Healthcare and Medicine Reference
In-Depth Information
system up to and including external cardiac massage. The Advanced
Life Support (ALS) course provides adequate evidence of these
skills, albeit in a simulated environment. Those providing sedation
regularly should spend time with an experienced anaesthetist in
the operating theatre to hone and maintain their airway skills. Any
sedationist should be prepared to demonstrate their experience,
training and assessment in the fi eld.
A competent individual must monitor and record the patient's
observations throughout the procedure. This may be the person
administering the sedation or the task may be delegated. If the
sedationist monitors the patient, then a second practitioner must
perform the procedure. If the task is delegated, and this individual
does not possess ALS skills, then the practitioner performing the
procedure must be prepared to abandon it immediately if compli-
cations arise from the sedation.
In other words, two qualifi ed people are needed to safely sedate a
patient and perform a procedure.
Dorsal digital nerve
Digital arteries
Extensor tendon
Phalanx
Flexor tendon
and sheath
Palmar digital
nerve
Equipment and monitoring
Facilities should be available to administer oxygen therapy, nasally
and by face mask, from the time of onset of the sedation until the
patient is fully awake. All patient trolleys used must be capable
of being tipped 'head down', and suction should be immediately
available.
A resuscitation trolley and airway equipment - to include
oropharyngeal/nasopharyngeal airways and a means of achieving
endotracheal intubation - must be present in all areas from induc-
tion through to recovery. Emergency drugs, including antagonists
to the agents used (e.g, naloxone) should be immediately available.
An absolute minimum standard of monitoring is the continuous
presence of a trained individual, with continuous pulse oximetry
recording and verbal communication with the patient. Blood pres-
sure and ECG recording may be advisable in lengthier procedures
or the patient with comorbidity. During recovery, a sedation score
system may be useful.
Figure 4.2 Cross-section of the fi nger showing positions of the digital
arteries and nerves with needle entry positions.
Each must be applied before the anticipated procedure (30 minutes
for Ametop, 60 minutes for EMLA) and covered with a waterproof,
occlusive dressing.
There is some evidence that Ametop provides slightly superior
topical anaesthesia compared with EMLA, and that it causes less
vasoconstriction which may make cannulation easier. Conversely,
skin reactions are marginally more common with Ametop.
Safe sedation
Defi nition
Sedation involves the use of one or more drugs to depress the CNS
to allow procedures to be carried out with minimal distress and
discomfort to the patient. It differs from general anaesthesia in that
the patient must remain conscious and in verbal contact with the
practitioner throughout the procedure.
Best practice uses a single therapeutic agent to achieve the desired
level of sedation. All drugs in common use (opiates, benzodiazepines
and others) depress the respiratory and cardiovascular systems in
addition to the CNS. These effects are compounded and become less
predictable when multiple agents are used. If analgesia using opiates
is necessary, this should be established fi rst and time allowed for the
drug to reach its peak effect before the hypnotic agent is added.
Agents in common use
Most sedation for practical procedures will be administered by
the intravenous route. If time allows, oral benzodiazepines may
be used, although at least an hour is normally required to achieve
sedation. Two classes of drug are in common use intravenously:
benzodiazepines (cause sedation, anxiolysis and amnesia), and
the anaesthetic drugs propofol (sedation) and ketamine (seda-
tion and analgesia). Opioids (analgesia and mild hypnosis) and
Entonox® (nitrous oxide/oxygen - analgesia and euphoria) will
also be discussed briefl y.
Who can perform sedation?
Sedative drugs may be administered by a suitably qualifi ed health-
care professional. In practice this will be a doctor, a nurse acting in
line with a Patient Group Directive, or an allied health professional
such as an Anaesthetic Practitioner. Whoever administers sedation
must be fully aware of the dose, side-effects, pharmacology and
interactions of the agent they are using.
The individual providing sedation must be adequately trained to
provide airway support and supplemental oxygen therapy, to admin-
ister bag-valve-mask ventilation and to support the cardiovascular
Benzodiazepines
This group of drugs, including midazolam, diazepam and loraze-
pam, act on GABA
subgroup) recep-
tors in the brain (Figure 4.3) by binding to specifi c benzodiazepine
binding sites on these larger receptors. There are two main types of
GABA receptor:
α
(
γ
-amino butyric acid,
α
2
subgroup cause anxiolysis. Both effects are benefi cial in this instance.
Some patients will experience anterograde amnesia following the
administration of benzodiazepines, which may be unpleasant.
α
1 GABA receptors confer sedation, while the
α
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