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Post-operative complications
Think about the operation, the day, and the drugs. Most post-operative problems follow a timeline. Know what the operation was, what day it is, and what drugs and fluids they've had, and the likely causes narrow quickly. Then assess A–E and don't miss bleeding, leaks, PE or MI. Built for revision, not live patient decisions.
Settle them, and check the basics
what op? what day?Red flags — what each should make you think
A new tachycardia or AF days after bowel surgery is an anastomotic leak until proven otherwise. Don't just rate-control it: look at the abdomen, the CRP trend and the drains, and ask for a CT.
First actions
- 📋Read the op note
- A–EAssess A–E
- 🩸Bloods
- 💧Fluid balance
- 💊Drug chart
- ☎Surgical team
Understand the timeline
by post-op dayPost-operative fever by day (a guide)
- Day 0–2 — physiological inflammatory response, atelectasis, transfusion reaction, early aspiration
- Day 3–5 — pneumonia, UTI, line infection
- Day 5–7+ — wound infection, anastomotic leak, collection/abscess, DVT/PE
- Any time — drugs, C. difficile, cellulitis around cannula sites
Common problems
- Hypotension — hypovolaemia/bleeding, sepsis, epidural (vasodilatation), cardiac (MI, arrhythmia), drugs
- Low urine output — check the catheter first (blocked?), then volume status, AKI, retention (if no catheter)
- Ileus — opioids, electrolytes (K⁺, Mg²⁺), immobility; but persisting ileus may be a leak or collection
- Delirium — infection, pain, retention, constipation, hypoxia, drugs, alcohol withdrawal
- VTE — mechanical and pharmacological prophylaxis per NICE NG89
Work A–E — assess and act as you go
The diagnoses you must not miss
tap to open eachWhat points toward it, what would rule it in, and how to manage it.
Tachycardia, hypotension, drains filling, wound haematoma, falling Hb (late).
VBG Hb, FBC, clotting.
Resuscitate, blood, reverse anticoagulation, surgical team — return to theatre.
Tachycardia, new AF, fever, ileus, abdominal pain, rising CRP, feculent drain fluid.
CT with contrast.
Antibiotics, resuscitation, surgical review — drainage or return to theatre.
Sudden dyspnoea, pleuritic pain, tachycardia, hypoxia.
CTPA.
Anticoagulation — discuss bleeding risk with surgeons. See the PE page.
Hypotension, arrhythmia, breathlessness or chest pain; often painless (analgesia).
ECG, troponin.
Cardiology; balance antithrombotics against bleeding.
New or worsening leg weakness or numbness after epidural/spinal anaesthesia, back pain, especially with anticoagulants.
Emergency MRI.
Stop epidural infusion, urgent anaesthetics and neurosurgery for decompression.
Investigate — what to order, when, and what it tells you
test with a question in mindBloods
Imaging
Other
How the plan comes together
disposition · handoverward + surgical plan
Problem identified and treated, improving, clear review time.
theatre / HDU
Haemorrhage, leak, sepsis, MI, epidural haematoma, or failing to respond.
Hand over: operation and day, problem, findings, what's been done, surgical plan.
What operation, what day, what drugs? Then A–E. Tachycardia after bowel surgery is a leak until proven otherwise, and back pain with leg weakness after an epidural is an emergency. Nicely done getting here.
Clerking template
copy or downloadPost-operative complications — documentation structure
A structure and prompt list to help you document and think systematically. It is not a completeness check and cannot guarantee nothing is missed — use your trust's own proforma, your seniors, and your clinical judgement.
Test yourself
active recallCover the answer, say it out loud, then reveal. Retrieval beats re-reading.
0 / 12 knownFrequently asked questions
quick answersWhat are the red flags for the unwell post-operative patient?
- Tachycardia + hypotension day 0–1 — think haemorrhage
- New AF, ileus, rising CRP days 3–7 — think anastomotic leak
- Sudden breathlessness, pleuritic pain — think PE
- Chest pain, or just hypotension in the elderly — think perioperative MI (often silent)
- Back pain + leg weakness after epidural — think epidural haematoma / abscess
- Low urine output — think hypovolaemia, AKI, blocked catheter
- Drowsy, slow breathing — think opioid toxicity
What is the initial management of the unwell post-operative patient?
- Read the op note — procedure, complications, blood loss, drains
- Assess A–E — —
- Bloods — FBC, U&E, CRP, LFT, clotting, G&S, VBG lactate
- Fluid balance — input, output, drains, NG losses
- Drug chart — opioids, anticoagulants, missed regular meds
- Surgical team — early
Always alongside senior support and your local guideline.
What diagnoses must you not miss in the unwell post-operative patient?
- Post-operative haemorrhage — day 0–1
- Anastomotic leak / collection — days 3–7
- Pulmonary embolism — sudden breathlessness
- Perioperative MI — often silent
- Epidural haematoma / abscess — back pain + weak legs
Open each one in the must-not-miss section for what points toward it, how to rule it in, and how to manage it.
What investigations should a junior doctor order for the unwell post-operative patient?
- Bloods — FBC, U&E, CRP (trend), LFT, clotting, G&S, lactate.
- Imaging — Chest symptoms.
- Other — Arrhythmia, ischaemia.
Admit or discharge: how is the plan decided for the unwell post-operative patient?
- Ward + surgical plan — Problem identified and treated, improving, clear review time.
- Theatre / hdu — Haemorrhage, leak, sepsis, MI, epidural haematoma, or failing to respond.
Is there a clerking template for the unwell post-operative patient?
Yes — there is a free clerking template for the unwell post-operative patient on this page, structured as presenting complaint, red flags asked, history, examination (A–E), investigations, differentials, plan and escalation. You can copy it or download it as a Word document. Jump to the template.
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