The present invention concerns a medical pump comprising: a. A hard housing comprising a top (24) and bottom (1 ) hard shells, within which a rigid wall (3) and a movable membrane (2) create three distinct chambers； wherein i. said movable membrane tightly separates said second (29) and third (22) chambers ii. said first and third chambers have a watertight interface iii. said second chamber (29) is designed to contain a fluid iv. said first chamber (23) comprises a first venting mean (20) which is arranged to provide a fluidic communication between said first chamber (23) and the external environment； v. said third chamber (22) comprises a second venting mean which is arranged to provide a fluidic communication between said third chamber (22) and the external environment b. A pumping element (4) located in the first chamber (23) c. A least one pressure sensor which measure the pressure gradient between the first chamber (23) and the second chamber (29) d. A fluid pathway which permits: i. a first fluid connection (27) between said second chamber (29) and said pumping element ii. a second fluid connection (28) between said pumping element and a patient line (30).Cette invention concerne une pompe médicale comprenant : a. un boîtier rigide comprenant des coques dures supérieure (24) et inférieure (1), une paroi rigide (3) et une membrane mobile (2) créant trois chambres distinctes à l'intérieur dudit boîtier : i. ladite membrane mobile sépare hermétiquement lesdites deuxième (29) et troisième (22) chambres, ii. lesdites première et troisième chambres ont une interface étanche à l'eau, iii. ladite deuxième chambre (29) est conçue pour contenir un fluide, iv. ladite première chambre (23) comprend un premier moyen de désaération (20) qui est agencé de façon à créer une communication fluidique entre ladite première chambre (23) et l'environnement extérieur； et v. ladite troisième chambre (22) comprend un second moyen de désaération qui est agencé de façon à créer une com
