System and methods for ventilating a patient

A method of ventilating a lung in a patient, the method performed by a ventilator, the method comprising the steps of:

• determining a first peak airway pressure, which is fixed in relation to a first fixed tidal volume;
• selecting a first level for PEEP;
• providing respiratory gas to the patient at the first peak airway pressure and PEEP to deliver the first fixed tidal volume of the respiratory gas;
• varying the peak airway pressure to a second value, which is fixed in relation to a second fixed tidal volume;
• monitoring respiratory gas flow over time to measure a second measure tidal volume;
• determining a second level for the PEEP based on the second measured tidal volume;
• automatically adjusting, through the ventilator, the second PEEP relative to the second fixed peak airway pressure to keep the second measured tidal volume at the second fixed tidal volume;
• and
• providing the respiratory gas to the patient at the second fixed peak airway pressure and the PEEP to deliver the second fixed tidal volume of the respiratory gas;
• wherein each of the volumes of the respiratory gas being delivered is based upon a corresponding predetermined PEEP.

A computer readable media comprising non-transitory computer readable program instructions for ventilating a patient, the computer readable program instructions comprising:

• a routine for placing a ventilator in a mode capable of delivering respiratory gas based on at least two fixed parameters and at least one variable parameter;
• the fixed parameters including tidal volume and peak airway pressure and the variable parameter including PEEP;
• a routine for identifying a first level for the PEEP;
• a routine for configuring the ventilator to deliver the respiratory gas at the first level of peak airway pressure and the PEEP to achieve the fixed tidal volume;
• a routine for monitoring respiratory gas flow over time to measure tidal volume;
• a routine for setting a second level for the PEEP based on the measured tidal volume;
• a routine for automatically adjusting the PEEP to the second level, relative to the fixed peak airway pressure to keep the measured tidal volume at the fixed tidal volume;
• and
• a routine for repeating the steps of configuring, monitoring, setting and automatically adjusting to achieve the ventilation.