EBM notebook
In addition to time pressures that we encounter when searching
CAP1 were rapidly retrieved through PubMed, UpToDate, and
for evidence to support care decisions for individual patients, it
MD Consult. The British Thoracic Society (BTS) guidelines for
may be difficult for clinicians to apply the evidence that we find.
the management of CAP in adults2 were also found in PubMed.
The rate limiting step may not be doing the search, but the steps
Both sets of guidelines were relevant to our patient, but neither
needed in “setting evidence-based medicine (EBM) in motion.”
guideline discussed the use of nebulised albuterol in the
We present an example of a search for evidence by a Physician
treatment of CAP. The BTS guidelines had a section on general
Assistant (PA) student that highlights this challenge. PAs receive
management, which discussed the use of adjunctive therapies
accelerated training in the medical model and work in teams
for CAP, but nebulised albuterol was not mentioned. Evidence
under physician supervision. Approximately 40 000 PAs cur-
from controlled clinical trials was mentioned in the guideline for
rently work in the US in a wide range of settings and specialties.
“bottle blowing,”3 but not for physiotherapy.
Practising EBM has become an important component of train-
Having not fully answered our question with a review of
relevant guidelines (and having not attracted the attention of
During an internal medicine rotation, a PA student encoun-
anyone who could change the patient’s treatment plan), we
tered a common clinical practice unsupported by current
searched PubMed again, this time specifically for studies on the
evidence—administration of nebulised albuterol in patients with
use of albuterol in patients with CAP. No relevant trials were
community acquired pneumonia (CAP). While this practice may
found on the use of nebulisers for CAP.
be justified in patients with underlying chronic obstructive pul-
To identify evidence about harm with the use of albuterol,
monary disease (COPD) who also present with CAP, this student
PubMed was searched using the terms nebulised albuterol, car-
questioned the grounds for its use in patients with CAP who do
diac arrhythmias, and randomised or controlled clinical trials.
No trials were found. When just the content terms weresearched, 9 articles, not directly relevant to our patient, were
Clinical scenario
found. One prospective, open label study on the effect of
A 68 year old man presented to the emergency department with
nebulised albuterol (for treatment of asthma) on cardiac rhythm
fever, chills, and a non-productive cough of 1 week’s duration.
was found.4 10 patients were studied, and although no adverse
He had fatigue, headache, rhinorrhoea, and mild nausea, but
effect on cardiac rhythm or blood pressure was found, the study
denied dyspnoea. He had no history of smoking or COPD. He
did not convince the team that no potential for harm existed in
had atrial fibrillation and was taking warfarin for stroke preven-
this, or other patients, especially when there was no clear indica-
On admission, his temperature was 38.4 °C, heart rate was
Recognising that searching and appraising the literature are
108 beats/minute, respiratory rate was 24 breaths/minute,
not the only important aspects of practicing EBM, we consulted
blood pressure was 156/88 mm Hg, and oxygen saturation was
an experienced pulmonologist, who practises and teaches using
86% by pulse oximetry on room air. Rales were heard in both
the EBM model. In addition to reviewing treatment plans for
lung bases and in the right middle lobe. Chest radiography
multiple cases of CAP requiring hospital admission with the
showed a diffuse infiltrate in the right middle and lower lobes.
Nurse Practitioner/Physician Assistant service, he recom-
Complete blood count showed a white blood cell count of
mended review of the Centre for Evidence-Based Medicine
22 000 cells/ml with a left shift, and arterial blood gases showed
website at Mount Sinai Hospital in Toronto, Ontario, Canada
(www.cebm.utoronto.ca/), which suggested bubble blowing as a
One dose of ceftriaxone was administered parenterally, and a
method for helping clear secretions.2–3 This served as an
course of azithromycin was started. Albuterol, 5% solution,
excellent, rapid approach to finding good information on treat-
delivered by nebuliser 3 times daily was also ordered, in addition
ment of CAP, and confirmed the evidence previously found in
to a combination of inhaled ipratropium and albuterol,
delivered by metered dose inhaler every 4 hours as needed. During the hospital stay, his pneumonia resolved, but his heartrate increased to 150 beats/minute and his blood pressure rosefrom 156/88 to 200/110 mm Hg. Application of the evidence to this, and future Clinical question patients
Although there was no institutional protocol for use of
The treatment plan for this patient was not altered by the
nebulised albuterol for treatment of CAP, the house staff often
student’s rapid search for evidence. Changes in usual care for a
ordered it. The PA student queried: In a 68 year old man with
common illness required a comprehensive search and discus-
CAP and no underlying COPD, does use of nebulised
sion among all clinicians in our institution caring for patients
nists improve symptoms? What is the risk of harm in this
with CAP. The clinical team reviewed the results of the search
and because no evidence was found to support use of albuterolin patients like ours, changes were made to future practice. As a
Search strategy
result of this process, which took a few hours and evolved over
Firstly, a treatment guideline was sought to clarify recommenda-
several weeks, orders for bronchodilators for patients with CAP
tions regarding use of nebulised albuterol for treatment of CAP.
