The position of the cannula (see Ch

The position of the cannula (see Chapter 6) in relation to the pressure monitoring may affect the pressure being read. The pressure could be falsely elevated if the cannula and tip of the indwelling catheter are close to each other, or too low if influenced by the negative pressure next to a drainage cannula. Many invasive monitoring devices (used mainly to assess cardiac output and derive parameters such as extra lung water) have not been validated in ECMO patients and should only be used with extreme caution. These devices have usually not been validated in extreme conditions, and ECMO is not only extreme but introduces a new physiological dimension(which could be called a new physiological bed .