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

to provide a more ‘realistic’ CV. The relative risk
reduction (RRR) of PONV after propofol compared
with inhalational agents is approximately
27% if N 2O is given with the inhalational agent. 46,48
Preliminary interviews suggested that respondents
were not generally good at comprehending a
relatively small difference in risk for PONV. This
suggested that the willingness-to-pay values they
gave would be lower than the full value of their
preferred alternative. The scenarios were
developed to reflect an intermediate position –
that PONV was not prevented totally, but was
reduced by double the reported RRR.
The descriptive scenarios were printed on coloured
card and given before discharge to the adult patients,
or parents or guardians, to take home. Patients were
told they would be asked about these scenarios
during the telephone interview at day 7 and were
invited to give their preferences for, and valuations of,
anaesthetics for day surgery. Individuals were asked
clearly to state the additional value of their preferred
TABLE 17 Summary of the data requirements for the empirical study
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Health Technology Assessment 2002; Vol. 6: No. 30
option over the other option, in order to provide
incremental monetary values. Although values were
attached to the VAS, patients or parents or guardians
were given the option of giving a valuation beyond
the extremes of the range.
A question was directed to test patients’ (or
parents’) understanding of the exercise, and thus
the validity of the valuation given (see appendix
16). 241,242 Those values where understanding was
not confirmed were excluded from analysis.
Costs
The cost per patient was estimated for each of
the events listed in Table 17 (resource use). The
costs for each event (e.g. induction and maintenance
of anaesthesia, adverse effect, PONV) were
estimated for each patient in the trial. The costs
were calculated as resource use multiplied by
the unit cost of the specific resource.
Data category Parameters Source (back-up source)
Demographic Patient details: name, hospital number, date of birth, sex, weight, Patient notes (patient)
patient data telephone number, surgical procedure,ASA category, smoking status, GP
Day 7 telephone interview
Patient history:previous experience of anaesthetics, previous
procedures
Patient Clinical outcomes: In situ data collection (patient
outcomes Intraoperative events: including adverse events notes, anaesthetic record)
Postoperative events: time to recovery room discharge, PONV, pain, In situ data collection (patient
awareness, time to readiness for hospital discharge, overnight admission notes, nursing records)
Postdischarge events: use of over-the-counter medication, Day 7 telephone interview
readmission, GP contact
Day 7 telephone interview
Patient preferences:CV
Resource use Intraoperative:induction and maintenance anaesthesia, other drugs, In situ data collection (patient
disposables, time in surgery, treatment of adverse events, staff time notes, anaesthetic record)
Postoperative:PONV, pain, other drugs, other equipment, resource In situ data collection, discharge
use associated with management of other adverse events, time to interview (patient notes,
discharge, overnight admission, staff time nursing records)
Postdischarge:NHS contact Day 7 telephone interview
Unit costs Variable resource use: anaesthetic, drug and disposables costs, Pharmacy and supplies
management of PONV and adverse events department
Staff resource use: standard costs for staff employed during pre- Personnel and national salaries
and postoperative assessment on the ward. Semi-fixed costs for
running an anaesthetic room and operating theatre Finance department from
one research site
Fixed resource use: maintaining a ward, anaesthetic room, theatre
and recovery area
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