'The gold standard of care'
UTHSC anesthesiologists at University Hospital are employing a conventional technique in a non-conventional way -- to make sure patients' hearts are functioning well during and after cardiac surgeries.
"The technique is called trans-esophageal echocardiography, and cardiologists traditionally have utilized it to assess heart disease," said Dr. Jaydeep Shah, chief of cardiothoracic and transplantation anesthesia in the department of anesthesiology. "We have moved echocardiography into the operating room and intensive care unit to monitor and direct the course of treatment of very sick patients."
Anesthesiologists generally measure cardiac function during surgery by threading a catheter through the heart and into the pulmonary artery. "Unfortunately, this records blood pressures in different parts of the cardiac system. Those pressures are dependent on several variables and might distort the results," Dr. Shah said.
Trans-esophageal echocardiography enables the operating room anesthesiologist to assess heart function during the entire operation and to fine-tune anesthesia to critically ill patients to prevent diminishing of heart and lung function. "With echocardiography, we actually look inside the heart and see how it is functioning, rather than relying on pressure numbers," Dr. Shah said. "This technique is rarely used in operating rooms in San Antonio currently."
Why is general anesthesia hard on the heart and lungs? "It can depress heart function and drop blood pressure, because what we are doing is trying to keep people asleep with potent chemical agents," Dr. Shah noted. "The drugs that are utilized in providing general anesthesia can have a significant depressive effect on the cardiac system."
That's why echocardiography, with the detailed information it provides about the heart and its functions, is so important in the operating room and in the hours after surgery.
"We are using echocardiography in our intensive care units with patients who are taking a turn for the worse," Dr. Shah said. "Beat by beat, the function of the heart is evaluated. We can calculate how well the heart pumps blood. We can see the patient having myocardial ischemia (oxygen deficit in the heart), and we don't have to wait for a deleterious event to occur."
Trans-esophageal echocardiography works by picturing the muscular movements of the heart walls, which tighten when the heart pumps blood. Changes in this pumping action may indicate that the anesthesiologist should change the mix of anesthetics being provided. "The goal is to supply as much blood as possible to the vessels that supply the heart," Dr. Shah said. "This may entail giving a patient specific medications that will improve the function of the heart."
UTHSC and University Hospital anesthesiologists also are using echocardiography to assist pediatric heart patients such as babies born with heart defects. "We can reveal defects using this technique when they enter the hospital," he said. "After surgery, we can see if the repair is successful in the operating room. We can tell the surgeons, yes, "this is good," or no, "something more is needed."
"The same applies to adults who need heart valve correction. We can ascertain right away whether the repair or the replacement of the valve is adequate prior to the patient leaving the OR."
Dr. Shah is assistant professor of anesthesiology at UTHSC, chief of the cardiology and transplantation anesthesia division and vice chair of anesthesia research at University Hospital. He also provides anesthesiology on cases at the South Texas Veterans Health Care System.
"What makes the cardiac anesthesiologist so special is that he or she works hand in hand with the surgeon in taking care of the patient and assessing the quality of the surgical outcome. It is definitely a team effort," Dr. Shah said.
The team sees about 600 cardiac patients a year and provides echocardiography on 800 to 1,000 patients a year. "This is something not offered in many clinical settings," he said. "It improves the care of these types of patients. In paper after paper, it is proved that echocardiography is the gold standard of care for these types of patients."