Mechanical ventilation has come a long way since the iron
lung was invented in 1927. Polio, responsible for many
of the iron lung's inhabitants, has been largely eradicated,
and the device itself no longer has any similarity in
name or appearance to a medieval torture instrument. However,
mechanical ventilation still opens a bacterial highway
into the lungs, often resulting in pneumonia. New recommendations
published in the August 17 issue of Annals of Internal
Medicine will hopefully strengthen our defenses against
ventilator-associated pneumonia (VAP).
A Canadian team, headed by Dr Peter
Dodek of the University of British Columbia, developed
the new recommendations. The struggle individual hospitals
faced in preventing VAP � documented in an earlier international
survey � was what motivated the BC task force to take
a closer look at the problem. According to Dr Dodek,
the survey showed that some effective strategies weren't
used enough. So, in an effort to remedy this glaring
discrepancy, the researchers developed an "evidence-based
clinical practice guideline."
The team began by searching databases
like MEDLINE, EMBASE and the Cochrane Database of Systemic
Reviews to unearth studies and literature reviews published
prior to April 2003 concerning the use of mechanical
ventilation in hospitalized adults.
After collecting the data, Dr Dodek
and colleagues teased out the pertinent information
that would influence practice guidelines. These factors
included how similar the outcomes were from patient
to patient, the practicality and bottom-line cost of
the anti-VAP procedure, patients' physical condition
and drugs that were used at the time of mechanical ventilation.
The analysis led to a number of
key recommendations. Mechanical ventilation should be
done via the orotracheal route. Brand new ventilator
circuits and suction parts should be used for each patient.
If the ventilator includes equipment to cycle heat and
moisture out of the patient, these parts should be replaced
for every week of use of the machine.
Finally, a semiprone position while
on the ventilator is best, if possible. Among the no-noes
in the panel's anti-VAP list were the use of the drug
sucralfate and topical antibiotics to zap potential
pneumonia-causing organisms.
There was not enough information
to get the goods on factors like chest physiotherapy,
when ventilation was done, and the intravenous use of
antibiotics. As well, the team did not consider patients'
views on the matter, although this was reasonable, given
the fragile and often uncommunicative state of the patient
at the time of ventilation.
Now that the guidelines are at
hand, the real work begins. As the authors write, "only
with effective implementation will guidelines have the
potential to decrease the risk of VAP and its attendant
morbidity and mortality in critically ill, mechanically
ventilated patients."
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