Evaluating anesthesia health care delivery for cardiac surgery. The role of process and structure variables

Anesthesia care is an integral component of cardiac surgery. Emphasis on cost-effectiveness and decreased hospital stay has prompted reevaluation of anesthesia practice. However, the role of anesthesia process and structure variables in relation to patient outcomes is largely unknown. Processes, Structures and Outcomes of Care in Cardiac Surgery is the first epidemiologic study to collect data on anesthesia processes, such as the pharmacologic components of anesthesia and types of cardiovascular monitors used. Structures of care, such as resident staffing, supervision, completeness of documentation, and training and experience of care providers, are also being assessed. Pilot data collected from September 1992 to September 1993 demonstrate substantial variation between the six study sites in selected processes and structures. Despite the near-universal use of narcotic anesthesia as the primary anesthetic technique, variation in the type of opioid and adjuvant benzodiazepine used was observed. Regarding invasive hemodynamic monitoring, most centers used only one type of catheter. Intraoperative transesophageal echocardiography was used commonly at several centers for valve surgery, whereas other centers did not use it at all. Its use during coronary artery bypass grafting was less common. Assessment of the preoperative anesthesia note revealed that coronary anatomy and ventricular function were noted in nearly all instances. However, a clear notation that risks and benefits of anesthesia were discussed was less frequent. Structures related to anesthesia attending staffing, board certification, and experience revealed variation. Some sites had smaller and/or more experienced attending staffs, whereas others had larger and/or less experienced staffs. These pilot findings appear to validate the authors' hypotheses that variations in anesthesia practice are present within the Veterans Affairs system. They suggest that the variable set is robust enough to relate processes and structures of anesthesia care to patient outcome.