Measurement of Exhaled Nitric Oxide Using End Tidal Value during Normal Breathing

Hakim, T. S.

doi:10.4172/2161-105x.1000219

Cited by 2 publications

(8 citation statements)

References 42 publications

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“…We have used the nitric oxide concentration at end expiration during normal breathing as representative of lung nitric oxide level in the peripheral regions. We have found this measurement to be highly reproducible, simple for the patient to repeat, unaffected by fluctuations in ambient NO concentration and perhaps more representative of NO in the periphery [22]. It allows quick and easy recording of repeated measurements with minimal effort from the patient.…”

Section: Discussionmentioning

confidence: 90%

“…The average end tidal NO values (NOet) from 7 to 10 breaths was calculated to represent end tidal NO concentration (NOet). NOet was shown to be independent of ambient NO concentration [22]. In order to account for changes or differences in minute ventilation, the product of NO concentration and minute ventilation was used as an estimate of NO production (NOpr) in nmole/min.…”

Section: Methodsmentioning

confidence: 99%

“…Our goal was to measure exhaled NO using end tidal value (NOet) which is independent of ambient NO and does not require patient cooperation [22]. Furthermore NOet measurement is much easier and quicker than the single vital capacity maneuver (FeNO50).…”

Section: Research Articlementioning

confidence: 99%

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2015

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Increased nitric oxide in exhaled gas in patients with asthma is thought to reflect the severity of airway inflammation and perhaps airway reactivity. Several studies attempted to identify a relationship between exhaled NO levels and airway reactivity or severity of airway inflammation for the purpose of finding out if exhaled NO could be used in place of pulmonary function testing and airway provocation test. Unfortunately, the relationship is not always evident. In recent years, it has become clearer that exhaled NO becomes elevated primarily in atopic asthma patients. All previous studies have used the single vital capacity slow exhalation maneuver to measure ENO (FeNO50). This method is subject to errors because it requires patient cooperation, is flow rate dependent and adds more stress on the patient. Recently, we showed that end tidal NO concentration (NOet) is clinically relevant, is much easier to measure and is not subject to flow variation or patient cooperation. We used NOet (ppb) measurement before and during methacholine challenge in patients with symptoms of mild, persistent asthma. In addition we calculated NO production (NOpr) (nmole/ min) to correct for possible changes in ventilation. Eleven patients exhibited hyper-responsiveness to methacholine (responders) and 17 exhibited negative response (non-responders). The responders had a slightly higher NO level than the non-responders whether expressed in ppb or in nmol/min but did not reach statistical significance: NOet values were 15.1±2.4 ppb (±SE) and 11.7±2.3 ppb respectively and NOpr values were 5.83±0.86 nmol/min and 5.12±1.13 nmol/min respectively.There was no correlation between baseline NOet levels and the change in FEV1 in the responders. Furthermore, there was no consistent change in NOet or NOpr levels during broncho-constriction with methacholine. We conclude that although exhaled NO levels may serve as a helpful adjunct in treatment of asthma, its level alone does not reflect severity of the disease in mild asthmatics nor the airway responsiveness to methacholine. Exhaled NO was estimated using the average NO value at end expiration during normal tidal breathing. This method was quicker, repeatable and much easier on the patients and none of the patients objected to doing the measurement. There was no need to put patients through the complicated single full vital capacity slow exhaled maneuver to obtain this information.

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Section: Discussionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

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2015

JLPRR

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“…NOet was shown to be independent of ambient NO concentration. 22 In order to account for changes or differences in minute ventilation, the product of NO concentration and minute ventilation was used as an estimate of NO production (NOpr) in nmole/min. Statistical analysis of the results was accomplished using ANOVA for repeated measures and post hoc t-test (Bonferroni test) for changes in NOet and NOpr.…”

Section: Methodsmentioning

confidence: 99%

“…21 Our goal was to measure exhaled NO using end tidal value (NOet) which is independent of ambient NO and does not require patient cooperation. 22 Furthermore NOet measurement is much easier and quicker than the single vital capacity maneuver (FeNO50). The goal was to see if NOet is more repeatable with a better relationship to pulmonary parameters or airway responsiveness.…”

Section: Introductionmentioning

confidence: 99%

Exhaled Nitric Oxide Using End-Tidal Concentration during Methacholine Challenge

Hakim¹

2015

JLPRR

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Abbreviations: FeNO50, exhaled nitric oxide measured using the ATS guidelines with Exhalation rate of 50 l/min; NOet, average end tidal nitric oxide concentration from 5-7 breaths; NOpr, average nitric oxide production in nmol/min; Mch, methacholine; FEV1, forced expired volume in 1 sec; PD20, dose of Mch that elicited 20% reduction in FEV1; FVC, forced vital capacity; PEF, peak expiratory flow; sGAW, specific airway conductance; NO, nitric oxide AbstractThere was no correlation between baseline NOet levels and the change in FEV1 in the responders. Furthermore, there was no consistent change in NOet or NO pr levels during broncho constriction with methacholine. We conclude that although exhaled NO levels may serve as a helpful adjunct in treatment of asthma, its level alone does not reflect severity of the disease in mild asthmatics nor the airway responsiveness to methacholine. Exhaled NO was estimated using the average NO value at end expiration during normal tidal breathing. This method was quicker, repeatable and much easier on the patients and none of the patients objected to doing the measurement. There was no need to put patients through the complicated single full vital capacity slow exhaled maneuver to obtain this information. Citation: Hakim TS, Cremona G, Mangar D, et al. Exhaled nitric oxide using end-tidal concentration during methacholine challenge. J Lung Pulm Respir Res. 2015;2(5):86-91. Citation: Hakim TS, Cremona G, Mangar D, et al. Exhaled nitric oxide using end-tidal concentration during methacholine challenge. J Lung Pulm Respir Res. 2015;2(5):86-91.

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Measurement of Exhaled Nitric Oxide Using End Tidal Value during Normal Breathing

Cited by 2 publications

References 42 publications

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Exhaled Nitric Oxide Using End-Tidal Concentration during Methacholine Challenge

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