the length of stay
and overnight stay rates for gynaecological surgery,
which probably reflected organisational differences
between the sites, as the anaesthesia
protocol did not differ. These factors may
mean that the variable costs observed in the
CESA RCT may be lower than those in other
settings. Overall, this would probably tend to
reduce the probability of finding a difference
in the costs of the alternative anaesthetic
regimens.