Veterinary perioperative risk is commonly summarized before anesthesia using patient characteristics, comorbidity, physical-status classification, laboratory findings, and anticipated procedural complexity. These variables are clinically important, but they describe vulnerability before the physiological consequences of anesthesia, surgery, instability, intervention, and recovery have unfolded. This article develops an original non-empirical framework in which perioperative risk is treated as a time-dependent clinical state rather than a fixed preoperative attribute. The synthesis distinguishes baseline physiological reserve and organ vulnerability from procedural stress, anesthetic exposure, evolving hemodynamic and respiratory instability, thermal and coagulation disturbances, cumulative physiological insult, response to rescue, and postoperative recovery. The proposed architecture interprets risk through repeated state updating: an animal with substantial baseline vulnerability may remain stable when stress is limited and abnormalities are rapidly reversible, whereas an apparently low-risk animal may acquire clinically important risk through sustained or interacting perioperative disturbances. Measurement quality and clinical context are treated separately from the physiological state being measured, and isolated thresholds are not assumed to represent equivalent risk across animals or procedures. The framework is intended to organize perioperative observation, interpretation, escalation, and reassessment rather than provide a validated risk score or universal intervention algorithm. Its applicability is constrained by predominantly canine evidence, heterogeneous surgical populations, observational outcome studies, limited feline data, device- and method-dependent measurements, and uncertain transferability across practice settings. Prospective multisite validation is required before predictive or decision-support use.
