The Annals of Thoracic Surgery, Vol 24, 68-76, Copyright © 1977 by The Society of Thoracic Surgeons
Mechanics of ventilation with positive end-expiratory pressure
CF Hobelmann Jr, DE Smith, RW Virgilio and RM Peters
The effect of graded increments in positive end-expiratory pressure (PEEP)
on arterial oxygen partial pressure (PaO2) and shunt fraction (Qs/QT),
oxygen delivery, and respiratory mechanics and work required to ventilate 8
critically ill patients is reported. The work required to ventilate the
patients increases markedly with the application and progressive increase
in the level of PEEP. However, improvement in lung mechanics lowers the net
work of ventilating the lungs. At 20 cm H2O PEEP, the mean value for the
work of ventilation in this group of patients is twice the mean value
without PEEP. The increase in work of ventilation with PEEP is critical in
the use of PEEP when patients are breathing spontaneously with or without
intermittent mandatory ventilation.