In their response to our article Dr Griffiths makes some important
remarks, which we would like to comment on.
We did indeed take clustering into account in the analysis of our
data. As stated in the methods section of our paper we used multilevel
models.[1] In this multilevel model practices were included as the level
of clustering in these models.
In their response to our article Dr Griffiths makes some important
remarks, which we would like to comment on.
We did indeed take clustering into account in the analysis of our
data. As stated in the methods section of our paper we used multilevel
models.[1] In this multilevel model practices were included as the level
of clustering in these models.
A second methodological question is about the successfully treated
weeks. This is indeed a new unvalidated method, which was not described in
detail in the original trial protocol. Initially only a comparison of
monthly/weekly symptom scores was planned. As the study progressed we
developed a more profound insight in how to express the day-to-day
variability of asthma symptoms, which is characteristic for the
intermittent nature of the disease. When we graphically plotted symptom
scores in time for each patient, scores were clearly skewed towards the
lower values. A pattern we have observed in several previous asthma
studies at our department. Our goal was to define an effect parameter that
would give expression to this observation in order to detect and count
episodes of perceived loss of asthma control as perceived by patients. For
most patients symptom scores were similar to the graphical representation
of symptom scores as shown in figure 1 in our paper. Our assumption was
that the peaks in this figure represent episodes of perceived loss of
asthma control. Ideally an individual (baseline) cut-off score should have
been defined before the start of the study. As this was not possible in
our study, we compared several cut-off points (individual median,
individual mode, individual median +1) with a 'blinded' manual count of
peaks in a sample of symptom score graphs. The individual median value
proved to have the best match with our counts. Possible strengths and
weaknesses of this analysis have been described in the discussion section
of our paper and we have planned further validation on other datasets at
our department.
Finally Dr Griffiths points out that benefits of self-management in
our study are at best marginal. He doubts if benefits described are worth
the efforts and resources spent. From the sole perspective of outcomes as
described in our paper it seems tempting to disqualify self-management
because of a lack of superiority. However, in a cost-effectiveness
analysis we demonstrated that self-management is at least equally
efficient as usual care. Savings in medication and productivity loss
equalled resources allocated for the implementation of self-management.
Effects in favour of self-management were more pronounced in the second
year, suggesting a long-term superiority (ie dominance in terms of cost-
effectiveness) of self management.[2] In addition patients were more
satisfied with the care provided by their GP.[3] Self-management of
asthma provides a unique opportunity for a more patient centered approach,
without compromising asthma control and without spending additional
resources.
We believe that self-management is worth the effort in spite of the
absence of clear clinical evidence of superiority. The economic benefits
of self management in terms of a reduced number of days out of work may
illustrate the need to take a broader view than just the process and
outcomes of the asthma care itself. It is in particular on these grounds
that we are confident to promote self-management.
References
(1) Thoonen BPA, Schermer TRJ, van den Boom G, Molema J, Folgering H,
Akkermans RP et al. Self-management of asthma in general practice, asthma
control and quality of life: a randomised controlled trial. Thorax
2003;58:30-6.
(2) Schermer TRJ, Thoonen BPA, van den Boom G, Akkermans RP, Grol RP,
Folgering HT et al. Randomized Controlled Economic Evaluation of Asthma
Self-Management in Primary Health Care. Am J Respir Crit Care Med
2002;155:1062–72.
(3) Thoonen BPA, Schermer TRJ, Jansen M, Smeele I, Jacobs JE, Grol R
et al. Asthma education tailored to individual patient needs can optimise
partnerships in asthma self-management. Patient Education and Counseling
2002;47:355-60.
In a reaction to our paper Dr Martin Olmedo asks what factors may
explain the observed better control of illness in our self-management
group.
The self-management program in our study consisted of education,
skills training and written instructions for autonomous adaptation of
maintenance therapy with inhaled corticosteroids. As this intervention
consisted of more than one element, it is n...
In a reaction to our paper Dr Martin Olmedo asks what factors may
explain the observed better control of illness in our self-management
group.
