http://informahealthcare.com/jas ISSN: 0277-0903 (print), 1532-4303 (electronic) J Asthma, Early Online: 1–7 ! 2014 Informa Healthcare USA, Inc. DOI: 10.3109/02770903.2014.914218
REVIEW ARTICLE
Incorrect use of peak flow meters: are you observing your patients? Timothy H. Self, PharmD1,3, Christa M. George, PharmD, BCPS, CDE1,4, Jessica L. Wallace, PharmD, BCPS2, Shanise J. Patterson, PharmD, BCPS1,3, and Christopher K. Finch, PharmD, BCPS, FCCM1,3
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1
Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA, 2Department of Pharmacy Practice, Lipscomb University College of Pharmacy, Nashville, TN, USA, 3Department of Pharmacy, Methodist University Hospital, Memphis, TN, USA, and 4University of Tennessee Family Medicine Clinic – St. Francis Hospital, Memphis, TN, USA Abstract
Keywords
Background: Monitoring peak expiratory flow (PEF) values is one option as part of asthma action plans per national guidelines. PEF assessment is also recommended in emergency department and hospitalized patients. Incorrect use of peak flow meters (PFM) has obvious implications for appropriate decisions by patients and clinicians. Methods: We searched the English literature via PubMed and SCOPUS using the following search terms: PEF maneuver; incorrect use of PFM. When pertinent articles were found, we assessed publications cited in those papers. All studies related to incorrect use of PFM in patients with asthma were included. Results: Nine studies have reported errors in performing the PEF maneuver, including three pediatric and six adult studies. Errors were found at most steps of the maneuver, and inability to perform all steps correctly was common in these investigations. Examples of errors included failure to inhale fully or give maximum effort on exhalation, accelerating air with the tongue and buccal musculature, and performing only one attempt versus three. Gender differences in correct use of PFM are suggested by three adult studies. One study described falsifying PEF values by manipulating the PFM indicator, and another investigation assessed the PEF maneuver in two positions in bed versus the correct posture of standing. Conclusion: Many pediatric and adult patients do not use PFM correctly. Clinicians should regularly observe patients use PFM to detect errors and help ensure correct use and accurate PEF measurements.
Asthma, errors, peak expiratory flow maneuver, peak flow meters
Introduction Peak expiratory flow (PEF) is a useful objective measure for monitoring asthma control [1]. National guidelines include the use of PEF as a component of written asthma action plans, and suggest that action plans may be symptom-based alone or may combine PEF and symptoms to guide decisions [1]. Monitoring PEF is also useful in the emergency department and hospital settings [1]. Accurate measurement of PEF using the correct PEF maneuver has obvious importance, yet several reports in the literature indicate that some patients have errors in the maneuver. Incorrect use of peak flow meter (PFM) has been documented in acute care as well as ambulatory settings. The overall aim of this brief review article is to focus on these reports, including a variety of incorrect PEF maneuvers in children and adults. Furthermore, our aim is to alert clinicians to routinely observe their patients use PFM.
Methods We searched the English literature via PubMed and SCOPUS using the following search terms: PEF maneuver and incorrect use of PFM. When pertinent articles were found, we assessed Correspondence: Dr. Timothy H. Self, Department of Clinical Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163, USA. E-mail: [email protected]
History Received 7 February 2014 Revised 4 April 2014 Accepted 7 April 2014 Published online 9 May 2014
relevant publications cited in those papers. All studies from 1987 to 2013 related to incorrect PEF maneuver or use of PFM in both children and adults with asthma were included. Correct steps for the PEF maneuver are shown in Table 1 [1].
Results Pediatric studies Scarfone et al. [2] conducted a prospective study in children and adolescents with asthma exacerbations in an urban pediatric hospital emergency department (ED). The purpose of this study was to assess the use of metered-dose inhalers and PFM. Regarding PFM, the investigators aimed to determine if patients used proper technique as well as PEF score interpretation by caregivers. In addition, prescribing patterns by primary care clinicians and home utilization prior to the ED visit were assessed. Pediatric patients aged 5 years or older with moderate to severe persistent asthma were given a PFM in the ED and asked to demonstrate its use ‘‘exactly as you would use it at home’’ [2]. Parents could help their children if necessary. Each step for correct use was recorded by the investigators. A PFM had been prescribed in 125 (62.8%) of eligible patients prior to admission to the ED. Among these patients/parents, only 27.2% had checked their PEF before coming to the ED. In patients who reported
2
T. H. Self et al.
Table 1. Steps for correct peak expiratory flow maneuver. 1. 2. 3. 4.
Move the indicator to the bottom of the numbered scale. Stand up. Take a deep breath, filling your lungs completely. Place the mouthpiece in your mouth and close your lips around it. Do not put your tongue inside the hole 5. Blow out as hard and fast as you can in a single blow. Write down the number you get. But if you cough or make a mistake, do not write down the number. Do it over again. Repeat steps 1 through 5 two more times, and write down the best of the three blows in your asthma diary.
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Expert Panel Report 3, 2007 [1].
