The use of exhaled nitric oxide measurements (FEno) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, FEno is a good surrogate marker for eosinophilic airway inflammation. High FEno levels may be used to distinguish eosinophilic from non-eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non-specific respiratory symptoms. Secondly, eosinophilic airway inflammation is steroid responsive. There are now sufficient data to justify the claim that FEno measurements may be used successfully to identify and monitor steroid response as well as steroid requirements in the diagnosis and management of airways disease. FEno measurements are also helpful in identifying patients who do/do not require ongoing treatment with inhaled steroids. Thirdly, portable nitric oxide analysers are now available, making routine testing a practical possibility. However, a number of issues still need to be resolved, including the diagnostic role of FEno in preschool children and the use of reference values versus individual FEno profiles in managing patients with difficult or severe asthma.

Source: http://thorax.bmj.com/content/61/9/817.abstract

Background: Exhaled nitric oxide (FENO) measurements may help to highlight when inhaled corticosteroid (ICS) therapy should or should not be adjusted in asthma. This is often difficult to judge. Our aim was to evaluate a decision-support algorithm incorporating FENO measurements in a nurse-led asthma clinic.

Methods: Asthma management was guided by an algorithm based on high (>45ppb), intermediate (30-45ppb), or low (<30ppb) FENO levels and asthma control status. This provided for one of eight possible treatment options, including diagnosis review and ICS dose adjustment.

Study measurements at each visit: FENO was measured according to current guidelines19 using a NIOX MINO electrochemical analyser20-22 or a NIOX chemiluminescence analyser (both Aerocrine, Solna, Sweden). The latter was available at the Research Unit, 5km. from the Health Centre, but was used only when there was technical failure of the NIOX MINO. To validate FENO results, the sensors from the NIOX MINO device were tested against a calibrated standard, and where appropriate, a correction factor was applied to take account of signal drift. Spirometry was performed according to accepted standards using a Spiro USB spirometer (Micro Medical, Kent, England). The study received ethical approval from the Lower South Island Ethics Committee, and each participant gave written informed consent. Each GP participated in a start-up meeting, but thereafter further directions regarding the conduct of the study were not given.

Source: http://bx.businessweek.com/health-20/outcomes-using-exhaled-nitric-oxide-measurements-as-an-adjunct-to-primary-care-asthma-management/10191006889617114657-51e7208d9510751bc632218ad12db87f/

Asthma is a chronic illness characterized by symptoms such as shortness of breath, wheezing and cough, which vary in intensity over time. The primary pathogenic process driving the manifestations of asthma is airway inflammation which leads to two pathophysiological features of asthma: hyper-responsiveness or twitchiness of the airways in response to stimuli such as exercise or allergen exposure, and airway obstruction.5

Airway obstruction in asthma is due to three main factors:

1. Bronchoconstriction, where the smooth muscle surrounding the airways tightens in response to a trigger (e.g. exercise) and narrows the airway
2. Swelling of the airway wall due to inflammation
3. Mucus formation within the airways that obstructs the airflow

Narrower airways obstruct the normal flow of air, making it difficult to breathe and leading to typical signs and symptoms of asthma (like wheezing, coughing, chest tightness and shortness of breath). Worsening symptoms can result in an episode of “asthma attack,” or exacerbation.

Source: http://www.apieron.com/

I came to know about my asthma one year back. My asthma gets worse when I feel stressed. I start wheezing heavily and my breathing starts to get labored.I have been using peak flow meter for monitoring asthma. Recently I came across medical journals and articles which states that exhaled nitric oxide can be measured in a breath test for asthma or other conditions characterized by airway inflammation. Also we have certain devices like NIOX MINO to measure exhaled nitric oxide in asthmatic patients.

