Silent and humming nasal NO measurements in adults aged 18-70 years

Nasal Nitric Oxide as a Biomarker in the Diagnosis and Treatment of Sinonasal Inflammatory Diseases: A Review of the Literature

OBJECTIVE

To critically review the literature on nasal nitric oxide (nNO) and its current clinical and research applicability in the diagnosis and treatment of different sinonasal inflammatory diseases, including acute bacterial rhinosinusitis (ABRS), allergic rhinitis (AR), and chronic rhinosinusitis (CRS).

METHODS

A search of the PubMed database was conducted to include articles on nNO and sinonasal diseases from January 2003 to January 2020. All article titles and abstracts were reviewed to assess their relevance to nNO and ABRS, AR, or CRS. After selection of the manuscripts, full-text reviews were performed to synthesize current understandings of nNO and its applications to the various sinonasal inflammatory diseases.

RESULTS

A total of 79 relevant studies from an initial 559 articles were identified using our focused search and review criteria. nNO has been consistently shown to be decreased in ABRS and CRS, especially in cases with nasal polyps. While AR is associated with elevations in nNO, nNO levels have also been found to be lower in AR cases with higher symptom severity. The obstruction of the paranasal sinuses is speculated to be an important variable in the relationship between nNO and the sinonasal diseases. Treatment of these diseases appears to affect nNO through the reduction of inflammatory disease burden and also mitigation of sinus obstruction.

CONCLUSION

nNO has been of increasing interest to researchers and clinicians over the last decade. The most compelling data for nNO as a clinical tool involve CRS. nNO can be used as a marker of ostiomeatal complex patency. Variations in measurement techniques and technology continue to impede standardized interpretation and implementation of nNO as a biomarker for sinonasal inflammatory diseases.

Correlation of Exhaled Nasal Nitric Oxide With Sinus Computed Tomography and Sinonasal Outcome Test Scores: A Cross-sectional Pilot Study

BACKGROUND

Computed tomography (CT) of the paranasal sinuses is the diagnostic reference standard for chronic rhinosinusitis and related inflammatory sinus pathology. Nasal nitric oxide (nNO) levels have been investigated as a diagnostic tool in sinus disease because it decreases with sinus obstruction.

OBJECTIVE

The primary aim of the study was to determine the correlation of passive (baseline) and dynamic (humming) nNO to CT findings of sinus inflammation and to sinonasal symptoms measured by the modified Sinonasal Outcome Test (26 items) (SNOT-26).

METHODS

From June 2015 through January 2016, subjects had baseline and humming nNO levels measured with a chemiluminescence NO analyzer, and each subject underwent CT imaging and completed the SNOT-26 survey. CT images were scored using the Lund-Mackay (LM) system (LM scores >3 indicated sinus inflammation). Correlation was measured by linear and ordinal regression analysis that compared SNOT-26 scores, LM scores, and nNO measurements.

RESULTS

Fourteen subjects were recruited. LM scores had a positive pairwise correlation with total SNOT-26 scores ( R² = .1457; correlation = .3817) and nasal-specific SNOT-26 scores ( R² = .4036; correlation = .6353). Baseline nasal nNO scores had a negative pairwise correlation with LM scores ( R² = .1580; correlation = -.3582), total SNOT-26 scores ( R² = .1515; correlation = -.3893), and nasal-specific SNOT-26 scores ( R² = .0805; correlation = -.4343). Although baseline nNO levels correlated with LM and SNOT-26 scores, humming nNO levels did not show a similar correlation.

CONCLUSION

Baseline passive nNO may be a useful and inexpensive point-of-care screening test for sinonasal opacification.