regular determination of the PEF at home, 28.9% did not know that PEF should be performed while standing and 35.4% were unaware that three attempts should be made. Lack of knowledge to record the highest of three values was seen in 39.5% of patients, and 35.5% did not understand that depending on the PEF value, more medication may be needed. Among 111 patients who had a PFM at home and agreed to demonstrate its use in the ED, the mean age was 11 years (SD 3.2 years), 58% male and 95% African American. Performance of each step correctly for the PEF maneuver was observed in 73.9% of children. For the 26.1% of children who did not perform perfectly, errors were recorded for the following steps: move the indicator to zero (18%), inhale completely (5%), tight seal (4%) and breathe out hard and fast (3%). The authors presented these data in a Figure, but the exact percentages for each error were hard to determine. Gorelick et al. [3] assessed the ability of children with asthma to adequately perform the PEF maneuver in an urban pediatric ED. Correct performance was globally assessed by registered respiratory therapists. Individual steps for the PEF maneuver were not evaluated. Among 291 patients, ages 6–18 years, PEF was attempted at least once. Adequate performance was observed in only 65% of patients, and at the start of therapy, 54% were able to correctly perform the maneuver [3]. For the 120 patients who could not correctly use the PFM initially, 76 children tried again at the conclusion of ED treatment yet 55 (72%) of them still were not able to perform adequately. Patients who were older (mean age 11.2 years) were able to perform the PEF maneuver correctly more often than younger patients (mean age 8.7 years). In addition, pediatric patients who required hospital admission were less likely to adequately perform PEF than those discharged home from the ED (p50.0001). Sleath et al. [4] evaluated the skill of children in using metered-dose inhalers, dry powder inhalers and PFM. Patients, ages 8–16, with persistent asthma were studied in five pediatric practices in non-urban areas of North Carolina. To ensure optimal assessment of patient skill in using the asthma devices, five research assistants received training, including a video with examples of correct technique and scoring sheets. Three children were recorded using the devices with various mistakes. The research assistants then viewed the videos and scored the patients, followed by a critique by a study investigator. Research assistants practiced until their scoring agreed with the scoring of the investigator. All children were asked if they used a PFM at home. If they responded that they did, then they were asked
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to demonstrate how they used the device. Only 23% of children/parents reported using a PFM at home. In scoring PEF technique of the 67 patients, the investigators used the following eight possible correct steps [percent correct shown for each step]: (1) set marker to 0 [68.2%], (2) hold meter upright [90.9%], (3) do not block marker movement [86.6%], (4) deep breath in with mouth open [84.6], (5) place meter in mouth and close lips tightly around meter [92.5%], (6) exhale hard and fast into meter [87.9%], (7) Check the result [83.6%] and (8) repeat steps 1–7 two more times [59.9%]. All steps were performed correctly by only 23.9% of children. Caucasian children were less likely to score correctly in using the PFM than non-white patients (p ¼ 0.018). Table 2 summarizes pediatric studies of incorrect use of PFM. In summary regarding pediatric studies, two studies were conducted in urban pediatric EDs and one investigation was done in rural pediatric practices. While many children performed well, the overall results were disappointing in terms of skill in using PFM. For the two studies that gave results for each step, Table 3 summarizes the results. Adult studies Strayhorn et al. [5] conducted a study of correct versus incorrect use of 5 PFM in 20 patients with clinically stable asthma. Incorrect use was specified as accelerating air in the mouth with the tongue (a ‘‘spitting maneuver’’). This investigation was triggered by a case report of a patient who used this incorrect maneuver and had 430% elevated PEF values [6]. Strayhorn et al. [5] demonstrated the correct technique for using the PFM to each study subject, and then demonstrated the ‘‘spitting maneuver’’ (mouthpiece not placed well into the mouth so that tongue and buccal musculature could be used to accelerate air). Fifteen minutes after administration of albuterol (MDI, 2 puffs via a valved holding chamber [AeroChamber]), patients performed the PEF maneuver correctly and incorrectly with 5 PFM. The order of PFM usage was random as the order of correct versus incorrect technique, and the best of three attempts for each device was used in the data analysis. Results were analyzed using percent change from personal best values. Each of the PFM tested had significant increases in percent increase in PEF with mean values as follows: Assess 68.2% ± 33.7 (p ¼ 0.0001), MiniWright 12.4% ± 9.3 (p ¼ 0.0161), Pocket Peak 23.8% ± 13.8 (p ¼ 0.0001), Personal Best 43.4% ± 24.4 (p ¼ 0.0001) and TruZone 42.6% ± 38.7 (p ¼ 0.0001). These dramatic increases in PEF using an incorrect maneuver obviously would create poor decision making in monitoring asthma control and use of written action plans. Nolan et al. [7] compared PEF values associated with correct use of 5 PFM to PEF observed with two incorrect techniques: positioning the PFM at a 20 angle to the left in the mouth and a 20 angle pointed downward (as the patient leaned forward). Study subjects were taught the correct and incorrect techniques demonstrated by the investigators, and before performing the maneuvers, subjects received albuterol (MDI, 2 puffs via a valved holding chamber [AeroChamber]). Clinically stable adults (n ¼ 16) with persistent asthma performed each maneuver with each of 5 PFM in random
Incorrect use of peak flow meters
3
Table 3. Pediatric studies-specific steps with correct use of PFM.
Specific step Set marker to 0 Hold PFM correctly Do not block marker movement Deep breath Tight seal Exhale hard and fast
23.9%
Performing technique only once rather than three times to obtain best of three (40.1%), not setting marker to zero (31.8%), not checking the result (16.4%), not taking a deep breath in with mouth open (15.4%) and blocking marker movement (13.4%).
a
ED, emergency department; PFM, peak flow meters.
67 8–16 Sleath et al. [4]
Five non-urban pediatric practices.
Urban pediatric emergency department 6 Gorelick et al. [3]
291
54% initially; 65% after conclusion of ED therapy
Specific errors not noted in study.
62.8% (111 patients) had been prescribed PFM prior to ED presentation and agreed to demonstration. Only 27.2% had used PFM prior to ED presentation. For those children initially unable to perform, upon repeat of PFM at conclusion of ED therapy, 55 (72%) were still unable to perform. Only 23% (67 patients) reported use of PFM at home and subsequently demonstrated PFM technique in study. Not moving indicator to zero, not inhaling completely, not achieving tight seal around mouthpiece and not breathing out hard and fast 73.9% 111 Urban pediatric hospital emergency department 5
Study setting Study
Scarfone et al. [2]
Common errors observed Percentage correctly performing all steps of PFM Number of patients who demonstrated PFM Patient age (years)
Table 2. Pediatric studies evaluating incorrect use of peak flow meters.
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Comments
DOI: 10.3109/02770903.2014.914218
Scarfone et al. [2] (%)
Sleath et al. [4] (%)
82a 100 100 95a 96a 97a
68.2 90.9 86.6 84.6 92.5 87.9
Scarfone et al.2 (refer text regarding these percentages).
