The rehabilitation. Moving onto the abstract it

The aim of this essay is to
critically appraise the research of Dyer et al., (2012)
on their study titled, ‘Ambulatory oxygen improves the effectiveness of
pulmonary rehabilitation in selected patients with chronic obstructive
pulmonary disease’. Moving on from the title the study has an abstract,
introduction, methods, results, discussion and conclusion section. Throughout
this paper each section will be looked at with the view of highlighting and
discussing relevant content.

  The
title is clear and concise giving the reader an idea about what the study is
based on. However, it can be viewed as being written with an element of
foresight into the results as it states ‘Ambulatory oxygen improves the
effectiveness of pulmonary rehabilitation…’ as opposed to a more neutral title
which just states the use of ambulatory oxygen in pulmonary rehabilitation.  

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Moving onto the abstract it
begins by suggesting that the effectiveness of ambulatory oxygen during
pulmonary rehabilitation (PR) has not yet been established although other
studies have found significant acute benefits from the use of oxygen (Eaton et al., 2002). The unclear establishment of
ambulatory oxygen in PR could be down to many factors such as the severity of
the chronic obstructive pulmonary disease (COPD) along with lack of motivation,
nonadherence, psychiatric illness and other pathologies effecting ones health,
this was suggested by Hill, (2006). In the abstract the
reader finds that 51 participants completed the trial and both groups showed
improvements to exercise tolerance.

 The introduction of the research
paper expands on the title and abstract telling the reader the main points of
the article and the purpose behind the research. The introduction reveals that
PR is recommended for all patients with COPD no matter the severity. However,
PR is not defined in either the abstract or introduction leaving one to assume
what the purpose of PR is based around the articles content. The study of the
article test the use of ambulatory oxygen on specific COPD patients during PR
against other COPD patients partaking in PR on room air. The study was a
single-blind, randomised controlled trial (RCT) comparing PR with or without
ambulatory oxygen in COPD patients that demonstrated benefits from oxygen at
baseline only, peripheral capillary oxygen saturation (SP02) at exertion was
not required to be tested prior to the PR programme. Dyer
et al., (2012) draws on previous studies of a similar nature by Bradley and O’Neill, (2005) to support the research in
that exercise tolerance and maximal exercise capacity are improved when oxygen
is used.

Although the abstract and
introduction could have be supported with background information on PR and COPD
to allow the reader to understand the underlying pathology and structure of the
treatment method as in Corhay et al., (2013) study of PR and COPD which explains
the prevalence of COPD how it affect people’s lives and how PR is used to change
such effects for the better nevertheless, the objective of the study and how it
is going to be carried out is clear along with why this particular research
being carried out is relevant.

This study underwent a RCT
which has been proven to be one of the best methods for testing hypotheses (Last, 2001) and for evaluating the effectiveness of
interventions (Watkins, 2003). Below is an image
detailing the build-up of an RCT, seen in image 1.

Image 1: Randomised controlled trial (RCT), (Akobeng,
2005)

 In relation to Dyer et
al., (2012) study, the sample population would be participants with COPD
which were recruited from PR services from community and acute hospitals across
Surrey. One could suggest that the sample group collection could be less
generalised and collected from a wider demographic beyond this sample group of
Surrey. The potential participants which showed benefits from Oxygen (02) at
baseline and desaturated by more than 4% and to less than 90% on exertion in
addition to walking up to at least 10% further with ambulatory O2 on the
endurance shuttle walk test (ESWT).

If
participants were unable to attend the PR class then they were encouraged to
carry out the same exercise where possible, although the participants were
encouraged to do so no evidence was recorded as to whether they had completed
set PR exercises leaving an element of uncertainty and potentially effecting
the results. The duration of an effective ambulatory PR programme is not known (Ries et al., 2007)
however, research from Vestbo et al., (2013) suggests
a period of 6 weeks with a minimum of 20 sessions needed to achieve
physiological benefits (Nici et al., 2006).  If all services were available throughout this
study the participants would have taken part in 12-14 sessions over 6-7 weeks.
Outcome measures in the form of ESWT, Hospital Anxiety and Depression scale
(HADS), Self-reported Chronic Respiratory Questionnaire, Surrey Information on
Function Tool (SIFT) were used. Power calculations based on the ESWT were
carried out and analysed using PASW Statistics Base, a software designed
statistical analysis.

Of the
participants eligible for the study (66), 55 agreed to take part in the study.
They were then randomised into two groups, room air (RA) (27) and oxygen group
(28). Those which completed the study, 23 from RA group and 24 from the oxygen
group, giving a total of 47 participants underwent two sessions a week over 6-7
weeks depending on the services available. 19 participants failed to complete
the trial through either being withdrawn for not being able to use oxygen
safely, personal opinions of oxygen, not wanting to use oxygen, not willing to
be in the RA group, exacerbation of their condition, other medical problems and
social reasons (Dyer et al., 2012). Akobeng, (2005) states that it is common for a number
of participants to not complete a study due a range of factors including those
mentioned above. The randomisation process is key to ensuring the validity of
the RCT. Having randomised groups allows for known and unknown cofounding
factors to be balanced in both controlled and treatment groups however, due to
the randomisation process participant incompletion is inevitable, (Akobeng, 2005).

