Anaesthesia: Perioperative care, pain and anaesthetic complications

• Perioperative care: Perioperative Fluids | Blood Loss and Transfusion | Temperature and Positioning | Recovery and the Deteriorating Postoperative Patient
• Pain: Pain Physiology and Assessment | Acute Postoperative Pain Management | PCA and Epidural Analgesia | Chronic Pain and Opioid Stewardship
• Complications: Postoperative Nausea and Vomiting | Airway and Respiratory Complications | Cardiovascular Complications | Delirium, Awareness and Nerve Injury | Postoperative Oliguria and AKI | Aspiration and Other Emergencies in Theatre
• Revision: Perioperative Care at a Glance | Spot the Diagnosis | Exam-style Scenarios | Key Points | Guidelines and Further Reading

🛏️ Perioperative care, pain and anaesthetic complications — page 3 of the Anaesthetics and Critical Care chapter. Most postoperative problems are first seen by ward doctors — the hypotensive patient after a laparotomy, the confused older person after a hip fracture repair, the patient in severe pain or with no urine output. Good fluid management, effective analgesia and early recognition of complications prevent most serious harm.
Your four questions for every postoperative patient: What operation and anaesthetic did they have — and what was the blood loss? Are their observations, urine output and pain under control? Is this the expected course, or an early complication (bleeding, sepsis, PE, MI, anastomotic leak)? Do they need escalation — senior review, critical care or return to theatre?

Perioperative Fluids

• Body water — about 60% of body weight in men (55% in women) — two-thirds intracellular, one-third extracellular (of which one-quarter is plasma).
• NICE CG174 (IV fluids in adults) — the 5 Rs — Resuscitation, Routine maintenance, Replacement, Redistribution, Reassessment.
• Resuscitation — 500 mL crystalloid bolus over less than 15 minutes (sodium 130–154 mmol/L — e.g. Hartmann's, Plasma-Lyte or 0.9% saline), reassess, repeat (up to 2,000 mL then senior review).
• Maintenance — 25–30 mL/kg/day water, about 1 mmol/kg/day of sodium, potassium and chloride, and 50–100 g/day glucose (to limit ketosis) — e.g. 0.18% saline with 4% glucose plus potassium (or isotonic in some groups); reduce to 20–25 mL/kg in older, frail, renal and cardiac patients; switch to oral as soon as possible.
• Replacement and redistribution — ongoing losses (vomiting, NG aspirate, drains, stomas, fistulae), fluid shifts (sepsis, pancreatitis, ileus — "third spacing").
• Balanced crystalloids vs saline — large volumes of 0.9% saline cause hyperchloraemic metabolic acidosis and possibly AKI; balanced solutions (Hartmann's, Plasma-Lyte) are often preferred.
• Hypotonic fluids — risk of hyponatraemia (high ADH after surgery) — especially in children (use isotonic fluids in children — NICE NG29).
• Colloids — albumin (selected uses — e.g. paracentesis, sepsis with large volumes); starches (HES) — withdrawn (AKI, mortality).
• Goal-directed fluid therapy — cardiac output monitoring (oesophageal Doppler) in major surgery; avoid both underfilling and overload; "zero balance" after surgery in ERAS.
• Fluid overload — oedema, pulmonary oedema, ileus, wound and anastomotic problems — weigh daily, fluid charts.