order, and the best of three attempts for each device was used in the data analysis. Mean results generally indicated no clinically relevant effect of incorrectly positioning of the PFM. However, for both incorrect techniques, some patients had inaccurate PEF values with each of the PFM. Chafin et al. [8] assessed the PEF maneuver in healthy adults, comparing men versus women. After a lecture regarding asthma, including demonstrations of correct use of a PFM, 83 health science center students (52 F, 31 M) were immediately divided into five small groups and scored in oneon-one sessions on their use of the PFM (three attempts). Men had superior performance for the first attempt, including total score (p50.05) and for the step ‘‘fully inhale’’ (p50.05). With the second attempt, men scored higher than women for the step ‘‘exhale as fast and as hard as you can’’ (p50.05). The results suggest that women generally need more coaching initially regarding maximum effort in the PEF maneuver. Self et al. [9] conducted a follow-up study in another group of healthy adult students (n ¼ 116) at the same institution, and assessed gender difference for PEF values as well as scores for correct use (the first study evaluated only scores for technique). Immediately following a lecture regarding correct use of asthma devices, including demonstration of correct PEF maneuver, students were then divided into small groups and scored on use of a PFM (three attempts) in individual sessions. Students were unaware that the study was evaluating gender differences. For the first attempt, men (n ¼ 40) scored higher than women (n ¼ 76) for the steps of ‘‘inhale fully’’ and ‘‘exhale as hard and as fast as you can’’ (p ¼ 0.03). PEF percentage increases improved in women but not in men from the second attempt to the third attempt (p ¼ 0.036). On the third attempt, 13.2% of women versus 2.6% of men had a PEF increase of 450%, but this finding did not reach significance. The conclusion of this study was that men learned the correct PEF technique and reached their best PEF quicker than women. Finch et al. [10] evaluated adult patients with asthma for potential gender differences in performing the PEF maneuver. Clinically stable patients (n ¼ 32) with persistent asthma were assessed for their technique during routine clinic visits. After three attempts, if any errors were found, patients were coached and then repeated three more attempts. Patients were not told that this was a ‘‘gender difference’’ study. Men (n ¼ 10) performed better than women (n ¼ 22) for ‘‘exhale as hard and as fast as you can’’ (p50.05). Although total correct scores for six steps were greater for men (4.2) versus women (3.8), the difference was not significant. PEF increased 410%
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after coaching in 57.9% of women versus 33.3% of men suggesting men learn the PEF maneuver quicker than women as in the previous studies in healthy subjects [8,9]. Wallace et al. [11] conducted a study in health science center students (n ¼ 94) to determine if performing the PEF maneuver in two different positions in bed resulted in the same PEF value performed when subjects were standing. The impetus for this investigation was an observation of respiratory therapists recording PEF values taken from patients in bed hospitalized for asthma exacerbations. Study participants (39 M, 55 F) were healthy, and were randomized to using a PFM in the following positions with three attempts in each position: (a) standing, (b) in bed lying back on pillows at a 45 angle and (c) in bed sitting, slumped forward 10 with legs extended. Mean PEF values in men were as follows: (a) Standing: 669 L/min, (b) lying back in bed: 621 L/min (p50.001) and (c) sitting slumped forward in bed 615 L/min (p50.001). In women, mean PEF values included the following: (a) Standing: 462 L/min, (b) lying back in bed: 422 L/min (p50.001) and (c) sitting slumped forward in bed 447 L/min (p50.05). Since national guidelines [1] recommend monitoring PEF in hospitalized patients with asthma, this study is a reminder to clinicians to ensure that patients are asked to stand to perform the PEF maneuver. Alternatively, for patients who do not feel like standing, a recent healthy subject study found that performing the PEF maneuver sitting in a chair with the back straight is acceptable [12]. Table 4 summarizes adult studies. In summary, regarding adult studies, three studies assessed the magnitude of effect of varying errors, such as a ‘‘spitting’’ maneuver and incorrect posture. Three other investigations focused on gender differences. In each of these studies, women did not perform as well as men in the step ‘‘Exhale as hard and as fast as you can – Blast!’’. In two of the studies, women also did not perform as well as men for the step ‘‘Inhale fully’’. For other steps in using PFM, there were no differences. These results are summarized in Table 4. Study with manipulation of peak flow meter indicator Ross and Cochran [13] reported a 13-year-old boy who found that if he retarded the movement of the Mini-Wright PFM indicator, he could falsely increase the results. Specifically, he would use his index finger to retard the indicator at the beginning of the PEF maneuver for a fraction of a second after initiating exhalation. The observation was the impetus for a study of 15 adults (one with asthma) in which subjects were observed using five correct attempts and five attempts with manipulation of the Mini-Wright PFM indicator. These attempts were made after practice of the two maneuvers. In 14 of the 15 subjects, increases were found in PEF using the incorrect technique [13]. Mean increase in PEF for the highest value was 56%, and the range was 4–86%. Using the mean PEF for the five attempts, the increase was 28% (range 2 to 66%). To avoid this manipulation of the PFM, Ross and Cochran [13] suggest that patients should be asked to ‘‘cradle’’ the PFM with a hand underneath the device. We note that regarding purposefully manipulating the device
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to achieve false PEF values, other authors have reported adults and children will lie to their clinicians about their PEF values [14,15].
Discussion Asthma significantly impacts the lives of children and adolescents in the United States. According to the Centers for Disease Control and Prevention, 7 million children in the US had asthma in 2010 [16]. In 2009, nearly 1 in 5 children with asthma required an emergency department visit and almost 1 of every 2 children with asthma miss at least 1 day of school every year [16]. While the evidence supporting long-term PFM use in children is conflicting, national guidelines recommend PFM be considered as part of written asthma action plans for patients with moderate or severe persistent asthma, a history of severe exacerbations or patients who poorly perceive symptoms of worsening asthma [1]. The pediatric literature reviewed herein [2–4] shows that children (especially younger children) and adolescents in urban and non-urban settings frequently make mistakes when using PFM. Given the number of children with asthma who may be using PFM to monitor disease control, incorrect PFM use has the potential to significantly decrease the health and quality of life of these patients. Consequently, national guidelines recommended that clinicians teach and reinforce skills for self-management including self-monitoring (either using PFM or symptom monitoring) at every opportunity [1]. Asthma also significantly impacts the lives of adults in the United States. In 2010, 18.7 million (1 in every 12) adults had asthma [16]. Asthma led to 14.2 million missed days of work in 2008 and yearly causes 3 in 5 patients with asthma to limit their daily activities [16]. Written asthma action plans (which may include PFM) are recommended for adults with asthma by national guidelines as stated previously [1]. The studies in adults reviewed herein show that women may need more instruction on correct PFM use than men and that incorrect PFM technique (e.g. lying down versus standing) leads to significantly different PFM measurements, which could impact asthma management [5–12]. Since accurate PFM is dependent upon effort and technique, it is imperative that clinicians frequently assess patients’ PFM technique. Expert Panel Report 3 [1] encourages asthma education, including instruction in use of inhalation devices and PFM, be conducted in clinics, EDs, hospitals, schools and pharmacies. Several reports describe the role of community pharmacists in teaching patients about asthma, including several devices [17–20]. Nurses, nurse practitioners and respiratory therapists all obviously have important roles in asthma patient education, including teaching patients the correct maneuver for PEF [1,21,22]. While more study is needed, Expert Panel Report 3 [1] also encourages community-based and home-based asthma education as well as computer-based education. As part of community-based education, we have encouraged volunteer asthma education by health science center students [23]. In a recent review, Chang [24] urges comprehensive asthma education, including appropriate use of PFM. We note that the disparity of methods used in the studies cited in this brief review article. For example, two pediatric
20 patients with clinically stable asthma
16 patients with clinically stable asthma.
