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Caffeine potentiates airway responsiveness in the neonatal lamb
Author(s) -
Keklikian Esteban N.,
Wolfson Marla R.,
Shaffer Thomas H.
Publication year - 1992
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950120106
Subject(s) - bronchoconstriction , caffeine , medicine , anesthesia , airway resistance , lung volumes , ventilation (architecture) , saline , acetylcholine , functional residual capacity , heart rate , airway , cardiology , blood pressure , lung , mechanical engineering , engineering
In contrast to its effect on airway smooth muscle in the adult, in vitro studies have shown that caffeine significantly increases active tension in airway smooth muscle in the neonatal lamb. To determine if caffeine has a physiological effect on airway function during early development, we studied the effect of caffeine on acetylcholine‐induced bronchoconstriction in two groups of neonatal lambs. The animals were anesthetized, paralyzed, and maintained normoxic and normocapnic with mechanical ventilation. Pulmonary mechanics were evaluated as indices of airway tone, and functional residual capacity was used as an index of lung volume; heart rate and mean arterial pressure were used to assess cardiovascular status. Acetylcholine‐induced bronchoconstriction was evaluated as percentage changes of airway conductance and lung compliance from baseline, before and 1 hour after administration of normal saline or caffeine, and it was further analyzed with respect to the dose that produced a 20% change in those values (PD 20 ). There were no significant alterations in baseline lung mechanics, lung volume, or mean arterial pressure following saline or caffeine infusion. However, caffeine produced a left shift in the acetylcholine dose‐response curve for conductance and compliance and a significant decrease (−52%; P < 0.001) in PD 20 for conductance. There were no significant alterations in any parameter following saline administration. Since caffeine is used commonly for the treatment of apnea of prematurity, it is noteworthy that caffeine increases airway reactivity at clinically relevant doses. These findings raise important issues regarding the use of caffeine for the treatment of apnea of prematurity.