are now made on an individual basis, depending on the
The American Thoracic Society guidelines for management of
presence of patient comorbid illnesses, such as COPD. Conclusion
residency in Respirology at St. Joseph’s Hospital, Division of
The need for a rapid search for evidence is sometimes, but not
always, important to the care of an individual patient. In this
Thanks also, to Bob McNellis, MPH, PA-C, of the American
case, the speed of the search did not affect the ability of the PA
Academy of Physician Assistants, Alexandria, Virginia, USA, for
student to apply the evidence to the patient. Setting the evidence
in motion may require communication of search results to other
members of the clinical team and may affect the care of future
patients. Although the catalyst for setting EBM in motion was a
student, the evidence, including the results of further research,
along with the judgment of the experienced pulmonologist,
convinced the clinical team to make changes to usual care and
to base future treatment of this common condition on the best
Niederman MS, Mandell LA, Anzueto A, et al. Guidelines for the manage-
ment of adults with community-acquired pneumonia. Diagnosis, assess-
ment of severity, antimicrobial therapy, and prevention. Am J Respir CritCare Med 2001;163:1730–54.
British Thoracic Society Standards of Care Committee. BTS Guidelines
Acknowledgements
for the Management of Community Acquired Pneumonia in Adults. Tho-rax 2001;56 Suppl 4:IV1–64.
We would like to thank Dermot Killian, MD, Mercy Pulmonary
Bjorkqvist M, Wiberg B, Bodin L, et al. Bottle-blowing in hospital-treated
patients with community-acquired pneumonia. Scand J Infect Dis
Associates, for his precepting and teaching of PA students
1997;29:77–82.
through the University of New England, Portland, Maine, USA,
Dickens GR, McCoy RA, West R, et al. Effect of nebulized albuterol on
serum potassium and cardiac rhythm in patients with asthma or chronic
and his help in preparing this manuscript. He served his
obstructive pulmonary disease. Pharmacotherapy 1994;14:729–33.
Evidence-based decision making—the six step approach
The basic concept of evidence-based medicine proposes to
education students are virtually “trained” to make decisions
make health related decisions based on a synthesis of internal
under the condition of uncertainty. Advanced students and to a
and external evidence. Internal evidence is composed of knowl-
greater extent clinicians lose some of their ability to differentiate
edge acquired through formal education and training, general
between scientific evidence and what seems to be evident. If we
experience accumulated from daily practice, and specific
intend to implement evidence-based medicine more efficiently,
experience gained from an individual clinician-patient relation-
we need to modify the way students and clinicians learn to make
ship. External evidence is accessible information from research.
It is the explicit use of valid external evidence (eg, randomised
Therefore, an additional step was introduced in our evidence-
controlled trials) combined with the prevailing internal evi-
based medicine teaching programme (step 2 in the table).
