Surgical F1: Common Ward Problems

What to do in the first ten minutes, for the calls you will get most often on a surgical ward.

Nobody expects an F1 to fix a post-operative bleed. Everybody expects an F1 to recognise one, start the right things, and get the right person there fast. This guide covers the problems that make up most surgical ward calls, written as the actions you take, in order.

Last reviewed: October 2026. Doses reflect common UK practice and national guidance at that date. Always check your trust protocol, the BNF and the drug chart before prescribing, and adjust for renal function, weight and allergies. If you are unsure, call your registrar. That is never the wrong answer.

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Before anything: the same first moves, every call

1. Go and see the patient. Most mistakes on the ward are made over the phone.
2. ABCDE and a full set of observations. Calculate the NEWS2.
3. Read the op note and the post-op plan. What operation, what day, any specific instructions (drains, NG, anticoagulation, diet).
4. Look at the drug chart and the fluid chart. A large share of ward problems are caused or fixed there.
5. Decide: can this wait, or do I need help now?

Three things that should make you more worried, whatever the numbers say: the nurse is worried, the patient says they feel like they are dying, or the patient is on steroids, beta-blockers or immunosuppressants (all of which hide the usual warning signs).

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PART ONE: ELECTROLYTES

1. Low potassium

Normal range 3.5-5.3 mmol/L.

Why surgical patients run low

Nasogastric losses, vomiting, diarrhoea, high-output stomas, diuretics, insulin, refeeding, and simply being nil by mouth on fluids with no potassium in them.

What to prescribe

Rules that keep patients alive

• Never give potassium as a bolus. Never draw up concentrated potassium chloride on the ward. Use premixed bags only.
• Maximum peripheral rate is 10 mmol per hour. Faster than that needs a central line and cardiac monitoring.
• Check the magnesium. If magnesium is low, potassium replacement will not stick.
• Recheck the potassium after each replacement and at least daily while losses continue.
• After bowel surgery and in ileus, many units aim for potassium of at least 4.0 and magnesium of at least 1.0, because low levels prolong the ileus.

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2. High potassium

Step 1: is it real?

Haemolysed samples, delayed processing and samples taken above a drip are common causes of a false high result. Repeat it immediately on a blood gas. But if the ECG is abnormal, treat while you wait.

Step 2: do an ECG

Look for tall tented T waves, flattened or absent P waves, a broad QRS, and in the worst cases a sine-wave pattern. Put the patient on a cardiac monitor if the potassium is 6.5 or above, or if the ECG is abnormal.

Step 3: treat by severity

Calcium: 30 mL of 10% calcium gluconate IV over 5-10 minutes. This protects the heart. It does not lower the potassium. Repeat the ECG; give again if changes persist.

Insulin and glucose: 10 units soluble insulin (Actrapid) in 25 g glucose (50 mL of 50% glucose, or 250 mL of 10% glucose) IV over 15 minutes. Works in 15-30 minutes, lasts 4-6 hours. Check capillary glucose hourly for 6 hours. Hypoglycaemia is the commonest harm from this treatment. If the glucose was below 7 before treatment, run 10% glucose at 50 mL per hour for 5 hours afterwards.

Salbutamol: 10-20 mg nebulised, as an add-on, not on its own.

Step 4: remove the cause

Stop potassium supplements and potassium-containing fluids, ACE inhibitors and ARBs, spironolactone, NSAIDs and trimethoprim. Treat any acute kidney injury.

In a surgical patient, unexplained high potassium with a metabolic acidosis can mean dead tissue. Think ischaemic bowel, an ischaemic limb, or compartment syndrome, and tell the registrar.

Insulin and salbutamol only shift potassium into cells temporarily. If it keeps coming back, the patient may need dialysis: involve the renal team or critical care.

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3. Low magnesium

Normal range 0.7-1.0 mmol/L.

Why it matters: arrhythmias (including torsades de pointes), potassium and calcium that will not correct, cramps, tremor and a prolonged ileus.

Common causes: proton pump inhibitors, diuretics, high-output stomas and diarrhoea, alcohol, refeeding and poor intake.

• Reduce the dose in renal impairment. Magnesium accumulates if the kidneys cannot clear it.
• Oral magnesium is poorly absorbed with a high-output stoma, so IV is often needed.

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4. Low sodium

The usual post-operative story is hypotonic fluids plus the anti-diuretic hormone released by surgery, pain, nausea and opioids.

