Monograph: |
Anaesthetic Ether
Anaesthetic ether is diethyl ether to which an appropriate
quantity of a non-volatile antoxidant may have been added.
The Ph. Eur. and USP state that ether suitable for anaesthesia
contains not more than 0.2% of water. The LJSP also specifies
that it contains 96 to 98% of(C;H-i);0. the remainder consist-
ing of alcohol and water. It is slowly oxidised by the action
of
air and light, with the formation of peroxides. A clear, colour
less. volatile, highly flammable, and very mobile liquid with
a characteristic odour. B.p. 34Β° to 35Β°.
Soluble 1 in 12 to 15 of water: miscible with alcohol, chloro-
Form, dichloromethane, petroleum spirit, and fixed and vola-
tile oils. Store at a temperature of 8Β° to 15 in airtight
containers. Protect from light. Ether remaining in a partly
used container may deteriorate rapidly.
The label should state that it is suitable for use as an anaes-
thetic. The Ph. Eur. also directs that the name and concentra-
tion of the antoxidant used should be specified.
CAUTION. Ether is volatile and flammable and mixtures of
its vapour with oxygen, nitrous oxide, or air at certain con-
centrations are explosive. It should not be used in the pres-
ence of an open flame or any electrical apparatus liable to
produce a spark. Precautions should be taken against the pro-
duction of static electrical discharge.
Storage. The Pharmaceutical Society's Department of Phar-
maceutical Sciences found that free ether, even in low con-
centrations. caused softening of PVC bottles and was
associated with loss by permeation.
Adverse Effects
Ether has an irritant action on the mucous membrane of the
respiratory tract; it stimulates salivation and increases bron-
chial secretion. Laryngeal spasm may occur. Ether causes va-
sodilatation which may lead to a severe fall in blood pressure
and it reduces blood flow to the kidneys; it also increases cap-
illary bleeding. The bleeding time is unchanged but the pro-
thrombin time may be prolonged. Ether may cause malignant
hyperthermia in certain individuals. Alterations in kidney and
liver function have been reported. Convulsions occasionally
occur. Hyperglycaemia due to gluconeogenesis has been
noted.
Recovery is slow from prolonged ether anaesthesia and post-
operative vomiting commonly occurs. Acute overdosage of
ether is characterised by respiratory failure and cardiac arrest.
Dependence on ether or ether vapour has been reported. Pro-
longed contact with ether spilt on any tissue produces necro-
sis,
See also Adverse Effects of General Anaesthetics, like halothane.
Precautions
Ether anaesthesia is contra-indicated in patients with diabetes
Mellilus, impaired kidney function, raised cerebrospinal fluid
pressure, and severe liver disease. Its use is not advisable in
hot and humid conditions in patients with fever as convul-
sions are liable to occur, particularly in children and in pa-
tients who have been given atropine.
See also Precautions for General Anaesthetics like halothane.
Interactions
Ether enhances the action of competitive neuromuscular
blockers to a greater degree than most other anaesthetics. Po-
tentiation of the arrhythmogenic effect of sympathomimetics,
including adrenaline, by ether is less than that seen with other
inhalarional anaesthetics.
See also Interactions of General Anaesthetics,like halothane.
Uses and Administration
Ether is an anaesthetic administered by inhalation. It has a
minimum alveolar concentration (MAC) value
of 1.92%. Ether is still used in some countries for the induc-
tion and maintenance of anaesthesia although it has been re-
placed in many other countries by the halogenated
anaesthetics. It possesses a respiratory stimulant effect in all
but the deepest planes of anaesthesia. Ether also possesses an-
algesic and muscle relaxant properties. Premedication with an
antimuscarinic such as atropine is necessary to reduce sali-
vary and bronchial secretions.
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