Reliability of a new hand-held device for the measurement of exhaled nitric oxide.

BACKGROUND: Given the importance of airway inflammation in asthma, there has been an effort to incorporate inflammatory markers into its management. Measurement of fractional exhaled nitric oxide (FeNO) is a noninvasive marker of airway inflammation; however, the use of the available FeNO analyzer is limited by several factors including its cost and lack of transportability. The aim of this study was to compare the performance of a new hand-held FeNO measuring device (NIOX MINO) to the current clinical standard - the chemiluminescence FeNO analyzer (NIOX). METHODS: Subjects 6 years and older presenting to an allergy and asthma clinic underwent FeNO evaluation by NIOX and each of three NIOX MINOs. The mean of two acceptable measurements from the NIOX and the first approved measurement from each NIOX MINO were used for analysis. RESULTS: One hundred ten patients aged 6-86 years completed the study. Intrasubject FeNO levels obtained by each of the three NIOX MINOs revealed no significant difference between the measurements (P = 0.59). There was a very strong correlation between FeNO measurements by NIOX and by NIOX MINO (r = 0.98, P < 0.0001). The mean intrasubject FeNO difference between NIOX and NIOX MINO was -0.5 p.p.b. which was not statistically significantly different from zero (P = 0.21). CONCLUSIONS: Fractional exhaled nitric oxide measurements by the NIOX MINO showed a strong correlation and a high degree of agreement with the current standard stationary device. The NIOX MINO may be reliably used in clinical practice.

Using statistical process control charts for the continual improvement of asthma care.

BACKGROUND: Home monitoring of lung function using simple, inexpensive tools to measure peak expiratory flow rate (PEFR) has been possible since the 1970s. Yet although current national and international guidelines recommend monitoring of PEFRs via traditional run charts, their use by both patients and physicians remains low. The role of statistical process control (SPC) theory and charts in the serial monitoring of lung function at home were explored and applied to the direct care of patients with asthma. The method represents an integration of collective professional and improvement knowledge with the related disciplines of continual improvement, SPC, system thinking/system dynamics, paradigms, and the learning community/organization. CASE STUDIES: Use of PEFR control charts for four patients cared for at the Asthma-Allergy Clinic and Research Center (Shreveport, La) is described. The key to good asthma control is the ability to optimize lung function by reducing the variation between serial lung function measurements and thereby generate a safe range of function. Knowledge of the type of variation (special cause or common cause) in the system helps in focusing clinical decision making. Case 4, an 11-year-old boy, for example, shows how control charts were used to learn the effects of a new inhaled corticosteroid. Comparison of the last 14 days of baseline and the last 14 days of open label use of the inhaled corticosteroid showed an obvious improvement in actual PEFR values--which a run chart or comparison of means would have easily demonstrated. The control chart showed that this child's care process at baseline was functionally at risk for severe asthma (46% personal best) and that the effect of the new medication not only elevated the mean function but shifted the range of function from 46%-72% personal best to 78%-102% personal best. At this new range of function the patient's system of care was not capable of delivering values that are at risk for severe asthma. Unless the range of function the change in care is capable of producing is specifically quantitated, misinterpretation of improvement data can occur. DISCUSSION: Developing the concept of the PEFR control chart involved examining and challenging traditional mental models for monitoring PEFR at home in the care of asthma, acquiring a better understanding of the workings of dynamic systems and with system thinking, and sharing what was learned with patients and seeking their input. CONCLUSIONS: The PEFR control chart employs an interesting statistical platform that enables the integration of knowledge of serial measurements and knowledge of the variation between those measurements into a tool with which to better assess the asthma care process being followed. This tool provides clinical insights, practical knowledge, and opportunities unavailable to patients and physicians via traditional PEFR charting.

Peak expiratory flow rate control chart in asthma care: chart construction and use in asthma care.

BACKGROUND: The home monitoring of peak expiratory flow rate (PEFR), although recommended in current asthma guidelines, remains seriously underutilized by both patients and physicians. Our assessment is that this is more a statement regarding the inability of current charting methods to fulfill the promises made for PEFR monitoring, rather than a commentary regarding the usefulness of peak expiratory flow rate monitoring per se. We have adapted the theory and charting tool of the discipline of statistical process control to the daily monitoring of PEFR in the care of patients with asthma. Statistical process control charts integrate the actual PEFR values and their day-to-day variation in a manner that permits more informed decision-making. This article introduces our adaptation of statistical process control theory and charts via three case presentations. OBJECTIVE: Report our experience in the use of statistical process control theory and charting to the monitoring of peak expiratory flow in the care of patients with asthma. METHODS: Discussion of methodology and case reports. CONCLUSION: This is the first report of the application of statistical process control (SPC) theory and charting to the home monitoring of peak expiratory flow rate and the clinical decision-making processes involved in the day-to-day care of patients with asthma. SPC charts integrate knowledge of actual serial PEFR measurements with knowledge of their associated serial variation. Our adaptation of this theory and its charting methodology results in a tool that loses nothing provided by the charting methods suggested in current guidelines and, at the same time, provides patient specific, statistically driven signals of significant change; facilitates identification of the reason(s) for the change in PEFR; predicts the range in which future function will occur; permits decision-making and care to be provided in an anticipatory manner; and, importantly, permits the early identification of the functionally at-risk patient. This report demonstrates that home monitoring of peak expiratory flow is a robust tool whose usefulness in the care of patients with asthma has been limited more by the paradigm in which we have required it be used than by any of the limitations of the measurement per se.

