Asthma is the most common chronic condition of childhood (Burkhart, Rayens, Oakley, Abshire, and Zhang, 2007; Burkhart, Rayens, Revelette, and Ohlmann, 2007) and one of the major causes of school absenteeism in the United States (Centers for Disease Control and Prevention, 2007). An estimated 10% of children in Georgia under the age of eighteen have asthma (Georgia Department of Human Resources, 2006). Nationally, an estimated 12.8 million school days were lost to asthma in 2004 (Centers for Disease Control and Prevention, 2007).
Estimated costs for treating asthma in people under the age of eighteen years of age in the United States alone are $3.2 billion dollars per year, with asthma being the third-ranking cause of hospitalization for children under the age of fifteen years of age. (Centers for Disease Control and Prevention, 2007). In Georgia alone, in the year 2004, there were more than 47,000 emergency room (ER) visits for asthma, totaling approximately thirty-five million dollars in healthcare costs. An additional 107 million dollars was spent for over 11,000 hospitalizations the same year in which asthma was the primary diagnosis. (Georgia Department of Human Resources, 2006). With such great economic burden and human suffering caused by childhood asthma, healthcare providers need to make the best possible evidence-based practice decisions in caring for children with asthma.
Overview of Asthma Monitoring
Asthma is characterized by inflammation and airway hyperresponsiveness, resulting in airflow obstruction. Historically, airway responsiveness has been monitored in a clinical setting by measuring forced expiratory volume (FEV1) via spirometry in children able to understand and perform the procedure. Spirometry is useful as a diagnostic tool, and when combined with clinical symptoms, assists the clinician in classifying the severity of a child's asthma and formulating a treatment plan (Gandhi and Blaiss, 2006). However, spirometry requires specialized equipment and is costly.
Peak expiratory flow measurement (PEF) is a simple and inexpensive means of monitoring airway responsiveness. However, peak flow monitoring is effort- and technique-dependent (National Heart, Lung, and Blood Institute, 2007), and there are concerns with patient compliance and accurate reporting of peak flow data (Thompson, Delfino, Tjoa, Nussbaum, and Cooper, 2006). Asthma action plans relying upon peak flow monitoring alone have not been shown conclusively to provide better outcomes than symptom-based asthma action plans. (Dinakar, 2006).
The National Heart, Lung and Blood Institute (2007) defines asthma control using the two domains of impairment and risk. The impairment domain includes the frequency and the intensity of symptoms as well as functional limitations that are a result of asthma. The risk domain includes the probability of future asthma exacerbations, the risks posed in the form of adverse medication effects, and the potential for declining lung function and/or stunted lung growth. Using this model, the concept of control is individualized for each child with asthma, yet with a common theme of maximum lung function and quality of life.
Statement of Problem
The question, therefore is as follows: is there better control of asthma among those children aged five and over who do regular peak-flow monitoring versus those who rely primarily upon symptom-based management? The most current available expert guidelines, as well as current research published in peer-reviewed journals, were reviewed in an effort to answer the question, and those findings synthesized.
Process of Discovery
A search of research databases with the subject term "asthma", not surprisingly, produced a very large number of articles, many with limited relevance to the question at hand. Because of the large and ever-growing body of research, all literature searches for this project were limited to articles published during the years 2004 - 2007, and to those published articles containing research relating to peak expiratory flow and/or symptom perception in pediatric asthma.
The Medical Subject Heading (MeSH) term "peak expiratory flow", was used, and the terms "child" and "adolescent" were used to further narrow the search. Databases searched were Medline, CINAHL and ProQuest. A second series of searches focused on the keywords "asthma" and "symptom perception", since the latter term does not map to a MeSH heading. This second series of searches was performed on the same three databases. From the compiled results of all searches, 12 articles were selected to assist in formulating an answer to the question.
The websites of the American Lung Association, American Thoracic Society, Centers for Disease Control and Prevention, and the National Institutes of Health/National Heart, Lung, and Blood Institute were searched as well for any current research and recommendations. Lastly, the most recent guidelines written under the auspices of the National Heart, Lung, and Blood Institute (2007) were accessed online; these guidelines will be reviewed and discussed further as pertaining to the issue at hand.
