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Metered-Dose Inhaler
The Emergency Department Orphan
Irene Tien, MD;
David Dorfman, MD;
Beth Kastner, MPH;
Howard Bauchner, MD
Arch Pediatr Adolesc Med. 2001;155:1335-1339.
ABSTRACT
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Objective Physicians providing emergency department care to children primarily
use nebulizers for the delivery of bronchodilators and these physicians have
misconceptions regarding the advantages and disadvantages of using metered-dose
inhalers (MDIs) with a spacer (MDI + S) for acute asthma exacerbations.
Design Self-administered mail survey.
Setting Emergency department.
Participants Emergency medicine section members of the American Academy of Pediatrics
and Canadian Pediatric Society.
Interventions Bronchodilator delivery methods in acute pediatric asthma.
Main Outcome Measures The 2 principal outcomes for bivariate analysis were self-reported nebulizer
use in all patients and MDI + S use in patients with mild acute asthma.
Results Of eligible physicians, 333 (51%) of 567 responded. The majority were
dual trained in pediatrics and pediatric emergency medicine (72%) and practiced
full time (83%) in an urban (83%) pediatric emergency department (80%). The
most commonly cited advantages of MDIs were their cost (33%) and speed of
use (28%). The most commonly cited disadvantages were patient or parent dissatisfaction
(24%) and relative ease of nebulizer use (23%). Only 10% to 21% of participants
used MDIs in the emergency department and reserved this delivery method for
children with mild asthma exacerbations. There were no significant associations
between selected respondent demographic variables and the use of MDIs.
Conclusions Misconceptions regarding the efficacy and safety of MDI + S for the
treatment of acute asthma exacerbations exist but are limited to a minority
of surveyed emergency medicine physicians caring for children. Nebulizers
remain the preferred method of routine bronchodilator delivery by physicians
providing care to pediatric asthmatics in the emergency department.
INTRODUCTION
ASTHMA IS the most common chronic disease of childhood, affecting an
estimated 4.8 million children in the United States. Its increasing severity
throughout the last 3 decades has been well documented by an increase in hospitalizations
from 386 000 to 466 000 (1980 to 1994) and deaths from 1.5 to 6.5
per million (1976 to 1995).1
One area of recent controversy in asthma therapy is the underuse of
metered-dose inhalers (MDIs) in adult and pediatric patients.1, 2, 3, 4
It is well documented that MDIs with an attached spacer device (MDI + S) require
less equipment and time to administer, are cheaper, and are more portable
than nebulizers. Furthermore, numerous studies in children and adults have
demonstrated that MDI + S are clinically as effective as nebulizers in the
delivery of bronchodilators. Clinical equivalence has been proven in many
randomized clinical trials using multiple types of spacer devices and bronchodilator
medications in children and adults.5, 6, 7, 8, 9, 10, 11, 12, 13, 14
The nebulizer system of aerosolized medication delivery is generally
accepted as the standard of care for children with acute asthma presenting
to the emergency department (ED). This occurs despite the equivalent clinical
efficacy and added cost and inconvenience of a nebulizer. The hypotheses of
this study were that physicians caring for children in the ED primarily use
nebulizers for bronchodilator delivery and that these physicians have misconceptions
regarding the advantages and disadvantages of MDI + S use in children with
acute asthma exacerbations.
PARTICIPANTS AND METHODS
PARTICIPANTS
We obtained a list of members of the emergency medicine (EM) sections
of the American Academy of Pediatrics and the Canadian Pediatric Society.
A 15-question survey and self-addressed stamped envelope were mailed to each
subject (available from the principal investigator on request). Second and
third mailings were sent to those not responding within a month of the previous
mailing. Surveys returned by self-identified pediatricians not caring for
children in an ED setting were excluded. This survey was piloted by a group
of 9 pediatric EM physicians and revised prior to the first mailing.
SURVEY INSTRUMENT
The 15-question survey instrument addressed professional characteristics
of the respondent and his or her clinical practice, the presence of asthma
management guidelines in their EDs, attitudes toward MDI + S use, self-reported
patterns of MDI + S and nebulizer use, and information influencing their choice
of bronchodilator delivery method. The survey included multiple choice, Likert
scale, and open-ended questions.