An excerpt from Primary Care Respiratory Journal (2009), states that FENO was measured according to current guidelines using a NIOX MINO electrochemical analyzer or a NIOX chemiluminescence analyzer (both Aerocrine, Solna, Sweden). The latter was available at the Research Unit, 5km. from the Health Centre, but was used only when there was technical failure of the NIOX MINO. It seems that the NIOX MINO Analyzer had frequent technical failures and significant sensor inaccuracy issues causing the researcher to apply a manual correction factor and/or rely on the expensive NIOX lab instrument as a backup.

Doesn’t these devices sounds cumbersome to use it? Any information about it.

Source: http://www.healthcentral.com/asthma/c/52325/97595/comments/

Ambient Nitric Oxide

Nitric oxide in air constitutes what is called ‘ambient NO’. Most of the inhaled ambient NO enters the pulmonary blood by diffusion and binds to hemoglobin. The residual NO becomes part of the exhaled breath that only appears in the initial wash-out phase of a typical 11-second exhaled breath. Ambient NO is a function of the location, time of day etc. and can vary between 0 ppb and upwards of 200 ppb.

Exhaled NO (eNO) Profile

The exhaled nitric oxide (eNO) measurement profile of the Insight eNO System is characterized by an initial rise followed by a plateau. The Insight System analyzes nitric oxide sampled when the profile has reached the plateau which occurs during the last 4 sec of the exhalation breath maneuver. Nitric oxide (NO) is washed out in the initial phase and therefore does not affect the eNO readings obtained from the Insight System.

Studies Confirm Theory

A study was conducted where 12 subjects each performed 5 eNO tests preceded by inhalation of NO free air alternating with 5 eNO tests preceded by inhalation of air containing a 200 ppb concentration of nitric oxide (NO). Testing based on these 120 measurements shows that the overall impact of high ambient NO on the results from
the Insight System is statistically insignificant (0.8 ppb). This result is consistent with a landmark publication2 confirming that the eNO results when sampled properly do not get affected by ambient NO.

Source: http://www.scribd.com/doc/23659899/Ambient-Nitric-Oxide

BACKGROUND: Exhaled nitric oxide (FENO) measurements may help to highlight when inhaled corticosteroid (ICS) therapy should or should not be adjusted in asthma. This is often difficult to judge. Our aim was to evaluate a decision-support algorithm incorporating FENO measurements in a nurse-led asthma clinic.

METHODS: Asthma management was guided by an algorithm based on high (>45ppb), intermediate (30-45ppb), or low (<30ppb) FENO levels and asthma control status. This provided for one of eight possible treatment options, including diagnosis review and ICS dose adjustment.

RESULTS: Well controlled asthma increased from 41% at visit 1 to 68% at visit 5 (p=0.001). The mean fluticasone dose decreased from 312 mcg/day at visit 2 to 211mcg/day at visit 5 (p=0.022). There was a high level of protocol deviations (25%), often related to concerns about reducing the ICS dose. The % fall in FENO associated with a change in asthma status from poor control to good control was 35%.

CONCLUSION: An FENO-based algorithm provided for a reduction in ICS doses without compromising asthma control. However, the results may have been influenced by the education and support which patients received. Reluctance to reduce ICS dose was an issue which may have influenced the overall results. Trial registration: Australian Clinical Trials Registry # 012605000354684

Source: http://www.thepcrj.org/journ/view_article.php?article_id=667

In the fourth part of the ongoing series, we discuss the findings from the reputed American Journal of Respiratory and Critical Care Medicine

An excerpt from American Journal of Respiratory and Critical Care Medicine in a study by Marie¨lle W. Pijnenburg, E. Marije Bakker, Wim C. Hop, and Johan C. De Jongste details the Titrating Steroids on Exhaled Nitric Oxide in Children with Asthma.

Rationale

Corticosteroids are the anti-inflammatory treatment of choice in asthma. Treatment guidelines are mainly symptom-driven but symptoms are not closely related to airway inflammation. The fraction of nitric oxide in exhaled air (FeNO) is a marker of airway inflammation in asthma.

Objective

We evaluated whether titrating steroids on FeNO improved asthma management in children.

