Extracorporeal membrane oxygenation (ECMO) is a life-saving modality, yet it carries inherent risks of device-related adverse events. This manuscript is a focused review of ECMO circuit mechanics, monitoring, and troubleshooting. Its narrow scope focuses specifically on mechanical complications originating from the blood pump and the extracorporeal circuit, up to the patient. Designed for surgeons and intensivists, the review provides an actionable, bedside framework for managing these complex systems. The interfacing of blood with artificial surfaces and high shear stress environments triggers profound hematologic injuries, including hemolysis, platelet consumption, acquired von Willebrand syndrome, and systemic thromboinflammation. To detect these insidious complications before catastrophic failure occurs, the authors emphasize the integrated interpretation of a core biomarker panel including plasma-free hemoglobin, lactate dehydrogenase, D-dimer, and fibrinogen. The review also addresses physical circuit emergencies, identifying recirculation associated with veno-venous ECMO, as well as clinical signs of oxygenator thrombosis, catastrophic pump failure, and cavitation. The hope is to equip clinicians with immediate troubleshooting steps, such as pump-speed titration, volume resuscitation, and emergent circuit-exchange protocols. This focused review arms surgeons and intensivists with the critical mechanical and hemodynamic insights required to safely anticipate, identify, and troubleshoot extracorporeal support systems.