Effect of lung mechanics on mechanically assisted flows and volumes

Jesús Sancho, Emilio Servera, Julio Marín, Pedro Vergara, F. Javier Belda, John R. Bach

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Objective: To correlate the air flows generated by mechanical insufflation-exsufflation as a function of pressure delivery in a lung model at two pulmonary compliance and three airway resistance settings. Design: With each combination of pulmonary compliances of 25 and 50 ml/cm H2O and airway resistances of 6, 11, and 17 cm H2O/liter/sec, ten cycles of mechanical insufflation-exsufflation were applied using pressure deliveries of 40 to -40, 50 to -50, 60 to -60, and 70 to -70 cm H2O. The resulting peak exsufflation flows and volumes were recorded. Results: In a multivariate analysis, the pulmonary compliance, airway resistance, and pressure delivery were all found to significantly affect exsufflation flows and volumes such that a decreased pulmonary compliance or an increased airway resistance produced a decrease in exsufflation flow and volume, whereas an increased pressure delivery produced greater exsufflation flow and volume. Conclusion: Although mechanical insufflation-exsufflation pressures of 40 to -40 cm H2O are generally adequate for most patients with normal lung compliance and airway resistance, higher settings are often required when compliance decreases, by obesity or scoliosis, and possibly when airway resistance is increased.

Original languageEnglish (US)
Pages (from-to)698-703
Number of pages6
JournalAmerican Journal of Physical Medicine and Rehabilitation
Issue number9
StatePublished - Sep 2004

All Science Journal Classification (ASJC) codes

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation


  • Assisted Cough
  • Cough
  • Exsufflation
  • Mechanically Assisted Cough
  • Neuromuscular Disease
  • Noninvasive Ventilation
  • Respiratory Care


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