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Differences in the response to methacholine between the tidal breathing and dosimeter methods: influence of the dose of bronchoconstrictor agent delivered to the mouth.
Chest. 2008 Oct; 134(4):699-703.Chest

Abstract

BACKGROUND

It has been postulated that differences in provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) values between the dosimeter method and tidal breathing method might be due to differences in the dose of agonist delivered to the mouth. The aim of the present study was to determine the influence of the dose of aerosol delivered to the mouth on differences in the response obtained with each challenge method.

METHODS

This study measured airway responsiveness to methacholine by dosimeter method and tidal breathing method in 27 subjects with suspected asthma. The dosimeter was modified to deliver an identical volume to that obtained with the tidal breathing method. Concentration-response curves were characterized by the PC20.

RESULTS

The dosimeter method PC20 was significantly higher than the tidal breathing method PC20, with geometric mean values of 4.03 (95% confidence interval [CI], 1.86 to 8.78 mg/mL) and 2.19 (95% CI, 1.32 to 3.64 mg/mL; p = 0.04), respectively. The mean difference in the PC20 value detected with each method was similar in subjects with tidal breathing method PC20 values > or = 2 mg/mL (0.77 doubling concentrations) and in those with PC20 values < 2 mg/mL (0.96 doubling concentrations; p = 0.83).

CONCLUSIONS

The tidal breathing method produces PC20 values significantly lower than a modified dosimeter method, which delivers the same volume of aerosol. These results suggest that the discordant PC20 values obtained with the two methods are not due to differences in the dose of agonist delivered to the mouth.

Authors+Show Affiliations

Sección de Alergologia, Hospital Universitario Dr Peset, Gaspar Aguilar 90, 46017 Valencia, Spain. prieto_jes@gva.esNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

18625670

Citation

Prieto, Luis, et al. "Differences in the Response to Methacholine Between the Tidal Breathing and Dosimeter Methods: Influence of the Dose of Bronchoconstrictor Agent Delivered to the Mouth." Chest, vol. 134, no. 4, 2008, pp. 699-703.
Prieto L, Lopez V, Llusar R, et al. Differences in the response to methacholine between the tidal breathing and dosimeter methods: influence of the dose of bronchoconstrictor agent delivered to the mouth. Chest. 2008;134(4):699-703.
Prieto, L., Lopez, V., Llusar, R., Rojas, R., & Marin, J. (2008). Differences in the response to methacholine between the tidal breathing and dosimeter methods: influence of the dose of bronchoconstrictor agent delivered to the mouth. Chest, 134(4), 699-703. https://doi.org/10.1378/chest.08-0093
Prieto L, et al. Differences in the Response to Methacholine Between the Tidal Breathing and Dosimeter Methods: Influence of the Dose of Bronchoconstrictor Agent Delivered to the Mouth. Chest. 2008;134(4):699-703. PubMed PMID: 18625670.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differences in the response to methacholine between the tidal breathing and dosimeter methods: influence of the dose of bronchoconstrictor agent delivered to the mouth. AU - Prieto,Luis, AU - Lopez,Victoria, AU - Llusar,Ruth, AU - Rojas,Rocio, AU - Marin,Julio, Y1 - 2008/07/14/ PY - 2008/7/16/pubmed PY - 2008/11/19/medline PY - 2008/7/16/entrez SP - 699 EP - 703 JF - Chest JO - Chest VL - 134 IS - 4 N2 - BACKGROUND: It has been postulated that differences in provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) values between the dosimeter method and tidal breathing method might be due to differences in the dose of agonist delivered to the mouth. The aim of the present study was to determine the influence of the dose of aerosol delivered to the mouth on differences in the response obtained with each challenge method. METHODS: This study measured airway responsiveness to methacholine by dosimeter method and tidal breathing method in 27 subjects with suspected asthma. The dosimeter was modified to deliver an identical volume to that obtained with the tidal breathing method. Concentration-response curves were characterized by the PC20. RESULTS: The dosimeter method PC20 was significantly higher than the tidal breathing method PC20, with geometric mean values of 4.03 (95% confidence interval [CI], 1.86 to 8.78 mg/mL) and 2.19 (95% CI, 1.32 to 3.64 mg/mL; p = 0.04), respectively. The mean difference in the PC20 value detected with each method was similar in subjects with tidal breathing method PC20 values > or = 2 mg/mL (0.77 doubling concentrations) and in those with PC20 values < 2 mg/mL (0.96 doubling concentrations; p = 0.83). CONCLUSIONS: The tidal breathing method produces PC20 values significantly lower than a modified dosimeter method, which delivers the same volume of aerosol. These results suggest that the discordant PC20 values obtained with the two methods are not due to differences in the dose of agonist delivered to the mouth. SN - 0012-3692 UR - https://www.unboundmedicine.com/medline/citation/18625670/Differences_in_the_response_to_methacholine_between_the_tidal_breathing_and_dosimeter_methods:_influence_of_the_dose_of_bronchoconstrictor_agent_delivered_to_the_mouth_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0012-3692(08)60297-4 DB - PRIME DP - Unbound Medicine ER -