dence that defines a clinical decision as “evidence-based.” To
Students were to provide answers to their clinical questions
realise this concept in day to day clinical practice, the Evidence-
based on their current knowledge (internal evidence) before
Based Medicine Working Group proposed a 5 step strategy,1corresponding to step 1 and steps 3 to 6 shown in the left hand
continuing with the remaining steps of the evidence-based
process.2 Our collective experience concerning this additional
In teaching this 5 step approach, we encountered several dif-
step was extremely positive. The students using this new step
ficulties. We noticed a growing hesitance to accept this strategy
were satisfied that their pre-existing knowledge had been
as students advanced in their medical training. In the presence
integrated into the evidence-based approach. By explicitly
of well established methods of treatment or diagnosis, this
documenting their internal evidence, students used the remain-
resistance rises even more, regardless of the level of training. We
ing steps of the process to evaluate not only the best evidence in
assume that this barrier is associated with the process of sociali-
making a clinical decision but also to assess the accuracy of their
sation into the health professions. Throughout medical
internal evidence, the grounds upon which their preconcep-
The 6 steps of evidence-based decision makingExplanation
Transformation of the clinical problem into 3 or 4 part question
(a) relevant patient characteristics and problem(s), (b) leading intervention,(c) alternative intervention, (d) clinical outcomes or goals.
Additional step: answer to the question based on “internal evidence” only
Internal evidence: acquired knowledge through professional training andexperience (in general and applied to the patient). Should be documentedbefore proceeding to step 3.
Finding “external evidence” to answer the question
External evidence: obtained from textbooks, journals, databases, experts. The value of the external evidence will be highly variable, see step 4.
Critical appraisal of the external evidence
Should answer 3 questions: (1) Are the results valid? (2) Are the resultsclinically important? (3) Do the results apply to my patient? (or is mypatient so different from those in the study that the results do not apply?)
Integrating external and internal evidence
The 2 sources of information (external and internal) may be supportive,non-supportive,
non-supportive or conflicting will depend on multiple factors.
Once the decision has been made, the process and the outcome areconsidered and opportunities for improvement are identified.
tions were based, and the usefulness of the available literature in
with the external evidence. They may determine that the exter-
supporting a decision for their patient.
nal evidence is not sufficiently convincing and remain with the
The health authority of Alto Adige in northern Italy initiated
original decision. Or, they may choose to discuss with the
and supported a project, the “Bressanone Model,” in which the
patient the conflict between the internal and external evidence
effects of implementing evidence-based medicine on the quality
in a manner that enables the patient to take part in the decision
of health care were to be shown. In this model we used the six
making process. This last approach is recommended because
step approach, which proved to be successful in the student
patient preference is considered an essential part of the
project to teach experienced clinicians.3 The participants were
evidence-based decision making process1 and decisions often
asked to name problems of their day to day practice that lacked
need to be made in the absence of clear research findings.
either an effective or an efficient solution. The evidence-based
medicine support group helped participants to phrase the 3 or
4 part questions. Subsequently, the physicians were asked to
submit their individual answers to the questions before continu-
Agreement between internal and external evidence varies.
Completing the full process could result in finding evidence that
confirms the internal evidence, validating and strengthening the
clinician’s or student’s confidence in the decision. The process
could also reveal that little evidence exists to support the
decision or that the available evidence is equivocal. In such
cases, other factors such as cost or inconvenience to the patient
may need to be given greater consideration. Possibly, the best
external evidence found is not in agreement with the internal
evidence. This represents a particularly valuable experience for
the clinician or student because it may avoid an ill advised deci-
sion. It also shows the fallibility of making decisions on
uncertain ground based on internal evidence alone. This in turn
will hopefully promote the routine assimilation of external evi-
Bureau for Education of Health-Care Personnel
dence in clinical decision making. The documentation and
Autonomous Province of Bolzano, Alto Adige, Italy
comparison of steps 2 and 5, used as a research tool or qualityassurance outcome measure, could provide valid information
Sackett DL, Straus SE, Richardson WS, et al. Evidence-based medicine: how topractice and teach EBM. Second edition. Toronto: Churchill Livingstone,
on the effects of evidence-based medicine on clinical decision
Porzsolt F, Sellentin C. Der sechste schritt in der anwendung der evidence-
based medicine. Z Arztl Fortbild Qual Sich 2000;94:619–20.
In case of conflicting internal and external evidence, clinicians
Porzsolt F, Thim A, Ruatti H, et al. Methode zur Implementierung des
Health Technology Assessment an einem Lehrkrankenhaus. Bundesgesund-
have several options. They may change their mind and align it
heitsblatt – Gesundheitsforschung – Gesundheitsschutz 2001;44:908–14.
*Approximately 60 additional journals are reviewed. This list is available on request.
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