DATA ENTRY AND ANALYSIS
Data were entered into a Microsoft Excel 97 spreadsheet (Microsoft Corp,
Redmond, Wash) and analyzed using Epi Info 6.015
and SPSS (Statistical Product and Service Solutions; SPSS Inc, Chicago, Ill)
software. Bivariate associations between the independent variables and principal
outcomes were analyzed using the  2 test. Multivariate analysis
was planned to test the associations between principal outcomes and independent
variables. The 2 principal outcomes were self-reported nebulizer use in all
patients and MDI + S use in patients with mild acute asthma. Respondent-related
independent variables included the average number of clinical hours worked
per week ( 16 hours vs >16 hours), number of years of postresidency practice
(<5 years, 5-10 years, 10-20 years, and >20 years), position at his or
her primary institution (full-time, part-time, or fellow), residency training
(EM vs pediatrics), fellowship training (pediatric EM [PEM] vs non-PEM training),
country of practice (United States or Canada), setting of practice (general
ED or pediatric ED/pediatric area in a general ED), environment in which the
respondent's ED was located (urban or suburban/rural), and training programs
offered in the respondent's institution (EM residency, pediatrics residency,
or PEM fellowship).
This study was approved by the Boston University (Boston, Mass) institutional
review board.
RESULTS
Of the 689 subjects contacted, 375 returned surveys. Forty-two respondents
not providing emergency care to children were ineligible and excluded from
analysis. The overall response rate was 51% (Figure 1).
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Flowchart of survey responses.
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DEMOGRAPHICS
The majority of physicians had training in pediatrics and PEM (72%).
They also generally practiced full-time (83%), commonly in an urban (83%)
pediatric ED (80%), and for 5 to 20 postresidency years (83%). Information
regarding the characteristics of nonresponders was limited to region of practice.
Subjects in the Midwest had the highest nonresponse rate of 65% (51/147 physicians)
followed by the West (60%, 29/72), the South (49%, 102/202), and the Northeast
(47%, 71/134) (Table 1).
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Table 1. Profile of Respondents*
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PERCEIVED ADVANTAGES AND DISADVANTAGES TO MDIs
When asked the open-ended question, "What do you think are the advantages
to the use of high-dose MDIs (6-8 puffs per treatment) over nebulizers in
the emergency department management of pediatric asthma?" the most commonly
cited answers addressed cost, speed, and portability. Eighty-five (33%) of
256 respondents stated that MDIs are cheaper. Seventy-two (28%) felt that
MDIs are faster to administer. Twenty-two (8%) felt that MDIs require less
staff time to use. Sixty-two respondents (24%) stated that the use of MDIs
in the ED allows for an opportunity to teach MDI technique to patients and
parents. Forty-one (16%) felt that the portability of MDIs is an advantage
to their use, and 77 respondents (21%) gave no response.
When subsequently asked: "What do you think are disadvantages to using
high-dose MDIs (6-8 puffs per treatment) over nebulizers in the emergency
department management of pediatric asthma?" responses most commonly addressed
issues of patient dissatisfaction and inconvenience in administration. Sixty-five
(24%) of 272 respondents felt that patients and parents expect nebulized therapy
when they arrive in an ED and that the use of MDIs would result in patient
and parent dissatisfaction. Sixty-two (23%) felt that nebulizers are easier
to administer. Similarly, 51 (19%) felt that MDIs would require more staff
supervision, 44 (16%) felt MDIs were too difficult to use in the young, and
30 (11%) felt that children are poorly compliant with MDI medication delivery.
Some clinical considerations were also voiced. Twelve percent (32/272) felt
that nebulizers were superior to MDIs because they can be administered with
supplemental oxygen, and 26 (10%) felt that MDIs are less effective than nebulizers
when used in children suffering from severe asthma exacerbations. Sixty-one
respondents (16%) gave no response.
SELF-REPORTED METHOD OF BRONCHODILATOR USE
The majority of physicians deliver bronchodilators by nebulization to
all children in the ED. When given a checkbox question asking for which age
groups of children (<2 years, 2-5 years, 5-7 years, 7-18 years) they used
either nebulizers, MDI + S, or MDI without spacers, 76% of respondents stated
that they use nebulizers for all acute patients with acute asthma between
7 and 18 years old. This proportion increased as the age of the patients decreased.
