Real-world medical decisions rarely involve binary Ðsole condition present or absent-
patterns of patient pathophysiology. Similarly, provider interventions are rarely unitary
in nature: the clinician often undertakes multiple interventions simultaneously.
Conventional approaches towards complex physiologic derangements and their associated
management focus on the frequencies of joint appearances, treating the individual
derangements of physiology or elements of intervention as conceptually isolated. This
framework is ill suited to capture either the integrated patterns of derangement displayed
by a particular patient or the integrated patterns of provider intervention. Here we
illustrate the application of a different approach-that of symbolic dynamics-in which the
integrated pattern of each patients derangement, and the associated provider response, are
captured by defining words based on the elements of the pattern of
failure. We will use as an example provider practices in the context of mechanical
ventilation- a common, potentially harmful, and complex life support technology. We also
delineate other domains in which symbolic dynamics approaches might aid in quantitating
practice patterns, assessing quality of care, and identifying best practices.