Inhaled Anesthetics and Myocardial Strain

The primary research activity will be: baseline transthoracic echocardiogram (TTE) views
taken upon the patient entering the operating room by one of the cardiothoracic
anesthesiology fellows or attendings, TEE views taken by the echocardiography fellow or
attending in the mid-esophageal 4C, 2C and LAX views once the patient has reached sevoflurane
end-tidal minimum alveolar concentration (MAC) of 0.5, 1.0, and 1.5. Following this,
sevoflurane will be changed to isoflurane and wait till complete washout of sevoflurane (i.e.
end-tidal sevoflurane concentration reaches zero). Isoflurane concentration will be adjusted
according to bispectral index and hemodynamics to maintain anesthesia during this period.
Once complete sevoflurane wash-out has been achieved, isoflurane concentration will be
adjusted and repeat images taken at the 0.5, 1.0, and 1.5 MAC values.

Investigators will establish stability at each MAC level (0.5, 1.0 and 1.5) for 5 minutes
before obtaining TEE images. The whole study is done during pre- cardiopulmonary bypass(CPB)
period while surgeon spending time dissecting internal mammary artery or other parts of
surgical dissection before heparinization. The entire study duration will be a maximum of
35-40 minutes and this will not prolong the operating time. The adjustment of the anesthetic
will be performed by the cardiac anesthesiology fellow or senior resident involved in this
research along with the faculty officially performing the case. All images will be acquired
prior to the initiation of cardiopulmonary bypass by the echocardiography rotating resident
or research resident, cardiac anesthesiology fellow or cardiac anesthesiology attending
anesthesiologist (all received extensive training in TEE to obtain those required images).
Following the completion of the case and the uploading of images to a central
echocardiography server, one of the study personnel will perform analysis of the images in
the anesthesiology offices on a computer with post-processing software to determine strain.

MAC up to 1.5 is very well tolerated in cardiac surgical patients and is routinely used to
achieve hemodynamic conditions during surgery. Use of vasopressor and inotrope to allow
maintain depth of anesthesia with inhalation anesthesia agents is also routine in cardiac
surgical patients and not in any way different from routine clinical care.

Hemodynamic information (heart rate, blood pressure, central venous pressure, cardiac index
or pulmonary artery pressure) will be obtained after stabilization with each MAC and will be
recorded immediately or extracted from the electronic medical records.

Inclusion Criteria:

Adult Patients (> 18 years of age) undergoing cardiovascular surgery at University of
Pittsburgh Medical Center (UPMC) Presbyterian hospital.

Exclusion Criteria:

Inability to comprehend and understand the study, Pregnancy Malignant hyperthermia Acute
cardiogenic shock and ongoing chest pain Permanent pacemaker with pacemaker dependency
Abnormal cardiac rhythms ( e.g. atrial fibrillation) Contraindications to TEE examination
such as recent esophageal surgery, esophageal cancer/stricture The use of anesthesia
maintenance with intravenous anesthesia drugs such as propofol infusions