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facilities is required during thiopentone infusions. Central venous pressure should be
monitored, and blood pressure monitored via an arterial line. Pulmonary artery pressure
monitoring is sometimes advisable, and EEG or cerebral function monitoring is essential if
thiopentone infusions are prolonged. A concomitant dopamine infusion is frequently needed
to maintain blood pressure. Thiopentone can react with polyvinyl infusion bags or giving sets.
The continuous infusion should be made up in 0.9% sodium chloride (normal saline). The
intravenous solution has a pH of 10.211.2, is incompatible with a large number of acidic or
oxidising substances, and no drugs should be added. The aqueous solution is unstable if
exposed to air.

The regimen commonly used is as follows: thiopentone is given as a 100250 mg bolus over
20 seconds, with further 50 mg boluses every 23 minutes until seizures are controlled, with
intubation and artificial ventilation. The intravenous infusion is then continued at the
minimum dose required to control clinical and electrographic seizure activity, usually
between 3 and 5 mg/kg per hour, and at thiopentone blood levels of about 40 mg/L. After 24
hours, the dose should be controlled by blood level monitoring. At this point, metabolism
may be near saturation, and daily or twice daily blood level estimations should be made to
ensure that levels do not rise excessively. The dose should be lowered if systolic blood
pressure falls below 90 mmHg, or if vital functions are impaired. There is some evidence to
suggest that barbiturate anaesthesia is more successful in those who have been loaded with
phenobarbitone. Thiopentone should be continued for no less than 12 hours after seizure
activity has ceased, and then slowly discontinued. The usual preparation is as a 2.5 g vial with
100 ml of dilutent to produce a 2.5% solution.

Propofol
In recent times, there has been a vogue for the use of non-barbiturate anaesthesia in status
epilepticus; of the currently available compounds, propofol is probably the drug of choice.
There is limited, but growing, published experience of its use in status epilepticus and as a
long-term infusion. Propofol is a highly effective and non-toxic anaesthetic. In experimental
models, it has anticonvulsant activity, probably via its action in potentiating GABA receptors.
Propofol also has neuroexcitatory effects possibly through subcortical disinhibition resulting
in muscle rigidity, opisthotonos, abnormal movements including myoclonus; these can be
and have been mistaken for seizures. Seizures have, however, been reported with propofol
withdrawal, and experimental evidence suggests that this is a rebound phenomenon similar
to the GABA withdrawal syndrome.

Propofol has also been reported at low doses to activate the electrocorticogram, but this is a
property that it shares with other anaesthetics including the barbiturates. Propofol is
extremely soluble in lipid and has a high volume of distribution. It thus acts extremely rapidly
in status epilepticus. Its effects are maintained while the infusion is continued, and recovery
following discontinuation of the drug is also very quick. Propofol administration causes
profound respiratory and cerebral depression, requiring the use of assisted respiration, the full
panoply of intensive care and monitoring, but only mild hypotension, and has few
cardiovascular side effects. Long-term administration (or high doses, > 5 mg/kg/h, over 48
hours) causes marked lipaemia and may result in acidosis, cardiac arrhythmias and
rhabdomyolysis (propofol infusion syndrome) which can be fatal. This is especially so in
young children in whom it should not generally be recommended.

In status epilepticus, the following regimen can be used: initially a 12 mg/kg bolus dose is
given, which can be repeated if seizures continue, succeeded by an infusion of 115 mg/kg
per hour guided by EEG. The dose should be gradually reduced, and the infusion tapered 12
hours after seizure activity is halted. Due to the risk of rebound seizures, the dose should be
tapered at a rate of 5% of the maintenance infusion per hour (i.e. over approximately 24