Monograph: |
Cyclopropane
A colourless highly flammable gas with a characteristic odour
and pungent taste. Freely soluble in alcohol: soluble in fixed
oils. One volume dissolves in about 2.7 volumes of water at
15Β°.
It is supplied compressed in metal cylinders. National stand-
ards are usually in operation for the labelling and marking of
such cylinders.
CAUTION. Mixtures of cyclopropane with oxygen or air at cer-
tain concentrations are explosive. Cyclopropane should not
be used in the presence of an open flame or of any electrical
apparatus liable to produce a spark. Precautions should be
taken against the production pf static electrical discharge.
Adverse Effects and Precautions
Cyclopropane depresses respiration to a greater extent than
many other anaesthetics. Laryngospasm, cardiac arrhythmias,
or hepatic injury may occur. Cyclopropane increases the sen-
sitivity of the heart to sympathomimetic amines. Malignant
hypenhermia has also been reported. Postoperative nausea.
vomiting, and headache are frequent.
Cyclopropane should be used with caution in patients with
bronchial asthma and cardiovascular disorders. Premedica-
tion with atropine may be advisable to reduce vagal tone.
See also Adverse Effects and Precautions for General Anaes-
thetics.
Abuse. A report following-on from a nationwide survey in
the US of four deaths from abuse of volatile anaesthetics in
operating rooms. Two of the deaths were attributed to cyclo-
propane.
Malignant hyperthermia. One case of malignant hyper-
thennia associated with cyclopropane has been reported.
Interactions
Care is advised if adrenaline or other sympathomimetics are
given during cyclopropane anaesthesia. Potentiation of com-
petitive neuromuscular blockers occurs after cyclopropane
administration.
See also Interactions for General Anaesthetics, halothane .
Uses and Administration
Cyclopropane is an anaesthetic administered by inhalation. It
has a minimum alveolar concentration (MAC) value of 9.2%. It has
been used for analgesia and induction and maintenance of
anaesthesia. It produces skeletal muscle relaxation, is non-
irritant, and induction and recovery are rapid. Because of the
risk of explosion, the usual method of administration has been
by means of a closed circuit.
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