Nature of the Operational Domain of Anesthesiology
The operational domain of anesthesia is a complex, dynamic world
[60]
that presents a cognitive profile common to
many real-world task domains. The analysis of complex dynamic worlds in the last
decade has departed sharply from previous conceptions of decision-making.[61]
Classic decision-making approaches, such as decision theory and multiattribute utility
theory, were mathematic techniques that were traditionally used as the dominant framework
for understanding human performance. They worked well in simplified laboratory experiments
on decision-making and action, yet a number of investigators had significant difficulty
in applying them to real-world decision and action settings.[61]
Orasanu and Connolly identified eight factors that characterize such naturally occurring
complex dynamic worlds. They apply to anesthesia as follows:
- Ill-structured problems. Unlike in traditional decision experiments, there
is not just a single decision to be made. Rather, there are a variety of interrelated
decisions to be made by the anesthetist and the surgeon. The patient's physiologic
behavior is not an independent random variable but is causally linked to previous
decisions and actions.
- Uncertain dynamic environment. Dynamism stems from the frequency of routine
and anomalous changes or events, the rapidity with which they evolve, and the unpredictability
of the patient's physiology and response to interventions. The anesthetized patient
during surgery is in a constant state of change, with many events outside the anesthetist's
control. Although preventive measures can reduce the likelihood of some events,
others cannot be avoided because they are inevitable side effects of medically necessary
procedures (e.g., surgical blood loss). Unpredictable and dynamic occurrences compete
with the preplanned aspects of the case, driving the anesthetist's actions. The
true state of the patient cannot usually be measured directly. It must be inferred
from ambiguous patterns of clinical observations and data from electronic monitors.
These data are imperfect because, unlike industrial systems that are designed and
built with sensors in key areas to measure the most important variables, patients
are typically instrumented to measure the variables that are easiest to monitor,
predominantly
using noninvasive methods. Most physiologic functions are observed indirectly through
weak signals available at the body surface and thus are prone to various types of
electrical and mechanical interference. Invasive measurements are also vulnerable
to artifacts and uncertainties of interpretation. Even if the anesthetist knew the
exact state of the patient, the patient's response to interventions would be unpredictable.
- Time stress. Because the OR is a scarce resource, there is an incessant
overall time pressure to use it efficiently. There is an even more intense immediate
time stress within each case, generated by dynamic situations that evolve rapidly
and that must be dealt with in a timely fashion.
- Shifting, ill-defined, or competing goals. Multiple goals of case management
(e.g., hemodynamic stability, good operating conditions for the surgeon, rapid emergence
from anesthesia) may compete with each other. The surgeon's goals may sometimes
compete with those of the anesthetist. All these goals shift as the patient's situation
shifts dynamically throughout the case.
- Action/feedback loops. The time constants of actions and their effects
are very short, on the order of seconds to minutes. There is a complete intermixing
of decision-making and action; these functions are not performed in separate cycles.
Most decisions and actions are implemented and evaluated incrementally, with the
effect of one cycle assessed before deciding on further possible actions.
- High stakes. The stakes are high because, even for elective surgery in
healthy patients, there is an ever-present and very real risk of injury, brain damage,
or even death. A catastrophe is often the end result of many pathways that begin
with seemingly innocuous triggering events. Each intervention, even if appropriate,
is associated with side effects, some of which are themselves serious. Some risks
cannot be avoided. Unlike an event such as a commercial flight, which can be delayed
or aborted if a problem occurs, during an event in the OR this usually is not possible,
and immediate surgery may be necessary to treat a medical problem that is itself
life-threatening. Analogous to military aviation, balancing the risks of action
(anesthesia and surgery) against those of inaction is often extremely difficult.
- Multiple players. Anesthesia domains involve multiple players from different
professional backgrounds. Each individual has a set of goals, abilities, and limitations.
In some situations, interpersonal interactions, both among anesthesia personnel,
and between them and other OR team members, will dominate the work environment.
- Organizational goals and norms. The anesthetist works within the stated
and unstated norms of the OR suite, the anesthesia department, the institution, and
the profession as a whole. Decisions are sometimes made to conform to these norms
that are not wholly subscribed to by the anesthetist.
Although many of these features apply to other domains of medicine,
anesthesiology is unique in that all eight factors are prominent. In particular,
what sets anesthesia apart from clinic-based or ward-based medicine is the intensity
of dynamism, time pressure, and uncertainty; with danger lurking just below the surface.
