|
Never EVER use force when inserting the probe. You will
injure the patient if you do so.
|
Important points are:
- Always use a bite block (properly positioned: small end towards the tip of the probe);
some experts use two sets of gloves (so that the outer pair can be discarded
if they become slippery).
- Position the patient in the left lateral decubitus position;
- A disposable sheath (these are available) will protect the
probe and patient;
- The most effective sedative is to continually
tell the patient what is going on, and reassure them when
things are going well.
- Flex the neck. When you insert the probe, the patient may
well try and extend the neck, but ensure that the neck is flexed,
to maximise the likelihood that the probe will enter the
oesophagus and not encroach on the trachea!
- Direct the probe centrally towards the back of the pharynx;
- Enlist patient co-operation when the head of the probe
is in the back of the pharynx at the level of the
cricopharyngeus, and resistance is met - ask them
to swallow, and the probe will enter the upper oesophagus;
- Advance the probe to ~ 40cm from the incisor teeth to
traverse the lower oesophageal sphincter; then work systematically
through your study, video-taping everything, and making sure that
you meet the objectives of the study. Withdraw and visualise
at the various levels required to complete the study.
- Do NOT let the study last longer than fifteen minutes in
the non-anaesthetised patient,
as the patient will then become restless and uncooperative,
if they are not already!
- Get two-dimensional information - do NOT develop a fixation
with colourful doppler pictures;
- Treat the probe like the $20 000(+) item it is.
Note that some experts advocate "going for the money" and looking
first at the important structures. Others start proximally at the
base of the heart, and then move more distally. Do what you find
to be best in your hands.
In the critically ill patient, it is often necessary to remove the
nasogastric tube to allow adequate visualisation; in addition partial
deflation of the endotracheal tube cuff may facilitate passage of the probe.
Risks of TOE
Properly performed, TOE is very safe. The death rate is reported as
0.04%, and the incidence of major complications as 0.5%. This is
however not zero, and far greater than, for example, the risk of
complications with 'routine' anaesthesia! Here is a list of potential
complications:
- Sedation may result in aspiration or apnoea
On the other side of the coin, patient discomfort is common,
especially without sedation!
The reason why the procedure is contra-indicated in oesophageal
disease (carcinoma, stricture, varices, diverticulae, bleeding,
fistulae and previous mediastinal irradiation) is that
this predisposes to injury or even death. There is at least one
report of a Mallory-Weiss tear related to TOE.
Accidental "transtracheal" insertion has occurred. This is
characterised by the triad of:
- unusual image orientation or quality;
- patient desaturation;
- resistance at 30 cm;
The incidence of infection and disease transmission should
be extremely low provided appropriate precautions are observed.
Other potential complications include hypertension, hypotension,
bradycardias due to vagotonia, respiratory distress, AV block,
tachyarrhythmias (atrial or ventricular), bronchospasm,
desaturation, and angina.
In a retrospective study of 10 419 examinations
the death rate was 0.01%, and intubations succeeded 98.5% of the time, but
the study was prematurely terminated in 0.88% because of a variety of
problems including intolerance, desaturation, arrhythmias, angina, or
haemorrhage.
|