Postoperative Haemorrhage

Postoperative haemorrhage is bleeding after surgery that causes haemodynamic compromise, needs transfusion or needs return to theatre or intervention. It is classed by timing: primary (during surgery, recognised later), reactionary (within 24 hours, as pressure rises and vasoconstriction or ligatures give way) and secondary (4 to 14 days, usually with infection, erosion or anastomotic breakdown).

Epidemiology. Return to theatre for bleeding is about 1% to 3% of major surgery, and higher in vascular, cardiac, thyroid, tonsil and prostate surgery. Mortality rises if recognition is delayed.

Causes. Slipped ligature or failed haemostasis, missed vessel injury, coagulopathy, anticoagulant or antiplatelet effect, thrombocytopenia, hypothermia, acidosis, hypertension, dilutional coagulopathy, hyperfibrinolysis and vessel erosion by infection or tumour.

Pathophysiology.

Loss of circulating volume reduces preload and oxygen delivery. Haemorrhage, dilution, hypothermia, acidosis and consumption produce a coagulopathy that worsens bleeding.

Hyperfibrinolysis and low fibrinogen are early features after major bleeding.

Tachycardia, hypotension (late in the young and in those on beta blockers), pallor, sweating, anxiety, oliguria, thirst and a falling haemoglobin. Local signs include wound swelling, blood in drains, haematemesis, melaena, haematuria and abdominal distension. Swelling in the neck, limb or retroperitoneum can conceal large volumes.

Red flags.

• Shock index (heart rate over systolic pressure) over 1.0.
• Drain output over 200 mL/h for 2 hours or sudden cessation of output with deterioration.
• Neck swelling with stridor.
• Lactate over 2 mmol/L or base deficit over 4 mmol/L.
• Pulsatile or rapidly expanding swelling.

• Assess airway, breathing and circulation, wound, drains and abdomen.
• Haemoglobin (may be normal early), platelets, prothrombin time, activated partial thromboplastin time, fibrinogen, lactate, blood gas, ionised calcium, cross-match and viscoelastic testing where available.
• Focused ultrasound for free fluid; CT angiography if stable.
• Check anticoagulant and antiplatelet timing and last doses.

Differential diagnosis.

• Hypovolaemia from third space loss.
• Sepsis.
• Anaphylaxis.
• Tamponade.
• Tension pneumothorax.
• Myocardial infarction.
• Vasodilation from neuraxial block.

Resuscitation. Two large bore cannulae, oxygen, warming, and early surgical call. Aim for systolic pressure 80 to 100 mmHg (mean arterial pressure 65 mmHg or more in older adults and chronic hypertension) until bleeding is controlled, except in head injury. Give blood early rather than large crystalloid volumes. Use massive transfusion with red cells, plasma and platelets in a ratio near 1:1:1 for major bleeding, and send repeat coagulation tests after each 4 to 6 units.

Targets.

• Haemoglobin 70 to 90 g/L (80 g/L or more with cardiovascular disease).
• Platelets over 50 x 10^9/L (over 100 x 10^9/L for central nervous system or ocular bleeding).
• Fibrinogen over 1.5 to 2.0 g/L.
• Prothrombin and activated partial thromboplastin times under 1.5 times normal.
• Ionised calcium 1.1 mmol/L or more, temperature 36 C or more, pH over 7.2.

Drugs.

• Tranexamic acid: 1 g IV over 10 minutes, then 1 g over 8 hours; continue 8 to 24 hours while bleeding; usual maximum 4 g daily.
• Tranexamic acid safety: monitor for seizures, thrombosis and renal function; reduce by half or more when creatinine exceeds 120 micromol/L; avoid in active thromboembolism and upper tract haematuria.
• Calcium chloride 10%: 10 mL (1 g) IV over 5 to 10 minutes through a large vein, repeated to keep ionised calcium 1.1 mmol/L or more; titrate to level during massive transfusion; monitor ionised calcium and ECG; extravasation causes necrosis; use caution with digoxin.
• Fibrinogen replacement: cryoprecipitate 2 pools (about 10 units) or fibrinogen concentrate 2 to 4 g IV when fibrinogen is under 1.5 g/L with bleeding; repeat after the next level; monitor fibrinogen and thrombosis; no renal adjustment.
• Protamine for heparin: 1 mg IV for each 100 units of heparin given in the last 2 to 3 hours, slowly at no more than 5 mg/min; single dose; maximum 50 mg.
• Protamine safety: monitor activated clotting time, blood pressure and for anaphylaxis; risk is higher with prior protamine, fish allergy and neutral protamine Hagedorn insulin.
• Warfarin reversal: prothrombin complex concentrate 25 to 50 units/kg IV (dose by INR), plus vitamin K 5 to 10 mg IV slowly; single dose; maximum 3000 units of prothrombin complex concentrate in many labels.
• Warfarin reversal follow-up: monitor INR at 30 minutes and thrombosis; reduce in recent venous thromboembolism.
• Dabigatran reversal: idarucizumab 5 g IV as two 2.5 g infusions within 15 minutes; single dose; monitor bleeding and thrombosis; no renal adjustment.
• Factor Xa inhibitor reversal: prothrombin complex concentrate 25 to 50 units/kg IV or the specific antidote where available; single dose; monitor bleeding and thrombosis.

Source control. Return to theatre or angioembolisation. Open the wound for a neck haematoma with airway threat before transfer.

Monitoring. Continuous haemodynamics, urine output, serial haemoglobin, coagulation, lactate, ionised calcium and temperature.

Referral and escalation. Immediate surgical and anaesthetic consultant involvement for any instability. Haematology advice for refractory coagulopathy. Interventional radiology for non-operative control.

Special groups. In Jehovah's Witness patients discuss accepted products before surgery and use cell salvage, tranexamic acid and erythropoiesis support. In pregnancy and the puerperium give tranexamic acid early. In older adults, a normal pressure may conceal serious loss.