83 healthy adult students
116 healthy adult students
32 patients with clinically stable asthma seen for routine clinic visit
Nolan et al. [7]
Chafin et al. [8]
Self et al. [9]
Finch et al. [10]
Patients
Strayhorn et al. [5]
Study
Same as previous study
Same as previous study
University Health Science Center
University Internal Medicine Clinic
At clinic visits, patients’ PFM technique and PEF values were evaluated. Patients received further coaching and repeated technique if errors were found.
Same as previous study
Participants, who were blinded to purpose of assessing gender differences, were observed in one-on-one sessions to evaluate participants’ PFM technique and measurements following a lecture on the correct PEF maneuver.
Incorrect use of peak flow meters (continued )
Study further emphasized the need to provide coaching with use of the PFM with women.
Males learned the correct PEF technique and subsequently reached a maximum PEF sooner than women.
Results emphasize need for coaching women to ensure maximum effort with PFM.
Assess effect of using two incorrect techniques: (1) positioning PFM at a 20 angle to the left in the mouth and (2) a 20 angle pointed downward (as patient leaned forward). Assess effect of gender difference on PEF values and scores for correct use.
University Health Science Center
University Health Science Center
Significant effects on PEF values were seen by patients utilizing the ‘‘spitting maneuver’’.
Increase in PEF values using incorrect technique: Assess 68.2% ± 33.7 (p ¼ 0.0001), MiniWright 12.4% ± 9.3 (p ¼ 0.0161), Pocket Peak 23.8% ± 13.8 (p ¼ 0.0001), Personal Best 43.4% ± 24.4 (p ¼ 0.0001), and TruZone 42.6% ± 38.7 (p ¼ 0.0001). Mean PEF values revealed no clinically relevant effect of positioning PFM; however, inaccurate PEFs were recorded for several subjects with both incorrect methods and all PFMs. Males demonstrated superior performance for first attempt overall (p50.05) as well as the step to ‘‘inhale fully’’ (65% F versus 90% M, p50.05) and second attempt for ‘‘exhale as fast and as hard as you can’’ (87% F versus 100% M, p50.05). Men achieved higher scores for steps of ‘‘inhale fully’’ (42% F versus 65%M, p ¼ 0.03) and ‘‘exhale as hard and fast as you can’’ (51%F versus 73%M, p ¼ 0.03). An increase in PEF of 450% from the second to third attempt was seen in 13.2% of women versus only 2.6% of men. On step of ‘‘exhale as hard and fast as you can’’, men performed superiorly (40.9%F versus 70%M, p50.05). Overall scores were higher for men, but statistical significance was not achieved. Women responded greater to coaching with a PEF increase of 410% in 57.9% Differences in PEF values compared between correct and incorrect technique (‘‘spitting maneuver’’) performed by patients on 5 PFM following albuterol administration and training.
Evaluate effect of using incorrect technique of ‘‘spitting maneuver’’ (when mouthpiece is not placed well into mouth so that tongue and buccal musculature are used to accelerate air).
University Pulmonary Medicine Clinic
Same design as previous study
Conclusions/Comments
Results
Design
Purpose of study
Study setting
Table 4. Adult studies assessing incorrect use of PFM.
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DOI: 10.3109/02770903.2014.914218
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T. H. Self et al.
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of women versus 33.3% men. Mean PEF values in men were as follows in the three positions: (a) 669 L/min, (b) 621 L/min (p50.001) and (c) 615 L/min (p50.001). In women, mean PEF values included the following: (a) 462 L/min, (b) 422 L/min (p50.001) and (c) 447 L/min (p50.05). Participants performed PFM for three attempts in each of the three positions in randomized order: (a) standing, (b) in bed lying back on pillows at a 45 angle and (c) in bed sitting, slumped forward 10 with legs extended.
Authors highlight the need to remind clinicians to ask patients to optimally stand to obtain optimal PEF values.
studies were conducted in urban, academic EDs and one was conducted in rural pediatric practices. We believe the various methods in different clinical arenas add strength to the evidence that incorrect use is common in different settings. Likewise with adults, the evidence indicates incorrect use of PFM in a variety of ways, such as accelerating air in the mouth with the tongue, lying back in bed or not giving maximum effort. Despite the varying methods of the available studies, errors with PFM use are frequent and, clinicians need to be vigilant in teaching patients correct use of PFM and ensuring correct use by observation of their technique. Obviously, health care professionals who educate patients with asthma need to be highly skilled in use of PFM and inhalation devices and have adequate time to perform asthma teaching. Although we hope a greater percentage of patients are skilled at using PFM, at this point in time, we are unaware of evidence to substantiate such skill. We hope that our review article, focusing on evidence showing that many patients do not have skill in using PFM, will help more healthcare professionals ensure appropriate use of these devices.
Declaration of interest Dr Finch has one potential conflict of interest to report – he is a speaker for GSK. The other authors have no conflicts of interest to report. The authors alone are responsible for the content and writing of this article.
References
PEF, peak expiratory flow; PFM, peak flow meters.
Wallace [11]
et
al.
94 healthy adult students
University Health Science Center
Evaluate effect on PEF values when PFM technique is performed in two alternate positions with the participant in bed (common positions of hospitalized patients) versus standing.