Methods

Eighty-five children with atopic asthma, using inhaled steroids, were allocated to a FeNO group (n _ 39) in which treatment decisions were made on both FeNO and symptoms or to a symptom group (n _ 46) treated on symptoms only. Children were seen every 3 months over a 1-year period.

Measurements

Symptoms were scored during 2 weeks before visits and 4 weeks before the final visit. FeNO was measured at all visits, and airway hyper responsiveness and FEV1 were measured at the start and end of the study. Primary endpoint was cumulative steroid dose.

Results

Changes in steroid dose from baseline did not differ between groups. In the FeNO group, hyper responsiveness improved more than in the symptom group (2.5 vs. 1.1 doubling dose, p _0.04). FEV1 in the FeNO group improved, and the change in FEV1 was not significantly different between groups. The FeNO group had 8 severe exacerbations versus 18 in the symptom group. The change in symptom scores did not differ between groups. FeNO increased in the symptom group; the change in FeNO from baseline differed between groups (p _ 0.02).

Conclusion

In children with asthma, 1 year of steroid titration on FeNO did not result in higher steroid doses and did improve airway hyper responsiveness and inflammation.

The full text of this study can be downloaded from http://ajrccm.atsjournals.org/cgi/reprint/172/7/831

Source: http://www.articlesbase.com/medicine-articles/exhaled-nitric-oxide-and-its-role-in-the-treatment-of-asthma-part-iv-1476602.html

In a recent study, the feasibility of obtaining FENO measurements in primary care has been confirmed.13 Here, we evaluated the utility of using FENO levels in an unselected population of patients with a diagnosis of asthma in a primary care setting. The aims were two-fold: firstly, to assess whether an open FENO-based protocol – similar to, but less resourceintensive than those used in previous randomised controlled trials – could be applied in the primary care setting, and what the impact on asthma outcomes would be; and secondly, to evaluate the practical issues associated with using and interpreting FENO levels in a nurse-led asthma clinic.

FENO was measured according to current guidelines using a NIOX MINO electrochemical analyser or a NIOX chemiluminescence analyser (both Aerocrine, Solna, Sweden).The latter was available at the Research Unit, 5km. from the Health Centre, but was used only when there was technical failure of the NIOX MINO. To validate FENO results, the sensors from the NIOX MINO device were tested against a calibrated standard, and where appropriate, a correction factor was applied to take account of signal drift.

Source: http://exhalednitricoxide.blogspot.com/2009/12/outcomes-using-exhaled-nitric-oxide.html

In a recent study, the feasibility of obtaining FENO measurements in primary care has been confirmed.Here, we evaluated the utility of using FENO levels in an unselected population of patients with a diagnosis of asthma in a primary care setting. The aims were two-fold: firstly, to assess whether an open FENO-based protocol – similar to, but less resourceintensive than those used in previous randomised controlled trials – could be applied in the primary care setting, and what the impact on asthma outcomes would be; and secondly, to evaluate the practical issues associated with using and interpreting FENO levels in a nurse-led asthma clinic.

FENO was measured according to current guidelines using a NIOX MINO electrochemical analyser or a NIOX chemiluminescence analyser (both Aerocrine, Solna, Sweden).The latter was available at the Research Unit, 5km. from the Health Centre, but was used only when there was technical failure of the NIOX MINO. To validate FENO results, the sensors from the NIOX MINO device were tested against a calibrated standard, and where appropriate, a correction factor was applied to take account of signal drift.

Source:http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=32743

The Insight eNO System measures exhaled nitric oxide (eNO), also known as FeNO, which is a well established indicator of airway inflammation in asthma. The Insight system is a highly accurate device, expressly designed for the physician’s office. It is non-invasive, safe, easy to use, and provides eNO results in less than a minute for better asthma management and care. Apieron’s medical solution is a unique biosensor that, helps in asthma care by detecting trace amounts of nitric oxide molecules in a single human breath utilizing a proprietary technology.

Source: http://www.apieron.com/