Saturation & Going Solid

"Going solid": A model of system dynamics and consequences for patient safety. Richard Cook, Jens Rasmussen. Quality and Safety in Health Care. May 2005. dx.doi.org/10.1136/qshc.2003.009530 researchgate

Rather than being a static property of hospitals and other healthcare facilities, safety is dynamic and often on short time scales. In the past most healthcare delivery systems were loosely coupled—that is, activities and conditions in one part of the system had only limited effect on those elsewhere. Loose coupling allowed the system to buffer many conditions such as short term surges in demand.

Modern management techniques and information systems have allowed facilities to reduce inefficiencies in operation. One side effect is the loss of buffers that previously accommodated demand surges. As a result, situations occur in which activities in one area of the hospital become critically dependent on seemingly insignificant events in seemingly distant areas.

This tight coupling condition is called “going solid”.

Rasmussen’s dynamic model of risk and safety can be used to formulate a model of patient safety dynamics that includes “going solid” and its consequences. Because the model addresses the dynamic aspects of safety, it is particularly suited to understanding current conditions in modern healthcare delivery and the way these conditions may lead to accidents.

We have observed situations where an entire hospital is saturated with work, creating a system wide bed crunch. The result is a dramatic change in workplace operational characteristics that creates new demands and increases the stakes for practitioner decisions and actions.

We describe this shift in operations as going solid. "Going solid" is a nuclear power slang term used to describe a difficult to manage technical situation. Manageable behavior of a steam boiler depends on having both steam and liquid water present in the boiler. When a boiler becomes completely filled with liquid (goes solid), its operating characteristics shift suddenly and dramatically. The resulting situation is both hazardous and difficult to control.

"Going solid" in hospitals creates problems that are, we believe, similar in many respects to those that accompany going solid in nuclear power plants. In particular, "going solid" in a hospital creates a series of critical relationships, tightly coupling the units of the hospital together so that events in one place have direct implications for the operations of all the others.

To describe, analyze, and assess this phenomenon, we introduce a model that explains how "going solid" works at a systemic level and its implications for the understanding of safety culture.

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