The tactus eruditus referred to 19 th century physicians’ obsession with palpating the quality, force, and duration of a patient’s pulse. They were interested in assessing blood pressure, but had no easy way to quantify or measure it. “Sphygmographs” were introduced in the mid-1800s, but required placement of invasive cannulas and were not clinically useful. It was not until the noninvasive sphygmomanometer was introduced into US surgical practice in the early 1900s that measuring blood pressure began to be utilized for patient care. Despite some initial resistance, further refinements, standardization, and experience with the instrument made it a standard piece of operating room equipment over the ensuing 50 years.
The evolution of perioperative echocardiography shares some similarities with the establishment of blood pressure monitoring. Intraoperative M-mode transthoracic echocardiography (TTE) was first utilized in the 1970s as a way to assess the cardiac effects of various anesthetics. While its potential as a tool for anesthesiologists was recognized, several hurdles prevented widespread acceptance—not the least of which was the impracticality of performing multiple chest wall examinations during surgery. This was partially overcome by the development of M-mode transesophageal echocardiography (TEE), which was first reported in the operating room in 1980. However, it was not until two-dimensional imaging became available that echocardiography really attracted the interest of non-cardiologists.
In 1984 Roizen et al published the use of two-dimensional TEE as an intraoperative monitor to detect regional wall motion abnormalities and changes in ejection fraction in a series of non-cardiac surgical patients. Subsequent comparisons between TEE and electrocardiography demonstrated TEE to be the superior monitor for ischemia in the operating room. Thus, intraoperative TEE became established as a diagnostic tool, mostly for cardiac surgery, as well as an intraoperative monitor for high risk patients. By 1988, of those North American institutions practicing intraoperative echocardiography, twice as many were primarily using TEE versus TTE. A decade later, intraoperative TEE guidelines firmly established TEE as the modality of choice for cardiac anesthesiologists. Ironically, it is probably this dominance of TEE, with its invasive nature and advanced application for cardiac surgery, that has prevented more anesthesiologists from embracing echocardiography into their routine practices.
Dr. Colin Royse, an anesthesiologist and echocardiography educator from the University of Melbourne Australia, commented in a recent interview that when you “…lock up your expertise in a small group of clinicians, such as cardiac anesthesiologists, it makes it difficult to make the technology more widely available.” It is interesting to note that the 2002 training guidelines for intraoperative echocardiography specifically excluded TTE since it was rarely performed in the operating room. As pointed out by Dr. Shernan in the October council statement, however, the intra operative council has become the council for peri operative echocardiography. It must be acknowledged that not all perioperative care involves intubated patients in the operating room, and TTE certainly offers some advantages over more invasive modalities.
The importance of point-of-care echocardiography was recognized 10 years ago, when the ASE drafted recommendations regarding hand carried ultrasound (HCU) devices. HCUs were likened to the use of pulmonary artery catheters, with multiple specialties, including anesthesiology and critical care, adopting the technology as need and training grew. With recent improvements in portability of the devices, however, it is probably more appropriate to compare HCUs to stethoscopes. Some precedent for goal-directed cardiac ultrasound already exists with the FOCUS exam used by emergency medicine physicians. Anesthesiologists and critical care physicians would be wise to adopt something similar for post anesthesia care unit and intensive settings.
While perioperative ultrasound will obviously continue to require invasive modalities like tranesophageal, epiaortic, and epicardial echocardiography, it must also evolve to include technology that can provide rapid screening in pre- and post-operative settings. Only then will echocardiography become routinely employed by all types of perioperative physicians. Perhaps it will even become the modern tactus eruditus .