<p>The invention relates to a heart-lung machine comprising a cardiotomy reservoir and an oxygenator in which a blood pump is disposed, wherein the cardiotomy reservoir is disposed directly on the oxygenator and the blood exit of the cardiotomy reservoir empties into the blood entry of the blood pump. The cardiotomy reservoir (1) is divided into an upper emergency supply (2) and a lower working supply (3), wherein the working supply (3) is formed by a channel (4), the upper end (4a) of which empties into the emergency supply (2) and the lower end (4b) of which empties into the blood entry (10) of the blood pump and that is located in a transparent lower section (1a) of the cardiotomy reservoir (1) disposed above and outside of the oxygenator (9) such that the fill level of the blood in said channel (4) may be ascertained visually.</p>
