ANZCA Bulletin June 2011 - Australian and New Zealand College of ...

Illuminating the intervertebral
abyss with neuraxial ultrasound
Dr Nico Terblanche is a
consultant anaesthetist at
the Royal Hobart Hospital in
Tasmania where he has an
interest in ultrasound guided
epidurals, a technique he
learnt in South Africa and
Canada. He has taught and
researched the technique
in Canberra and his work
continues in Hobart. In this
article he gives his views on
the advantages of neuraxial
ultrasound.
One of my favourite quotations is by
Ralph Waldo Emerson who said “Life is
a journey, not a destination”.
My anaesthetic journey began while
I was doing a diploma in anaesthesia
as part of a group of medical mates in
Livingstone Hospital, Port Elizabeth,
South Africa. Try to imagine an 800-bed
referral hospital stretched to the limits
by serving a multitude of people on the
south-east coast of Africa. We had to
mature and take responsibility quickly.
This included regular night shifts in the
labour ward theatre.
I’ll never forget the image of walking
through labour ward on my way to
theatre. Women were literally giving
birth everywhere and if you were not
careful you could become side-tracked
and unintentionally end up playing
midwife. This became a common
introduction to an on-call production
line of “rapid sequence spinal
anaesthetics” for caesarean delivery.
Thinking back, I admit that this was
a good environment to hone neuraxial
anaesthesia skills. However this was
a serious reality check with regards to
the limitations of a “blind” technique,
especially in the morbidly obese
parturient with a potentially difficult
airway.
A couple of years later I completed
my specialist anaesthesia training at
Tygerberg Hospital, Cape Town. At the
time, urbanisation of rural Western
Cape was placing an enormous burden
on the resources of the labour ward as
the delivery rate rapidly rose within a
decade from only a couple of thousand
to more than 6000 per year. This had
implications for maternal morbidity
and mortality and it motivated me to get
involved in obstetric anaesthesia.
An audit of my high-risk obstetric
anaesthesia practice over three years
(2006-2008) revealed that 150 women
had a body mass index (BMI) of more
than 45. Of those patients 33 per cent
had a BMI of more than 55 and 67 per
cent had a BMI of more than 50. In
theory you can advise colleagues that
most of these patients should receive
a neuraxial technique while sitting in
your nice comfortable chair in the clinic,
but in practice it is technically very
challenging to execute.
A substantial proportion of these
women have subcutaneous tissue
distributed in large quantities over their
spine, turning the successful application
of the landmark technique into a
lottery. In these patients, epiduralists
often do not know where the midline
or the intervertebral space is, what the
angle of the puncture should be and
also how deep the epidural space is
below the skin. This has implications
for needle length selection. A couple of
colleagues gently reminded me of the
technical complexity of these patients
by posing questions along the lines of:
“Do you really expect us to consistently,
successfully and safely place a needle
into the epidural space”
Professor Jose Carvalho helped
solve the problem for me after I joined
his group in Mount Sinai Hospital,
Toronto, for an anaesthesia and research
fellowship. He introduced me to preprocedural
neauraxial ultrasound.
From recollection, his journey was
slightly different from mine. Epidurals
suddenly became more challenging
for him after he exchanged the bodysculptured
backs of his pregnant
cohort in Sao Paulo, Brazil, for his new
obstetric anaesthesia practice in the
Canadian heartland. His group showed
that there is a good correlation between
ultrasound and needle insertion
depth in both non-obese and obese
parturients 1,2 .
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ANZCA Bulletin June 2011