EVALUATION OF THE PNEUPAC VENTIPAC PORTABLE VENTILATOR - COMPARISON OF PERFORMANCE IN A MECHANICAL LUNG AND ANESTHETIZED PATIENTS

The performance of the Pneupac Ventipac portable gas-powered ventilato r was evaluated in two stages. The accuracy of delivery of the ventila tor was assessed using a mechanical lung model at different combinatio ns of compliance and airway resistance to simulate normal and diseased lungs. The performance of the ventilator was then assessed in 20 anae sthetized patients. The tidal volume delivered by the ventilator in ai rmix mode (nominal inspiratory oxygen fraction (Fl(o2)) 0.45) was betw een -20 and +30% of the preset tidal volume with the mechanical lung m odel adjusted to normal adult values of compliance and airway resistan ce. The corresponding value with the ventilator set to deliver 100% ox ygen was between -22 and -7% of the preset tidal volume. The performan ce of the ventilator decreased when either compliance was reduced or a irway resistance was increased in the mechanical lung model; this effe ct was greater in airmix mode. Delivered tidal volume was between -19 and +12% of the present tidal volume in the group of anaesthetized pat ients using the ventilator in airmix mode. The ventilator was reliable and simple to use, and performance was within acceptable limits in th e anaesthetized patients. However, we recommend that a means of verify ing the adequacy of ventilation should always be used when transportin g critically ill or anaesthetized patients with any portable ventilato r, particularly when lung compliance or airway resistance may be abnor mal.