Seventy-nine percent, 87%, and 90% of respondents use nebulizers for children
in the 5- to 7-year old, 2- to 5-year old, and younger than 2-year-old age
groups, respectively. In contrast, a significant minority of respondents stated
that they use MDI + S in selected children. The proportion of respondents
using MDI + S in children with mild acute asthma decreased with age. Twenty-one
percent, 20%, 15%, and 10% stated that they would selectively use MDI + S
in children with mild acute asthma aged 7 to 18 years, 5 to 7 years, 2 to
5 years, and younger than 2 years, respectively. The small minority of respondents
(3%) who reported selective MDI without spacer use do so only for those with
mild acute asthma in the 7- to 18-year-old age group (Table 2).
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Table 2. "Please Check Off the Method You Most Commonly Use to Deliver
Bronchodilator Medication to Children in the Emergency Department Based on
Age and Your Definition of Asthma Severity."*
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When asked the open-ended question, "How do you decide which method
of bronchodilator delivery you use for any particular child in the emergency
department with an asthma exacerbation?" 159 (58%) of 275 respondents stated
that they always use nebulized bronchodilators, and 59 (22%) of 275 decide
based on the severity of the child's exacerbation. Twenty-five (9%) of 275
reported that they only use the MDI for teaching prior to discharge, 23 (8%)
decide based on the age of the patient, and 15 (6%) use their judgment of
the patient's ability to cooperate with an MDI to decide (Table 3).
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Table 3. "How Do You Decide Which Method of Bronchodilator Delivery
You Use for Any Particular Child in the Emergency Department With an Asthma
Exacerbation?"*
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ASTHMA PATHWAYS AND MDI+S USE
Of the 19 respondents from 16 institutions who provided a copy of their
asthma pathway, 3 specified the MDI + S as an option for bronchodilator delivery
in the ED.
BIVARIATE ANALYSES
No differences emerged in bivariate analyses of the independent variables
and the principle outcomes of nebulizer use for all patients, and MDI + S
use for patients presenting with mild acute asthma. Results of a multivariate
analysis are not reported due to small sample size.
COMMENT
The results of this survey suggest that the majority of physicians use
nebulizers as their primary method of delivering bronchodilators to children
in the ED setting. Despite this, the majority of those surveyed do use MDI
+ S in some capacity in select children in the ED. Additionally, while some
are unaware of the benefits of MDIs, including quicker delivery, lower cost,
and increased efficacy in medication delivery, most of the physicians surveyed
did not cite inaccurate opinions regarding the efficacy of MDIs in the pediatric
acute asthma setting.
The data supporting the use of MDI + S in acute asthma are not new.
Meta-analyses reviewing adult and pediatric literature conclude that the 2
methods are equally effective.16, 17
These data have been consistent across multiple prospective studies in adults16, 17, 18, 19, 20, 21
and children.6, 7, 8, 9, 10, 11, 12
Leversha et al22 clearly demonstrated the cost-benefit
of using MDI + S in the ED. Williams et al5
also showed that using MDI + S in the pediatric ED was feasible. The 1997
National Heart Lung and Blood Institute and 1993 British Thoracic Society
asthma management guidelines both acknowledged the clinical equivalence of
MDI + S and nebulizers.23, 24 They
suggested that MDIs be considered in the ED setting to deliver bronchodilators
to children who do not have severe asthma and are able to cooperate. Even
this conservative recommendation, however, does not seem to have translated
into practice.
Eleven percent of our respondents cited a concern for patient cooperation
in MDI medication delivery, and 16% felt the method was too difficult to use
in the very young. Clearly, prior to significant improvements in aerosol reservoir
technology, MDIs were difficult to use even in cooperative adults and children.25, 26 The development of valved spacers
has allowed medication delivery to occur efficaciously even when delivered
via tidal breathing.5, 6, 11, 12, 22, 27
Child and infant studies have also documented the equivalence of pulmonary
medication delivery using MDI + S and nebulizers to deliver radioactively
labeled aerosol vehicles.27, 28, 29
Studies have also demonstrated that MDI + S bronchodilator administration
requires less staff time.5, 12
While it may seem that nebulizers, in practice, require less staff attention,
all of the studies comparing these 2 modalities use a facemask with the nebulizer
to minimize wasted aerosol. In our opinion, keeping a facemask on an uncooperative
young child's face for 10 to 15 minutes requires more effort and supervision
than holding a facemask attached to an MDI + S for 3 minutes.
