Decreasing the Incidence of Delirium After Cardiac Surgery

In critically ill surgical patients, delirium (confusion and disorientation) is extremely common and is associated with longer hospital length of stay, mortality, cost, and long term cognitive impairment. The goal of the study is to establish whether benzodiazepines (a sedative, anti-anxiety drug) should be used as part of standard of care or be eliminated by comparing the chances of delirium in cardiac surgery patients between two groups: a group that receives benzodiazepines during surgery versus a group that does not receive benzodiazepines during surgery. Benzodiazepines have historically been used in cardiac anesthesia to decrease the risk of anesthesia awareness. The current standard of care is to keep the patient on inhaled anesthesia throughout the surgery which eliminates the need for intraoperative use of benzodiazepines. Benzodiazepines are still used based on practitioner preference. Findings of this study will allow all anesthesiologists to make more informed decisions about what level of care our patients need.

In critically ill surgical patients, delirium is extremely common and is associated with longer hospital length of stay, mortality, cost, and long term cognitive impairment. Benzodiazepine usage is common in anesthetic practice, and ICU literature demonstrates that limiting post-operative benzodiazepines decreases the incidence of delirium. However, the avoidance of preoperative and intraoperative benzodiazepines during cardiac surgery has not been studied in terms of its effect on delirium. The goal of the study is establish whether benzodiazepines should be used as part of standard of care or be eliminated by comparing the incidence of delirium in cardiac surgical patients when randomized to a group that receives benzodiazepines versus a group that does not receive benzodiazepines.

Potential subjects will be identified and recruited the day before surgery by primary investigators. Patients undergoing coronary artery bypass grafting or single valve procedures that consent to participate will be enrolled in the study. These patients may be consented during the pre-operative period. Patients will be informed that whether they enroll in the study or not, they will be receiving standard clinical care. Only subjects meeting all inclusion criteria and requirements for continuation in the study will be consented.

Patient will be randomized by age (age is a predictor of delirium) to 3 groups:

* \>80 years of age;
* 70-80 years of age;
* \< 70 years of age.

Within these 3 groups, patients will be randomized to receive benzodiazepines during cardiac surgery or not. The anesthesiologist in the operating room will not be blinded to the group; however, the intensive care physician evaluating for delirium will be blinded to the treatment groups.

Benzodiazepine group:

1. Premedication 0.02mg/kg-0.1mg/kg of midazolam;
2. Maintenance 0.8 minimum alveolar concentration of inhaled anesthetic (MAC) and 10-30mcg/kg of fentanyl;
3. Postoperative 10-100mcg/kg/min of propofol

Non-benzodiazepine group:

1. Premedication 0-50mg of propofol and/or 0-250mcg of fentanyl;
2. Maintenance 0.8 minimum alveolar concentration of inhaled anesthetic (MAC) and 10-30mcg/kg of fentanyl;
3. Postoperative 10-100mcg/kg/min of propofol

Delirium can now be reliably diagnosed by non-psychiatrists in critically ill patients in less than 2 minutes through the use of validated monitoring instruments such as the Confusion Assessment Method for the ICU (CAM-ICU).

Eligibility Criteria:
Inclusion Criteria:

* Adult patients' undergoing coronary artery bypass grafting or single valve procedures.

Exclusion Criteria:

* Patients who have baseline cognitive dysfunction,
* Patients with hearing problems,
* Patients currently on benzodiazepines