Results Design Purpose of study Study setting Patients Study
Table 4. Continued
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Conclusions/Comments
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1. Expert Panel Report 3. Guidelines for the diagnosis and management of asthma. Bethesda: National Institutes of Health; 2007. NIH Publication No. 08-4051. 2. Scarfone RJ, Capraro A, Zorc JJ, Zhao H. Demonstrated use of metered-dose inhalers and peak flow meters by children and adolescents with acute asthma exacerbations. Arch Pediatr Adolesc Med 2002;156:378–383. 3. Gorelick MH, Stevens MW, Schultz T, Scribano PV. Difficulty in obtaining peak expiratory flow measurements in children with acute asthma. Pediat Emerg Care 2004;20:22–26. 4. Sleath B, Ayala GX, Gillette C, Williams D, Davis S, Tudor G, Yeatts K, Washington D. Provider demonstration and assessment of child device technique during pediatric asthma visits. Pediatrics 2011;127:642–648. 5. Strayhorn V, Leeper K, Tolley E, Self T. Elevation in peak expiratory flow by a ‘spitting maneuver’: measured with five peak flow meters. Chest 1998;113:1134–1136. 6. Connolly CK. Falsely high PEFR due to acceleration in the mouth. BMJ 1987;294:285. 7. Nolan S, Tolley E, Leeper K, Smith VS, Self T. Peak expiratory flow associated with change in positioning of the instrument: comparison of five peak flow meters. J Asthma 1999; 36:291–294. 8. Chafin CC, Tolley E, George C, Demirkan K, Kuhl D, Pugazhenthi M, Self TH. Are there gender differences in use of peak flow meters? J Asthma 2001;38:541–543. 9. Self TH, Cross LB, Nolan SF, Weibel JB, Hilaire M, Franks AR, Finch CK, Tolley EA. Gender differences in the use of peak flow meters and their effect on peak expiratory flow. Pharmacotherapy 2005;25:526–530. 10. Finch CK, Tolley E, James A, Fisher K, Self TH. Gender differences in peak flow meter use. Nurse Practitioner 2007;32: 46–48. 11. Wallace JL, George CM, Tolley EA, Winton JC, Fasanella D, Finch CK, Self TH. Peak expiratory flow in bed? A comparison of 3 positions. Respir Care 2013;58:494–497. 12. McCoy EK, Thomas JL, Sowell RS, George C, Finch CK, Tolley EA, Self TH. An evaluation of peak expiratory flow monitoring: a
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19. Bosnic-Anticevich SZ, Sinha H, So S, Reddel HK. Metered-dose inhaler technique: the effect of two educational interventions delivered in community pharmacy over time. J Asthma 2010;47: 251–256. 20. Basheti IA, Reddel HK, Armour CL, Bosnic-Anticevich SZ. Improved asthma outcomes with a simple inhaler technique intervention by community pharmacists. J Allergy Clin Immunol 2007;119:1537–1538 (letter). 21. Distler JW. Access Carroll: community asthma education initiative. J Am Acad Nurse Pract 2011;23:357–360. 22. Shelledy DC, Legrand TS, Gardner DD, Peters JI. A randomized, controlled study to evaluate the role of an in-home asthma disease management program provided by respiratory therapists in improving outcomes and reducing the cost of care. J Asthma 2009;46: 194–201. 23. Self TH, Economides AK, Airee R, Clark DE. Education inner-city patients with asthma: a compelling opportunity for volunteer service by health science center students. J Asthma 2004;41:1–3. 24. Chang C. Asthma in children and adolescents: a comprehensive approach to diagnosis and management. Clin Rev Allergy Immunol 2012;43:98–137.
REVIEW ARTICLE
Incorrect use of peak flow meters: are you observing your patients? Timothy H. Self, PharmD1,3, Christa M. George, PharmD, BCPS, CDE1,4, Jessica L. Wallace, PharmD, BCPS2, Shanise J. Patterson, PharmD, BCPS1,3, and Christopher K. Finch, PharmD, BCPS, FCCM1,3
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1
Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA, 2Department of Pharmacy Practice, Lipscomb University College of Pharmacy, Nashville, TN, USA, 3Department of Pharmacy, Methodist University Hospital, Memphis, TN, USA, and 4University of Tennessee Family Medicine Clinic – St. Francis Hospital, Memphis, TN, USA Abstract
Keywords
Background: Monitoring peak expiratory flow (PEF) values is one option as part of asthma action plans per national guidelines. PEF assessment is also recommended in emergency department and hospitalized patients. Incorrect use of peak flow meters (PFM) has obvious implications for appropriate decisions by patients and clinicians. Methods: We searched the English literature via PubMed and SCOPUS using the following search terms: PEF maneuver; incorrect use of PFM. When pertinent articles were found, we assessed publications cited in those papers. All studies related to incorrect use of PFM in patients with asthma were included. Results: Nine studies have reported errors in performing the PEF maneuver, including three pediatric and six adult studies. Errors were found at most steps of the maneuver, and inability to perform all steps correctly was common in these investigations. Examples of errors included failure to inhale fully or give maximum effort on exhalation, accelerating air with the tongue and buccal musculature, and performing only one attempt versus three. Gender differences in correct use of PFM are suggested by three adult studies. One study described falsifying PEF values by manipulating the PFM indicator, and another investigation assessed the PEF maneuver in two positions in bed versus the correct posture of standing. Conclusion: Many pediatric and adult patients do not use PFM correctly. Clinicians should regularly observe patients use PFM to detect errors and help ensure correct use and accurate PEF measurements.
Asthma, errors, peak expiratory flow maneuver, peak flow meters
Introduction Peak expiratory flow (PEF) is a useful objective measure for monitoring asthma control [1]. National guidelines include the use of PEF as a component of written asthma action plans, and suggest that action plans may be symptom-based alone or may combine PEF and symptoms to guide decisions [1]. Monitoring PEF is also useful in the emergency department and hospital settings [1]. Accurate measurement of PEF using the correct PEF maneuver has obvious importance, yet several reports in the literature indicate that some patients have errors in the maneuver. Incorrect use of peak flow meter (PFM) has been documented in acute care as well as ambulatory settings. The overall aim of this brief review article is to focus on these reports, including a variety of incorrect PEF maneuvers in children and adults. Furthermore, our aim is to alert clinicians to routinely observe their patients use PFM.
Methods We searched the English literature via PubMed and SCOPUS using the following search terms: PEF maneuver and incorrect use of PFM. When pertinent articles were found, we assessed Correspondence: Dr. Timothy H. Self, Department of Clinical Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163, USA. E-mail: [email protected]
History Received 7 February 2014 Revised 4 April 2014 Accepted 7 April 2014 Published online 9 May 2014
relevant publications cited in those papers. All studies from 1987 to 2013 related to incorrect PEF maneuver or use of PFM in both children and adults with asthma were included. Correct steps for the PEF maneuver are shown in Table 1 [1].
Results Pediatric studies Scarfone et al. [2] conducted a prospective study in children and adolescents with asthma exacerbations in an urban pediatric hospital emergency department (ED). The purpose of this study was to assess the use of metered-dose inhalers and PFM. Regarding PFM, the investigators aimed to determine if patients used proper technique as well as PEF score interpretation by caregivers. In addition, prescribing patterns by primary care clinicians and home utilization prior to the ED visit were assessed. Pediatric patients aged 5 years or older with moderate to severe persistent asthma were given a PFM in the ED and asked to demonstrate its use ‘‘exactly as you would use it at home’’ [2]. Parents could help their children if necessary. Each step for correct use was recorded by the investigators. A PFM had been prescribed in 125 (62.8%) of eligible patients prior to admission to the ED. Among these patients/parents, only 27.2% had checked their PEF before coming to the ED. In patients who reported
2
T. H. Self et al.
Table 1. Steps for correct peak expiratory flow maneuver. 1. 2. 3. 4.
Move the indicator to the bottom of the numbered scale. Stand up. Take a deep breath, filling your lungs completely. Place the mouthpiece in your mouth and close your lips around it. Do not put your tongue inside the hole 5. Blow out as hard and fast as you can in a single blow. Write down the number you get. But if you cough or make a mistake, do not write down the number. Do it over again. Repeat steps 1 through 5 two more times, and write down the best of the three blows in your asthma diary.
