Table 1

Comparison between pressure and volume-targeted ventilators

Pressure curve patternEmbedded ImageEmbedded Image
Flow curve patternEmbedded ImageEmbedded Image
Type of ventilatory assistance deliveredFixed volume in spite of changing resistance (R) and compliance (C)Fixed pressure. Tidal volume may vary with changes in C and R
Controlled variableMaintains a constant inspiratory preset flowMaintains a constant inspiratory preset pressure
Breath-to-breath adjustmentsNot possible: ventilator delivers a fixed assistancePossible: flow and volume can be varied in a breath-to-breath basis
Possibility to guarantee a fixed delivered tidal volumeYes (if no leaks)No
Peak airway pressureNot limited*Limited (useful in patients at risk of barotrauma or gastric distension
Leak compensationPoor, leaks may significantly reduce delivered volume and induce hypoventilationGood for mild to moderate leaks
  • * Except if pressure reaches predetermined high pressure security limit.