The self-management program in our study consisted of education,
skills training and written instructions for autonomous adaptation of
maintenance therapy with inhaled corticosteroids. As this intervention
consisted of more than one element, it is not possible to clearly identify
what caused the effects. We can only speculate on that, but we have some
indications about factors that may have contributed to our findings. In a
cost-effectiveness analysis we observed that a larger proportion of
subjects took domestic house dust mite avoidance measures and there were
significantly more influenza vaccinations in the self-management group.[1]
In another secondary analysis we explored possible determinants of
resource use. Although we have reasons to believe that in this study some
relevant factors may have remained unrevealed, we concluded that subjects
that are more self-efficacious are likely to benefit most from self-
management of asthma.[2]
Our findings indicate that asthma patients may be more aware of their
own responsibilities in the management of their asthma. This may also
explain the observed better control of illness with less inhaled
corticosteroids.
We would like to stress that our study was not designed to identify
individual factors to improve asthma care. There are strong indications
that a combined approach is needed in order to improve outcomes of asthma
care.[3,4] Rearranging the organisation and delivery of asthma care into
a mode of cooperation, aiming at shared responsibilities is a more patient
centred approach. It may be the key to bridge the gap between efficacy and
effectiveness of asthma care. Our findings demonstrate that the typical
features of asthma self-management may provide the means for such mode of
cooperation. In our view the self-management program can only be
successful as a whole. It's success can best be explained by the
integrated patient-centred approach.
References
(1) Schermer TRJ, Thoonen BPA, van den Boom G, Akkermans RP, Grol RP,
Folgering HT et al. Randomized Controlled Economic Evaluation of Asthma
Self-Management in Primary Health Care. Am J Respir Crit Care Med
2002;155:1062–72.
(2) Thoonen BPA, Schermer TRJ, Fejzic Z, van Schayck CP. Determinants
of resource use in a cost-effective asthma self management program. Eur
Resp J 2002; Supplement 38:396s.
(3) Gibson PG, Coughlan J, Wilson AJ, Abramson M, Bauman A, Hensley
MJ, et al. Self-management education and regular practitioner review for
adults with asthma (Cochrane review). The Cochrane Library 2000;3.
(4) Thoonen BPA, van Weel C. Role of family physicians in
implementing asthma self-management programs. Disease Management and
Health Outcomes 2002;10:141-6.
Thank you for a well-reasoned explanation on the effect of yoga on
asthma.
The study quoted [1] which justifies the Buteyko technique was flawed
by:
* unequal groups in that the Buteyko group initially required 1½ times the
steroids of the control group
* the Buteyko group receiving seven times the follow-up phone calls as the
control group, plus extra breathin...
Thank you for a well-reasoned explanation on the effect of yoga on
asthma.
The study quoted [1] which justifies the Buteyko technique was flawed
by:
* unequal groups in that the Buteyko group initially required 1½ times the
steroids of the control group
* the Buteyko group receiving seven times the follow-up phone calls as the
control group, plus extra breathing classes.
Also, no significant difference was found in quality of life scores at the
end of the trial.
However, there is anecdotal evidence of excellent results in some
patients, representing the overlap of hyperventilation syndrome and asthma.[2] If patients with asthma are given the simple Nijmegen questionnaire [3] to identify coexisting hyperventilation syndrome, a chartered
physiotherapist can usually treat them successfully.[4]
References
(1) Bowler SD, Green A, Mitchell CA (1998) Buteyko breathing
techniques in asthma: a randomised controlled trial. Med.J.Aust, 169, 575-8.
(2) Demeter SL (1986) Hyperventilation syndrome and asthma. Am J Med 1986;81:989-94.
(3) Hough A. Physiotherapy in Respiratory Care, 3rd edition. (www.nelsonthornes.com), 2001.
In the results we can observe that the control of illness is better
in the SM group but you say also that there were a saving in inhaled
corticosteroids.... so how can you explain the best control? May be the
environmental control or there are others explanations?
Evidence that self management programmes for asthma are effective in
primary care is elusive.[1] Thoonen and colleagues have carried out a
complex and impressive cluster randomised trial from which they conclude
that a
self management programme implemented in Dutch general practices lowers
the burden of illness.[2] Parts of their analysis require comment.
Evidence that self management programmes for asthma are effective in
primary care is elusive.[1] Thoonen and colleagues have carried out a
complex and impressive cluster randomised trial from which they conclude
that a
self management programme implemented in Dutch general practices lowers
the burden of illness.[2] Parts of their analysis require comment.
It is not
clear whether clustering has been taken into account in the analysis.[3]
This could materially affect the conclusions of the study. The main
difference observed between groups was in the percentage of successfully
treated weeks. This is an unusual and unvalidated outcome measure and it
would be of interest to know if its method of analysis was pre-specified
in the trial protocol. Although changes in quality of life (on which the
power calculation was based) approached statistical significance they were
rather far from being clinically significant. Given that there were no
changes in exacerbation frequency, lung function or health service use it
would seem that benefits are at best marginal.