Blood Loss and Transfusion

• Patient blood management — treat anaemia before surgery (IV iron), minimise blood loss (tranexamic acid, surgical technique, cell salvage), restrictive transfusion thresholds.
• Transfusion thresholds (NICE NG24):
  • Hb under 70 g/L — transfuse (target 70–90 g/L) for most patients.
  • Hb under 80 g/L with acute coronary syndrome (target 80–100 g/L).
  • Single-unit transfusions with reassessment (non-bleeding patients).
  • Major haemorrhage — not guided by Hb — activate the major haemorrhage protocol.
• Estimating blood loss — swabs, suction, drains; signs of hypovolaemia (tachycardia, narrow pulse pressure, oliguria, rising lactate); Hb lags behind acute loss.
• Massive transfusion — red cells, FFP and platelets in balanced ratios (e.g. 1:1 in trauma), tranexamic acid, cryoprecipitate or fibrinogen concentrate if fibrinogen under 1.5 g/L (2 g/L in obstetrics), viscoelastic testing (ROTEM/TEG), avoid the "lethal triad" (hypothermia, acidosis, coagulopathy), calcium replacement.
• Complications of transfusion — ABO incompatibility (wrong blood — fever, hypotension, haemoglobinuria — stop immediately), TACO (transfusion-associated circulatory overload — commonest cause of serious harm; risk in older, small, cardiac and renal patients — slow rate, diuretic), TRALI (acute lung injury within 6 hours — non-cardiogenic pulmonary oedema), febrile non-haemolytic reactions, allergic reactions and anaphylaxis, hyperkalaemia, hypocalcaemia (citrate), infection (rare), TA-GvHD (irradiated blood for at-risk patients).
• Cell salvage — intraoperative recovery of shed blood — major orthopaedic, cardiac, vascular and obstetric surgery; acceptable to many Jehovah's Witnesses.
• Report serious reactions to SHOT (Serious Hazards of Transfusion) and MHRA (SABRE).

Temperature and Positioning

• Inadvertent perioperative hypothermia (core under 36°C) — very common — anaesthesia impairs thermoregulation (vasodilatation, redistribution of heat to the periphery), cold theatres, exposure, cold fluids.
• Consequences — wound infection, coagulopathy and bleeding, myocardial ischaemia, shivering (raises oxygen demand), delayed drug metabolism and slow emergence, longer recovery stay.
• Prevention (NICE CG65) — measure temperature before, during (every 30 minutes) and after surgery; forced-air warming for operations over 30 minutes (or high risk); warmed IV fluids and blood (over 500 mL); don't start anaesthesia if temperature under 36°C (unless urgent).
• Positioning injuries:
  • Peripheral nerve injury — ulnar nerve (elbow — commonest), brachial plexus (arm abducted over 90°), common peroneal nerve (lithotomy — fibular head — foot drop), radial nerve (arm hanging over the edge).
  • Pressure ulcers — long procedures, older people.
  • Eye injury — corneal abrasion (tape eyes closed); postoperative visual loss (prone spinal surgery — ischaemic optic neuropathy).
  • Compartment syndrome in prolonged lithotomy.
  • Physiological effects — prone (pressure on abdomen, airway access), steep head-down (Trendelenburg — raised ICP and intraocular pressure, airway oedema), sitting (venous air embolism, hypotension).
• Diathermy burns, tourniquet injuries, alcohol skin prep fires — part of the WHO checklist and theatre safety.

Recovery and the Deteriorating Postoperative Patient

• Post-anaesthesia care unit (PACU) — one-to-one nursing until the airway is maintained; monitoring; pain, PONV and temperature managed; discharge criteria (awake, airway reflexes, stable observations, pain and nausea controlled).
• Postoperative care levels — ward (level 0–1), enhanced care or HDU (level 2 — single organ support), ICU (level 3 — advanced respiratory support or two or more organs) — high-risk patients (predicted mortality over 5%) should go to critical care (NELA, RCS).
• Early warning — NEWS2 (score of 5 or more, or 3 in one parameter — urgent review; 7 or more — emergency response and critical care outreach).
• Timing of complications:

  Timing	Typical complications
  Immediate (hours)	Airway obstruction, residual paralysis, hypoxia, primary haemorrhage, hypotension, PONV, pain, hypothermia, anaphylaxis, LAST
  Early (days 1–7)	Atelectasis (day 1–2 — fever), reactionary haemorrhage (within 24 hours — slipped ligature, rising BP), AKI, urinary retention, delirium, pneumonia, MI, AF, wound infection (day 3–5), anastomotic leak (days 5–7), ileus, UTI, line infections, VTE (any time — peaks days 5–10)
  Late (weeks)	Secondary haemorrhage (infection — 7–14 days), wound dehiscence, incisional hernia, adhesions, chronic pain