Nasal Nitric Oxide in Healthy Adults – Reference Values and Affecting Factors

Nitric oxide (NO) is an important endogenous mediator with significant role in the respiratory system. Many endogenous and exogenous factors influence the synthesis of NO and its level is significantly changed during the inflammation. Analysis of nasal nitric oxide (nNO) is not validated so far as the diagnostic method. There is a lack of reference values with possible identification of factors modulating the nNO levels. In healthy adult volunteers (n=141) we studied nasal NO values by NIOX MINO® (Aerocrine, Sweden) according to the recommendations of the ATS & ERS. Gender, age, height, body weight, waist-to-hip ratio, FEV1/FVC, PEF and numbers of leukocytes, eosinophils, basophils and monocytes were studied as potential variables influencing the levels of nNO. The complexity of the results allowed us to create a homogenous group for nasal NO monitoring and these data can be used further as the reference data for given variables. Because of significant correlation between nNO and exhaled NO, our results support the “one airway – one disease” concept. Reference values of nasal NO and emphasis of the individual parameters of tested young healthy population may serve as a starting point in the non-invasive monitoring of the upper airway inflammation.

A European Respiratory Society technical standard: exhaled biomarkers in lung disease

Breath tests cover the fraction of nitric oxide in expired gas (F_eNO), volatile organic compounds (VOCs), variables in exhaled breath condensate (EBC) and other measurements. For EBC and for F_eNO, official recommendations for standardised procedures are more than 10 years old and there is none for exhaled VOCs and particles. The aim of this document is to provide technical standards and recommendations for sample collection and analytic approaches and to highlight future research priorities in the field. For EBC and F_eNO, new developments and advances in technology have been evaluated in the current document. This report is not intended to provide clinical guidance on disease diagnosis and management.Clinicians and researchers with expertise in exhaled biomarkers were invited to participate. Published studies regarding methodology of breath tests were selected, discussed and evaluated in a consensus-based manner by the Task Force members.Recommendations for standardisation of sampling, analysing and reporting of data and suggestions for research to cover gaps in the evidence have been created and summarised.Application of breath biomarker measurement in a standardised manner will provide comparable results, thereby facilitating the potential use of these biomarkers in clinical practice.

Measuring nasal nitric oxide in allergic rhinitis patients

OBJECTIVE

This study aimed to compare two sampling methods for nasal nitric oxide in healthy individuals and allergic rhinitis patients, and to examine the within-subject reliability of nasal nitric oxide measurement.

METHODS

The study included 23 allergic rhinitis patients without concomitant asthma and 10 healthy individuals. For all participants, nitric oxide levels were measured non-invasively from the lungs through the mouth (i.e. the oral fractional exhaled nitric oxide) and the nose. Nasal nitric oxide was measured by two different methods: (1) nasal aspiration via one nostril during breath holding and (2) single-breath quiet exhalation against resistance through a tight facemask (i.e. the nasal fractional exhaled nitric oxide).

RESULTS

Compared with healthy participants, allergic rhinitis patients had significantly higher average oral and nasal nitric oxide levels. All methods of nitric oxide measurement had excellent reliability.

CONCLUSION

Nasal nitric oxide measurement is a useful and reliable clinical tool for diagnosing allergic rhinitis in patients without asthma in an out-patient setting.

Exhaled nasal nitric oxide during humming: potential clinical tool in sinonasal disease?

The use of nasal nitric oxide (nNO) in sinonasal disease has recently been advocated as a potential tool to explore upper inflammatory airway disease. However, it is currently hampered by some factors including the wide range of measurement methods, the presence of various confounding factors and the heterogeneity of the study population. The contribution of nasal airway and paranasal sinuses communicating with the nose through the ostia represents the main confounding factor. There is accumulating evidence that nasal humming (which is the production of a tone without opening the lips or forming words) during nNO measurement increases nNO levels due to a rapid gas exchange in the paranasal sinuses. The aim of this review is to discuss the basic concepts and clinical applications of nNO assessment during humming, which represents a simple and noninvasive method to approach sinonasal disease.

Nasal nitric oxide levels do not allow for discrimination between olfactory loss due to various etiologies

OBJECTIVES/HYPOTHESIS

Nasal nitric oxide (NO) and olfactory function are decreased in patients with chronic inflammatory sinonasal disease, suggesting a link between these two parameters. The aim of the study was to investigate nasal NO levels in patients with olfactory dysfunction due to different causes.

STUDY DESIGN

Prospective study in a university clinic setting (tertiary referral center).