Primary care clinicians
continue to devote considerable resources to providing self management
advice to their patients but proof of substantial benefits remains
difficult to demonstrate.
References
(1) Fay JK, Jones A and Ram FSF Primary care based
clinics for asthma (Cochrane Review). The Cochrane Library (Issue 4).
2002. Oxford: Update Software.
(2) Thoonen BPA, Schermer TRJ, van den Boom G, Molema J, Folgering H,
Akkermans RP et al. Self-management of asthma in general practice, asthma
control and quality of life: a randomised controlled trial. Thorax 2003;58:30-6.
(3) Campbell MK, Mollison J, Steen N, Grimshaw J, Eccles M. Analysis
of cluster randomised trials in primary care: a practical approach. Fam Pract 2000;17:192-6.
We thank Dr Agarwal for responding to our article. We agree that the
commonest cause of steroid resistant asthma is failure to take the
prescribed steroids. However, there are perhaps more diagnostic aids than
is acknoweldged. Compliance can be taken out of the equation by doing a
therapeutic trial of a single intramuscular injection of depot
triamcinolone.[1-4] If asthma persists, then it can truly be...
We thank Dr Agarwal for responding to our article. We agree that the
commonest cause of steroid resistant asthma is failure to take the
prescribed steroids. However, there are perhaps more diagnostic aids than
is acknoweldged. Compliance can be taken out of the equation by doing a
therapeutic trial of a single intramuscular injection of depot
triamcinolone.[1-4] If asthma persists, then it can truly be said to be
steroid resistant. Alternatively, measuring serum prednisolone and
cortisol levels may also be illuminating, if the child is supposedly
taking oral steroids.
References
(1) Veeraraghavan S, Sharma OP. Parenteral triamcinolone acetonide:
an alternative corticosteroid for the treatment of asthma. Curr Opin Pulm
Med 1998;4:31-5.
(2) McLeod DT, Capewell SJ, Law J, MacLaren W, Seaton A.
Intramuscular triamcinolone acetonide in chronic severe asthma. Thorax
1985;40:840-5.
(3) Willey RF, Fergusson RJ, Godden DJ, Crompton GK, Grant IW. Comparison
of oral prednisolone and intramuscular depot triamcinolone in patients
with severe chronic asthma. Thorax 1984;39:340-4.
(4) Ogirala RG, Aldrich TK, Prezant DJ, Sinnett MJ, Enden JB,
Williams MH Jr. High-dose intramuscular triamcinolone in severe, chronic,
life-threatening asthma. N Engl J Med 1991;324:585-9.
Medication compliance in asthma is disappointingly low and leads to poor asthma control in children. It is very common that parents do not supervise treatment and often report poor asthma control. Many difficult-to-manage asthmatics have ongoing exposure to allergens or other asthma
triggers. In such instances, required medication may be very high and the results may be disappointing. Only 30% of pediatric a...
Medication compliance in asthma is disappointingly low and leads to poor asthma control in children. It is very common that parents do not supervise treatment and often report poor asthma control. Many difficult-to-manage asthmatics have ongoing exposure to allergens or other asthma
triggers. In such instances, required medication may be very high and the results may be disappointing. Only 30% of pediatric asthmatics, age 7 to 15, have optimal environmental control at home. Children who are
nonadherent to both medications and environmental control measures can be challenging to manage.
Despite the fact that many immunologic abnormalities have been identified, there is no laboratory test that can be used in making the diagnosis of steroid-resistant asthma. As a result the diagnosis of steroid-resistant asthma remains a clinical one.
Experts were given no clinical details except for times of waking and
sleeping, and times of starting and leaving work. They were asked to make
judgements based on the peak expiratory flow record alone, similar to the
judgements made by the Oasys program. Oasys-2 has been shown to have a
sensitivity of around 70%, when tested against independent objective
diagnoses (mostly specific bronchial provocation t...
Experts were given no clinical details except for times of waking and
sleeping, and times of starting and leaving work. They were asked to make
judgements based on the peak expiratory flow record alone, similar to the
judgements made by the Oasys program. Oasys-2 has been shown to have a
sensitivity of around 70%, when tested against independent objective
diagnoses (mostly specific bronchial provocation testing), and a
specificity of 94%. The need is therefore to achieve increased sensitivity.