• Postoperative pyrexia — "5 Ws" — Wind (atelectasis, pneumonia — days 1–2), Water (UTI — days 3–5), Wound (days 5–7), Walking (DVT/PE — days 5+), Wonder drugs (drug fever, transfusion); also anastomotic leak, abscess, line infection, C. difficile.
• Postoperative hypotension — hypovolaemia (bleeding — look at drains, wounds, abdomen; under-replacement), sepsis, epidural (sympathetic block), drugs (opioids, antihypertensives), cardiogenic (MI, arrhythmia), PE, anaphylaxis, adrenal crisis — ABCDE, fluid bolus, Hb and lactate, call senior and surgical team.

Pain Physiology and Assessment

• Nociception — tissue injury → nociceptors (free nerve endings) → Aδ fibres (fast, sharp, well-localised pain) and C fibres (slow, dull, burning) → dorsal horn (substantia gelatinosa) → spinothalamic tract → thalamus → somatosensory cortex and limbic system.
• Gate control theory (Melzack and Wall) — large Aβ fibre input (rubbing, TENS) inhibits pain transmission in the dorsal horn; descending inhibition from the periaqueductal grey (opioids, noradrenaline, serotonin).
• Sensitisation — peripheral (inflammatory mediators — prostaglandins, bradykinin) and central ("wind-up" — NMDA receptors — ketamine) → hyperalgesia (more pain from a painful stimulus) and allodynia (pain from a non-painful stimulus).
• Types of pain:
  • Nociceptive — somatic (well localised — skin, bone, muscle) or visceral (poorly localised, referred, colicky — organs).
  • Neuropathic — damage to the nervous system — burning, shooting, electric, numbness, allodynia (post-herpetic neuralgia, diabetic neuropathy, phantom limb, post-surgical nerve injury).
  • Nociplastic — altered pain processing without clear tissue or nerve damage (fibromyalgia).
• Assessment — site, character, severity (0–10 numeric rating score; at rest and on movement — e.g. coughing and deep breathing), functional impact; tools for cognitive impairment (Abbey Pain Scale, PAINAD) and children (FLACC, faces).
• Functional goal — pain controlled enough to breathe deeply, cough, mobilise and sleep.

Acute Postoperative Pain Management

• Multimodal analgesia — combinations of drugs and techniques acting at different points — better analgesia, fewer opioid side effects:
  • Regular paracetamol (1 g four times a day; reduce to 15 mg/kg or 3 g/day if under 50 kg, liver disease, malnutrition).
  • NSAIDs (ibuprofen, naproxen, diclofenac; IV parecoxib) — unless contraindicated (AKI risk, bleeding, peptic ulcer, severe asthma with NSAID sensitivity, heart failure).
  • Opioids — oral (oxycodone, morphine) for moderate to severe pain; immediate-release "as required" in preference to modified-release after surgery (FPM/RCoA guidance); IV PCA after major surgery.
  • Regional anaesthesia — epidurals, spinal opioids, nerve and plexus blocks, fascial plane blocks (TAP, rectus sheath, erector spinae), wound catheters, local infiltration.
  • Adjuncts — dexamethasone, ketamine, IV lidocaine infusion (colorectal surgery), clonidine, magnesium.
• WHO analgesic ladder — originally for cancer pain; postoperative pain usually starts at the top and steps down ("reverse ladder").
• Monitor — pain scores, sedation score (sedation precedes respiratory depression), respiratory rate, oxygen saturation, nausea, bowels.
• Opioids in renal failure — avoid morphine and codeine (active metabolites accumulate) — use oxycodone (reduced dose), fentanyl, alfentanil or buprenorphine.
• Opioid-tolerant patients (chronic opioids, methadone or buprenorphine for dependence) — continue baseline opioid (confirm doses), add multimodal and regional analgesia, expect higher requirements; acute pain team involvement.
• Acute pain team — nurse-led service for epidurals, PCAs, nerve catheters and complex pain.

