Patent ID: 8701663

Claim:
A breathing apparatus comprising: an inspiratory valve, and a control unit that is adapted to determine a transpulmonary pressure (Ptp) in a patient connected to said breathing apparatus, wherein said control unit is configured to: set said breathing apparatus in a first mode of operation for ventilating said patient with a first Positive End Expiratory Pressure (PEEP) level by controlling said inspiratory valve and an expiratory valve; set said breathing apparatus in a second mode of operation for ventilating said patient with a second PEEP level starting from said first PEEP level, wherein said second PEEP level is based on a target PEEP level different from said first PEEP level, by controlling said inspiratory valve and said expiratory valve; determine a change in end-expiratory lung volume (ΔEELV) from a difference of end-expiratory lung volume (EELV) present at said first PEEP level and said second PEEP level, based on measurements from an inspiratory flow transducer and an expiratory flow transducer; and determine said Ptp based on said change in ΔEELV and a difference between said first PEEP level and said second PEEP level (ΔPEEP), measured by an expiratory pressure sensor.