The experts underscored compared with Oasys-2, and did not appear to be
detecting work-related changes missed by Oasys-2. In practice tests are
interpreted in the light of clinical information (requiring expertise),
however in our practice occupational asthma often occurs in unlikely
places, and is frequently diagnosed when the specific exposures are
unknown.
We hope we have provided a tool for use by the non-expert inthe
initial assessment of occupational asthma. We agree that these records
need to be made as soon as the diagnosis is suspected, and before workers
are removed from their jobs. Supervising such records does however needs a
degree of expertise, with particular emphasis on recording working times,
keeping treatment constant, and recording the timings of readings. Help is
provided for this on the website occupationalasthma.com, as well as
suitable record forms with instructions which can be downloaded.
Ideally, OASYS should be used interactively. The patient returns to
clinic with his PEF record stored in an electronic meter. The clinician
and patient review the record together. This allows the clinician to ask
those question suggested by the record such as "did you have a respiratory
infection last week" (if there was an unexpected fall in PEF crossing
work/rest interfaces), or "remind me of your work pattern on the 25th of
last month" (when a single work-day shows no deterioration when others
do). Thus the integration of clinical information and record is even
closer enhancing the diagnostic toolkit mentioned by David Fishwick and
colleagues.
We read with interest the article by Baldwin et al.[1] relating to
the level of agreement between expert clinicians and OASYS software when
making a diagnosis of occupational asthma. Our clinical unit uses OASYS
plotting regularly, and find this of great use as one element of the
diagnostic toolkit available for the confirmation of a diagnosis of
occupational asthma.
We read with interest the article by Baldwin et al.[1] relating to
the level of agreement between expert clinicians and OASYS software when
making a diagnosis of occupational asthma. Our clinical unit uses OASYS
plotting regularly, and find this of great use as one element of the
diagnostic toolkit available for the confirmation of a diagnosis of
occupational asthma.
We were interested to note that there was a low level of agreement
between experts and OASYS when asked to interpret peak expiratory flow
(PEF) records, but agreement within experts was better. We would be
interested to know whether the information provided to the experts on the
nature of work was used in determining their final outcome, i.e. if an
individual was working with a known sensitiser or was in a perceived high
risk job, did this influence the outcome more than the graphical and
mathematical data.
Practically in clinic, a decision is made to perform regular PEF
monitoring in those patients who are thought to have a reasonable chance
of having occupational asthma, as judged by the clinical information to
date. Perhaps a further study option would be to give experts clinical
data first (more like the real life situation), and ask for a likelihood
of occupational asthma based on this assessment, followed by a revision of
that likelihood after PEF data is supplied. Would then revealing the work
effect score lead to further revision of the perceived estimate?
Individual experts may be more or less swayed by the clinical data due to
variation in their own practice, types of cases seen, geographical
location and so on.
Again, experts were deemed to "under report" possible cases of
occupational asthma. Whilst this may indeed be the case, an alternative
explanation is that the experts were more realistic, taking into account
the clinical likelihood as well as the PEF pattern. OASYS systems clearly
invoke complex comparisons between known cases of occupational asthma and
the record being assessed.
Finally, the authors suggest that PEF interpretation is best left to
experts. Whilst we agree that expert centres, consistently diagnosing
occupational asthma are needed, as many as one in ten adult asthmatics are
likely to have a substantial effect from work.[2] It is therefore
important for all such patients in the UK to have access to competent
individuals trained to assess these patients. This is where OASYS (or
similar) systems are likely to be very important as an initial screen, and
could be carried out by primary care or occupational health nurses or
other competent non clinical people in the workplace. This would enable
patients currently working to undergo PEF assessment, as opposed to the
common situation of seeing patients in secondary care already following
prolonged period of sickness absence, making diagnosis even more
challenging.
At present, the consistency of diagnosis of occupational asthma
throughout the UK is likely to be highly variable. We are currently
involved in a multicentre UK based study assessing the application of the
toolkit to diagnose occupational asthma, and it is evident that practice
remains disparate between various expert centres.
We are sure that the future of occupational asthma evaluation will
and should rely on OASYS like programmes, but that the diagnosis must be
seen also in broader terms, taking into account clinical, immunological
and exposure data.
