The Effects of Dexmedetomidine to Postoperative Awakening and Extubation-related Changes in Blood Pressure

Tampere University Hospital50 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Enrollment

Conditions

Interventions

DexmedetomidineDRUG

Dexmedetomidine will be diluted into a saline solution to a recommended concentration of 4 micrograms per millilitre. The saline will then be initially administered at the rate of 0.5 micrograms/kg/h and from that point the amount will be reduced to the point where the patient breathes well and is calm (compare dexmedetomidine recommendation at 0.2-1.4 ug/kg/h). The infusion rate will then be approximately 1-10 ml/h for a patient of 80 kgs weight. The exact dosage cannot be predetermined because it differs in each individual. In the control group the infusion speed is matching.

Saline (placebo)OTHER

Saline placebo infusion will be adjusted the same fashion as the active comparator drug.

Eligibility

Sex: ALLMin age: 60 YearsMax age: 90 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Highest value of systolic blood pressure during extubation period

The values of this variable will be collected from the point when propofol infusion is cut. This data will be used to estimate the base level of SAP for further analysis within this study.

Time frame: Starting five minutes before the extubation, lasting up to 1.5 hours.

Secondary Outcomes

Risk index calculated from systolic blood pressure value and time spent in that value.

With the risk index we are better able to assess the total risk of the high levels of blood pressure to the patient. The risk index is dependant on the time integral of the blood pressure, for which the zero-value may be calculated from average pre-extubation SAP level.

Time frame: Starting at the point when propofol infusion is halted and lasting up to three hours after extubation.