<p>Perioperative risk assessment still relies largely on models that estimate outcomes from variables measured at a single time point. These tools remain useful for cohort stratification, communication of baseline risk, and perioperative planning, but they often underrepresent the temporal dynamics that shape individual postoperative trajectories. That mismatch may reflect more than ordinary clinical variability. At least in part, it may point to a limitation in how perioperative risk itself is conceptualized. This paper offers a conceptual analysis drawing on physiology, critical care medicine, and dynamic systems theory. Its central claim is simple: perioperative risk may be better understood as a trajectory through physiological state space than as a fixed probability assigned before surgery. Surgical interventions can then be viewed as structured perturbations imposed on already reconfigured biological systems, with responses shaped by prior states, adaptive capacity, and physiological resilience. From this perspective, postoperative complications are not merely isolated adverse events. They may instead mark transitions between physiological regimes. Processes such as sterile inflammation, microcirculatory dysfunction, organ crosstalk, and loss of physiological complexity may help explain why postoperative trajectories diverge so sharply. Cardiac surgery provides a particularly clear setting in which these dynamics become visible, although the broader argument likely extends beyond it. The analysis has practical implications for clinical reasoning in high-risk settings. Rather than displacing static prediction, it highlights dimensions of perioperative risk, such as state dependence, irreversibility, and loss of resilience, that static models represent only incompletely. That shift does not solve the problem of perioperative uncertainty. It does, however, describe it more faithfully.</p>