References
(1) DR Baldwin, P Gannon, P Bright, DT Newton, A Robertson, K Venables, B Graneek, RD Barker, A Cartier, J-L Malo, M Wilsher, CFA Pantin, and PS Burge. Interpretation of occupational peak flow records: level of agreement between expert clinicians and OASYS-2. Thorax 2002;57: 860-864.
(2) Blanc P, Toren K. How much adult asthma can be attributed to occupational factors? Am J Med 1999;107:580-587.
The recent case report from Smyth and Riley[1]
describes nicely an extremely uncommon chronic respiratory failure due to
hypoventilation secondary to brainstem stroke, and documents a new
treatment
option with medroxyprogesterone acetate.
We recently saw two patients also with central hypoventilation
resulting in chronic type II respiratory failure and treated both with,
among other things, me...
The recent case report from Smyth and Riley[1]
describes nicely an extremely uncommon chronic respiratory failure due to
hypoventilation secondary to brainstem stroke, and documents a new
treatment
option with medroxyprogesterone acetate.
We recently saw two patients also with central hypoventilation
resulting in chronic type II respiratory failure and treated both with,
among other things, medroxyprogesterone acetate (30 mg b.i.d.) with good
results.
The first patient, a 69-year-old man, with in his medical history a glomus
caroticum resection due to malignancy with postoperative radiotherapy in
1979
presented to our outpatient clinic with polyglobulia. His arterial blood
gas revealed marked hypoxemia (PaO2 4.8 kPa) and hypercapnia (PaCO2 6.9
kPa). An intensive search for the cause showed no abnormalities, his
lungfunction
showed only marginally COPD (FEV1/VC of 68 %), but his hypoxic ventilatory
response was markedly decreased and his hypercapnic ventilatory response
was absent. We treated the patient with acetazolamide, theofyllin and
medroxyprogesterone acetate and his blood gas improved within days to
normal values (PaO2 10.3 kPa, PaCO2 5.1 kPa).
The second patient, a 38-year-old female, was known from birth on with a
hypothalamic-pituitary gland deficiency and with (stable) adipositas
(quetelet index of 53). She complaint about dizziness, general malaise and
dyspnoe d’effort for several time before she was sent to our department.
Arterial blood gas analysis again revealed hypoxemia and marked
hypercapnia (PaO2 8.0 kPa, PaCO2
7.2 kPa). She probably suffers from Pickwick syndrome, formal
polysomnografic measurements will be performed shortly, but she also has
totally absent hypoxic and hypercapnic ventilatory responses. Again
treatment
with theofyllin, acetazolamide and medroxyprogesterone acetate normalised
her arterial blood gas analysis within days. She furthermore now follows
an intense weight
reduction programme and has lost within weeks more than 10 kg.
Acetazolamide has been shown to augment both the hypoxic and
hypercapnic ventilatory response and decrease PaCO2 levels significantly
in COPD patients.[2,5] The mechanism of the effect is possibly due to a
direct effect on
the peripheral chemoreceptors (carotid bodies) as well as to an effect on
the cerebral blood flow regulation.[2,3]
It has been shown that medroxyprosterone acetate also acts on the
peripheral chemoreceptors (directly) as well as on the central
chemoreceptors (indirectly) and progesterone receptors in the hypothalamus
in cats.[4] This was also found in hypercapnic COPD patients indicating
that medroxyprogesterone acetate is a central acting drug of the
respiratory centres.[5] This supports the use of medroxyprogesterone
acetate in central hypoventilation. Furthermore, the combined treatment of
acetazolamide and medroxyprogesterone acetate yields an increase in
ventilation and an improvement of the arterial blood gas values i.e a
decrease in PaCO2 to normocapnic values and an increase in PaO2 to almost
normoxic values in hypercapnic and hypoxic COPD patients.[5]
In conclusion we agree with the authors that medroxyprogesterone
acetate can be used in patients with central hypoventilation disorders.
References
(1) Smyth A and Riley M. Chronic respiratory failure: an unusual cause and treatment. Thorax 2002;57: 835-836.
(2)Vos PJ, Folgering HT, de Boo TM, Lemmens WJ, van Herwaarden CL. Effects of chlormadinone acetate, acetazolamide and oxygen on awake and asleep gas
exchange in patients with chronic obstructive pulmonary disease (COPD). Eur
Respir J. 1994;7:850-5.
