Post-CPB Bleeding Care
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Direct answer
A technically perfect operation can still end in a coagulopathic ooze, and the first triage is surgical versus non-surgical: localised, pulsatile or torrential bleeding points toward a surgical source, while diffuse ooze from raw surfaces, venous lines and the donor site points toward the bypass-induced coagulopathy of platelet dysfunction, hypofibrinogenaemia, residual heparin, dilution, hypothermia and hyperfibrinolysis. Management runs on correction and measurement together — warmth above 36 degrees, ionised calcium normal, residual heparin reversed and checked, then viscoelastic testing (TEG or ROTEM with a heparinase comparison) steering products: protamine for heparin effect, cryoprecipitate or fibrinogen concentrate when fibrinogen sits below about 1.5-2 g/L, platelets for a low MA/MCF, tranexamic acid for lysis. Persistent high-volume bleeding after correction is re-exploration, not more plasma.
What you must remember
- Bypass hits platelets hardest: numbers fall and remaining platelets are dysfunctional from activation and hypothermia — platelet therapy is functional, judged by viscoelastic tests, not just counts.
- Residual heparin first: ACT or, better, a heparinase TEG/ROTEM comparison — if the heparinase channel clots better than the plain channel, residual heparin is still contributing; protamine in 25-50 mg steps, guided, because overdose is itself anticoagulant and antiplatelet.
- Fibrinogen is the first factor to fall: target above roughly 1.5-2 g/L in the bleeding patient; cryoprecipitate (fibrinogen-rich) or fibrinogen concentrate where available.
- Viscoelastic algorithm: prolonged CT/R or EXTEM CT — heparin or factor deficiency (protamine or plasma); low MA/MCF — platelets; low FIBTEM — fibrinogen; lysis on the tracing — tranexamic acid.
- The physical floor: temperature above 36 degrees (cold platelets do not work), pH corrected, ionised calcium 1.1-1.3 mmol/L after citrate loads, haematocrit around 24-25 plus.
- Products and autologous options: platelets (an apheresis unit or a pooled random-donor pack), fresh frozen plasma about 10-15 mL/kg, cryoprecipitate 3-5 units per 10 kg (Indian protocol habit), tranexamic acid per policy — alongside cell salvage of shed blood and residual pump blood processed rather than returned raw.
- Re-exploration threshold: continued bleeding at roughly 300-400 mL in the first hour (centre-defined) despite correction warrants surgical re-exploration — tamponade physiology kills quietly.
- Antifibrinolytic context: tranexamic acid is widely used; aprotinin, where available again, is selected for high-risk redo and complex cases per programme policy.
One hour after the cross-clamp, worked through
The field oozes; chest drain output is 350 mL in the first hour. Sequence, not guesswork. Warmth: bladder temperature 35.9, forced-air on, fluids warm. Check heparin reversal: ACT 145 against a baseline of 105 — but the heparinase TEG shows the heparinase channel reaching clot strength minutes earlier than the plain channel, so 25 mg protamine is given in steps. ROTEM follow-up: EXTEM CT now normal, FIBTEM A5 low, platelet channel MCF low — fibrinogen 1.3 g/L. Give cryoprecipitate and one apheresis platelet unit; ionised calcium 0.98 is corrected with calcium chloride because transfused citrate is still arriving. Tranexamic runs as a continuation of the intraoperative infusion. Over the next 40 minutes the drains fall to 60 mL/h and the field dries; the record shows a cause-effect chain any examiner could reconstruct. Had the output stayed at 300 mL/h with normal viscoelastic values, the next sentence in the record would have been "return to theatre".
Where the exam probes
Indian papers set "causes and management of bleeding after cardiopulmonary bypass" as a classic ten-marker, and the pass answer separates surgical from coagulopathic before listing mechanisms; the strong answer then orders therapy by measurement (viscoelastic algorithm) rather than by recipe. Viva favourites: which factor falls first (fibrinogen), why platelets dysfunction (activation, hypothermia, the pump itself), why the ACT alone misleads after protamine (its insensitivity at low heparin levels — hence heparinase channels), and the numeric re-exploration trigger your unit defends. The Indian-practice dimension is real: blood products depend on voluntary donation, random-donor platelet pools and apheresis units differ in availability by centre and by night, and examiners respect the candidate who says "fibrinogen concentrate where available, cryoprecipitate where not" — the answer of someone who has actually stood at the console.
Frequently asked questions
What is the first laboratory check in post-bypass bleeding?
Confirm heparin reversal — ACT with a heparinase TEG or ROTEM comparison, since ACT alone is insensitive at low heparin levels; give protamine in small guided steps.
What fibrinogen level triggers replacement after bypass?
Below roughly 1.5-2 g/L in the bleeding patient, corrected with cryoprecipitate or fibrinogen concentrate per availability.
Why is platelet dysfunction central to post-CPB coagulopathy?
The circuit activates and hypothermia cripples remaining platelets, so functional platelet therapy is guided by viscoelastic testing rather than count alone.
What does a low FIBTEM value indicate and what is given?
Fibrinogen deficiency — cryoprecipitate or fibrinogen concentrate, prioritised ahead of plasma because fibrinogen falls first and furthest.
When does postoperative bleeding mandate surgical re-exploration?
Centre-defined thresholds — commonly around 300-400 mL in the first hour despite full correction, or signs of tamponade — send the patient back to theatre.