The NHBLI 2007 Asthma Guidelines
The National Heart, Lung, and Blood Institute, a division of the National Institutes of Health, produced this expert panel report. The report uses the previously published 1997 and 2004 guidelines as a framework, and utilizes a systematic review of current literature and randomized clinical trials to issue guidelines as to the diagnosis and management of asthma. The report focuses on four basic components of asthma care: assessment and monitoring, patient education, control of factors contributing to asthma severity, and pharmacologic treatment. (NHBLI, 2007, p. 1). This systematic review combines current research findings to form a basis for evidence-based practice in the management of asthma.
Preparation Of The Guidelines
NHBLI panel members searched literature relating to peak flow usage that was published between January 1, 2001 and March 15, 2006. Key text words and relevant MeSH terms were used to search the MEDLINE database for English-language studies published in peer-reviewed journals. The articles were systematically reviewed by committee, first by abstract review and progressing to full-text review of selected articles. Newer relevant research published during the writing period ending December 2006 was considered for inclusion as well. Lastly, the findings were posted on the NHBLI website in February 2007 for public review and commentary (NHBLI, 2007, p. 3).
Inclusion And Ranking Of Evidence
For the topic "Assessment and Monitoring", which included the subtopic of usage of peak flow management, a total of 3.996 citations were screened, 214 of which made it to the stage of full-text review. Of these, a total of 14 articles were cited as relating to peak flow measurement. The evidence was rated using four evidence categories, ranked in order from strongest to weakest as follows: (a) Category A, randomized clinical trials (RCT's) with rich body of data; (b) Category B, RCT's with limited body of data, including smaller sample sizes, meta-analyses and post-hoc analyses of RCT's; (c) Category C, nonrandomized trials and observational studies; (d) Category D: expert panel consensus judgment, primarily based on clinical experience or knowledge but with lacking available supportive research in categories A through C. (NHBLI, 2007, p. 7).
The guideline authors have made the literature review and guideline writing process transparent in the introduction section. The reader is directed by the authors to the NHBLI website for an evidence table applicable to the topic of peak flow usage, as well as for lists of reviewed articles and names of committee members. This transparency of proceedings, as well as the exhaustive systematic review and guideline writing process, make the 2007 Expert Panel Report a high-quality and useful guideline for asthma management.
What The Guidelines Say About Peak Flow Usage
The 2007 guidelines recommend that long-term daily peak flow monitoring be performed by patients with moderate to severe persistent asthma and those with a prior history of severe exacerbations (NHBLI, 2007, p. 59). These individuals are more likely than others to be "poor perceivers" who are less able to detect subtle changes in worsening lung function (NHBLI, 2007, p. 58). The guidelines go on to say that peak flow monitoring during an asthma exacerbation can also be helpful in guiding management according to an asthma plan. The guidelines state, however, that PEF is effort- and technique- dependent, and that "instructions, demonstrations and frequent reviews of technique" (NHBLI, 2007, p. 383) are necessary.
Self-monitoring is an essential component of asthma care, and the new guidelines state that either peak flow monitoring or symptom monitoring can be equally effective with proper instruction and adherence. The guidelines state that the method of monitoring should be based on a number of factors to include symptom perception accuracy, severity of asthma, personal preference and availability of peak flow monitoring equipment (NHBLI, 2007, p. 60). Therefore, for many asthmatic children and their families, the usage of PEF monitoring in their asthma management is a matter of personal preference.
Critical Appraisal of Related Evidence
A study by Wensley and Silverman (2004) sought to discover whether the addition of recorded peak expiratory flow (PEF) measurements to a symptom-based self-management plan improved outcomes in school-aged children with moderate persistent asthma. In this open randomized, controlled trial 90 children between the ages of seven and fourteen with moderate asthma on regular inhaled corticosteroid (ICS) therapy received either symptom-based management alone or with the addition of PEF monitoring. Subjects in both groups performed PEF spirometry twice daily at home on electronic spirometers, and a symptom diary completed each morning. PEF values were blinded to the control group, requiring them to manage on the basis of symptoms alone. Daily PEF values for both groups, however, were transmitted to the investigators. Outcomes were measured in terms of quality of life and utilization of health services (both answered via questionnaires), mean daily symptom scores and lung function. The children increased dosage of inhaled steroids during acute episodes according to symptom changes and not their PEF readings. At the end of the 12-week study period, the investigators found no difference in any of the four outcome measures between the two groups, concluding that the addition of peak flow measurement did not enhance asthma management in the children studies. The authors note limitations to the study including insufficient power as a result of a small sample size, noting that for a statistically significant study 800 children would have to be studied. Another interesting limitation is the fact that both groups received self-management education prior to the study, possibly enhancing the skills of the control group (Wensley and Silverman, 2004). In spite of its limitations, however, this is an important and well-performed study that fills an evidence gap.
