Kenneth Nugent MDa
Correspondence to Kenneth Nugent MD
Email: Kenneth.nugent@ttuhsc.edu
SWRCCC 2014;2(8)1-2
doi:10.12746/swrccc2014.0208.095
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The National Institutes of Health NHLBI
ARDS network has published more than 150 articles
on patients with acute respiratory distress syndrome.
The studies have provided essential information about
the management of patients with acute respiratory
failure requiring mechanical ventilation, including the
low tidal volume strategy, fluid and catheter management,
and late corticosteroid rescue treatment. This
network recently published the ARDSNet Long-Term
Outcomes Study (ALTOS) in the American Journal of
Respiratory and Critical Care Medicine in May 2014.1
This was a prospective longitudinal study of 203 patients
who had acute lung injury and were evaluated
at 6 and 12 months for physical impairment. The outcome
measurements included muscle strength based
on the abbreviated Medical Research Council (MRC)
score, the 6-minute walk test, and the Medical Outcomes
Study SF–36 Physical Function domain score.
The MRC score requires testing 12 motor functions,
including shoulder abduction, elbow flexion, wrist extension,
hip flexion, knee extension, and ankle dorsiflexion.
Scores range from 0 (no contraction) to 5
(normal power) resulting in a total score of 0 to 60.
The SF-36 Physical Function domain score is based
on answers to ten questions about activities during a
typical day with three possible responses (yes-limited
a lot, yes-limited a little, no-not limited at all). The
mean age in this cohort was 48 ± 15 years, 51% were
women, and 92% lived at home before hospitalization.
Eighty percent of the patients had a PaO2/FiO2
less than 200 at some point during the first three days
of mechanical ventilation, 43% received corticosteroids,
27% received a neuromuscular blocking agent,
and 16% required dialysis. At the six month followup
the percentage of maximum MRC sum score was
92% ± 8%, and 8% were classified as having ICUacquired
weakness with a score of less than 48 out
of 60. The mean percent predicted 6-minute walk test
result was 64% ± 22%, and the mean percent predicted
SF-36 PF score was 61% ± 36%. There was
not much improvement between 6 and 12 months
follow-up. Multivariable analysis indicated that corticosteroids
and length of time in this ICU adversely
influenced these outcomes. There was a strong interaction
between these two factors, and patients with
longer ICU stays on corticosteroids up to 40 mg per
day had worse outcomes. APACHE 3 scores and the
use of any neuromuscular blocking agent did not appear
to affect physical outcomes. Comorbidity did not
have a consistent effect on outcomes.
This study suggests that medical management
in the ICU influences physical impairment in
patients with acute lung injury. Physical therapy and
early mobilization can potentially reduce ICU length
of stay and limit the development of muscle weakness
and atrophy. Limiting the use of corticosteroids can
also reduce adverse effects on muscle strength without
any change in mortality.2 This study demonstrated
that individual muscle testing using the MRC score
does not necessarily provide a good indicator of overall
impairment since the 6-minute walk test results
were clearly worse than individual muscle strength
testing scores. In addition, other outcomes were not
reported. For example, it would be important to know
what percentage of patients returned to their former
employment and what percentage of patients has
some significant impairment in specific activities of
daily living.3 Herridge has reported that approximately
77% of patients who survive hospitalization for acute
respiratory failure return to work following hospitalization.4 This result suggests that physical performance
tests may not correlate with global outcomes such as
productive employment. In addition, the ALTOS investigators
did not provide information about the use
of pulmonary rehabilitation following hospitalization,
and we don’t know if this contributed to outcomes.
In summary, the ALTOS study suggests that
more attention to routine aspects of care, including limiting sedation, increasing physical activity in the
ICU, and limiting or avoiding corticosteroids, can have
important effects on outcomes, including physical
impairment and disability. In addition, these patients
likely benefit from outpatient rehabilitation. A 2011
Cochrane review has concluded that pulmonary rehabilitation
is highly effective and safe in patients with
chronic obstructive pulmonary disease who have recently
had an acute exacerbation, and we need more
studies with rehabilitation in patients with ARDS.5 Finally,
patients with ARDS need regular follow-up for
complications, such as tracheal stenosis, depression,
and post-traumatic stress disorder, post-hospitalization.
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