Agitated Saline, Albumin, or Propofol-albumin Mixture for Enhanced Contrast in TEE Examinations

This is a prospective, randomized, controlled study to determine if albumin and propofol or albumin only will provide superior qualitative contrast enhancement during TEE bubble studies compared to the current standard of care contrast agent, agitated saline. The study will take place in the Operating Rooms (OR) at the UCSD Sulpizio Cardiovascular Center. The TEE studies will be reviewed by UCSD Anesthesiology or Cardiology faculty who are credentialed to read and interpret echocardiographic studies.

The study population will consist of 20 English-speaking patients and all will receive two doses of contrast, namely agitated albumin or propofol and albumin mixture, undergoing cardiac surgery who require TEE. Each patient will undergo qualitative review by 10 anesthesiologists and/or cardiologists credentialed to read echocardiographic studies at the time of the surgical procedure, and also with retrospective review of the echo video. The multiple reviewers per patient will increase the power of the study (~200 studies). Each patient will receive three bubble studies using 10 ml of agitated contrast agent as named above. The order in which each contrast agent is utilized, as well as the experimental contrast agent, is randomized and the interpreting physician is blinded to this information. Agitated saline (AS) alone will be used as a (third dose) control for each patient, which is the current standard contrast agent for TEE bubble studies. The other bubble studies will use an experimental agitated contrast agent, either a mixture of 7 mL albumin and 3 mL propofol (10 mg/ml) or 10 mL albumin (human). Saline and albumin 5% are intravenous fluids FDA approved for the use in restoration and maintenance of circulating of blood volume. Propofol is FDA approved for the use in induction or maintenance of general anesthesia.

The anesthesia care team, as per the standard care during UCSD cardiac surgical procedures, will place a TEE probe after induction of general anesthesia and endotracheal intubation. During the initial TEE exam, a bicaval view will be obtained. Both the order and type of experimental agitated contrast agent will be randomized and blinded to the sonographer and reviewer. A 20 beat loop will be recorded for each bubble study. Hemodynamic variables prior to injection of contrast agent; and 30 seconds, 1 minute and 2 minutes after injection are monitored and recorded. All recorded data will be anonymized prior to review. TEE is standard of care and routinely used in the care of cardiac surgery patients and is not performed solely for this study.

All anesthetic, surgical and medical interventions will be chosen and carried out by the surgical and anesthesia teams, including those involving invasive monitor placement, fluid administration, ventilator management and patient positioning.

Appropriate statistical analysis will be utilized to evaluate the difference in contrast enhancement in the saline only, albumin, and albumin and propofol groups.

The results of the study will be published in the peer-reviewed medical literature.

Inclusion criteria

• cardiac surgical patients requiring a transesophageal echocardiogram (TEE)

Exclusion criteria

• allergy to propofol
• inability to place a TEE probe
• inability to obtain a TEE bicaval image
• known right to left intracardiac shunt
• pt refusal to accept human blood products including albumin
• pt refusal to participate in study
• vulnerable patients (pregnant women, prisoners, cognitively impaired, or institutionalized)