Table 2

Ventilatory variables during intermittent positive pressure ventilation (IPPV) and negative pressure ventilation (NPV)

VariableIPPVNPV
Minute volume (ml/kg)150 to 220140 to 220
Frequency (breaths/min)15 to 2230 to 50
Tidal volume (ml/kg)10 to 15 5 to 7
Pinsp (cm H2O)
 Group 1+16 to +20 −18 to −24
 Group 2+18 to +23
Pexp (cm H2O)0 to 2+1 to + 4
Paw (cm H2O)+ 5 to + 9− 6 to −9
Pressure support (cm H2O)+ 3 to + 5
Fio 2 Group 10.25 to 0.35 as IPPV
    Group 2 0.3 to 0.6as IPPV
  • Pinsp, inspiratory pressure; Pexp, expiratory pressure; Paw, mean airway pressure; Fio 2, inspired oxygen fraction.