Peak Expiratory Flow Assessment Research Articles

Aerosol Generation During Peak Flow Testing: Clinical Implications for COVID-19.

Peak flow testing is a common procedure performed in ambulatory care. There are currently no data regarding aerosol generation during this procedure. Given the ongoing debate regarding the potential for aerosol transmission of SARS-CoV-2, we aimed to quantify and characterize aerosol generation during peak flow testing. Five healthy volunteers performed peak flow maneuvers in a particle-free laboratory space. Two devices continuously sampled the ambient air during the procedure. One device can detect ultrafine particles 0.02-1 μm in diameter, while the second device can detect particles 0.3, 0.5, 1.0, 2.0, 5.0, and 10 μm in diameter. Five different peak flow meters were compared to ambient baseline during masked and unmasked tidal breathing. Ultrafine particles (0.02-1 μm) were generated during peak flow measurement. There was no significant difference in ultrafine particle mean concentration between peak flow meters (P = .23): Respironics (1.25 ± 0.47 particles/mL), Philips (3.06 ± 1.22), Clement Clarke (3.55 ± 1.22 particles/mL), Respironics Low Range (3.50 ± 1.52 particles/mL), and Monaghan (3.78 ± 1.31 particles/mL). Ultrafine particle mean concentration with peak flow testing was significantly higher than masked (0.22 ± 0.29 particles/mL) and unmasked tidal breathing (0.15 ± 0.18 particles/mL, P = .01), but the ultrafine particle concentrations were small compared to ambient particle concentrations in a pulmonary function testing room (89.9 ± 8.95 particles/mL). In this study, aerosol generation was present during peak flow testing, but concentrations were small compared to the background particle concentration in the ambient clinical environment. Surgical masks and eye protection are likely sufficient infection control measures during peak expiratory flow testing in asymptomatic patients with well controlled respiratory symptoms, but COVID-19 testing remains prudent in patients with acute respiratory symptoms prior to evaluation and peak expiratory flow assessment while the community prevalence of SARS-CoV-2 cases remains high.

Peak Expiratory Flow Assessment in Smokers Liabilities

Introduction: The world health organization (WHO) recognizes smoking as a chronic and epidemic disease encouraged through personal experiences and/or public advertisements, and is considered to be the single largest preventable cause of illness and early death worldwide. The inhalation of smoke resulting from the burning of derivatives of all types of tobacco, by non-smoker, constitutes the so-called secondhand tobacco smoke. It is the third avoidable cause of death in the world, after active smoking and alcoholism. Purpose: To evaluate Peak Expiratory Flow (PEF) in smokers liabilities. Methods: The sample consisted of 40 participants who were divided into two groups: 20 smokers liabilities (exposed group) and 20 participants not exposed to environmental tobacco smoke (ETS - control group). The Peak Flow Meter Medicate® was used to measure expiratory flow. Student’s t-test was used to compare the variables obtained. Data were analyzed using BioEstat® 5.3 software. Results: No statistical differences were observed in the comparison of PEF values between the group exposed and not exposed to ETS (p=0.82). There was no difference among those practicing and not practicing physical activity in the group exposed to ETS (p=0.29) and in the PEF values between the group exposed to ETS with age above and below 25 years (p=0.73). Conclusion: there were no significant changes in the PEF in the passive of smokers. Passively smoking does not seem to alter lung function.

Provider adherence to a clinical practice guideline for acute asthma in a pediatric emergency department.

Critics of the use of clinical practice guidelines (CPGs) in an emergency department (ED) setting believe that they are too cumbersome and time-consuming, but to the best of the authors' knowledge, potential barriers to CPG adherence in the ED have not been prospectively evaluated. To measure provider adherence to an ED CPG based on National Asthma Education and Prevention Program (NAEPP) recommendations, and to determine factors associated with provider nonadherence. Prospective, cohort study of children aged 1-18 years with the diagnosis of an acute exacerbation of asthma who were seen in a pediatric ED and requiring admission, as well as a random selection of children discharged to home following pediatric ED care. The following adherence parameters were assessed: at least three nebulized albuterol treatments in the first hour; early steroid administration (after the first nebulizer treatment); clinical assessments using pulse oximetry and peak expiratory flow (PEF) (for children >6 years old); and use of a clinical score to assess acute illness severity (Asthma Severity Score). Nonadherence was defined as any deviation of the above parameters. Between July 1, 1998, and June 30, 1999, 369 patients were studied. Of these, 38% (139) were discharged to home, 38% (140) were admitted to the observation unit, and 24% (90) were admitted to the inpatient unit. Illness severities at initial presentation to the ED were: 24% (86) had mild exacerbations, 59% (212) had moderate exacerbations, and 17% (62) had severe exacerbations. Sixty-eight percent (95% CI = 63% to 73%) of the patients were managed with complete adherence to the CPG. Of the 32% with some form of nonadherence, most (63%) were children older than 6 years; in this group 64% (48/75) were nonadherent due to lack of PEF assessment. When PEF assessment was disregarded, an 83% (95% CI = 79% to 87%) adherence to the CPG was achieved. Other nonadherence factors included: lack of at least three nebulized albuterol treatments provided timely within the first hour (5%); delay in steroid administration (6%); lack of pulse oximeter use (0.5%); and failure to record clinical score to assess severity (1.1%). Patient age, illness severity (acute and chronic), first episode of wheezing, and high ED volume periods (evenings and weekends) did not worsen adherence. Clinical practice guidelines can be used successfully in the pediatric ED and provide a more efficient management and treatment approach to acute exacerbations of childhood asthma. With a systematic and concise CPG, barriers to adherence in a pediatric ED appear to be minimal, with the exception of using PEF in the routine ED assessment.

