Tourniquet physiology, bone cement implantation syndrome, and fat embolism

Model answer

Framing. Know three linked orthopaedic crises: tourniquet inflation/deflation physiology with practical time/pressure anchors per local protocol (pneumatic tourniquets reduce blood loss and improve visualisation; mitigate skin injury, compression neuropraxia, and ischaemia-reperfusion pain via pressure, duration, and padding);^[4] BCIS grades at cementation with hypoxia/hypotension management per the Donaldson classification (check the current reference for exact grade definitions);^[1] and fat embolism syndrome (skin petechia plus respiratory distress plus neurological disturbance) after long-bone instrumentation — prevention via early surgical fixation where appropriate, early recognition, and supportive critical care.^[5]

Must cover.

• Tourniquet pressure principles and time limits per local protocol (taught anchors; pressure/duration/padding scope)^[4]
• Inflation and deflation physiological effects (taught; ischaemia-reperfusion scope)^[4]
• BCIS grades with exact definitions per the Donaldson reference^[1]
• BCIS prevention (venting, lavage, cement technique, uncemented option in high-risk groups)^[1]
• FES triad and hours-later timing (taught window; triad scope)^[5]
• Differential hypoxia at cementation (BCIS until proven otherwise)^[1]
• Resuscitation priorities for BCIS arrest (oxygen, vasopressors including adrenaline, surgeon stops pressurisation)^[1]
• Communication with surgeon at cementing^[1]

Crisis. BCIS grade 3 cardiac arrest during cemented hemiarthroplasty — call for help, 100 percent oxygen, support circulation with vasopressors including adrenaline per local arrest algorithms, surgeon stops pressurisation, treat as embolic RV failure; no lipid indication here (lipid is for LAST, not BCIS).^[1]