Aminophylline and respiratory muscle interaction in normal humans

Massimo Gorini, Roberto Duranti, Gianni Misuri, Tommaso Valenza, Alessandro Spinelli, Patrizio Goti, Francesco Gigliotti, Giorgio Scano

Research output: Contribution to journalArticlepeer-review


The effects of intravenous infusion of aminophylline on respiratory muscle interaction were examined in seven normal subjects breathing at rest. Rib cage (RC-Ap) and abdominal (AB-Ap) volume displacements, pleural (Ppl), gastric (Pg), and transdiaphragmatic (Pdi) pressure swings, and electromyographic activity of the diaphragm (Edi) and the parasternal (Eps) muscles were measured under control and during infusion of either aminophylline or placebo in a double-blind randomized manner. Compared with placebo, aminophylline induced an increase in ventilation (p <0.01) that was mainly accounted for by an increase in tidal volume (p = 0.01). Aminophylline induced a significant and similar increase in RC-Ap and AB-Ap associated with increased Ppl and Pg swings (p = 0.002, and p <0.01, respectively). On the contrary, no changes in end-expiratory RC and AB volume and in Ppl and Pg at end-expiration were observed, indicating that expiratory muscles did not contribute to the increase in tidal volume. Edi and Eps increased significantly with aminophylline, whereas Pdi/Edi ratio remained unchanged. We conclude that in normal humans breathing at rest: (1) aminophylline increases ventilation, promoting larger tidal volume; (2) this effect is due to increased neural drive to inspiratory muscles; (3) aminophylline does not promote any appreciable expiratory muscle recruitment and distortion in the pattern of chest wall motion.

Original languageEnglish
Pages (from-to)1227-1234
Number of pages8
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number5
Publication statusPublished - May 1994

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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