THE STUDY OF HUMAN PERFORMANCE

The study of human performance involves research paradigms that are different from those typical in the science of anesthesia. There are many obstacles to obtaining hard, statistically valid data on human performance. There are no animal models for expert human performance, no 'Sprague Dawley anesthesiologists" to be studied in detail, nor can studies of professional performance be conducted using the psychologist's typical experimental subject, the university undergraduate student. Recruiting expert anesthetists to be the subjects of study is difficult, raising issues of selection bias concerning those who do volunteer. Especially if conducted during actual patient care, investigations of human performance are strongly influenced by concerns about litigation, credentialing, and confidentiality, thus making it difficult to execute optimal studies.

Furthermore, the variability among individual anesthetists is quite striking, because different anesthetists respond to the same situation in different ways, and each individual may act differently on different days or at different times of the same day. The magnitude of this intra-individual variability is often nearly the same as the inter-individual variability.

"Performance" itself is an intuitively meaningful concept that is difficult to define precisely. There are no gold standards for the clinical decisions and actions of anesthetists. They depend heavily on the context of specific situations. In addition, determining how anesthetists perform their jobs, whether successfully or unsuccessfully, means delving into their mental processes. This cannot be measured easily. On the one hand, one can use experimental designs that involve artificial laboratory tasks, for which performance can be objectively measured. These tasks will then be far removed from the real world of administering anesthesia. On the other hand, investigating the actual performance of trained practitioners in the real world yields primarily subjective and indirect data. Understanding the anesthetist's performance must be seen as analogous to solving a jigsaw puzzle. Pieces of the puzzle likely come from a variety of sources, none of which by itself captures the entire picture. These pieces include objective data from artificial laboratory tasks, prospective observation of routine patient care, analysis of retrospective reports of near misses or anesthetic

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Why Study Human Performance in Anesthesia?

How can an improved understanding of the human performance of anesthetists help them to provide patient care more safely, in a wider variety of clinical situations, with greater efficiency, and with increased satisfaction to both patients and practitioners? The possibilities include the following:

1. Improved operational protocols and enhanced training of anesthetists. The way in which individuals conduct anesthesia is based, in part, on knowing the limits of their performance envelope. Anesthetic techniques and OR practices should draw on anesthetists' abilities and should mitigate their weaknesses. Anesthetists' abilities are strongly affected by training. Understanding the required performance characteristics and inherent human limitations will lead to improved training, which will develop most fully the strengths and counter the existing vulnerabilities of the anesthetist. This process should make patient care safer, less stressful, and more efficient.
2. A more rational view of professional work and legal responsibility (see Chapter 89 ). Modern medicine, especially in the United States, is strongly influenced by medicolegal concerns. The litigation system has a major selection bias in that every case that comes before it involves an adverse outcome for a patient. The duty of the practitioner is to render care as a "reasonable and prudent" specialist in the area of anesthesia. What is reasonable and prudent? What type of performance is to be expected from appropriately trained human beings in a complex and dynamic environment? By understanding human performance, it may be possible to generate a more rational view of what is, and is not, within the standard of care.
3. A more effective work environment. Anesthetists now perform their tasks using an array of technologies, most of which has not been designed to support the anesthetist's work optimally. By understanding the anesthetist's tasks and performance requirements, the workspace and tools could be improved to better support the most difficult tasks. This, too, can lead to greater safety and to greater efficiency and work satisfaction.
4. A more efficient organizational system (see Chapter 86 ). Anesthesia is embedded within a larger system of organized medical care that involves interactions among numerous institutions, organizations, and professional domains. Understanding how the anesthetist's work relates to the larger system may enable the development of more rational and efficient flows of information and organizational control.

The first section of this chapter covers the analysis of human performance based on individual actions, decisions, and mental models. The second section looks at the influence of organizational factors and safety culture. Although anesthesiologists have been considering these issues for some time (see survey papers ^{[1] [2] [56]} ) their importance to health care in general has only recently been appreciated.^{[3] [57] [58] [59]}

The assessment of performance is a prerequisite for a rational use of simulation, and many assessments of anesthetists' work, especially in critical situations, are only possible in a simulator environment. Therefore, performance assessment and the classification and scores of technical and non-technical skills are dealt with in Chapter 84 , which discusses simulators. Simulators are the basis on which such scores are developed and evaluated.