Strategic factors for the sustainability of a health intervention at municipal level of Brazil.

The present study aims to describe the evolution of an intervention, using a methodology that adopts the critical event as the unit of analysis, and to identify strategic factors that facilitate the continuation of the interventions. Six critical events were identified: dispute care models for health; area of advice: dispute field; change policy; break of interorganizational relations; lack of physical structure and turnover of staff; difficulty in organizing practices in the work process. these are developed into strategic factors: enabling network of allies; meetings and educational activities/building capacity; benefits perceived by community members; mobilization of key actors; intervention's compatibility with the government's vision; restoration of interrelationship; and stability of the workforce. These strategic factors form a group of interrelated conditions that provide the strengthened linkages between elements in the intervention, supporting the hypothesis that they collaborate for the sustainability of the interventions in health. Tracking down the transformations of an intervention set by the critical events, it was verified that these factors performed a protective role at times of changes in the intervention process.