Free Flap Microvascular Reconstruction
Patient phenotype
Post-cancer (head/neck, breast), post-trauma, or chronic wound reconstruction. Often: smoker, chemo-treated, age 40-70. Long surgery (8-14h). Goal: protect the flap.
Procedure
Surgeon harvests a flap (DIEP, ALT, fibular, latissimus) with its vascular pedicle, transfers to defect, anastomoses artery + vein under microscope. Flap survival depends on perfusion in first 48-72h.
Anesthetic plan
GETA, long-case management. Goal: warm, well-perfused, normotensive patient. Avoid vasoconstrictors that compromise flap perfusion. Multimodal pain control. Foley + a-line + central access for long case.
Setup
- ·A-line
- ·Central line (IJ or PICC) for long-term access + pressors if needed
- ·Two large-bore PIVs
- ·Forced air warmer + fluid warmer
- ·Foley + temp + UOP monitoring
- ·Bispectral index for accurate depth (long case, drug accumulation)
- ·DVT prophylaxis (mechanical + chemical)
- ·Type & screen 2 units
Biggest concerns by phase
Smoking cessation + flap survival
Smoking → vasoconstriction + carboxyhemoglobin → flap failure. Patients should stop smoking ≥ 4 weeks pre-op. Failure rate doubles in active smokers. Verify cessation; document.
Standard induction, but plan for long case
Standard GA induction. Use BIS to titrate maintenance accurately over 8-14 h. Avoid drug accumulation (limit benzos, use shorter-acting agents). Plan for awake extubation at end despite duration.
Maintain flap perfusion — warm, hydrated, normotensive
Goal: MAP 65-85, normothermia (≥ 36 °C), euvolemia, hematocrit 25-30 (lower is better for flow viscosity). AVOID phenylephrine (peripheral vasoconstriction) as primary BP support — use norepinephrine (less peripheral effect) or volume + lighter anesthetic instead. Some surgeons request milrinone for flow.
Avoid cold, avoid hypotension, avoid vasoconstrictors
Keep room warm (75-78 °F). Warm all fluids. BAIR all surfaces. Document MAP every 15 min — surgeon will reject perfusion problem from anesthesia even if not. After anastomosis, flap will look pink + bleeding from edges (good) or pale (bad — surgeon will redo).
Heparin protocols — institutional
Some surgeons use 2000-3000 U heparin pre-anastomosis for vessel patency, sometimes systemic infusion. Aspirin + dextran + leech protocols for some flaps. Coordinate carefully — bleeding risk vs. clotting risk in microvascular anastomosis.
PACU + postop flap monitoring (q1h × 24h)
Flap checks: color (pink = good, pale = arterial issue, dusky/blue = venous issue), temperature, capillary refill, doppler signal. Avoid: pressure on flap, cold, vasoconstrictors, hypotension. Surgical re-exploration window is 4-6h — don't delay.
Mock-defense scenarios
Practice answering these out loud. The probes show what an examiner is listening for.
8 hours into a DIEP free flap reconstruction. The surgeon just completed the venous anastomosis. He says the flap looks dusky and the venous outflow is sluggish. BP is 95/60, MAP 72, temp 35.4. What might be going wrong and what do you do?
What an examiner probes for
- ▹Possible causes: hypothermia → vasoconstriction, hypotension, kinked anastomosis, hematoma compression, intrinsic flap problem
- ▹Anesthesia interventions: warm aggressively, judicious volume bolus, lighten anesthetic to raise MAP without phenylephrine
- ▹Communication: tell surgeon, may need re-anastomosis vs. heparin push
- ▹DON'T reach for phenylephrine first
Sources
- Miller's Ch 71
- Nematodes/Adams Plastic Surgery Anesthesia
- ASRA microvascular consensus
Anatomy reference
Sourced reference images. 4 matches for "vessels arterial vein blood".
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