Interpretation of Cough Provoked by Airway Challenges

doi:10.1378/chest.128.5.3329

Chest

Volume 128, Issue 5, November 2005, Pages 3329-3335

https://doi.org/10.1378/chest.128.5.3329 Get rights and content

Study objective: To analyze the cough response to three airway challenges in order to clarify whether the recording of the provoked coughs would be beneficial in the management of asthma.

Design: A prospective study.

Setting: University hospital.

Participants: Fifteen healthy subjects, 16 steroid-naïve subjects with asthma, and 16 subjects with steroid-treated asthma.

Interventions: Inhalation challenges with isotonic histamine, hypertonic saline solution, and hypertonic histamine, using an ultrasonic nebulizer and 2-min tidal breathing method.

Measurements: Airflow parameters were measured with a spirometer, and the coughs were recorded manually.

Results: Coughing during the isotonic histamine challenge was associated with the degree of the bronchoconstriction induced. When this was taken into account, the healthy subjects coughed as frequently as the asthmatic subjects. During the two hypertonic challenges, the asthmatic subjects coughed more frequently than did the healthy subjects when the induced bronchoconstriction had not yet developed. At that stage of the hypertonic saline solution challenge, the mean coughing frequency was 0.7 coughs per minute (95% confidence interval [CI], 0.03 to 1.3 coughs per minute) for the healthy subjects, 2.7 coughs per minute (95% CI, 0.8 to 4.5 coughs per minute) for the steroid-naïve asthmatic subjects, and 1.3 coughs per minute (95% CI, 0.6 to 1.9 coughs per minute) for the steroid-treated asthmatic subjects (p = 0.018). For the hypertonic histamine challenge, the respective values were 0.8 coughs per minute (95% CI, 0.4 to 1.2 coughs per minute), 3.6 coughs per minute (95% CI, 2.4 to 4.9 coughs per minute), and 2.1 coughs per minute (95% CI, 1.0 to 3.1 coughs per minute; p = 0.001). This cough did not correlate with airway hyperresponsiveness.

Conclusions: Coughing during isotonic histamine challenge seems to be a manifestation of bronchoconstriction, and recording of the coughs may not provide additional information to airflow measurements. Frequent coughing during hypertonic saline solution and hypertonic histamine challenges in the absence of bronchoconstriction is a pathologic phenomenon. Sensitivity to the cough-provoking effect of hypertonic challenges seems to be enhanced in patients with asthma but unrelated to airway hyperresponsiveness. Therefore, the recording of the provoked coughs during these challenges may add to the information obtained from airflow measurements.

Section snippets

Study Design

A detailed description of the study population and the challenges has been published previously,⁹ and this is another analysis of the same data set. In the previous publication,⁹ the airway responsiveness to the challenges was described, whereas the present publication describes the cough responses. All subjects underwent the following three airway challenges: the isotonic histamine challenge; the hypertonic saline solution challenge; and the hypertonic histamine challenge. The challenges were

RESULTS

The hypertonic histamine challenge provoked more coughs than the other two challenges. The mean Cf values were 1.4 coughs per minute (95% CI, 0.8 to 1.9 coughs per minute) for the isotonic histamine challenge, 1.7 coughs per minute (95% CI, 1.0 to 2.4 coughs per minute) for the hypertonic saline solution challenge, and 2.8 coughs per minute (95% CI, 2.1 to 3.5 coughs per minute) for the hypertonic histamine challenge (p < 0.001).

DISCUSSION

To the best of our knowledge, this is the first study to compare the cough responses among direct, indirect, and combined airway challenges. The study showed that all challenges were able to provoke cough, but the significance of the cough response differs considerably among the challenges. The recording of the provoked coughs during the isotonic histamine challenge may not provide clinically useful information. On the contrary, the recording of the coughs during hypertonic saline solution and

ACKNOWLEDGMENTS

The authors thank Raija Tukiainen, RN, for her assistance.

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The study was supported by Kuopio University Hospital without other financial sources

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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Chest

Clinical Investigations: RESPIRATORY SYMPTOMSInterpretation of Cough Provoked by Airway Challenges

Section snippets

Study Design

RESULTS

DISCUSSION

ACKNOWLEDGMENTS

Chest

Respir Med

Respir Physiol

Respir Physiol

Respir Physiol

Pulm Pharmacol Ther

Chest

Chest

Lancet

J Allergy Clin Immunol

Chest

Respir Med

Indirect airway challenges.

Eur Respir J

Dissociation in the effect of nedocromil on mannitol-induced cough or bronchoconstriction in asthmatic subjects.

Respirology

Effects of pH and osmolarity on aerosol-induced cough in normal volunteers.

Clin Sci (Lond)

Clinical Investigations: RESPIRATORY SYMPTOMS
Interpretation of Cough Provoked by Airway Challenges