HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Guest Access | Sign In via User Name/Password

This Article Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Google Scholar Articles by Duarte, A. G. Articles by Lick, S. PubMed PubMed Citation Articles by Duarte, A. G. Articles by Lick, S.

Restoration of cough reflex in lung transplant recipients

¹University of Texas Medical Branch, Department of Medicine, Galveston, TX ²Johns Hopkins University, Bayview Hospital, Baltimore, MD ³University of Texas Medical Branch, Department of Pathology, Galveston, TX ⁴University of Texas Medical Branch, Department of Surgery, Galveston, TX

aduarte{at}utmb.edu

Abstract

Background: Lung transplantation involves vagal nerve interruption resulting in sensory airway denervation and impairment of the cough reflex. Following lung transplantation it is unclear whether functional recovery of the cough reflex occurs over time. Our objective was to evaluate the afferent limb of the cough reflex in lung-transplant recipients.

Methods: Assessment of cough reflex involved upper airway anesthesia, conscious sedation and fiberoptic bronchoscopy through which biopsy forceps and 5 % dextrose were applied to airway mucosa at the main carina, proximal and distal to the anastomosis. A cross sectional group of 7 subjects underwent a single assessment while 8 subjects in a longitudinal group underwent assessment at 1.5 and 12 months. Cough frequency was determined by counting audible coughs and abdominal muscle contractions measured with a surface electromyogram recorder. The airway anastomosis from deceased subjects in the longitudinal group was examined for nerves.

Results: All seven subjects from the cross sectional group demonstrated a similar cough frequency after mechanical and chemical irritation of all airway sites. All subjects in the longitudinal group evaluated at 1.5 weeks had a cough response at all sites except distal to the anastomosis. Twelve months after transplantation, cough was present at all sites. Immunohistochemical staining for protein gene product 9.5, low affinity neurotrophin and vanilloid receptors demonstrated nerves in subepithelial regions proximal and distal to the airway anastomosis.

Conclusion: In human lung transplant recipients, recovery of the cough reflex was noted twelve months after lung transplantation.

Key Words: Cough • lung transplantation • innervation • denervation • neurobiology