First successful public demonstration of anaesthesia
Massachusetts General Hospital, Boston
Anaesthetist: William Thomas Green Morton
Agent: Diethyl Ether
Patient: Gilbert Abbott
Operation: Excision of tumour under jaw
Surgeon: John Collins Warren
Comment: “Gentlemen, this is no humbug”
What is anaesthesia?
General Anaesthesia - reversible unrousable unconsciousness, usually drug induced.
Local anaesthesia - useless vague term referring to the use of local anaesthetics
Topical anaesthesia - anaesthesia of skin or mucous membranes by topical appliation
of local anaesthetics.
Infiltration anaesthesia - anaesthesia of tissues by direct injection of local anaesthetic
where it is needed - ie for excision of skin lesions.
Regional anaesthesia (`conduction blocks' or `blocks') - anasthesia of a part of
the body by injecting local anaesthetic into the nerves that go there. Simple blocks include finger blocks, ankle blocks,
etc; more complex blocks include plexus blocks, and `major regionals' mean epidural or spinal anaesthesia.
Conscious Sedation - sedation and anxiolysis with consciousness retained.
Neurolept Analgesia - analgesia, disinterest and psychomotor retardation; often little
What do Anaesthetists do?
Patients are usually seen by the anaesthetist preoperatively. We have a chat and
decide what we think is the best way to provide anaesthesia for surgery and what techniques and drugs will be used. A discussion
of the risks and benefits of the various approaches should result in an agreed plan. This is very important as the safety
of an anaesthetic depends a lot on individualisation and selecting the appropriate technique. Exactly what will happen should
be explained to the patient. Both common risks (pain, nausea, sore throat, muscle pain after sux, etc etc) and rare but serious
risks (death, paraplegia, etc) should be explained and the patients consent obtained. Usually it is not signed separately.
Responsibility for anaesthesia rests with the anaesthetist, not the surgeon.
The anaesthetist stays with the patient from the time we send them off to sleep until
care is passed on to recovery staff, however our responsibility legally relates to the entire period from the time the premed
is given until full recovery from the anaesthetic.
Once the patient is asleep, we continuously monitor the adequacy of breathing, arterial
oxygen saturation and pulse, heart beat, CO2 and ariway pressures while ventilated, etc; more specialised monitoring is used
in special circumstances, ie brain monitoring in neurosurgery. The patient is carefully positioned so as to not cause nerve
or skin damage. We try to give the right doses of the right drugs and hope the patient is unconscious.
Fortunately if the patient is able to hear something (or even feel something) they
usually can't remember it. There is no way that we can be sure that a given patient is asleep, particularly once they are
paralysed and cannot move; in a way the art of anaesthesia is a sophisticated form of guesswork. It reallys is art more than
science; the latter seems more obvious when one first gets a look at the `technical' nature of our practice, but if you ever
watch new people doing it you realise that experience is far more important than knowledge alone.
At the end of the operation we wake the patient up, extubate them or remove the laryngeal
mask or whatever and transport the patient to recovery, or ICU. Usually we then wait awhile to make sure the patient is OK.
We are responsible for ensuring that adequate analgesia is ordered. Usually the anaesthetist tries to visit the patient post-op.
Anaesthetists run most acute pain services and often have substantial input to ICU
and the ER.
Anaesthesia alone in healthy well patients has a mortality (due to unexpected drug
reactions, haste, device malfunction, etc) of 1:500,000. This contrasts with the 1:30 chance of being killed or maimed if
you are a driver from the age of 17 to 25, and is far less than the risk of surgery. Overall the risk of death due to anaesthesia
in all patients undergoing surgery is about 1:30,000. This is about the same risk of death and/or disablility as driving 10km
to and from work in busy traffic for a few months.