The
power calculations were used to determine the statistical power of the RCT
which will show the difference between the groups if a difference has occurred.
One of the key factors into enabling a successful power calculation is the
sample size (Last, 2001). In order for research
question to be answered the sample size needs to be large with both participant
groups containing large numbers. This is to allow for a true difference to be
seen between the groups however many studies have been undertaken with similar
or less participants Devane, Begley and Clarke, (2004), and have found no or little statistical
difference however the results still produced clinical importance such as this
study by Dyer et al., (2012). It could be argued that recruiting and
assessing a large number of potential participants could be a waste in
resources and time if a drop-out of participants is inevitable. Ringbaek, Martinez and Lange, (2013) found 165 eligible
candidates for their trial on the long term effect of ambulatory oxygen in
normoxaemic COPD patients however, only 45 of those agreed to participate and a
further 16 withdrew from the study, 10 from the oxygen group and 6 from the RA
group. The results of this study found no statistical difference between the
two groups.

The
results found by Dyer et al., (2012) show that the majority of participants in
the oxygen group still desaturated post PR however their exercise tolerance had
increased. As expected the RA group desaturated throughout and post PR class
bar-one, with no desaturation difference found between pre and post PR. The
only measurement on physiological change is the SPO2 desaturation, according to
Vestbo et al., (2013) it would take a period of 6
weeks with a minimum of 20 sessions needed to achieve physiological benefits so
it could be said that due to the participant’s desaturation and sessions attended
in this study that no physiological changes were made however exercise
tolerance was increased.

Dyer et al., (2012) displayed the data through
figures within text and numerical data presented in tables. The results were
externally sourced through a statistician from the University of Surrey and the
local strategic health authority (KC). To process the data on SPSS a two –
tailed paired t test was used as it tests the difference between the two
groups.

The
results presented for the effect of ambulatory oxygen during PR on ESWT show a
mean improvement of 516m (p0.0001) between the two groups compared to baseline
results with a combined mean of 283m. The p value presented suggests that the
difference between the two groups is of statistical significance as it is less
than 0.05 therefore the null hypothesis can be rejected. Confidence Interval
(CI) found was at 95% suggesting that the effects of ambulatory oxygen found in
this study group would also be found in the rest of the population with the
same presentations. P values and CI’s are both presented to show a statistical
significance as well as to give the precision of the estimation. However, the
mean difference presented does not correlate with the base line (283m) and post
(926m) PR values. Through subtracting these values from each other the mean difference
would equal 643m, contradicting the mean difference presented by Dyer et al., (2012).

Dyer et al., (2012) set out to determine whether
the use of ambulatory O2 during PR for hypoxaemic patients would provide
additional benefits in comparison to patients on RA along with, exploring the
extent of the acute response of ambulatory O2 benefit. Although not mentioned
in the study one can believe the purpose of this study is due to the prevalence
of COPD where in the UK 1.2 million people are now living with diagnosed COPD a
figure which is 835,000 more than predicted by the Department of Health in
2011, with the prevalence continuing to grow (Statistics.blf.org.uk,
2018). The use of PR has shown to be reduce exacerbations and increase
the quality of life for those diagnosed with COPD (Corhay
et al., 2013) therefore using a supplementary aid in the form of oxygen
can lead to an increase in exercise tolerance and daily living as found by Dyer et al., (2012) in this study.

The
results showed that 47 participants completed the trial however in the abstract
it states that 51 participants completed the study leading one to think how
reliable the data is. It has been noted that a number of participants dropped
out throughout the study in addition to errors in the results which may also
contribute to obscure results and the so far unestablished effectiveness of
ambulatory oxygen in PR, implementing strategies that could also reduce the
fallout rate could help in obtaining measurable data. Dyer
et al., (2012) achieved what they intended to find out and from that
point of view it was a successful study for the researchers.

The
conclusion of the study was short and precise and details that their study was
successful in what was set out to be achieved and suggests that the use of
ambulatory oxygen is beneficial to PR which could encourage clinicians and
future researchers to use their methods in practice or build on this current
study. The study was presented well with clear sections displayed in a
chronological order and results displayed in a format that gives optimal
clarity of what is being presented.

This
study can persuade therapist and clinicians to incorporate ambulatory oxygen
into their PR programmes and encourage others to carry out further research. This
research is important for clinical investigations and clinical practice as PR
has been proven to be the most effective nonpharmacological intervention for
COPD patients and is now a formality for such patients (Vestbo
et al., 2013) and any methods to further
enhance this treatment should be welcomed.