First steps

1. Is the patient symptomatic? Headache, nausea and vomiting, confusion, seizures or a reduced conscious level make this an emergency. Call the registrar and critical care. Hypertonic saline is a critical care decision, not a ward one.
2. Look at what is running. If the sodium is falling, stop 5% glucose and 0.18% saline.
3. Assess fluid status and send paired serum osmolality, urine osmolality and urine sodium before you change the treatment.

Treat by fluid status

Never correct sodium faster than 8-10 mmol/L in 24 hours. Overcorrection causes osmotic demyelination, which is permanent.

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5. Low calcium after neck surgery

After thyroidectomy or parathyroidectomy, the parathyroid glands may be bruised or removed. Watch for tingling around the mouth and fingertips, cramps, and twitching (Chvostek's and Trousseau's signs).

• Check adjusted calcium and magnesium. Low magnesium makes low calcium hard to correct.
• Symptomatic, or adjusted calcium below about 1.9 mmol/L: 10-20 mL of 10% calcium gluconate in 50-100 mL 5% glucose IV over 10 minutes with ECG monitoring, followed by an infusion per local protocol. Tell the registrar.
• Mild and asymptomatic: oral calcium, with or without alfacalcidol, per the surgical or endocrine plan.

A swelling neck after thyroid surgery is a different emergency entirely. See section 7.

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6. Low phosphate and refeeding

Patients who have eaten little for days are at risk of refeeding syndrome when feeding restarts: insulin drives phosphate, potassium and magnesium into cells and the blood levels crash, causing heart failure, arrhythmias and respiratory muscle weakness.

• Identify who is at risk (NICE criteria include BMI under 16, more than 15% weight loss in 3-6 months, or little or no intake for over 10 days). Involve the dietitian.
• Give thiamine before feeding starts.
• Start feeding slowly and check potassium, magnesium and phosphate daily for the first few days.
• Phosphate below 0.32 mmol/L is severe and usually needs IV replacement per local protocol; milder lows can be treated orally.

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PART TWO: POST-OPERATIVE PROBLEMS

7. Post-operative bleeding

Timing tells you the likely cause

How it presents

• Early: tachycardia, anxiety, cool hands, a narrowing pulse pressure, falling urine output.
• Local: blood in the drain, a swelling or tense wound, bleeding through the dressing, a distending abdomen.
• Late: low blood pressure, confusion, a falling haemoglobin.

Low blood pressure is a late sign. Young patients hold their blood pressure until they suddenly cannot. A normal haemoglobin does not exclude bleeding: it takes hours to fall.

The first ten minutes

1. Call for help early. Registrar now. Put out a peri-arrest call if the patient is crashing.
2. ABCDE, high-flow oxygen, lie the patient flat.
3. Two large-bore cannulae (16 gauge or bigger).
4. Bloods: full blood count, clotting including fibrinogen, U&E, crossmatch 4 units, and a blood gas for a quick haemoglobin and lactate.
5. Fluids: a 500 mL crystalloid bolus while blood is coming, but blood is the right fluid. Activate the major haemorrhage protocol if bleeding is ongoing or the patient is unstable.
6. Press on anything you can see bleeding. Firm, direct pressure.
7. Check the drug chart. Hold LMWH, anticoagulants and antiplatelets. Reversal is a senior decision.
8. Measure the losses. Empty and record drains, mark the edge of any soaked dressing, catheterise for hourly urine output.

Surgical bleeding is stopped in theatre or by interventional radiology. Your job is to recognise it, resuscitate, and get the right people there quickly. Tranexamic acid may be given on senior advice.

Neck swelling after thyroid or parathyroid surgery

This is an airway emergency. A haematoma under the neck muscles compresses the airway, and the patient can obstruct within minutes. Stridor, difficulty breathing, a rapidly swelling neck or difficulty swallowing: do not wait for anyone to arrive. Call 2222 and the surgical and anaesthetic teams at the same time as you act.

Open the wound at the bedside using SCOOP:

• Skin exposure
• Cut the sutures or remove the clips
• Open the skin
• Open the muscles
• Pack the wound and apply pressure

Clip removers or stitch cutters should be at the bedside of every patient after neck surgery. Check they are.

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8. Low urine output

The usual threshold for concern is below 0.5 mL/kg per hour.

