Proportional Assist Ventilation

  • R. B. Light
  • W. Patrick
  • M. Younes


Proportional assist ventilation (PAV) is a new mode of synchronized partial ventilatory support in which, on a moment-by-moment basis, the ventilator delivers airway pressure in proportion to patient effort; the more the patient pulls, the more pressure the machine generates. The ventilator simply amplifies patient effort and provides a pressure assist to allow the patient to reach self-selected tidal volume and inspiratory flow targets, without any externally determined volume or pressure targets being set by the physician or respiratory therapist. It is in this respect in particular that PAV is unlike other available ventilator modes. We describe here the design and application of the PAV delivery system that we have developed, discuss our initial clinical experience with PAV in ventilator-dependent critically ill patients, and examine some of what we believe to be the potential advantages and limitations of this new mode of ventilatory support. A more detailed discussion of the theoretical basis of PAV and its initial application can be found in two previous publications [5, 6], and a more detailed description of the practical application of PAV is also in press [7].


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  1. 1.
    Marantz S, Webster K, Patrick W, Roberts D, Oppenheimer L, Younes M (1992) Respiratory responses to different levels of proportional assist (PAV) in ventilator dependent patients. Am Rev Respir Dis 145: A 525 (abstr)Google Scholar
  2. 2.
    Mettias M, Mendoza M, Wiebe P, Younes M, Light B (1993) Effect of proportional assist ventilation (PAV) vs controlled mandatory ventilation and pressure support ventilation (CMV, PSV) on gas exchange in patients with hypoxemic respiratory failure. Clin Invest Med 16: B 23 (abstr)Google Scholar
  3. 3.
    Patrick W, Webster K, Wiebe P, Roberts D, Light B, Oppenheimer L, Kassum D, Younes M (1993) Effect of proportional assist ventilation on the hemodynamics of patients in septic shock. Am Rev Resp Dis 147: A 611 (abstr)Google Scholar
  4. 4.
    Patrick W, Webster K, Wiebe P, Roberts D, Light RB, Ludwig L, Oppenheimer L, Younes M (1993) The use of non-invasive proportional assist ventilation to avoid intubation in patients with acute respiratory failure. Am Rev Respir Dis 147: A 984 (abstr)Google Scholar
  5. 5.
    Younes M (1992) Proportional assist ventilation, a new approach to ventilator support. Theory. Am Rev Respir Dis 145: 114–120CrossRefGoogle Scholar
  6. 6.
    Younes M, Puddy A, Roberts D, Light RB, Quesada A, Taylor K, Oppenheimer L, Cramp H (1992) Proportional assist ventilation. Results of an initial clinical trial. Am Rev Respir Dis 145: 121–129PubMedCrossRefGoogle Scholar
  7. 7.
    Younes M (1994) Proportional assist Ventilation. In: Tobin M (ed) Principles and practice of mechanical ventilation. McGraw-Hill, New YorkGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • R. B. Light
  • W. Patrick
  • M. Younes

There are no affiliations available

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