Objective. Currently, vital parameters are commonly displayed as trends alo
ng a timeline. However, clinical decisions are more often based upon concep
ts, such as the depth of anesthesia, that are derived by combining paramete
r relationships and additional context information. The current displays do
not visualize such concepts and therefore do not optimally support the dec
ision process. A new display should present an ecological interface (EI). T
he principle of EI design is to visualize all of the information necessary
for decision making in one single display. Methods. In the first approach,
we developed an EI that visualizes 35 relevant parameters for anesthesia mo
nitoring. All of the parameters are generated by an anesthesia software sim
ulator. Sixteen anesthetists had to administer two simulated general anesth
etics: in one setting working only with the simulator's monitors ("SimOnly"
), and in another setting working with the simulator's monitors in combinat
ion with the EI ("Combi1"). During each experiment, one unexpected critical
incident (either blood loss or a cuff leakage) had to be identified. The c
ontrol and monitoring behavior was analyzed by recording the subjects' eye
movements and think-aloud protocol. With the help of the eye-tracking resul
ts, we re-designed the EI. The new EI was then tested with no eye tracking
("Combi2") on eight anesthetists under analogous conditions as in "Combi1."
Results. Cuff leakage was identified significantly quicker in "Combi1" (7
of 8 cases; time (T): 65 s +/- 73 s) than in "SimOnly" (6 of 8 cases; T: 22
2 s +/- 187 s). Blood loss was identified in 5 of 8 cases (T: 215 s +/- 76
s) in "Combi1" as quickly as in "SimOnly" (all cases; T: 217 s +/- 72 s). I
n "Combi1," the EI was used as the main source of information (in 43 +/- 19
% of time) and was frequently favored when identifying an evolving critical
incident. In "Combi2," cuff leakage was identified in 7 of 8 cases (T: 70s
+/- 111s) as quickly as in "Combi1." Blood loss was identified significant
ly quicker in all cases (T: 147 s +/- 62 s) in "Combi2" than in "Combi1" an
d in "SimOnly." Conclusion. The results have shown that appropriately desig
ned EIs may improve the anesthetist's decision making and focus attention o
n specific problems. Now, the findings have to be tested in future studies
by widening the scope using other simulated scenarios and being closer to r
eality under real conditions in the OR. Eye tracking proved to be a useful
method to analyze the anesthetists' decision making and appropriately re-de
sign interfaces.