(3) Wagenaar M, Teppema L, Berkenbosch A, Olievier C, Folgering H. Effect
of
low-dose acetazolamide on the ventilatory CO2 response during hypoxia in
the
anaesthetized cat. Eur Respir J 1998;12:1271-7
(4) Wagenaar M, Teppema LJ, Berkenbosch A, Olievier CN, Folgering HT.
Medroxyprogesterone acetate with acetazolamide stimulates breathing in
cats.
Respir Physiol 2000;119:19-29
(5)Wagenaar M, Vos PJ, Heijdra YF, Teppema LJ, Folgering HTM. Combined
treatment with acetazolamide and medroxyprogesterone acetate in COPD
patients. Eur Respir J 2002, in press (November)
Dr GP Bootsma, MD PhD
Dr Y Heydra, MD PhD
Dr M Wagenaar, MD
Department of Pulmonary Diseases
University Medical Centre, St Radboud, Nijmegen
PO Box 9101
6500 HB Nijmegen
The Netherlands
Dr GP (Gerben) Bootsma, MD, PhD
University Medical Centre Nijmegen
Dept. of Pulmonary Diseases, 549
P.O. Box 9101
6500 HB Nijmegen
The Netherlands
Tel: ++31-24-3614579
Fax: ++31-24 3610324
Email: :G.Bootsma@long.azn.nl
Dear Editor
In their response to our article Dr Griffiths makes some important remarks, which we would like to comment on.
We did indeed take clustering into account in the analysis of our data. As stated in the methods section of our paper we used multilevel models.[1] In this multilevel model practices were included as the level of clustering in these models.
A second methodological questio...
Dear Editor
In a reaction to our paper Dr Martin Olmedo asks what factors may explain the observed better control of illness in our self-management group.
The self-management program in our study consisted of education, skills training and written instructions for autonomous adaptation of maintenance therapy with inhaled corticosteroids. As this intervention consisted of more than one element, it is n...
Dear Editor
Thank you for a well-reasoned explanation on the effect of yoga on asthma.
The study quoted [1] which justifies the Buteyko technique was flawed by:
* unequal groups in that the Buteyko group initially required 1½ times the steroids of the control group
* the Buteyko group receiving seven times the follow-up phone calls as the control group, plus extra breathin...
Dear Editor
I would like to ask the authors a question:
In the results we can observe that the control of illness is better in the SM group but you say also that there were a saving in inhaled corticosteroids.... so how can you explain the best control? May be the environmental control or there are others explanations?
Dear Editor
Evidence that self management programmes for asthma are effective in primary care is elusive.[1] Thoonen and colleagues have carried out a complex and impressive cluster randomised trial from which they conclude that a self management programme implemented in Dutch general practices lowers the burden of illness.[2] Parts of their analysis require comment.
It is not clear whether clustering has bee...
Dear Editor
We thank Dr Agarwal for responding to our article. We agree that the commonest cause of steroid resistant asthma is failure to take the prescribed steroids. However, there are perhaps more diagnostic aids than is acknoweldged. Compliance can be taken out of the equation by doing a therapeutic trial of a single intramuscular injection of depot triamcinolone.[1-4] If asthma persists, then it can truly be...
Dear Editor
Medication compliance in asthma is disappointingly low and leads to poor asthma control in children. It is very common that parents do not supervise treatment and often report poor asthma control. Many difficult-to-manage asthmatics have ongoing exposure to allergens or other asthma triggers. In such instances, required medication may be very high and the results may be disappointing. Only 30% of pediatric a...
Dear Editor
Experts were given no clinical details except for times of waking and sleeping, and times of starting and leaving work. They were asked to make judgements based on the peak expiratory flow record alone, similar to the judgements made by the Oasys program. Oasys-2 has been shown to have a sensitivity of around 70%, when tested against independent objective diagnoses (mostly specific bronchial provocation t...
Dear Editor
We read with interest the article by Baldwin et al.[1] relating to the level of agreement between expert clinicians and OASYS software when making a diagnosis of occupational asthma. Our clinical unit uses OASYS plotting regularly, and find this of great use as one element of the diagnostic toolkit available for the confirmation of a diagnosis of occupational asthma.
We were interested...
Dear Editor
The recent case report from Smyth and Riley[1] describes nicely an extremely uncommon chronic respiratory failure due to hypoventilation secondary to brainstem stroke, and documents a new treatment option with medroxyprogesterone acetate.
We recently saw two patients also with central hypoventilation resulting in chronic type II respiratory failure and treated both with, among other things, me...
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