1. Is the catheter blocked? This is the commonest cause. Check for kinks and flush it.
2. No catheter? Bladder scan. Urinary retention is very common after surgery (opioids, epidurals, anticholinergics, immobility).
3. Assess fluid status. If the patient is dry, give a fluid challenge of 250-500 mL crystalloid over 15-30 minutes and reassess.
4. Check the U&E for an acute kidney injury.
5. Stop or hold nephrotoxic drugs: NSAIDs, ACE inhibitors, ARBs, diuretics and metformin (in AKI). Check gentamicin and vancomycin levels.

Do not give furosemide to make the number look better in a patient who is dry. It worsens the kidney injury.

Some reduced urine output on day 0-1 is a normal stress response. Do not drown the patient chasing it, but do not ignore it either. Think bleeding and sepsis if it comes with a rising heart rate.

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9. Post-operative fever

Day of onset narrows the cause

What to do

1. Is the patient septic? If so, start the sepsis pathway now: blood cultures, lactate, IV antibiotics within an hour, fluids, urine output monitoring.
2. Examine everything: chest, wound, abdomen, cannula and line sites, catheter, calves.
3. Investigate: full blood count, CRP, blood cultures before antibiotics, urine, chest X-ray if there are chest signs, wound swab if the wound is discharging.

A well patient with a low-grade fever on day 1 does not automatically need antibiotics. Encourage deep breathing, mobilise, and control pain.

Suspect an anastomotic leak in a patient who is "not quite right" on days 3-7: tachycardia, new atrial fibrillation, a rising CRP, worsening abdominal pain, ileus that will not settle, or confusion. Escalate to the registrar. The usual investigation is a CT with contrast.

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10. Low blood pressure

Common causes: bleeding, under-replaced fluid losses, sepsis, epidural, cardiac events (MI, new AF), pulmonary embolism, anaphylaxis, and antihypertensives restarted too early.

1. ABCDE, NEWS2, and look for bleeding (section 7).
2. Check the fluid balance, the drug chart and the epidural.
3. Give a 250-500 mL crystalloid bolus and reassess.
4. Send a lactate. Above 2 mmol/L is concerning, above 4 mmol/L suggests shock.

Epidural-related low blood pressure: check the block height. If the block is high or the patient is hypotensive, contact the acute pain team or on-call anaesthetist. They may reduce or stop the infusion. Do not remove an epidural catheter yourself.

If the blood pressure does not respond to fluid, call the registrar.

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11. Chest pain or breathlessness

Surgical patients are at high risk of pulmonary embolism, and post-operative MI is often silent or atypical.

• Do immediately: ECG, blood gas, chest X-ray, troponin, oxygen to target saturations.
• Think: PE, MI, pneumonia or aspiration, atelectasis, fluid overload, and pneumothorax after a central line or chest surgery.
• Suspected PE: CTPA. Anticoagulation in a fresh post-operative patient must be discussed with the registrar because of bleeding risk.
• Fluid overload: stop IV fluids, sit the patient up, give oxygen, and consider furosemide 40 mg IV.

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12. Nausea and vomiting

First ask why. Antiemetics treat symptoms, not causes.

• Ileus or obstruction (distended abdomen, no flatus, bilious or large-volume vomiting): pass an NG tube on free drainage. Antiemetics alone are not enough.
• Other causes to check: opioids, constipation, urinary retention, low potassium, low sodium, and early sepsis.

If you will feed a patient or give drugs down an NG tube, its position must be confirmed according to local NG safety guidance first.

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13. Glucose problems in diabetic patients

Low glucose (below 4 mmol/L)

Glucagon works poorly in malnourished patients, those with liver disease, and hypoglycaemia caused by sulfonylureas.

Rules that matter

• Never stop insulin completely in a type 1 diabetic. Without insulin they develop ketoacidosis within hours, even if they are not eating.
• On a variable-rate insulin infusion, do not simply switch it off for a low reading. Check the glucose-containing fluid is running and follow the trust protocol.
• In a type 1 diabetic with a glucose above 12 mmol/L, check ketones.

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14. Confusion

Post-operative delirium is common, frightening for the patient and family, and usually has a treatable cause.

Check these first

• Capillary glucose
• Oxygen saturation and a blood gas (hypoxia and CO2 retention)
• Observations (sepsis)
• Bladder scan (urinary retention)
• The drug chart (opioids, anticholinergics, benzodiazepines, steroids)
• Sodium and calcium
• When did they last open their bowels?

PINCH ME is a useful prompt: Pain, Infection, Nutrition, Constipation, Hydration, Medication, Environment.

Alcohol withdrawal typically appears 2-3 days after admission. Give IV Pabrinex and use the trust withdrawal protocol.

