Applications of Task Analysis and Workload Methodologies
The results of the task analyses and workload measurements have
primarily provided objective confirmation for a number of intuitive beliefs about
anesthesia practice. The real importance of these studies is that a coherent methodology
has been developed that may be useful for studying a variety of interesting questions.
The question of the impact of electronic automated record-keeping systems is addressed
earlier. Another question concerns trans-esophageal echocardiography (TEE). This
newer monitoring modality has become commonplace during cardiac anesthesia and anesthesia
for other patients with cardiovascular disease who undergo complex operations. It
is widely recognized that evaluating TEE images and manipulating the TEE probe require
substantial visual and mental attention.
The UCSD/VA-Stanford group has published data suggesting that
vigilance (as measured by response latency to illumination of a red light) was substantially
lower when the anesthesiologist was involved with manipulating, adjusting, or examining
the TEE compared with other patient care tasks ( Fig.
83-9
).[110]
This may be due, in part,
to the layout of the workspace. The TEE machine is large and is often placed near
the left side of the head of the OR table, whereas the anesthesia machine and attendant
monitors, by convention, are typically placed near the right side of the head of
the table. Remote displays slaved to the primary monitor are also more likely to
be on the
Figure 83-9
Vigilance test data during anesthetic tasks with and
without automated record-keeping. The range of data is shown for each of four taskcategories
in electronic automated record-keeping (EARK) and manual record-keeping (MAN). Each
box contains 50% of the data for that subgroup (upper limit of box is the 75th percentile;
lower limit is the 25th percentile), whereas the maximum and minimum are shown by
the upper and lower horizontal bars. The response latency during record-keeping
was not significantly different between EARK and MAN. In both record-keeping groups,
subjects had significantly slower responses when observing or adjusting the transesophageal
echocardiogram (TEE), compared with recording, observing monitors, or adjusting intravenous
lines (IVs). Subjects in both groups had faster response latency when observing
the monitoring array, which contained a red light, compared with the other three
tasks. *, P < .05; †, P
< .05. (From Weinger MB, Herdon OW, Gaba DM: The effect of electronic
record keeping and transesophageal echocardiography on task distribution, workload,
and vigilance during cardiac anesthesia. Anesthesiology 87:144–145, 1997.)
patient's right side. This arrangement makes it difficult physically to glance from
one modality to another. The degree to which the mental concentration required to
use TEE itself detracts from vigilance for other signals remains to be determined
explicitly.
Furthermore, it is important to differentiate the various uses
of TEE. When it is used to answer specific clinical questions triggered by events
or milestones during the procedure, the value of the information may be worth an
investment of effort even though there is a reduction in overall vigilance. When
it is used as a continuous monitor for myocardial ischemia, or when conducting a
detailed routine examination, the reduction of vigilance must be considered when
evaluating the potential benefits of the technology. Some practitioners describe
special ways to handle the attention requirements of TEE, including tightening alarm
thresholds (to provide audio warnings of changed values) and assigning specific patient
monitoring functions to another individual while conducting the initial TEE placement
and examination.
There remain many other interesting questions concerning the performance
of anesthetists that can be addressed with the techniques of task analysis and workload
and vigilance assessment, including the following:
- How do the task load and task density differ between private practice settings
and academic settings?
- Are there characteristic "patterns" for experts and novices (or should
we say for "good" and "bad" anesthesiologists?) in the analysis of tasks and their
densities? And if yes:
- How do the work patterns of novices change to become those of "experts"?
How can the training of novices be focused to support these changes best? Is suboptimal
performance of novices detectable through analysis of task distributions and mental
workload?
- Can work patterns be linked to safe anesthetic practice, or can special
patterns be linked to unsafe behaviors? Perhaps this could be done by assessing
high-workload simulator scenarios. In a proactive safety culture, this would allow
us to identify those colleagues and train them individually.
- How much task load can the average anesthetist handle? How are tasks distributed
among personnel (e.g., between resident and faculty, between CRNA and supervisor,
and among staff anesthetists) during the high-workload periods of patient care?
This question is just beginning to be addressed by applying the task-analysis techniques
described earlier to videotapes of actual anesthetic cases. Using these tapes, the
task sequences of multiple anesthesia personnel can be elicited separately, as can
the communications used to coordinate their activities.
Ability Requirements for Anesthetists
Unlike in military aviation, there are few formal selection criteria
for entry into anesthesia practice. Instead, the criteria are decided on by each
department's trainee selection committee. Nearly every student who chooses anesthesia
as a specialty will be accepted by some training institution. Moreover, few residents
are terminated from their anesthesia training, and then usually only because of drug
abuse or too persistent or egregious lack of normal or technical skill.
There has been recent work on defining the underlying ability
characteristics of the successful anesthetist. Greaves and Grant[31]
presented an inventory of 16 characteristics of "good" anesthetic practice—knowledge,
skill, perception, confidence, prudence, vigilance, fluency, decisiveness, anticipation,
organization, flexibility, responsiveness, good manner, assertiveness, good management,
and good communication. This inventory can serve as a basis for discussion of anesthetists'
education and training. The authors of the inventory recommended its use for a formalized
consultant feedback to their trainees, although they pointed out the unproven validity
and reliability.
An interdisciplinary group in Germany conducted an evaluation
of another list of critical abilities for anesthetists published in German.[243]