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Expert Panel Report 3, 2007 [1].
regular determination of the PEF at home, 28.9% did not know that PEF should be performed while standing and 35.4% were unaware that three attempts should be made. Lack of knowledge to record the highest of three values was seen in 39.5% of patients, and 35.5% did not understand that depending on the PEF value, more medication may be needed. Among 111 patients who had a PFM at home and agreed to demonstrate its use in the ED, the mean age was 11 years (SD 3.2 years), 58% male and 95% African American. Performance of each step correctly for the PEF maneuver was observed in 73.9% of children. For the 26.1% of children who did not perform perfectly, errors were recorded for the following steps: move the indicator to zero (18%), inhale completely (5%), tight seal (4%) and breathe out hard and fast (3%). The authors presented these data in a Figure, but the exact percentages for each error were hard to determine. Gorelick et al. [3] assessed the ability of children with asthma to adequately perform the PEF maneuver in an urban pediatric ED. Correct performance was globally assessed by registered respiratory therapists. Individual steps for the PEF maneuver were not evaluated. Among 291 patients, ages 6–18 years, PEF was attempted at least once. Adequate performance was observed in only 65% of patients, and at the start of therapy, 54% were able to correctly perform the maneuver [3]. For the 120 patients who could not correctly use the PFM initially, 76 children tried again at the conclusion of ED treatment yet 55 (72%) of them still were not able to perform adequately. Patients who were older (mean age 11.2 years) were able to perform the PEF maneuver correctly more often than younger patients (mean age 8.7 years). In addition, pediatric patients who required hospital admission were less likely to adequately perform PEF than those discharged home from the ED (p50.0001). Sleath et al. [4] evaluated the skill of children in using metered-dose inhalers, dry powder inhalers and PFM. Patients, ages 8–16, with persistent asthma were studied in five pediatric practices in non-urban areas of North Carolina. To ensure optimal assessment of patient skill in using the asthma devices, five research assistants received training, including a video with examples of correct technique and scoring sheets. Three children were recorded using the devices with various mistakes. The research assistants then viewed the videos and scored the patients, followed by a critique by a study investigator. Research assistants practiced until their scoring agreed with the scoring of the investigator. All children were asked if they used a PFM at home. If they responded that they did, then they were asked
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to demonstrate how they used the device. Only 23% of children/parents reported using a PFM at home. In scoring PEF technique of the 67 patients, the investigators used the following eight possible correct steps [percent correct shown for each step]: (1) set marker to 0 [68.2%], (2) hold meter upright [90.9%], (3) do not block marker movement [86.6%], (4) deep breath in with mouth open [84.6], (5) place meter in mouth and close lips tightly around meter [92.5%], (6) exhale hard and fast into meter [87.9%], (7) Check the result [83.6%] and (8) repeat steps 1–7 two more times [59.9%]. All steps were performed correctly by only 23.9% of children. Caucasian children were less likely to score correctly in using the PFM than non-white patients (p ¼ 0.018). Table 2 summarizes pediatric studies of incorrect use of PFM. In summary regarding pediatric studies, two studies were conducted in urban pediatric EDs and one investigation was done in rural pediatric practices. While many children performed well, the overall results were disappointing in terms of skill in using PFM. For the two studies that gave results for each step, Table 3 summarizes the results. Adult studies Strayhorn et al. [5] conducted a study of correct versus incorrect use of 5 PFM in 20 patients with clinically stable asthma. Incorrect use was specified as accelerating air in the mouth with the tongue (a ‘‘spitting maneuver’’). This investigation was triggered by a case report of a patient who used this incorrect maneuver and had 430% elevated PEF values [6]. Strayhorn et al. [5] demonstrated the correct technique for using the PFM to each study subject, and then demonstrated the ‘‘spitting maneuver’’ (mouthpiece not placed well into the mouth so that tongue and buccal musculature could be used to accelerate air). Fifteen minutes after administration of albuterol (MDI, 2 puffs via a valved holding chamber [AeroChamber]), patients performed the PEF maneuver correctly and incorrectly with 5 PFM. The order of PFM usage was random as the order of correct versus incorrect technique, and the best of three attempts for each device was used in the data analysis. Results were analyzed using percent change from personal best values. Each of the PFM tested had significant increases in percent increase in PEF with mean values as follows: Assess 68.2% ± 33.7 (p ¼ 0.0001), MiniWright 12.4% ± 9.3 (p ¼ 0.0161), Pocket Peak 23.8% ± 13.8 (p ¼ 0.0001), Personal Best 43.4% ± 24.4 (p ¼ 0.0001) and TruZone 42.6% ± 38.7 (p ¼ 0.0001). These dramatic increases in PEF using an incorrect maneuver obviously would create poor decision making in monitoring asthma control and use of written action plans. Nolan et al. [7] compared PEF values associated with correct use of 5 PFM to PEF observed with two incorrect techniques: positioning the PFM at a 20 angle to the left in the mouth and a 20 angle pointed downward (as the patient leaned forward). Study subjects were taught the correct and incorrect techniques demonstrated by the investigators, and before performing the maneuvers, subjects received albuterol (MDI, 2 puffs via a valved holding chamber [AeroChamber]). Clinically stable adults (n ¼ 16) with persistent asthma performed each maneuver with each of 5 PFM in random
Incorrect use of peak flow meters
3
Table 3. Pediatric studies-specific steps with correct use of PFM.
Specific step Set marker to 0 Hold PFM correctly Do not block marker movement Deep breath Tight seal Exhale hard and fast
23.9%
Performing technique only once rather than three times to obtain best of three (40.1%), not setting marker to zero (31.8%), not checking the result (16.4%), not taking a deep breath in with mouth open (15.4%) and blocking marker movement (13.4%).
a
ED, emergency department; PFM, peak flow meters.
67 8–16 Sleath et al. [4]
Five non-urban pediatric practices.
Urban pediatric emergency department 6 Gorelick et al. [3]
291
54% initially; 65% after conclusion of ED therapy
Specific errors not noted in study.
62.8% (111 patients) had been prescribed PFM prior to ED presentation and agreed to demonstration. Only 27.2% had used PFM prior to ED presentation. For those children initially unable to perform, upon repeat of PFM at conclusion of ED therapy, 55 (72%) were still unable to perform. Only 23% (67 patients) reported use of PFM at home and subsequently demonstrated PFM technique in study. Not moving indicator to zero, not inhaling completely, not achieving tight seal around mouthpiece and not breathing out hard and fast 73.9% 111 Urban pediatric hospital emergency department 5
Study setting Study
Scarfone et al. [2]
Common errors observed Percentage correctly performing all steps of PFM Number of patients who demonstrated PFM Patient age (years)
Table 2. Pediatric studies evaluating incorrect use of peak flow meters.