Avoid sedation unless the patient is a danger to themselves or others. If it is needed, use small doses and discuss with a senior. Avoid haloperidol in Parkinson's disease and Lewy body dementia.

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15. Pain

• Check what is prescribed and whether it is being given. Regular analgesia works far better than as-required.
• Use more than one drug: paracetamol (reduce the dose if under 50 kg), an NSAID if there is no contraindication (avoid in AKI, GI bleeding, and where the surgical team says no), and an opioid if needed.
• PCA or epidural not working? Call the acute pain team.

New or suddenly worse pain is a new problem until proven otherwise: an anastomotic leak, bleeding, ischaemic bowel or compartment syndrome. Examine the patient before giving more morphine.

Opioid toxicity

Signs: respiratory rate below 8, pinpoint pupils, drowsiness.

1. Stop the opioid. Give oxygen. Support the airway.
2. Naloxone 100 micrograms IV, repeated every 2 minutes, titrated to breathing rather than full wakefulness (full reversal also reverses their pain relief).
3. Naloxone wears off faster than most opioids. Watch for re-sedation, and consider an infusion with senior advice.

Prescribe a laxative alongside any regular opioid.

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16. VTE prophylaxis questions

• Standard prophylaxis: usually enoxaparin 40 mg subcutaneously once daily, adjusted for weight and kidney function (eGFR below 30 usually 20 mg). Follow the trust VTE risk assessment.
• Extended prophylaxis: NICE recommends 28 days of LMWH after major abdominal or pelvic cancer surgery.
• Epidurals: with prophylactic LMWH, wait at least 12 hours after a dose before the catheter is removed, and at least 4 hours after removal before the next dose. Coordinate with the acute pain team.
• Bleeding: hold the LMWH and discuss with the registrar.
• Restarting warfarin or a DOAC: this is a surgical team decision, usually written in the op note or post-op plan. Ask, never guess.

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17. IV fluids

Maintenance needs (NICE CG174), per day: 25-30 mL/kg water, about 1 mmol/kg each of sodium, potassium and chloride, and 50-100 g glucose. For a 70 kg adult that is roughly 2 litres.

• Replace losses separately. NG aspirate, stoma output and drain losses are rich in sodium and potassium: replace with 0.9% sodium chloride or Hartmann's, with potassium as needed.
• Review fluids every day: weight, fluid balance, U&E, and whether the patient is now drinking.
• Stop IV fluids once the patient is drinking enough.
• Hypotonic fluids (5% glucose, 0.18% saline) are the commonest cause of post-operative low sodium. Check sodium daily on any patient receiving them.
• Be cautious in the elderly and in heart failure. Overload causes as much harm as dehydration.

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PART THREE: ESCALATION

18. When to call the registrar now

• NEWS2 of 5 or more, or 3 in any single parameter
• Low blood pressure that does not respond to fluid
• Suspected bleeding
• Any airway concern, especially after neck surgery
• New chest pain or sudden breathlessness
• A falling conscious level
• New peritonism or suspected anastomotic leak
• Potassium of 6.5 or above, or any electrolyte with ECG changes
• Symptomatic low sodium
• Any time you find yourself hoping the patient will look better in an hour

19. How to make the call

Use SBAR, then say what you think and what you want.

• Situation: "I'm calling about Mr Smith in bed 12, day 2 after a right hemicolectomy. He's tachycardic at 125 and his blood pressure has dropped to 95/60."
• Background: "He was stable this morning. His drain has put out 400 mL of fresh blood in the last two hours."
• Assessment: "I think he's bleeding. I've put in two large cannulae, sent a crossmatch and given 500 mL of fluid. His haemoglobin on the gas is 82, down from 118."
• Recommendation: "I'd like you to come and see him now."

That is a good call. "Hi, I've got a patient with a high heart rate" is a much harder one to act on.

20. Document every review

• What you were called about, and when
• What you found: observations, examination, results
• What you did and what you prescribed
• Who you discussed the patient with
• The plan, and when you or someone else will review the patient again

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QUICK REFERENCE

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Educational resource for foundation doctors and surgical trainees. Doses reflect common UK practice and national guidance (UK Kidney Association, JBDS-IP, NICE CG174 and NG89, Difficult Airway Society) at the date of review. Local protocols vary. Always check your trust guidance and the BNF, and seek senior advice whenever you are unsure. Not a substitute for clinical judgement or supervision.