Do subjects investigated for occupational asthma through serial peak expiratory flow measurements falsify their results?

Background and aim: Serial assessment of peak expiratory flow (PEF) rates has been advocated as a sensitive and specific means of investigating occupational asthma. The possibility that, for several reasons, subjects do not accurately report their values has been raised. The availability of portable instruments that assess PEF and store timings and values now makes it possible to estimate compliance and accuracy of results. Methods: Twenty-one subjects consecutively investigated for occupational asthma were asked to assess their PEF every 2 hours during the day, both at work and away from work, with a VMX instrument (Clement Clarke International, Columbus, Ohio) and record the times and values on a sheet of paper. The subjects were not aware that the data were also being stored on a computer chip. The diagnosis was occupational asthma in eight subjects, personal asthma in four subjects, and neither condition in nine subjects. Results: The mean duration of recording was 36 days (range, 14 to 79 days). At least 6048 values should have been recorded, but only 4839 (80%) were either recorded or stored. Reported values corresponded precisely to stored values in 2533 of 4839 recordings (52%). The timing of the recording was also examined in relation to the time at which the recording was solicited; values recorded within 1 hour of the solicited time were judged as acceptable. Of the total of 3342 recordings stored, 2375 (71%) satisfied this criterion. Compliance was significantly less satisfactory in those referred by the Workers' Compensation Board (n = 11). Conclusion: In this survey of 21 subjects investigated for possible occupational asthma, compliance with PEF recording, as assessed by comparing recorded and stored results and the time at which the recording was solicited, was poor.

Do subjects investigated for occupational asthma through serial peak expiratory flow measurements falsify their results?

Background and aim: Serial assessment of peak expiratory flow (PEF) rates has been advocated as a sensitive and specific means of investigating occupational asthma. The possibility that, for several reasons, subjects do not accurately report their values has been raised. The availability of portable instruments that assess PEF and store timings and values now makes it possible to estimate compliance and accuracy of results. Methods: Twenty-one subjects consecutively investigated for occupational asthma were asked to assess their PEF every 2 hours during the day, both at work and away from work, with a VMX instrument (Clement Clarke International, Columbus, Ohio) and record the times and values on a sheet of paper. The subjects were not aware that the data were also being stored on a computer chip. The diagnosis was occupational asthma in eight subjects, personal asthma in four subjects, and neither condition in nine subjects. Results: The mean duration of recording was 36 days (range, 14 to 79 days). At least 6048 values should have been recorded, but only 4839 (80%) were either recorded or stored. Reported values corresponded precisely to stored values in 2533 of 4839 recordings (52%). The timing of the recording was also examined in relation to the time at which the recording was solicited; values recorded within 1 hour of the solicited time were judged as acceptable. Of the total of 3342 recordings stored, 2375 (71%) satisfied this criterion. Compliance was significantly less satisfactory in those referred by the Workers' Compensation Board ( n = 11). Conclusion: In this survey of 21 subjects investigated for possible occupational asthma, compliance with PEF recording, as assessed by comparing recorded and stored results and the time at which the recording was solicited, was poor. (J A LLERGY C LIN I MMUNOL 1995;96:601-7.)

An Assessment of PeaK Expiratory Flow as a Surrogate Measurement of FEV1 in Stable Asthmatic Children

We examined the relationship over 24 hours between percent-predicted values (PPV) of peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1) in a group of 23 stable untreated asthmatic children 6 to 17 years of age by means of regression analysis as well as the percentage difference between the PPV of these two measurements. Although the Pearson correlation coefficient between the PPV was consistently high, ranging between 0.854 and 0.892, the assumption that such a finding substantiates the substitution of PEF for FEV1 is called into question. Over 50 percent of the subjects displayed a 10 percent or greater difference in the PPV between the two measurements, regardless of the time of day the two respiratory variable were determined, while over one-third of all subjects evidenced a 20 percent or greater discrepancy between the PPV of the two measures. While, on a group basis, there was no statistically significant difference in the mean percentage difference over 24 hours between the PPV of FEV1, when compared with the corresponding measurement of PEF, reliance on PEF alone in individual subjects may result in a false impression of the patency of the airways in comparison to the FEV1.

A self management plan in the treatment of adult asthma.

To determine whether routine assessment of peak expiratory flow (PEF) in association with a self management plan based on inhaled corticosteroid use is effective in the management of chronic asthma, 36 consecutive adult patients with asthma attending an outpatient chest clinic were admitted to an open prospective study. Patients were treated with inhaled salbutamol and beclomethasone dipropionate in an attempt to achieve normal lung function. Each patient had a "potential normal value," which was either the predicted normal or the maximum PEF value achieved by the patient, whichever was the higher. Patients measured PEF at home and if it fell by more than 30% from the potential normal value the dose of beclomethasone was doubled until PEF returned to the potential normal value, then continued at 20 mg/day for the same number of days. If PEF fell to below 150-200 l/min patients were asked to obtain emergency medical assistance. In the 30 patients who completed the trial the six months before and the six months after intervention with the self management plan were compared. There was a substantial improvement in both subjective and objective measurements of asthma severity, with a significant reduction in nights woken, days lost from work, and requirement for oral corticosteroids and a significant increase in baseline lung function. Routine measurement of PEF in association with a self management plan appears to be effective in reducing symptoms of asthma and improving lung function.