RESUMO
RATIONALE: COVID-19 has fundamentally changed the practice of Emergency Medicine (EM). Care delivery on the front lines has historically depended upon ostensibly reliable input-output models for staffing, supplies, policies, and therapies. Challenged by the complexity of healthcare during the pandemic, the fallibility of these reductionist models was quickly revealed. Providers and systems quickly had to reconceptualize their dependence on the wider, complex system in which healthcare operates and find adaptive solutions to rapid changes. AIMS/METHOD: This papers seeks to review and describe how Systems Thinking and Complexity Theory (ST/CT)-concepts, principles, and tools that can be used to understand and impact our constantly evolving health system-can be applied to better understand and enact change in complex settings such as during COVID-19. Some of these ST/CT are described through the real world example of the Alameda Health System Vaccine Taskforce. RESULTS: ST/CT concepts such as Unintended Consequences, Interrelationships, Emergent Behavior, Feedback Loops, and Path Dependence can help EM providers and planners understand the context in which their system operates. Key principles such as Collaboration, Iterative Learning, and Transformational Leadership can help these actors respond to current and future challenges. The integration of these concepts and principles into the Learning Health System offers a model for tying these key concepts and principles together into an adaptive, cross-sectoral organizational approach. CONCLUSION: By integrating ST/CT into the practice of EM, we can not only improve our ability to care for patients but also our capacity to understand and strengthen our wider systems of care.