Non-invasive positive pressure ventilation to treat respiratory failure resulting from exacerbations of chronic obstructive pulmonary disease: Cochrane systematic review and meta-analysis
BMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7382.185 (Published 25 January 2003) Cite this as: BMJ 2003;326:185
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Dear Sir,
I thank Dr Petrucci for her interest in our paper (1). It is obvious
that there has been a typographical error in the sentence referred to by
Dr Petrucci as it is missing the word "NOT" and the sentence should read
as follows: "Where heterogenity was NOT present, the fixed effect model
was used to report results; otherwise the random effects model was used."
Dr Petrucci herself highlights that it is a typographical error as she
states that "Indeed, the authors correctly used in their analysis fixed
effect model as the test for heterogeneity was not statistically
significant."
On a related issue it is not entirely correct to state that "...the
use of the random effects model is justified when heterogeneity is
present." The random effects model can also be used when no heterogeneity
is present, the decision on which model to use is down to personal choice.
We decided to use the fixed effect model in our meta-analysis and reserve
the use of random effects model where heterogeneity was present.
(1) Non-invasive positive pressure ventilation to treat respiratory
failure resulting from exacerbations of chronic obstructive pulmonary
disease: Cochrane systematic review and meta-analysis. Josephine V
Lightowler, Jadwiga A Wedzicha, Mark W Elliott, and Felix S F Ram BMJ
2003;326:185-187.
Competing interests:
None declared
Competing interests: No competing interests
Dear Sir,
I read with great interest the systematic review and meta-analysis by
Lightowler et Al (1). In the full text of the review (see www.bmj.com) the
authors state that "Where heterogenity was present, the fixed effect model
was used to report results; otherwise the random effects model was used."
Actually, this sentence is wrong, as the use of the random effects model
is justified when heterogeneity is present. Indeed, the authors correctly
used in their analysis fixed effect model as the test for heterogeneity
was not statistically significant. The text should be amended accordingly.
1. Non-invasive positive pressure ventilation to treat respiratory
failure resulting from exacerbations of chronic obstructive pulmonary
disease: Cochrane systematic review and meta-analysis
Josephine V Lightowler, Jadwiga A Wedzicha, Mark W Elliott, and Felix S F
Ram
BMJ 2003;326:185-187.
Competing interests:
None declared
Competing interests: No competing interests
I have read the paper by Lightowler et al titled Non-invasive
positive pressure ventilation to treat respiratory failure resulting from
exacerbations of chronic obstructive pulmonary disease: Cochrane
systematic review and meta-analysis with great interest. The result is
promising despite of all the shortcoming of met-analysis approach because
our daily clinical practice support author's outcome. we should use this
novel therapy more frequently in our COPD patients and take a step forward
to close the widen gap between the evidence and our practice.
Competing interests:
None declared
Competing interests: No competing interests
In hospital care of acute COPD
We note the Cochrane systematic review and meta-analysis confirming
the effectiveness of non-invasive positive pressure ventilation (NPPV)1 in
the management of acute exacerbations of COPD with respiratory failure.
However, optimal standard medical care is essential to maximise
benefit from NPPV. We have audited the management of chronic obstructive
pulmonary disease (COPD) exacerbations in one district general hospital
before routine availability of NPPV across respiratory and non-respiratory
medical firms with reference to the most recent available BTS guidelines2
(although updated guidelines are imminent). Use of NPPV was not assessed
as this was not routinely available off intensive care (ITU) at the time.
100 consecutive acute exacerbations of COPD were audited. There was
no significant difference in performance between respiratory and non-
respiratory firms. In history taking, pre-admission antibiotic therapy was
documented in only 29% of cases, and previous ITU admission in 14% of
cases. Conscious level (41%), peak flow rate (15%) and FEV1 (2%) were
under-documented. Chest radiography was incorrectly interpreted in 39% of
cases (over 50% being pneumonia). Antibiotics were often administered
(90%) but were justified on BTS criteria much less often (48%)3, with a
tendency for combination therapy (64%). Peak flow chart (42%) and inhaler
technique (23%) were underused. 6 week followup was attempted in only 11%
of cases. Discharge FEV1 (17%) and arterial blood gases (22%) were done in
the minority of cases.
In summary, there were many deficiencies in management in both
respiratory and non-respiratory firms. Proposed local strategies for
improvement include the increasing availability of portable spirometers, a
rolling programme of educational seminars, development of a COPD care
pathway, use of “antibiotic stickers”, and utilising other sources of
follow-up eg) primary care, respiratory specialist nurse clinics, ward
attenders as well as medical outpatients to improve follow-up times.
We feel standard medical care of COPD should be optimised to allow
NPPV to have its full potential benefit.
References
1 JV Lightowler, JA Wedzicha, MW Elliott, FSF Ram. Non-invasive
positive pressure ventilation to treat respiratory failure resulting from
exacerbations of chronic obstructive pulmonary disease: Cochrane
systematic review and meta-analysis. BMJ 2003;326:185-189.
2 British Thoracic Society Standards of Care Committee. Guidelines on
the Management of COPD. Thorax 1997 52 (Suppl 5);S1-S28.
3 Anthonisen NR, Manfreda J, Warren CP, Hershfield ES, Harding G,
Nelson NA. Antibiotic therapy in exacerbations of chronic obstructive
pulmonary disease. Ann Intern Med 1987;106(2):196-204.
Competing interests:
None declared
Competing interests: No competing interests