Clinical Trial: Determine the Effective Dose 95 of Sevoflurane in Adult Patients

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational

Official Title: Determine the Effective Dose 95 of Sevoflurane in Adult Patients Undergoing Cardiac Surgery Under Cardiopulmonary Bypass.

Brief Summary:

Introduction: Sevoflurane is the most volatile anesthetic used during CPB. In addition to the cardioprotective effect, Sevoflurane also promotes reduction in systemic vascular resistance and also an important role in anesthesia maintenance during surgery, preventing patients awaken in the intraoperative. To avoid the awakening during surgery, assessment of the level of consciousness through the bispectral index (BIS) has been the most common method used by anesthesiologists. During cardiac surgery the most critical moment may be the patient is awaken during the warm up phase of CPB. The monitoring of this phase with the BIS has become efficient as to alert the anesthetist that the patient may be waking up.

Aims: The primary endpoint of this study is to determine the ideal minimum dose of sevoflurane (ED 95) that 95% of patients undergoing anesthesia during CPB in cardiac surgery have no intraoperative awareness.

Methodology: Dixon's up-and-down technique is a commonly used method to define MAC (27-30). The anesthetic concentration applied to the first patient is estimated by clinical experience. If there BIS values below 50, the concentration of inhalational anesthetic in subsequent patient is decreased by 20%. If the BIS show values greater than or equal to 50 for a period ≥ 1 minute steadily, the concentration is increased by 20% in the next patient. In each series of patients, the pairs of independent cross in order measurements are identified. Logistic regression is used to determine the ideal minimum dose of sevoflurane (ED 95) that 95% of patients undergoing anesthesia during CPB in cardiac surgery have no intraoperative awareness.


Detailed Summary:

Introduction Some studies showed evidence of cardio-protection and reduction in mortality due to the use of volatile agents during cardiac surgery. (1) These findings seems to be associated when the volatile agents are used during all the surgical procedure, including the period of CPB. (2) Sevoflurane is the most volatile anesthetic used during CPB. In addition to the cardioprotective effect, Sevoflurane also promotes reduction in systemic vascular resistance (4.5) and also an important role in anesthesia maintenance during surgery, preventing patients awaken in the intraoperative (6.7). To avoid the awakening during surgery, assessment of the level of consciousness through the bispectral index (BIS) has been the most common method used by anesthesiologists. During cardiac surgery the most critical moment may be the patient is awaken during the warm up phase of CPB. The monitoring of this phase with the BIS has become efficient as to alert the anesthetist that the patient may be waking up. (3) In addition, several studies have been trying to find what is the ideal minimum dose of inhaled anesthetics that 95% of patients do not awaken during some surgical procedures (ED 95). (8-25). However, there are no studies that demonstrate what is the ideal minimum dose of inhaled anesthetics used during CPB in cardiac surgery, so patients do not have any conscience at this stage. Case we have this information, even when it is not possible to monitor the level of consciousness using the BIS, the risk for patients to awaken during the intraoperative period, especially the CEC, would become significantly reduced.

The primary endpoint of this study is to determine the ideal minimum dose of sevoflurane (ED 95) that 95% of patients undergoing anesthesia during CPB in cardiac surgery have no intraoperative awareness. Secondary endpoints include neurocognitive assessment using the Mini Men
Sponsor: Instituto Dante Pazzanese de Cardiologia

Current Primary Outcome: The effective dose of sevoflurane (ED 95) in cardiac surgery have no intraoperative awareness. [ Time Frame: 6 months ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Neurocognitive assessment using the Mini Mental Test [ Time Frame: 6 months ]
  • Recall intraoperative reported by the patient in post-operative period [ Time Frame: 6 months ]
  • Time of endotracheal intubation [ Time Frame: 6 months ]
  • Length of stay in intensive care unit (ICU) [ Time Frame: 6 months ]
  • Length of stay in hospital stay. [ Time Frame: 6 months ]


Original Secondary Outcome: Same as current

Information By: Instituto Dante Pazzanese de Cardiologia

Dates:
Date Received: March 8, 2016
Date Started: October 2016
Date Completion: July 2017
Last Updated: October 30, 2016
Last Verified: October 2016