In healthcare systems management, control of hospital flows and anticipation of overcrowding situations are major issues. The purpose of this paper is to contribute to the scheduling and orchestration of multi-skill health care tasks to manage bottlenecks in the Pediatric Emergency Department (PED). Our solution integrates a collaborative workflow approach to model the patient journey in order to identify dysfunctions and peaks of medical staff activities within the PED. The dynamic and uncertain aspect of the problem has led us to adopt an alliance between the Multi-Agent Systems (MAS) and workflow approach for the optimization of the health care process.