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Comments
DOI: 10.3109/02770903.2014.914218
Scarfone et al. [2] (%)
Sleath et al. [4] (%)
82a 100 100 95a 96a 97a
68.2 90.9 86.6 84.6 92.5 87.9
Scarfone et al.2 (refer text regarding these percentages).
order, and the best of three attempts for each device was used in the data analysis. Mean results generally indicated no clinically relevant effect of incorrectly positioning of the PFM. However, for both incorrect techniques, some patients had inaccurate PEF values with each of the PFM. Chafin et al. [8] assessed the PEF maneuver in healthy adults, comparing men versus women. After a lecture regarding asthma, including demonstrations of correct use of a PFM, 83 health science center students (52 F, 31 M) were immediately divided into five small groups and scored in oneon-one sessions on their use of the PFM (three attempts). Men had superior performance for the first attempt, including total score (p50.05) and for the step ‘‘fully inhale’’ (p50.05). With the second attempt, men scored higher than women for the step ‘‘exhale as fast and as hard as you can’’ (p50.05). The results suggest that women generally need more coaching initially regarding maximum effort in the PEF maneuver. Self et al. [9] conducted a follow-up study in another group of healthy adult students (n ¼ 116) at the same institution, and assessed gender difference for PEF values as well as scores for correct use (the first study evaluated only scores for technique). Immediately following a lecture regarding correct use of asthma devices, including demonstration of correct PEF maneuver, students were then divided into small groups and scored on use of a PFM (three attempts) in individual sessions. Students were unaware that the study was evaluating gender differences. For the first attempt, men (n ¼ 40) scored higher than women (n ¼ 76) for the steps of ‘‘inhale fully’’ and ‘‘exhale as hard and as fast as you can’’ (p ¼ 0.03). PEF percentage increases improved in women but not in men from the second attempt to the third attempt (p ¼ 0.036). On the third attempt, 13.2% of women versus 2.6% of men had a PEF increase of 450%, but this finding did not reach significance. The conclusion of this study was that men learned the correct PEF technique and reached their best PEF quicker than women. Finch et al. [10] evaluated adult patients with asthma for potential gender differences in performing the PEF maneuver. Clinically stable patients (n ¼ 32) with persistent asthma were assessed for their technique during routine clinic visits. After three attempts, if any errors were found, patients were coached and then repeated three more attempts. Patients were not told that this was a ‘‘gender difference’’ study. Men (n ¼ 10) performed better than women (n ¼ 22) for ‘‘exhale as hard and as fast as you can’’ (p50.05). Although total correct scores for six steps were greater for men (4.2) versus women (3.8), the difference was not significant. PEF increased 410%
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after coaching in 57.9% of women versus 33.3% of men suggesting men learn the PEF maneuver quicker than women as in the previous studies in healthy subjects [8,9]. Wallace et al. [11] conducted a study in health science center students (n ¼ 94) to determine if performing the PEF maneuver in two different positions in bed resulted in the same PEF value performed when subjects were standing. The impetus for this investigation was an observation of respiratory therapists recording PEF values taken from patients in bed hospitalized for asthma exacerbations. Study participants (39 M, 55 F) were healthy, and were randomized to using a PFM in the following positions with three attempts in each position: (a) standing, (b) in bed lying back on pillows at a 45 angle and (c) in bed sitting, slumped forward 10 with legs extended. Mean PEF values in men were as follows: (a) Standing: 669 L/min, (b) lying back in bed: 621 L/min (p50.001) and (c) sitting slumped forward in bed 615 L/min (p50.001). In women, mean PEF values included the following: (a) Standing: 462 L/min, (b) lying back in bed: 422 L/min (p50.001) and (c) sitting slumped forward in bed 447 L/min (p50.05). Since national guidelines [1] recommend monitoring PEF in hospitalized patients with asthma, this study is a reminder to clinicians to ensure that patients are asked to stand to perform the PEF maneuver. Alternatively, for patients who do not feel like standing, a recent healthy subject study found that performing the PEF maneuver sitting in a chair with the back straight is acceptable [12]. Table 4 summarizes adult studies. In summary, regarding adult studies, three studies assessed the magnitude of effect of varying errors, such as a ‘‘spitting’’ maneuver and incorrect posture. Three other investigations focused on gender differences. In each of these studies, women did not perform as well as men in the step ‘‘Exhale as hard and as fast as you can – Blast!’’. In two of the studies, women also did not perform as well as men for the step ‘‘Inhale fully’’. For other steps in using PFM, there were no differences. These results are summarized in Table 4. Study with manipulation of peak flow meter indicator Ross and Cochran [13] reported a 13-year-old boy who found that if he retarded the movement of the Mini-Wright PFM indicator, he could falsely increase the results. Specifically, he would use his index finger to retard the indicator at the beginning of the PEF maneuver for a fraction of a second after initiating exhalation. The observation was the impetus for a study of 15 adults (one with asthma) in which subjects were observed using five correct attempts and five attempts with manipulation of the Mini-Wright PFM indicator. These attempts were made after practice of the two maneuvers. In 14 of the 15 subjects, increases were found in PEF using the incorrect technique [13]. Mean increase in PEF for the highest value was 56%, and the range was 4–86%. Using the mean PEF for the five attempts, the increase was 28% (range 2 to 66%). To avoid this manipulation of the PFM, Ross and Cochran [13] suggest that patients should be asked to ‘‘cradle’’ the PFM with a hand underneath the device. We note that regarding purposefully manipulating the device
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to achieve false PEF values, other authors have reported adults and children will lie to their clinicians about their PEF values [14,15].
