Lorenz butterfly showing effect of two attractors over time in a complex, chaotic system. Such systems are deterministic - i.e. they are not random, but indeed are completely determined by a fixed set of differential equations. However these systems are extremely sensitive in an "unpredictable" way to very slight perturbations, in that apparently trivial changes can sometimes (but unpredictably) produce a large effect. In a sense, such perturbations "cause" the ensuing effect, but not in any reproducible manner. Some risk factors for disease may be like such perturbations of a complex chaotic system in that they sometimes have a large effect but generally have no effect. Understanding how particular factors might influence disease processes in an unpredictable way may be important for managing some disease conditions.
Complexity science and chaos theory are proposed as further explaining the nature of medical knowledge[1][2] and education[3].
In health services research, although complexity theory has not advanced to the state of being able to mathematically model healthcare delivery, it has been used as a framework for case study[4][5][6][7][8] and traditional bivariate analysis[9][10] of healthcare delivery. For example, a systematic review of organizational interventions to improve the quality of care of diabetes mellitus type 2[9] and heart failure[10] suggests that interventions based on complexity theory will be more successful.
Complexity science has been proposed as a model for organization change in medicine.[11][11] However, if the goal of modeling healthcare is to comply with specific quality indicators, interventions based on systems theory may be more effective than those based on complexity theory.[12]
In basic science research, fractal patterns have been found in cardiac conduction and fluctuations in vital signs over time.[13]Fractals are evidence of a system that follows the non-linear mathematics of a complex adaptive system. That are many other examples of fractal patterns in nature including the prediction of weather patterns.[14]
↑Sturmberg JP (2007). "Systems and complexity thinking in general practice: part 1 - clinical application". Australian Family Physician36: 170–3. PMID 17339983. [e]
↑ 9.09.1Leykum LK et al. (2007). "Organizational interventions employing principles of complexity science have improved outcomes for patients with Type II diabetes". Implementation Science : IS2: 28. DOI:10.1186/1748-5908-2-28. PMID 17725834. Research Blogging.
↑Goldberger AL (1996). "Non-linear dynamics for clinicians: chaos theory, fractals, and complexity at the bedside". Lancet347: 1312–4. PMID 8622511. [e]Full text at Ebsco