Pharmacology for Anaesthesia and Intensive Care

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8 General anaesthetic agents

N 2 O NN———N —O ——N ——O

Halothane

CI

Br F

F

H—C—C—F

— —

— —

Enflurane

F

F

F

F

H

CI

H—C—O—C—C—F

— —

—

—

— —

Isoflurane

F

F

H

CI

F

F

H—C—O—C—C—F

— —

—

—

— —

Desflurane

F

F

H

F

F

F

H—C—O—C—C—F

— —

—

—

— —

Sevoflurane

F

H

CF 3

CF 3

H—C—O—C—H

—

—

—

—

Compound A ——

F

FCF 3

—

—

O—CH 2 F

CC

—

—

Figure 8.10.Structure of some inhaled anaesthetics and Compound A.Crepresents a chiral

centre.

Effects


Cardiovascular – by sympathetic stimulation it increases heart rate, blood pressure,

cardiac output and dilates the coronary arteries. Arrhythmias are more likely in the

presence of a raised PaCO 2.


Respiratory – the respiratory centre and peripheral chemoreceptors respond to

araised PaCO 2 resulting in an increased minute volume and bronchodilation.

However, a PaCO 2 above 10 kPa may result in respiratory depression.