ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005. Am J Respir Crit Care Med. 2005 Apr 15;171(8):912-30.
The field of exhaled nitric oxide (NO) and nasal NO measurement
has developed remarkably over the last 15 years, with more than
1,000 publications in the field. The understanding is increasing
of how the measurement of inflammation may contribute to the
management of lung disease, and the incorporation of this measurement
into clinical practice, has commenced.
Despite numerous publications, the field of exhaled and nasal NO measurement has been characterized from its onset by a marked variation in published fractional exhaled NO (FENO) levels in health and disease, much of which is still attributable to variable techniques of measurement.
A taskforce of the European Respiratory Society (ERS) published European recommendations in 1997 (1), and the American Thoracic Society (ATS) published a statement in 1999, which is updated in this document (2). Recently, a separate statement on pediatric exhaled NO measurement was approved by the boards of the ATS and ERS (3).
The recommendations in the ATS document from 1999 were updated by international investigators in the field of exhaled and nasal NO, at a workshop sponsored by the ATS (December 2002, Toronto, Canada). Also attending as committee members to provide expertise in the technical recommendations were scientists from NO analyzer manufacturers: Aerocrine, Eco Physics, Eco Medics, Ionics Instruments, and Ekips Technologies. The workshop reviewed the following areas: adult online exhaled NO measurement, offline exhaled NO measurement, pediatric online exhaled NO measurement, nasal NO measurement, and technical recommendations. New areas were identified for mention in the revised document—namely, technologic advances, NO in ventilated patients, and physiologic models of NO excretion from the lung.
The standardization of techniques has opened the way for the collection of comparable data in numerous centers in normal subjects and in those with disease states. As in the previous ATS statement from 1999, the document is divided into a background section, which deals with aspects common to all sections, followed by sections dealing with adult online/offline measurement, pediatric measurement, nasal NO measurement, new developments, and technical aspects of NO analysis. Wherever possible, the recommendations are based on published material, including abstracts, as referenced; in the absence of clear data, the document relied on the experience of participants in the workshop. Where aspects concerning exhaled NO measurement are undetermined, this has been clearly stated in the text.
Although these recommendations encourage uniformity of measurement techniques in future studies, this document does not intend to invalidate previous or ongoing studies that have used other techniques. Wherever practical, investigators are encouraged to include the recommended method in addition to the measurement techniques with which they are familiar, so that the knowledge concerning the recommended methods will increase. This will allow future modifications to these recommendations to be made on scientific grounds.