Ipratropium bromide nasal spray in non-allergic rhinitis: efficacy, nasal cytological response and patient evaluation on quality of life.

Intranasal fluorocarbon anticholinergic agents have been used to treat the nasal hypersecretion of perennial non-allergic rhinitis, but chronic use has been restricted either due to the potential for systemic anticholinergic adverse events or due to the irritating properties of the fluorocarbon metered dose formulations. This study evaluates a new aqueous nasal formulation of ipratropium bromide (Atrovent Nasal Spray 0.03%) in subjects with perennial non-allergic rhinitis in a double-blind, placebo-controlled trial. Two hundred and twenty-eight patients were randomized to receive two sprays per nostril of either ipratropium bromide (42 micrograms/nostril) or placebo-administered three times a day as an aqueous nasal spray over an 8-week interval. Patients were evaluated bi-weekly and maintained daily diaries for duration and severity of nasal symptoms. Ipratropium bromide reduced the mean severity and duration of rhinorrhoea within the first week and throughout the 8 weeks of active treatment compared with placebo (P < 0.05). Secondary endpoints of efficacy (patient and physician global assessments and a quality of life assessment) also supported the use of ipratropium bromide nasal spray for rhinitis symptom control. With the reduction in rhinorrhoea by the ipratropium bromide nasal spray, patients reported a marked improvement in daily moods vs placebo (P < 0.01). Both placebo and ipratropium bromide nasal spray induced a modest reduction of nasal congestion, sneezing and postnasal drip. This improvement in these other nasal symptoms was consistent with the known soothing effects of a nasal saline vehicle. There were no drug-related serious or systemic anticholinergic adverse events.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-blind, placebo-controlled study of terfenadine and hydroxyzine in patients with chronic idiopathic urticaria.

Results of a double-blind, randomized, placebo-controlled, parallel study in 37 patients indicate that terfenadine, 60 mg bid, is significantly more effective than placebo and as effective as hydroxyzine, 25 mg qid, in the treatment of chronic idiopathic urticaria without causing the somnolence that was associated with the use of hydroxyzine.

Use of respiratory care procedures in the management of hospitalized asthmatics.

The current management of the hospitalized asthmatic includes a number of respiratory therapy techniques, both diagnostic and therapeutic. These include measures to increase arterial oxygen content, monitoring of gas exchange, administration of bronchodilator aerosols, chest physiotherapy techniques, breathing exercises, and mechanical ventilation. While many of these are potentially helpful, some are misused or are not of proven benefit. This review is designed to acquaint the clinician with the procedures commonly used, their potential benefits, or lack thereof, and their possible hazards. Recommendations are given for the rational use of these techniques, based upon the experience of the authors.

Evaluation of lung sounds by telephone.

We evaluated the utility of a newly designed electronic stethoscope that can be used with the telephone system. Nine patients with wheezing, crackles, or other adventitious sounds were evaluated by a physician examiner who used a conventional stethoscope and another physician who received the signal of the electronic stethoscope via telephone. When their findings were compared, it was found that physicians agreed in 95% of observations. The potential uses of the electronic stethoscope are discussed.

Volume-adjusted maximal mid-expiratory flow (Iso-volume FEF25-75%): definition of "Significant" responsiveness in healthy, normal subjects.

Iso-volume FEF25-75% was evaluated in 30 non-smoking, healthy subjects (16-58 years) to define the percentage change over baseline required for responsiveness to inhaled bronchodilators using this measurement to be significant. The mean percentage change from baseline for Iso-volume FEF25-75% was 15.3% +/- 17.2% (1 SD). Improvement of greater than 49.6% (mean +/- 2 SD) over baseline is required for the change reflected by the Iso-volume FEF25-75% to be significant.

The clinical significance of volume-adjusted maximal mid-expiratory flow (Iso-volume FEF25-75%) in assessing airway responsiveness to inhaled bronchodilator in asthmatics.

The clinical significance of Iso-volume FEF25-75% in assessing airway responsiveness to an inhaled bronchodilator was evaluated in 167 asthmatics who presented with variable degrees of airway dysfunction. Iso-volume FEF25-75% identified responsiveness in one patient (5%) out of 20 of the most dysfunctional asthmatics, in three (20%) out of 15 of the least dysfunctional asthmatics and over-all in four (8%) out of 47 asthmatics not showing significant responsiveness via the FEV1. Over-all, FEV1 identified significant responsiveness in more patients (68.6%) than did the Iso-volume FEF25-75% (61%). The authors conclude that the Iso-volume FEF25-75% adds little to the FEV1 in the assessment of obviously dysfunctional asthmatics, the FEF25-75% as conventionally measured is a relatively useless post-bronchodilator measurement and that the FEV1 remains the single best spirometric test with which to assess airway responsiveness in asthmatics.