A blind, randomized controlled trial was conducted by Burkhart, et al (2007) to investigate whether peak flow monitoring improved health outcomes; the same randomized controlled trial was used to test an intervention that would increase children's adherence to asthma self-management. A convenience sample of seventy-seven children between the ages of seven and eleven with diagnosed asthma who were not using PEF meters at time of enrollment was recruited from pediatric practices in Kentucky. All of the children received initial instruction during the run-in period in the use of an electronic PEF monitor, and were instructed to use the PEF monitor twice daily, recording their readings in a diary. At week 4 of the study an asthma action plan was developed for each participant based on a "personal best" value from the PEF readings to date, with instructions to continue PEF monitoring once daily in the am unless symptomatic. The participants were then randomized to an intervention group that was given more intensive asthma education and reinforcement based on cognitive social learning theory, and to a control group that continued daily PEF monitoring, but without the additional education. The researchers looked at not only PEF adherence but health outcome indicators including missed school days, physician/ED visits and asthma episodes. The study was sixteen weeks in duration, at the end of which the intervention group displayed an increased adherence to daily PEF monitoring, with all of the children displaying improved asthma outcomes over the study period. Study results were communicated in two different peer-reviewed journals with one journal article emphasizing the overall improved outcomes with PEF usage and the other emphasizing the effects of the behavioral interventions in promoting adherence to PEF monitoring. Limitations of this study include a relatively small sample size and a largely homogenous study group, composed of majority Caucasian, middle-class children with educated parents and with private insurance. Although the study was sound and internally valid, its generalizability to other subsets of pediatric asthma patients is questionable.
A study by Brouwer, Roorda, and Brand (2006) sought to examine the relationship of peak flow using electronic home spirometry with other parameters of asthma severity. A sample of 42 children, ages 6-16 years diagnosed with mild to moderate persistent asthma on ICS therapy was recruited from a pediatric clinic in the Netherlands. Using electronic spirometers, peak flow and FEV1 were monitored twice daily. Asthma severity symptoms were recorded twice daily via a visual analogue scale in an asthma diary; the diary was also used to record usage of rescue bronchodilator medication. At the end of a three month study period data for six children was excluded due to <80% compliance with the symptom diary and spirometry. In the remaining 36 children, the researchers found inconsistent correlation between spirometry results and other parameters of asthma severity. In fact, the investigators classify 36% of the study participants as "poor perceivers" due to the discordance between an increase in asthma symptoms and an increase in spirometry values. Because of the very small sample size, it is improbable that these results could be generalized to larger populations, but they are noteworthy and show the need for further research in this arena, particularly relating to the concept of the "poor perceiver".
A non-concurrent cohort study by Fonseca, Fonseca, Rodrigues, Lasmar, and Camargos (2006) followed 75 children aged five to sixteen years old with persistent asthma for a 12-week period. The sample for this study was a convenience sample obtained from a Brazilian pediatric pulmonology clinic, with all study participants using ICS and with no symptom exacerbations for the previous three-month period. The purpose of the study was to correlate 1-second forced expiratory volume and peak expiratory flow with other clinical parameters in children with moderate to severe asthma. Over the three-month study period, symptom questionnaires and peak expiratory flow measures were completed at routine intervals by blind "independent examiners" (Fonseca, et al., 2006). Analysis of the data, in combination of a literature review from previous randomized controlled trials, showed little or no evidence of correlation between clinical severity scores, forced expiratory volume and peak flow measurement, but does show a positive correlation between peak expiratory flow measurement and forced expiratory volume. The authors state that their findings reinforce the use of peak expiratory flow measurement for the management of asthmatic children, but state that peak flow should not be the only objective parameter used in monitoring asthma control. The authors acknowledge that study participants were well controlled and on medication, and that patients adapting to limitations of their disease might have difficulty in recognizing deteriorated pulmonary function.
