The postoperative removal of intubation tube induces a noticeable sympathic response and increase of blood pressure. The risk of complications is especially elevated with the patients having cardiac surgery. Though sedation inhibits the sympathetic responses to extubation, according to the current protocol the propofol infusion has to be discontinued well before extubation because of its inhibitory effects on breathing centers.

Dexmedetomidine is relatively new anesthesia drug. Dexmedetomidine is unique in its characteristic that it does not have the paralyzing effect on breathing. The aim of our study is to work out whether dexmedetomidine-extended propofol sedation over the extubation diminishes the aforementioned harmful effects of the extubation procedure.

Study design is prospective double-blinded randomized study. The investigators compare two groups of 25 patients (total 50), who are of 60-90 years of age and are having either aortic valve surgery or the mentioned accompanied with cardiopulmonary bypass operation. The first group receives dexmedetomidine infusion and the other receives placebo infusion after the end of propofol infusion.

The specific goal of the study is to figure what haemodynamic - mostly blood pressure related - changes can be observed when the postoperatively cut propofol infusion is continued with dexmedetomidine over the extubation procedure.

Our hypothesis is that by using dexmedetomidine supplemented sedation the normally notifiable peak in blood pressure may be avoided.

The study will be carried out completely in Cardiac ICU in Tampere University Hospital.

Inclusion Criteria:

• Patient has to be scheduled for aortic valve surgery OR previous AND coronary artery bypass
• Patient has to be 60 to 90 years of age

Exclusion Criteria:

• If a patient is unable to give informed concent to participate the study
• If a patient is allergic or otherwise hypersensitive to the drug used in the study
• If the patient has either insufficient kidney or insufficient liver function