METHODS

Posttraumatic (n = 11), idiopathic (n = 13), and sinonasal-related olfactory-impaired patients (n = 55) were compared with healthy subjects (n = 11). Nasal NO levels, olfactory testing (Sniffin' Sticks), and rhinosinusitis questionnaires (Short-Form 36, Sinonasal Outcome Test 22, Rhinosinusitis Disability Index) were obtained.

RESULTS

No significant difference in nasal NO levels were found between the different olfactory dysfunction causes. Nasal NO correlated negatively with age and positively with overall olfactory function, olfactory discrimination, and identification but not with olfactory thresholds. The more nasal symptoms prevailed in the Rhinosinusitis Disability Index, the lower the nasal NO.

CONCLUSIONS

Nasal NO levels do not allow for discrimination between olfactory loss due to various etiologies based on the present data. Nasal NO production seems to decrease with age and also seems to be associated to overall olfactory function and in particular to central nervous system tasks such as olfactory discrimination and identification but not to olfactory thresholds. These findings raise questions about the link and interaction between olfactory function and nasal NO.

Nasal nitric oxide in a random sample of adults and its relationship to sensitization, cat allergen, rhinitis, and ambient nitric oxide

BACKGROUND

There is conflicting evidence whether nasal nitric oxide (NO) is associated with current rhinitis and with other possible predictors. Most studies have been performed in clinical cohorts and there is a lack of studies based on a general population sample. The aim of the present study was to investigate predictors for levels of nasal nitric oxide (NO) in a general population.

METHODS

The population consisted of 357 subjects from Gothenburg participating in the follow-up of the European Respiratory Health Survey in 1999-2001. All subjects completed an extensive respiratory questionnaire. Nasal NO was measured from one nostril at a time with a sampling rate of 50 mL/s for 16 seconds and the nasal NO concentration was determined as the mean value within the plateau phase. Mattress dust samples were collected for cats and mites in a subsample of subjects. Ambient and exhaled NO was also measured. The predictors for nasal NO were analyzed in multiple linear regression models.

RESULTS

There was no relation between the levels of nasal NO and reporting current rhinitis. Nasal NO was significantly increased among those with high levels of IgE against cats and current smokers had significantly lower nasal NO. There was also a positive association between ambient NO and nasal NO. There were no significant associations between nasal NO and sex, age, or height, or between nasal NO and measured levels of cat antigen.

CONCLUSION

In this general population sample we found no relation between current rhinitis and nasal NO levels. There was a clear association between sensitization to cat and nasal NO, but there was no relation to current exposure to cat allergen. Our data support that nasal NO has a limited value in monitoring upper airway inflammation.

Hand-held nitric oxide sensor NIOX MINO® for the monitoring of respiratory disorders

Measurements of exhaled nitric oxide have been proposed as a tool to improve the control of asthma and inflammatory airways disease, including the patient's response to anti-inflammatory treatment and to predict loss of control and to monitor compliance with treatment. Several techniques have been used to assess exhaled nitric oxide gas and the majority of studies have used the chemiluminescence method. More recently, a new hand-held electrochemical sensor NIOX MINO(®) has been developed. Here, we will review the use of the NIOX MINO for the study of respiratory disorders.

Measurement of nasal nitric oxide: evaluation of six different sampling methods

BACKGROUND

Specific guidelines are developed for the measurement of bronchial FE(NO), however, nasal nitric oxide (nNO) measurement is not standardised yet, resulting in divergent nNO values. This study compares six different sampling methods for nNO as described in the literature, to analyse their outcome and short term and long term reproducibility.

DESIGN

nNO concentrations were measured in 38 healthy subjects. Each subject performed nNO measurements during tidal breathing (nNO-TB), single breath quiet exhalations (nNO-QE), QE with oral exhalation against a resistance (nNO-QE + R), breath holding (nNO-BH) and during single-breath humming exhalations at 128 and 440 Hz (nNO-HE(128) and nNO-HE(440), respectively). To assess short term and long term reproducibility all manoeuvres were repeated after one and 24 h.

