[The heart and weaning]

The initiation of and weaning from mechanical ventilation with extubation cause significant changes in intrathoracic pressures and have profound consequences for the cardiovascular function. However, in spite of the known pathophysiological relationships, frequently little attention is paid to the cardiovascular situation during the weaning period. The currently available guidelines concerning weaning and extubation/reintubation are based on only limited evidence and are thus rather general. Moreover, recommendations for the cardiovascular management during weaning reflect mainly the pathophysiological rationale. In patients with known cardiac disease, studies have demonstrated the necessity for a prolonged weaning process. On the contrary, many intensive care patients have subclinical or undiagnosed cardiac disease, and cardiovascular compensation mechanisms are frequently hampered by the underlying critical illness. Therefore, in a significant proportion of patients, weaning and extubation attempts fail due to the patient's limited cardiovascular reserves. This review summarises the relevant information for a successful weaning and extubation with special respect to the cardiovascular function.