In a study by Feldman, McQuaid, Klein, Kopel, Nassau, Mitchell, Wamboldt, and Fritz (2007), researchers at Brown Medical School, University of Colorado and Yeshiva University, under a grant from the National Heart, Lung, and Blood Institute, examined the association between asthma symptom perception measured during a 5-6 week baseline and functional morbidity measured prospectively across a one-year follow-up. Study subjects were children were 198 children between seven and seventeen years old with physician-diagnosed asthma for at least six months who were currently anti-inflammatory or bronchodilator medications. Using a home electronic sprirometer that allowed the child to enter a guess for their PEF before three consecutive blows, lung function was monitored twice daily. Functional morbidity was assessed with the asthma function severity scale (AFSS), a six-item scale, at baseline and at one year. Correlations between guesses and actual PEF measurements were plotted into an "Asthma Risk Grid" with zones indicating underestimating of compromise, symptom magnification, or close correlation; with the grid for each child being based on his or her personal best (Feldman, et al., 2007). The study showed FEV1 achieved via spirometry to have a closer correlation to symptoms than PEF alone, and therefore demonstrated the importance of including multiple measures of pulmonary function when examining symptom perception. This study appeared to be well-performed with sampling from several different locations and demographic groups, but presentation of the results could be more straightforward to make the data more useful.
In a secondary analysis of data collected during a multicenter trial conducted by the American Lung Association Asthma Clinical Research Centers, in which the safety of influenza vaccine was evaluated in respect to asthma exacerbations (the SIIVA trial), McCoy, Shade, Irvin, Mastronarde, Hanania, Castro, and Anthonisen (2006) examined methods of predicting "episodes of poor asthma control". Data was collected in a multicenter trial supported by the American Lung Association, from a diverse group of 2032 subjects from ages 3 to 64 receiving care for asthma; of this group 37.6% were aged 3 to 19. The objectives of this analysis were to find how three asthma questionnaires utilized in the primary study characterized asthmatic episodes and predicted future exacerbations. Prior severe asthma exacerbations were the highest predictor in the population of children aged less than 10, but questionnaire data was useful in predicting exacerbations in the study population aged 10 and over. Although this study did not pertain specifically to pediatric patients with asthma, the large sample size and diversity of the subject population are noteworthy. McCoy, et al. (2006) acknowledge that the performance of the study during the fall and winter months might have accounted for the large number or reported exacerbations, but also point out that the large exacerbation number (43.2% of enrolled patients over the 28 days of the study) might be an indicator of less-than-optimal asthma control across the spectrum of patients. The authors concluded that asthma questionnaires could be beneficial in the prediction of asthma exacerbations in the population aged 10 and older, but did not support the use of asthma questionnaires in the younger population, age less than 10. Therefore, it is suggested that symptom assessment and history is a useful parameter for monitoring in patients 10 and older.
A prospective cohort study by Zhang, Avila, Leyraud, Grassi, Thiago-Bonfanti, and Ferruzzi (2005) undertook to evaluate the accuracy of parental and child's reports of changes in asthma symptoms. The participants were enrolled from those children aged 6 to 18 years of age with diagnosed asthma from a pediatric pulmonology clinic in Brazil, with a sample size of 53 children. During the eight-week study period, daily PEF rate and daily symptom scores, using a 15-point scale, were recorded. At the end of the eight weeks, parents and children were interviewed separately as to changes in asthma symptoms and control since the 4-week visit, with responses rated on a separate 15-point scale. Parental reports correlated more strongly than the child's mean daily symptom score with clinical control in the 6 to 10 age group. In the 11 and older age group, the children themselves were able to provide information consistent with clinical control. Neither of the age groups showed a consistent correlation between parental and child reports and PEF score, which the authors state "casts doubt on the validity of routine use of peak flow meter for monitoring asthma severity in children (Zhang et al., 2006). This article acknowledged that poor compliance of patients was an important limitation to this study; the sample size at 53 children was also very small.
