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

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National survey of anaesthetic practice for paediatric and adult day surgery
propofol used to induce anaesthesia for paediatric
day patients was 4.0 mg/kg (95% CI, 3.6 to 4.3;
n = 122). The stated mean concentration of
sevoflurane used to induce anaesthesia in
paediatric patients was 6.6% (95% CI, 5.6 to
7.7; n = 20).
Maintenance
Table 9 shows the most popular maintenance
agents used routinely for day surgery. Some of the
respondents (4% (n = 8) for urology, 6% (n = 12)
for orthopaedics, 6% (n = 11) for paediatrics)
named more than one maintenance agent, and
these responses were weighted accordingly. The
exception to this was the respondent who named
remifentanil and propofol. This was recorded
separately because remifentanil can be used to
reduce the required dose of general anaesthetic.
A number of respondents stated the dose as a
range, and these values were converted to a mean
maintenance dose (Table 10). The adult maintenance
dose for propofol was assumed to be the
‘target’ dose measured in micrograms per millilitre
for a controlled infusion. Target controlled infusion
pumps cannot be set for paediatric patient
characteristics, and so propofol must be given to
paediatric patients as a bolus or manual infusion.
Here the units used were milligrams per kilogram
body weight per hour.
Fresh gas flow rates
Respondents were asked to state the flow rate
of oxygen and N 2O used during the induction
and maintenance of anaesthesia (Table 11). Some
respondents stated a flow range, and this was more
often the case for the paediatric day-case patients.
If respondents stated a range then a variable was
created to represent an ‘average flow rate’, which
was the midpoint of the stated range.
Perioperative supplementary therapy
in day-case anaesthesia
Prophylactic anti-emetics
The use of prophylactic anti-emetics for day
surgery varied slightly between the three clinical
areas. In this sample of anaesthetists, no antiemetic
is given prior to the patient complaining
of nausea or vomiting by 50% in urology, 44%
in orthopaedics and 58% in paediatrics. A minority
of the respondents (2% for urology, 4% for orthopaedics)
named more than one prophylactic anti-
TABLE 9 Named maintenance agents used routinely for day surgery in the three specified clinical areas
Maintenance agent Respondents (%)
Urology Orthopaedics Paediatrics
Isoflurane 56 58 54
Sevoflurane 23 24 38
Propofol 13 13 4
Enflurane 4 3 2
Desflurane 4 1 0
Halothane 0 0 0.6
Propofol and remifentanil 0.6 0.6 0
TABLE 10 Concentrations (%) or doses (µg/ml) of the named maintenance agents
Maintenance Mean concentration or dose (95% CI; n)
agent
Urology Orthopaedics Paediatrics
Isoflurane 1.5% (1.35 to 1.55; 75) 1.5% (1.40 to 1.58; 82) 1.5% (1.41 to 1.66; 66)
Sevoflurane 2.0% (1.79 to 2.19; 28) 2.0% (1.82 to 2.20; 32) 2.4% (2.13 to 2.72; 50)
Propofol 5.2 µg/ml (3.37 to 6.92; 12) 5.2 µg/ml (3.50 to 6.78; 13) 10.3 mg/kg/h (6.54 to 14.13; 3)
Enflurane 2.3% (1.46 to 3.13; 5) 2.1% (0.00 to 4.22; 3) 2.3% (0.90 to 3.78; 3)
Desflurane 4.5% (3.52 to 5.48; 4) 4% (–; 1) –
Halothane – – Not known
Propofol and
remifentanil
5 µg/ml (–; 1) 6 µg/ml (–; 1) –