The Anticoagulated Patient Needing Emergency Surgery
A 71-year-old man presents with a 12-hour history of generalised abdominal pain and distension. He has a mechanical mitral valve replacement (current-generation bileaflet valve) and takes warfarin, with a recent INR of 2.8. He also takes aspirin 100 mg. CT shows small bowel obstruction with a closed loop and signs of ischaemia; there is no free gas. Observations: HR 122, BP 96/60, temperature 37.1 C, lactate 4.2, WCC 21.0. He is alert and understands the situation. The theatre coordinator says the emergency list is full and asks whether he can wait until the morning, approximately 8 hours away.
1. Justify why this patient cannot wait and outline the pre-operative preparation you would initiate immediately.
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This is a closed-loop small bowel obstruction with ischaemia, indicated by a lactate of 4.2, tachycardia, hypotension and a raised white cell count. Closed-loop obstruction can progress to infarction and perforation within hours, so delay of 8 hours risks avoidable death. The correct response is to escalate to the on-call consultant surgeon and anaesthetist and declare this a priority case that must displace lower-priority work on the emergency list.
Immediate preparation:
- Resuscitation: oxygen, two large-bore cannulae, cautious crystalloid boluses with reassessment, urinary catheter, arterial line and critical care involvement.
- Anticoagulation reversal: he is anticoagulated with warfarin for a mechanical mitral valve. Give intravenous vitamin K 5-10 mg and prothrombin complex concentrate to correct the INR urgently, aiming for an INR near 1.5 or below for surgery. This is a genuine tension: reversal risks valve thrombosis, but uncontrolled bleeding and ischaemic bowel are immediately life-threatening.
- Aspirin: continue; do not stop antiplatelet therapy in this setting.
- Blood products: cross-match 4-6 units, check fibrinogen and platelets, and activate the major haemorrhage protocol if needed.
- Antibiotics: broad-spectrum cover for translocation and ischaemia.
- Nasogastric tube for decompression.
- Document a clear discussion with the patient and family about the risks of valve thrombosis and bleeding, and involve cardiology and haematology if time allows.
- Post-operative planning: early restart of warfarin or heparin, with bridging, once bleeding risk allows.
2. The patient undergoes laparotomy with resection of infarcted small bowel and primary anastomosis. On day 2 he develops atrial fibrillation with a fast ventricular rate. Discuss the causes and your management, with particular attention to his mechanical valve.
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Causes: New atrial fibrillation after major surgery is usually multifactorial: sepsis, hypovolaemia, electrolyte disturbance (hypokalaemia, hypomagnesaemia), pain, anaemia, hypoxia, and the underlying cardiac disease. In this patient, the mechanical mitral valve means the arrhythmia carries a high thromboembolic risk, and loss of atrial contraction can precipitate cardiac failure.
Assessment: Check electrolytes, magnesium, haemoglobin, thyroid function, and look for sepsis or a collection. Obtain an ECG and consider echocardiography if there is haemodynamic compromise.
Rate and rhythm control:
- Correct electrolytes and treat reversible causes.
- Use a beta-blocker such as metoprolol or, if there is heart failure, digoxin or amiodarone, with careful monitoring. Avoid verapamil if there is impaired ventricular function.
- If he is haemodynamically unstable, proceed to urgent synchronised cardioversion.
Anticoagulation: This is the critical issue. He has a mechanical mitral valve and is at high risk of valve thrombosis and stroke. He needs therapeutic anticoagulation as soon as surgical bleeding risk permits. Options are intravenous unfractionated heparin, which is titratable and reversible, or restarting warfarin with heparin bridging. Discuss with cardiology and haematology. Do not leave him without anticoagulation once haemostasis is secure.
Monitoring: Continuous cardiac monitoring, daily INR once warfarin is restarted, and vigilance for embolic events or valve dysfunction. Document the plan clearly and involve the patient in decisions about risk.