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

TABLE 7 The premedication agents of choice in day surgery
than one agent, and these responses were weighted
accordingly. In some cases respondents referred to
using a benzodiazepine, such as midazolam, with a
general anaesthetic to reduce the dose required
for induction of anaesthesia, and this is recorded
in Table 8.
Respondents were asked to state the dose of
induction agent (in milligrams per kilogram body
weight) or the concentration of volatile induction
agent used. Some respondents (34% for urology,
34% for orthopaedics, 14% for paediatrics) stated
a dose range. If respondents stated a range then
a variable was created to represent the ‘average
dose’, which was the midpoint of the stated range.
If the propofol dose was stated as a single milligram
dose (8% for urology, 7% for orthopaedics)
then the average weight of an adult of 70 kg was
used to calculate a milligram per kilogram dose.
Two per cent of respondents stated a paediatric
propofol dose as a single milligram dose, and these
responses were excluded because it is not practical
© Queen’s Printer and Controller of HMSO 2002. All rights reserved.
Health Technology Assessment 2002; Vol. 6: No. 30
Premedication agent Respondents (%)
Urology Orthopaedics Paediatrics
Benzodiazepine 2 2 8
NSAID or paracetamol 2 8 9
Any combination of NSAID, anti-emetic or H2-antagonist 1 4 0
Topical anaesthetic 0 0 5
Trimeprazine 0 0 0.5
TABLE 8 Named induction agents used routinely for day surgery in the three specified clinical areas
Induction agent Respondents (%)
Urology Orthopaedics Paediatrics
Propofol 89 86 60
Propofol and midazolam 6 9 2
Sevoflurane 2 1 28
Thiopentone 0.3 0 7
Propofol and midazolam and opioid 1 1 0
Sevoflurane and midazolam 0.3 2 0.6
Etomidate 1 0.3 0
Propofol and opioid 0 0.6 0.6
Thiopentone and opioid 0 0 0.6
Etomidate and midazolam 0.3 0 0
Thiopentone and midazolam 0 0 0.6
Isoflurane 0 0 0.3
to assume an average weight for a child in the
age range 3–12 years. One response for urology
and orthopaedics was excluded because the dose
range was not legible.
In 7% of urology and 8% of orthopaedic
responses, the propofol dose was stated as ‘TCI’
(target controlled infusion) or propofol was stated
as the anaesthetic agent of choice for induction
and maintenance, thus making an estimation of
the induction dose difficult. The range of values
provided by this sample of respondents was 3–
12 µg/ml. These values refer to the reading on
the target controlled infusion pump rather than
the quantity of drug given to the patient, and
were excluded when calculating the mean dose
of propofol used to induce anaesthesia.
The mean induction dose of propofol used
was 2.4 mg/kg (95% CI, 2.3 to 2.6; n = 115)
for urology and 2.3 mg/kg (95% CI, 2.2 to 2.5;
n = 115) for orthopaedics. The mean dose of
29