Clinical Trial: The Effect of Deliberate Hypotension on QTc, Tp-e Intervals and Heart Rate Variability

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title:

Brief Summary: Deliberate hypotension is defined as lowering the systolic blood pressure to 80-90mmHg, or the mean blood pressure to 50-65mmHg. This technique is usually employed for operations that have a high risk of intraoperative hemorrhage, such as orthognathic surgery. Several different regimens are used to lower the patient's blood pressure, such as vasodilators, autonomic nervous system inhibitors, opioids and inhalation anesthetics. However, the effects that these agents have on the QTc and Tp-e intervals during deliberate hypotension is not known. Virtually every kind of anesthetic is reported to have some effect on the QTc and Tp-e intervals. Because orthognathic surgery usually takes 3-4 hours to complete, the amount of anesthetics and drugs used to maintain low blood pressure is not small. Therefore, the effect that these agents may have on the QTc and Tp-e intervals may not be negligible. The investigators of the present study found that the high dose of commonly used hypotensive agents tend to prolong these variabilities to some extent. This study will be able to provide insight as to which hypotensive anesthesia regimen has the least effect on the QTc and Tp-e intervals, and therefore will be helpful in minimizing cardiovascular risks of deliberate hypotensive anesthesia.

Detailed Summary:
Sponsor: Yonsei University

Current Primary Outcome: Changes in QTc, Tp-e interval during deliberate hypotension [ Time Frame: Before induction of anesthesia (T1), 10 minutes after induction of anesthesia (T2), 30 minutes after target blood pressure is reached (T3), every 60 minutes after from the end of surgery ]

Original Primary Outcome: Same as current

Current Secondary Outcome: Changes in Tp-e interval during deliberate hypotension [ Time Frame: Before induction of anesthesia (T1), 10 minutes after induction of anesthesia (T2), 30 minutes after target blood pressure is reached (T3), every 60 minutes after from the end of surgery ]

Original Secondary Outcome: Same as current

Information By: Yonsei University

Dates:
Date Received: June 25, 2012
Date Started: June 2012
Date Completion:
Last Updated: February 13, 2013
Last Verified: February 2013