Doctors.net a web-based service, free to doctors, now
provides a most useful service to those of us concerned about the evidence for
the headlines produced by newspapers and which often confuse our patients and
ourselves.
Www.doctors.net.uk, in partnership with the NHS National
Electronic Library for Health has set up this service to assist busy health
professionals by providing rapid and reliable analysis of the evidence behind
selected news reports. The reviews are prepared by NHS Centre for Reviews and
Dissemination (CRD) and the aim is to publish news analysis within 48 hours of
publication. One example they quote, from the Guardian has been shortened here,
but gives a flavour of the approach.
The heading was ‘GPs could curb asthma deaths'
The Guardian 20 August reported that GPs could reduce
asthma deaths by having oxygen supplies available for the treatment of acute
asthma attacks. The newspaper article was based on a poor quality review
published in the BMJ which did not provide any evidence of the benefit of oxygen
therapy for acute asthma attacks.
The review was non-systematic and generally of poor quality.
No studies investigating the effects of oxygen therapy during acute asthma
attacks were included in the review. The authors' conclusion that '... if the
signs of a severe or life threatening attack are present ... oxygen before and
after treatment with a beta-2 agonist nebulised with oxygen should be the
standard treatment wherever the patient happens to be' is not supported by the
evidence presented.
The review was accurately reported in the newspaper article.
However, the conclusions which the authors draw are far too strong and not
supported by any evidence presented in the review. The research was originally
conducted by research and clinical staff from a number of hospitals and
university departments in London.
An interesting point has been raised regarding the
affiliation of the first author. In a rapid response to the article published on
the BMJ website, Dr Evans notes that '(t)his paper calls for large scale
investment in oxygen and new nebuliser equipment by the nation's GPs. The first
author gives his address as the 'Portex Department of Anaesthesia, Intensive
Care and Respiratory Medicine'.
SIMS Portex manufactures medical hardware, mainly for
anaesthetists, including oxygen masks and nebulisers. Dr Evans says ‘I am not
suggesting that this did truly influence the paper, but surely it should have
been declared as a potential competing interest'.
The authors selected 24 publications for inclusion in the
review, these came from personal collections and a MEDLINE search. None of the
studies were assessed for methodological quality.
The potential benefits of administering oxygen to patients with acute severe
asthma were discussed, but none of the research presented appeared to
investigate oxygen therapy. Most of the studies focused on the outcome of
decreasing levels of arterial
blood oxygen saturation following inhalation of
bronchodilators nebulised with air, not whether patients had a better outcome if
oxygen was used as a nebuliser instead of air.
The authors state that 'a systematic literature review was
not conducted as there have never been any randomised controlled trials of
oxygen in severe asthma'. This is not a valid reason for failing to conduct a
systematic review as any type of study design can be included in such research.
It is not clear from the review how studies were selected for
inclusion in the review and no details of the included studies are provided. The
studies which are discussed in the review appear to investigate whether
significant falls in arterial blood oxygen saturation are found in asthmatics
following treatment with salbutamol and other beta-2 nebulisers. Very few study
details are provided and so it is not possible to draw any conclusions regarding
the validity of these studies.
The evidence provided does not provide strong evidence for
any such association, although the reviewers appear to interpret it as such. No
studies which looked at the effects of oxygen therapy during severe or life
threatening asthma attacks appear to have been included in the review, and
without such studies it is not possible to draw conclusions regarding the
benefits of oxygen therapy for acute asthma attacks.
The conclusions which the authors draw are far too strong and
not supported by any evidence presented in the review.
A protocol for a Cochrane review which will look at studies
that compare oxygen and air for nebulising beta-agonist bronchodilators in acute
asthma was identified (4). No existing systematic reviews were found so it is
not possible to comment on this review's findings in the light of the results of
other systematic reviews.
Ref:
(Web)
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The widespread practice of starving patients in the immediate
period after gastrointestinal surgery has been challenged by a systematic review
and meta-analysis in the BMJ, which finds that “nil by mouth” after
gastrointestinal surgery may not be beneficial. Further, the apparently
beneficial effects of early postoperative enteral feeding on infection rates and
length of stay in hospital are compelling arguments in favour of a change in
clinical practice.
There is no evidence that bowel rest and a period of
starvation are beneficial for healing of wounds and anastomotic integrity.
Indeed, the evidence is that luminal nutrition may enhance wound healing and
increase anastomotic strength, particularly in malnourished patients.
The findings of the meta-analysis raise some important
questions. Pre-existing malnutrition has been shown to be a major clinical
problem in surgical patients. Although several factors – age, coexisting
disease, type and extent of surgical procedure, blood loss, duration of
procedure, skill of the surgeon, and the disease itself – have been shown to
be associated with postoperative complications, nutritional depletion is an
independent determinant of serious complications after major gastrointestinal
surgery.
As a follow-up to last months article on diabetes readers may
be interested to know that, according to the Health Services Journal, the DoH is
delaying implementation of the diabetes NSF for a year citing the structural
upheaval facing primary care trusts and health authorities as the reason.
Instead 'top line standards' are due out shortly with a
separate 'delivery strategy' scheduled for the summer of 2002.
Meanwhile, SIGN, Scottish Intercollegiate Guidance Network
has announced their Management of Diabetes guideline will be published on the
14th November.