Despite the evidence supporting the use of MDI + S over nebulizers in
acute asthma, it does not seem to be the current standard of care in practice.
Our attempt to identify populations of pediatric ED physicians who are using
MDI + S did not yield any predictive variables by bivariate analysis. Respondent
residency or fellowship training, years of practice, and location of practice
did not seem to affect how often they used MDI + S in the ED. This, in addition
to statements of uniform use of nebulizers, suggests that it is perhaps the
culture of the ED and not the individual physician that influences the initial
bronchodilator delivery technique used in children. However, it can also be
the individual physician who strives to change the culture of the ED.
Changing physician behavior and practicing evidence-based medicine has
become an important focus for medicine over the past decade. Evidence-based
medicine originates from the ongoing concerns about quality of care, including
variation in hospitalization rates, therapeutic interventions, and patient
outcomes.30 Despite the overwhelming data suggesting
that MDI ± S are equivalent and possibly superior to nebulizers, the
results from this survey suggest that they are not being used. As we have
previously described, physician decisions are governed by 3 domains: evidence,
physician experience, and patient factors.31
The participants in our survey demonstrated a generally good grasp of the
evidence supporting the use of MDIs for acute asthma exacerbations. Additionally,
the literature suggests a preference for MDIs by patients and parents in the
ED. This, in our opinion, suggests that the largest barrier to the routine
use of MDIs is the lack of motivation for physicians to change their practice
and the culture of their practice environment. Additional environmental barriers
to adoption of this technique, including perceived staff reluctance to change,
departmental financial barriers, and barriers at the hospital administration
level most likely also contribute to the sluggish adoption of new technologies.
Changing physician behaviors is quite difficult. The myriad reviews have suggested
that education alone is insufficient, and that reminders, opinion leaders,
audit and feedback, and administrative interventions can work in specific
situations.30, 31, 32
While we will need to adopt some of these techniques to encourage the use
of MDI + S, motivating physicians to strive for evidence-based practice is
ultimately of the utmost importance.
As with any survey, there are limitations of this methodology, including
self-reporting bias that may not accurately reflect current practice patterns.
However, it is difficult to imagine that the use of MDI + S is greater than
reported. Secondly, our response rate was 51%, which may limit generalizability.
We have few data on nonresponders, although there is no reason to think that
MDI use is greater in nonresponders.
In conclusion, we found that many ED physicians are familiar with the
benefits of MDIs. However, a majority do not use them. No differences in MDI
+ S and nebulizer use patterns were noted based on respondent demographics.
External factors may be primarily responsible for the observed underuse of
MDI + S in the ED setting among children. Further research is needed to explore
ED culture and systems barriers to MDI + S use.
AUTHOR INFORMATION
Accepted for publication June 25, 2001.
This study was supported in part by grant #5T32PE1001406 from the Institutional
National Research Service Award.
The authors would like to thank Robert Vinci, MD, for his input toward
the preparation of the manuscript.
What This Study Adds
Published literature supports the use of MDI+S for the treatment of
acute asthma exacerbations in children; however, our anecdotal experience
is that they are rarely used in the ED. To our knowledge to date, there is
no published literature regarding current practice by physicians caring for
children in an ED setting regarding the type(s) of delivery system(s) used
for brochodilator therapy, and attitudes and knowledge toward MDI use for
acute asthma exacerbations.
This study defines the current attitudes, knowledge, and use of MDI
in the ED for acute asthma exacerbations in children. A majority of physicians
caring for pediatric patients with asthma in the emergency department do not
use MDIs despite evidence in the literature supporting their use. This study
demonstrates the underutilization of evidence-based decisions regarding bronchodilator
delivery methods in the ED and will hopefully raise awareness and help to
catalyze change of behavior in this area.
From the Divisions of Pediatric Emergency Medicine and General Pediatrics,
Boston Medical Center and Boston University School of Medicine, Boston, Mass.
Corresponding author and reprints: Irene Tien, MD, Division of Pediatric
Emergency Medicine, Boston Medical Center, 1 Boston Medical Center Place,
Maternity 6, Boston, MA 02118 (e-mail: irene.tien{at}bmc.org).
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