Acute Pain - final version - Faculty of pain medicine - Australian and ...

Adjuvant drugs
The
efficacy
of
adding
of
adjuvant
drugs
such
as
adrenaline
(epinephrine),
clonidine,
ketamine,
midazolam,
neostigmine
and
magnesium
to
solutions
used
for
epidural
analgesia
has
also
been
investigated
(see
Section
5.3).
7.2.3 Patient-controlled epidural analgesia
The
use
of
patient‐controlled
epidural
analgesia
(PCEA)
has
become
increasingly
popular;
it
is
based
on
similar
concepts
as
for
other
patient‐controlled
techniques.
Comparison with continuous epidural infusions
A
meta‐analysis
comparing
PCEA,
continuous
epidural
infusions
and
IV
PCA
opioids
after
surgery
showed
that
both
forms
of
epidural
analgesia
(with
the
exception
of
hydrophilic
opioid‐only
epidural
regimens)
provided
better
pain
relief
with
rest
and
with
activity
than
PCA
opioids,
but
that
analgesia
with
a
continuous
epidural
infusion
was
superior
to
PCEA,
although
the
incidence
of
nausea,
vomiting
and
motor
block
was
higher
(Wu
et
al,
2005
Level
I).
However,
results
from
other
more
recent
studies
are
conflicting.
In
a
large
study
looking
specifically
at
patients
after
colonic
resection,
PCEA
was
superior
to
continuous
epidural
infusion
with
regard
to
pain
control,
requirements
for
top‐ups
and
systemic
analgesia
as
well
as
patient
satisfaction
(Nightingale
et
al,
2007
Level
II).
In
contrast,
comparisons
of
PCEA
and
continuous
epidural
infusions
for
pain
relief
after
thoracotomy
using
both
high
(5
mg/mL)
and
low
(1.5
mg/mL)
concentrations
of
levobupivacaine
showed
no
differences
in
quality
of
analgesia,
morphine
consumption
or
satisfaction;
more
patients
in
the
high
concentration
continuous
epidural
infusion
group
had
significant
motor
blockade
(Dernedde
et
al,
2006
Level
II).
For
pain
relief
during
labour,
a
comparison
of
demand
dose‐only
PCEA,
PCEA
with
a
continuous
infusion,
and
a
continuous
epidural
infusion
only
during
labour,
showed
that
dose‐only
PCEA
resulted
in
less
total
epidural
dose
compared
with
the
other
modalities;
no
differences
were
noted
with
respect
to
pain
scores,
motor
block,
duration
of
labour,
number
of
staff
interventions,
delivery
outcome,
and
maternal
satisfaction
score
(Vallejo
et
al,
2007
Level
II).
Concurrent background (continuous) infusions
The
addition
of
a
continuous
background
infusion
to
PCEA
using
bupivacaine
and
fentanyl
following
gastrectomy
resulted
in
significantly
better
dynamic
pain
scores,
higher
total
doses
and
a
greater
incidence
of
pruritus
than
PCEA‐bolus
dose
only
(Komatsu
et
al,
1998
Level
II).
The
use
of
a
night‐time‐only
infusion
with
PCEA
bupivacaine‐fentanyl,
also
in
postgastrectomy
patients,
resulted
in
better
sleep,
but
total
cumulative
doses
were
similar
and
pain
scores
were
only
better
in
the
morning
of
the
second
postoperative
day
(Komatsu
et
al,
2001
Level
II).
However,
pain
relief
is
not
always
improved.
After
lower
abdominal
surgery
there
was
no
difference
in
pain
scores,
but
higher
total
cumulative
doses
and
incidence
of
side
effects
when
a
background
infusion
was
added
to
PCEA
with
ropivacaine
and
fentanyl
(Wong
et
al,
2000
Level
II).
The
addition
of
a
background
infusion
to
bupivacaine‐fentanyl
PCEA
did
not
improve
pain
relief
after
pelvic
reconstruction
(Nolan
et
al,
1992
Level
II).
In
a
systematic
review
of
PCEA
in
labour
analgesia,
the
use
of
a
continuous
background
epidural
infusion
combined
with
PCEA
resulted
in
improved
maternal
analgesia
and
reduced
unscheduled
clinician
interventions
(Halpern
&
Carvalho
2009,
Level
I).
CHAPTER
7
Acute
pain
management:
scientific
evidence
 185