RESULTS

Lowest values were found during quiet exhalation (mean nNO-QE was 364 p.p.b., SEM 27). Methods in which there is turbulence of nasal flow (as in TB, HE(128) and HE(440)) result in higher nNO levels. Highest values were found in methods with decreased nasal flow [when there is no nasal flow as in BH or when the velum is closed as in QE + R: mean nNO 763 p.p.b. (SEM 61)]. NNO during humming at 440 Hz was significantly higher than at 128 Hz (P < 0.01). The within-subject coefficient of variation of repeated measurements was lowest during humming and breath holding, 3.4 and 3.8%, respectively. Concerning short term and long term reproducibility, best agreement is reached with humming and second best with breath holding.

CONCLUSIONS

Different methods result in different levels and reproducibility of nNO. In regard to this, methods of humming and breath holding are recommended for standardised measurement of nasal NO.

Documentation of the nasal nitric oxide response to humming: methods evaluation

RATIONALE

Nitric oxide (NO) is present at higher concentrations in the nasal cavity than in the lower airway, and at even higher concentrations within the paranasal sinuses proper. When the paranasal sinus ostia are patent, acoustic activity produced by vocalization with closed lips (humming) promotes mixing of sinus with nasal gases, producing a further increase in nasal NO. We wished to evaluate procedures for the documentation of the nasal NO response to humming.

MATERIALS AND METHODS

We compared two ATS-recommended sampling methods: 1) active exhalation of lower airway gas (parallel technique) and 2) passive aspiration of nasal gas with closed velopharynx (series technique). Variables controlled for included sampling rate, external resistance (parallel method), humming frequency, humming duration, and intertrial interval. Prior to upper airway sampling, exhaled lower airway NO was determined utilizing ATS-standardized technique.

RESULTS

Ten volunteers (seven males and three females, aged 21-58) with no history of respiratory allergies or sino-nasal disease were studied in a single session each. The parallel technique documented an increase in nasal NO during the humming manoeuvre in all subjects (mean ratio of humming-to-quiet NO, 4.2), whereas the series technique did so in eight of 10 subjects (mean ratio 2.1). Correcting for admixture from the lower airway, the ratio of humming-to-quiet NO was greater with the parallel than series sampling technique (P < 0.05).

CONCLUSIONS

Documentation of the response of nasal NO to humming in subjects without sino-nasal disease was consistently achievable by parallel sampling using commercially available equipment. Specific operational procedures are proposed.

Measurement of nasal nitric oxide

Nasal nitric oxide (nNO) is produced in high quantity in the upper airways. It is thought to be involved in host defence functions and regulation of mucociliary function, and to serve as a biochemical airborne transmitter. The measurement of nNO is easy and non-invasive. It has evolved as a screening test to exclude primary ciliary dyskinesia (PCD) in patients with suggestive symptoms, because nNO is extremely low in this condition. Nasal NO is also altered in other nasal, sinus and pulmonary pathologies, but is without diagnostic value outside of PCD.

Nasal nitric oxide in cystic fibrosis with and without humming

BACKGROUND

Nasal nitric oxide (nNO) values are reduced in patients with cystic fibrosis (CF). Humming during nNO measurement increases nNO values in healthy subjects. Nasal NO is reduced in patients with CF, sinus disease or nasal polyps. Humming nNO values have not been reported in CF patients yet. Our aim was to explore humming nNO values in CF patients and assess whether nNO during humming is a better discriminator than silent nNO measurements in this patient group.

MATERIALS AND METHODS

In a cross sectional study we measured nNO concentrations in healthy controls (HC) and in CF patients (n = 23 and 31, respectively). The participants held their breath for 10 s while air was passively extracted from one nostril with 700 mL min(-1) for direct NO measurements (NIOX chemiluminescence analyser). Subsequently nNO was measured during humming with the mouth closed for 10 s.

RESULTS

Mean nNO in parts per billion (p.p.b.) (SD) during breath hold was 499 (164) and 240 (139), respectively. The median nNO peak (p.p.b., minimum-maximum) during humming was 1500 (425-4100) for HC and 120 (23-500) for CF. There was a highly significant difference between nNO both with and without humming between CF and HC (P < 0.01). The sensitivity and specificity of nNO for detecting CF were better with humming.

CONCLUSION

Nasal NO concentrations with and without humming are significantly decreased in CF. Humming nNO is an excellent discriminator between HC and CF and performs better than silent nNO.