The quality of self-administered home PEF monitoring measurements was evaluated by Thompson, et al. (2006). The sample was composed of children ages 9-18 from two locations in Southern California who had diagnosed mild to moderate persistent asthma, and 67 children completed the study. In this study electronic "ndd" brand spirometers provided feedback on maneuver acceptability; patients also received intensive education on spirometry usage and behavioral incentives to help with compliance. The electronic monitors also tallied repeatability and acceptability of maneuvers both daily and over time for each child. Study results showed a higher quality of maneuvers overall with the 13-18 age group than with the 9-12 age group; and a higher degree of compliance in those groups that had more frequent investigator monitoring. The study points out the superiority of portable electronic spirometers to regular peak flow meters due to their ease of use and quality assurance prompts; the study primarily suggests their use for further research, though, rather than regular patient monitoring. However, the success of the feedback mechanisms built into the ndd device points to the necessity of education and reinforcement in technique with any type of home spirometry or PEF.
Effectiveness of an interdisclipinary intervention for pediatric asthma was examined by Walders, Keresmar, Schluchter, Redline, Kirchner, and Drotar (2006) in a randomized, controlled study involving 175 patients between the ages of 4 and 12. For inclusion, patients must have had either two or more emergency department (ED) visits or one hospitalization for asthma in the past year and no current asthma treatment plan. Patients were excluded if they were under the care of a pediatric asthma specialist. All patients, after initial evaluation, received a written pediatric pulmonologist-prepared written asthma action plan, a metered dose inhaler with spacer, a peak flow meter, and a one-month supply of asthma medications. Participants were randomized via block scheme stratified by age. The intervention group received additional asthma education on the second visit and tailored cognitive-behavioral therapy (CBT) educational sessions on the third visit, followed by access to a 24-hour nurse advice line, and follow-up telephone contact. Differences in asthma symptom reports were the primary outcome measure, with healthcare utilization and quality of life being secondary outcomes (Walders, et al., 2006). The results showed no reduction in symptoms or increase in quality of life among the intervention group, but did show a significant reduction in healthcare utilizations (i.e. ED visits or hospitalizations) for asthma in the intervention group over the 12-month follow-up period. The investigators acknowledge that both groups received an enhanced level of care. Also, 28% of the healthcare utilizations among the intervention group were in patients who had not attended the third study visit receiving the CBT and nurse advice line information. The researchers also state that the "intervention may have been too brief in duration and too limited in scope to impact the full spectrum of outcomes" (Walders, et al., 2006).
]Synthesis of Related Evidence
With all of the available research on asthma there still appear to be gaps in knowledge and different interpretations of evidence. More large-scale research is needed, especially in the arena of peak flow usage as a management modality for pediatric asthma patients. As per the 2007 Expert Panel Report of the National Heart, Lung, and Blood Association, peak flow monitoring is an optional part of asthma management for all but moderate to severe asthmatics, for whom it is recommended (NHBLI, 2007). Prior research has shown that adherence to PEF monitoring has been linked to fewer asthma episodes (Burkhart et al., 2002; Tinkleman & Schwartz, 2004). Therefore, PEF can be a valuable adjunct to symptom-based management, especially with the risk of some patients being "poor perceivers". That being said, it can also be shown from the research that PEF is technique and effort dependent, and therefore must be combined with patient and family education for maximum benefit.
For younger children, data does not support daily PEF usage, nor are current findings suggesting that PEF is effective. PEF monitoring is a widely accepted and inexpensive means of monitoring asthma. Studies suggest that especially in the pediatric asthmatic, that there is a significant disparity in the perception and the actual control of symptoms. Accurate symptom perception is a critical component of asthma management with a marked reduction when the child's PEF reading is < 80% of personal best during "sick times".
Our question of the role of PEF is an important one because it is the only cheap, widely available means of gaining lung function information (Wensley & Silverman, 2004). A PEF meter varies in cost from $15 to $150.00, with most insurance companies covering this cost with a documented asthma diagnosis. This portable handheld device is designed for home use to monitor lung status in comparison to baseline or personal best PEF. Not only is this objective tool cost effective, it is safe and has been supported and accepted by health professionals worldwide.
One of the major obstacles appears to be adherence to asthma protocols in the home setting. The Burkhart (2007) study showed that children with persistent asthma who received asthma education plus a behavioral management protocol would show a higher adherence to peak expiratory flow monitoring for asthma self management and thus would experienced fewer asthma episodes. The results concluded that such an intervention to teach children to adhere to a recommended regimen was effective in the 7 to 14 age group. Providers should discuss adherence with families, tailor adherence interventions to the families' particular needs and emphasize parent partnership in the child's individualized management plan.
