Methacholine Chloride and methacholine and KoKo Digidoser in Asthma - Clinical Trials Registry

Study Overview

Status

Completed

Conditions

Asthma

Intervention / Treatment

Detailed Description

Bronchoprovocation with methacholine is used to confirm the diagnosis of asthma. The procedure involves inhaling methacholine through a nebulizer attached to a dosimeter that delivers a precise volume of methacholine. The endpoint of the test is the provocational concentration that produces a 20% decrease in FEV1 (PC20). To standardize the procedure, the American Thoracic Society (ATS) recommends that the nebulizer output be calibrated to deliver an output of 0.9 ± 0.09 mL/min.

The Rosenthal Dosimeter and the KoKo Digidoser are two commonly used dosimeters. In an attempt to follow the ATS guideline we discovered that the nebulizer output was lower with the KoKo Digidoser and could not be calibrated. However, it is unclear whether the apparent lower output is a result of the Digidoser delivering less solution or that the ATS method of determining output is not applicable to this dosimeter. To answer this question, we propose to determine the methacholine PC20 in subjects with asthma using the two dosimeters. It is our hypothesis that the Digidoser delivers less methacholine and thus will produce a higher PC20 than the Rosenthal Dosimeter.

Twelve nonsmoking subjects with mild asthma will be selected on the basis of > 18 years of age, a baseline FEV1 of > 60% predicted and a screening PC20 of < 8mg/ml. Subjects will be randomized to perform a methacholine challenge with the Digidoser and the Rosenthal Dosimeter on two different days in an unblinded, crossover manner. The geometric mean PC20 with each dosimeter will be compared with a paired t test. The results of this study will indicate whether the Digidoser has the potential of causing false negative test results or whether the ATS method of determining output should not be used with this dosimeter.

Study Type

Interventional

Enrollment

12

Phase

Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

United States
- Florida
  - Gainesville, Florida, United States, 32610
    - University of Florida Asthma Research Lab

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 60 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

Non-smoking male or female >18 years of age, with a previous diagnosis of asthma.
Women of child bearing age must not be pregnant or nursing and be using an acceptable method of contraception.
Screening FEV1 > 70% of predicted for height, age, sex, and race when bronchodilators are withheld for appropriate intervals.
At least a 20% decrease in FEV1 after inhaling ≤ 8 mg/ml of methacholine (i.e., a PC20 FEV1 ≤8 mg/ml) using the KoKo Digidoser system.
Ability to perform ATS-acceptable and reproducible spirometry.

Exclusion Criteria:

Cigarette smoking in past year or > 10 pack year smoking history.
Respiratory tract infection within the last four weeks.
History of severe asthma attack requiring hospitalization in the previous 12 months.
Short course of oral corticosteroids in the past 3 weeks.
Inability to withhold caffeinated beverages for 12 hours or medications for appropriate intervals prior to each methacholine challenge.
If female, a positive urine β-HCG test.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Interventional Model: Crossover Assignment
Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Geometric mean PC20 methacholine for each dosimeter method.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Florida

Collaborators

GlaxoSmithKline

Investigators

Principal Investigator: Yasmeen Khan, MD, University of Florida

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2005

Primary Completion (Actual)

December 1, 2005

Study Completion (Actual)

December 1, 2005

Study Registration Dates

First Submitted