Discussion Asthma significantly impacts the lives of children and adolescents in the United States. According to the Centers for Disease Control and Prevention, 7 million children in the US had asthma in 2010 [16]. In 2009, nearly 1 in 5 children with asthma required an emergency department visit and almost 1 of every 2 children with asthma miss at least 1 day of school every year [16]. While the evidence supporting long-term PFM use in children is conflicting, national guidelines recommend PFM be considered as part of written asthma action plans for patients with moderate or severe persistent asthma, a history of severe exacerbations or patients who poorly perceive symptoms of worsening asthma [1]. The pediatric literature reviewed herein [2–4] shows that children (especially younger children) and adolescents in urban and non-urban settings frequently make mistakes when using PFM. Given the number of children with asthma who may be using PFM to monitor disease control, incorrect PFM use has the potential to significantly decrease the health and quality of life of these patients. Consequently, national guidelines recommended that clinicians teach and reinforce skills for self-management including self-monitoring (either using PFM or symptom monitoring) at every opportunity [1]. Asthma also significantly impacts the lives of adults in the United States. In 2010, 18.7 million (1 in every 12) adults had asthma [16]. Asthma led to 14.2 million missed days of work in 2008 and yearly causes 3 in 5 patients with asthma to limit their daily activities [16]. Written asthma action plans (which may include PFM) are recommended for adults with asthma by national guidelines as stated previously [1]. The studies in adults reviewed herein show that women may need more instruction on correct PFM use than men and that incorrect PFM technique (e.g. lying down versus standing) leads to significantly different PFM measurements, which could impact asthma management [5–12]. Since accurate PFM is dependent upon effort and technique, it is imperative that clinicians frequently assess patients’ PFM technique. Expert Panel Report 3 [1] encourages asthma education, including instruction in use of inhalation devices and PFM, be conducted in clinics, EDs, hospitals, schools and pharmacies. Several reports describe the role of community pharmacists in teaching patients about asthma, including several devices [17–20]. Nurses, nurse practitioners and respiratory therapists all obviously have important roles in asthma patient education, including teaching patients the correct maneuver for PEF [1,21,22]. While more study is needed, Expert Panel Report 3 [1] also encourages community-based and home-based asthma education as well as computer-based education. As part of community-based education, we have encouraged volunteer asthma education by health science center students [23]. In a recent review, Chang [24] urges comprehensive asthma education, including appropriate use of PFM. We note that the disparity of methods used in the studies cited in this brief review article. For example, two pediatric
20 patients with clinically stable asthma
16 patients with clinically stable asthma.
83 healthy adult students
116 healthy adult students
32 patients with clinically stable asthma seen for routine clinic visit
Nolan et al. [7]
Chafin et al. [8]
Self et al. [9]
Finch et al. [10]
Patients
Strayhorn et al. [5]
Study
Same as previous study
Same as previous study
University Health Science Center
University Internal Medicine Clinic
At clinic visits, patients’ PFM technique and PEF values were evaluated. Patients received further coaching and repeated technique if errors were found.
Same as previous study
Participants, who were blinded to purpose of assessing gender differences, were observed in one-on-one sessions to evaluate participants’ PFM technique and measurements following a lecture on the correct PEF maneuver.
Incorrect use of peak flow meters (continued )
Study further emphasized the need to provide coaching with use of the PFM with women.
Males learned the correct PEF technique and subsequently reached a maximum PEF sooner than women.
Results emphasize need for coaching women to ensure maximum effort with PFM.
Assess effect of using two incorrect techniques: (1) positioning PFM at a 20 angle to the left in the mouth and (2) a 20 angle pointed downward (as patient leaned forward). Assess effect of gender difference on PEF values and scores for correct use.
University Health Science Center
University Health Science Center
Significant effects on PEF values were seen by patients utilizing the ‘‘spitting maneuver’’.
Increase in PEF values using incorrect technique: Assess 68.2% ± 33.7 (p ¼ 0.0001), MiniWright 12.4% ± 9.3 (p ¼ 0.0161), Pocket Peak 23.8% ± 13.8 (p ¼ 0.0001), Personal Best 43.4% ± 24.4 (p ¼ 0.0001), and TruZone 42.6% ± 38.7 (p ¼ 0.0001). Mean PEF values revealed no clinically relevant effect of positioning PFM; however, inaccurate PEFs were recorded for several subjects with both incorrect methods and all PFMs. Males demonstrated superior performance for first attempt overall (p50.05) as well as the step to ‘‘inhale fully’’ (65% F versus 90% M, p50.05) and second attempt for ‘‘exhale as fast and as hard as you can’’ (87% F versus 100% M, p50.05). Men achieved higher scores for steps of ‘‘inhale fully’’ (42% F versus 65%M, p ¼ 0.03) and ‘‘exhale as hard and fast as you can’’ (51%F versus 73%M, p ¼ 0.03). An increase in PEF of 450% from the second to third attempt was seen in 13.2% of women versus only 2.6% of men. On step of ‘‘exhale as hard and fast as you can’’, men performed superiorly (40.9%F versus 70%M, p50.05). Overall scores were higher for men, but statistical significance was not achieved. Women responded greater to coaching with a PEF increase of 410% in 57.9% Differences in PEF values compared between correct and incorrect technique (‘‘spitting maneuver’’) performed by patients on 5 PFM following albuterol administration and training.
Evaluate effect of using incorrect technique of ‘‘spitting maneuver’’ (when mouthpiece is not placed well into mouth so that tongue and buccal musculature are used to accelerate air).
University Pulmonary Medicine Clinic
Same design as previous study
Conclusions/Comments
Results
Design
Purpose of study
Study setting
Table 4. Adult studies assessing incorrect use of PFM.
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DOI: 10.3109/02770903.2014.914218
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T. H. Self et al.
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of women versus 33.3% men. Mean PEF values in men were as follows in the three positions: (a) 669 L/min, (b) 621 L/min (p50.001) and (c) 615 L/min (p50.001). In women, mean PEF values included the following: (a) 462 L/min, (b) 422 L/min (p50.001) and (c) 447 L/min (p50.05). Participants performed PFM for three attempts in each of the three positions in randomized order: (a) standing, (b) in bed lying back on pillows at a 45 angle and (c) in bed sitting, slumped forward 10 with legs extended.
Authors highlight the need to remind clinicians to ask patients to optimally stand to obtain optimal PEF values.
studies were conducted in urban, academic EDs and one was conducted in rural pediatric practices. We believe the various methods in different clinical arenas add strength to the evidence that incorrect use is common in different settings. Likewise with adults, the evidence indicates incorrect use of PFM in a variety of ways, such as accelerating air in the mouth with the tongue, lying back in bed or not giving maximum effort. Despite the varying methods of the available studies, errors with PFM use are frequent and, clinicians need to be vigilant in teaching patients correct use of PFM and ensuring correct use by observation of their technique. Obviously, health care professionals who educate patients with asthma need to be highly skilled in use of PFM and inhalation devices and have adequate time to perform asthma teaching. Although we hope a greater percentage of patients are skilled at using PFM, at this point in time, we are unaware of evidence to substantiate such skill. We hope that our review article, focusing on evidence showing that many patients do not have skill in using PFM, will help more healthcare professionals ensure appropriate use of these devices.
Declaration of interest Dr Finch has one potential conflict of interest to report – he is a speaker for GSK. The other authors have no conflicts of interest to report. The authors alone are responsible for the content and writing of this article.
References
PEF, peak expiratory flow; PFM, peak flow meters.
Wallace [11]
et
al.
94 healthy adult students
University Health Science Center
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Results Design Purpose of study Study setting Patients Study
Table 4. Continued
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Conclusions/Comments
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