Proposed Application and Evaluation
At the time of a child's diagnosis with asthma, data from a thorough history and physical should be combined with the NHBLI severity classification guidelines, and an asthma action plan developed in consultation with the family. The child and family should be as involved as possible in treatment decisions and in formulation of the action plan. If the child's asthma is moderate to severe according to the 2007 NHBLI guidelines, referral to a pediatric asthma specialist should be part of the treatment plan, along with PEF as a part of home management, age permitting.
Symptom questionnaires have been proven to provide crucial information in pediatric patients, particularly in those 10 and older. Ethnicity, cultural and lifestyle information to include second hand smoke, environmental triggers, and nutritional habits are all also important data to obtain prior to formulating an asthma action plan.
If the decision is to institute PEF as a component of the asthma plan, there should be detailed instruction on the proper usage of PEF and on record-keeping of data. Ideally, this should be in the context of at least a 1-hour pt education visit, with return demonstration an important component.
There are a number of commercially available PEF devices that are reasonably priced, and a number of such devices are provided by pharmaceutical companies as promotional items. The electronic PEF devices, if available and economically feasible, provide for data storage and are superior to the standard PEF models, although these devices are also more expensive and perhaps therefore not realistic in our healthcare system.
The goals for the pediatric asthmatic patient are reducing the frequency and severity of both symptoms and exacerbations, maintaining normal levels of activity and achieving optimal lung functioning. Effectiveness is measured as evidenced by a decrease in the occurrence of exacerbations resulting in the reduction of school absences, episodic office visits and hospitalizations. Strategies to be adapted in pediatric practices might include detailed parent/child questionnaires, individualized asthma action plans, telephone reminders, "Asthma 101" classes, child rewards and parent support groups.
"Asthma 101" classes should be offered at least quarterly to all newly diagnosed asthma patients and to those children and their parents needing reinforcement education. Classes would be developed with age-appropriate and culturally sensitive information and be a fun, relaxed learning environment for children and their families. If there were limited reimbursement availability for asthma education, the classes could perhaps utilize student nurses or nurse practitioners, or could serve as community service or continuing education hours for licensed healthcare professionals. Perhaps a support group meeting quarterly for parents of asthmatic children could be also developed using similar methods.
Regardless of whether PEF is used in tandem with symptom-based monitoring, every pediatric asthma patient needs an asthma action plan customized with instructions on when to use rescue medications and when to contact the healthcare provider and/or go to the ED. Every pediatric patient with asthma also deserves routine telephone follow-up to remind of upcoming visits, classes, and to solicit questions; this might also be accomplished by the use of electronic mail for those clients having internet access.
Outcome measures would be a lessened number of episodic visits, less or no use of oral corticosteroids, less missed school days, and compliance with scheduled routine follow-up visits. These parameters could easily be tracked by a simple form developed for use in whatever charting system a practice uses. The data could be obtained at office visits and from telephone/electronic mail follow-up as described above.
There is no single answer to the question posed in this evidence-based research practice project. The 2007 NHBLI guidelines and most research articles reviewed agree that PEF is not a useful monitoring tool in very young children under age five. In children above five, however, there are differences in interpretation of literature and research findings. With the idea that some more severe asthmatics could be "poor perceivers" likely not to recognize deteriorating lung function, an objective measurement such as PEF should be readily available in the home setting. Since it is likely beyond the scope of anyone but a pediatric asthma specialist to classify a child as a "poor perceiver", it would seem prudent to offer PEF as an option in developing an asthma action plan for a pediatric patient over the age of five.
The reviewed literature has shown, however, that neither PEF nor symptom-based management can be effective without adherence. Likewise, PEF, because of its technique-dependent nature, cannot be effective if not performed properly. Therefore, regardless of whether symptom-based or PEF monitoring is used as a basis for an asthma action plan, it must be combined with education and behaviorally-based interventions for maximum effectiveness.
Asthma is a chronic condition that can result in significant morbidity and mortality, especially in young children. It also can place significant limitations on the quality of life both of affected children and their families. It is the responsibility of nurses at all levels of practice to deliver the highest standards of evidence-based care to pediatric clients with asthma, and by doing so increase their overall health and enjoyment of their childhood years.
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