PCA and Epidural Analgesia

• Patient-controlled analgesia (PCA):
  • IV opioid (e.g. morphine 1 mg bolus with a 5-minute lockout; no background infusion in opioid-naive patients) — the patient presses the button.
  • Safety — only the patient presses the button (not relatives or staff — "PCA by proxy"), dedicated IV line with an anti-reflux valve, monitoring (pain, sedation, respiratory rate, SpO₂), antiemetic and naloxone prescribed.
  • Unsuitable for confused patients, those who can't use the button, or patients unwilling to use it.
• Epidural analgesia:
  • Infusion of dilute local anaesthetic (e.g. levobupivacaine 0.1–0.125%) with an opioid (fentanyl) — thoracic epidurals for major abdominal and thoracic surgery; lumbar for labour and lower limb.
  • Monitoring — observations, pain score, sedation, block height (cold sensation — target dermatomes), motor block (Bromage score), pressure areas, catheter site.
  • Complications — hypotension (fluids, vasopressors, reduce infusion), inadequate or one-sided block, high block (arm weakness, breathlessness — stop infusion), urinary retention (catheter), itch, nausea, respiratory depression, epidural haematoma or abscess (back pain, increasing leg weakness — stop infusion, urgent MRI), LAST (rare).
  • Anticoagulant timings before insertion and removal (e.g. 12 hours after prophylactic LMWH; next dose at least 4 hours after removal).
  • Thoracic epidurals are now used less in some surgery (laparoscopic, ERAS) — replaced by spinal opioids, fascial plane blocks and lidocaine infusions.
• Intrathecal (spinal) opioids — e.g. diamorphine or morphine — long-lasting analgesia (up to 24 hours) — delayed respiratory depression (monitor for 12–24 hours), itch, nausea, urinary retention.

💡 Clinical Pearl: Increasing leg weakness in a patient with an epidural is not "just the block". Stop the infusion and reassess within an hour — if the weakness doesn't improve, an MRI is needed urgently to exclude haematoma or abscess.

Chronic Pain and Opioid Stewardship

• Chronic pain — pain lasting more than 3 months; chronic post-surgical pain affects about 10% after surgery (higher after amputation, thoracotomy, mastectomy, hernia repair) — risk factors: severe acute pain, preoperative pain, anxiety, nerve injury.
• Chronic primary pain (NICE NG193, 2021) — exercise programmes, psychological therapy (CBT, ACT), acupuncture; antidepressants (amitriptyline, duloxetine, SSRIs) can be considered; don't start opioids, gabapentinoids, NSAIDs, paracetamol, benzodiazepines or local anaesthetic injections.
• Neuropathic pain (NICE CG173) — amitriptyline, duloxetine, gabapentin or pregabalin first line (switch if not effective); capsaicin cream for localised pain; tramadol only as short-term rescue; carbamazepine for trigeminal neuralgia.
• Opioids for chronic non-cancer pain — limited benefit long term; harms — dependence, tolerance, hyperalgesia, endocrine suppression, falls, overdose; doses above 120 mg oral morphine equivalent a day rarely help and increase harm (FPM "Opioids Aware").
• Opioid stewardship after surgery — short courses (e.g. up to 5–7 days) of immediate-release opioids on discharge, clear plan to stop, avoid modified-release opioids for acute pain, GP communication — reduces persistent postoperative opioid use.
• Gabapentinoids — controlled drugs (Schedule 3) since 2019 — misuse and respiratory depression with opioids.
• Interventions — nerve blocks, radiofrequency denervation, spinal cord stimulation (specialist pain clinics); complex regional pain syndrome — early physiotherapy and pain team.

Postoperative Nausea and Vomiting

• Common — up to 30% of patients (up to 80% in high-risk) — distressing, delays discharge, causes dehydration, wound strain and aspiration.
• Apfel score (risk factors — each 1 point):
  • Female sex.
  • Non-smoker.
  • History of PONV or motion sickness.
  • Postoperative opioids.
  — risk roughly 10%, 20%, 40%, 60% and 80% for 0–4 factors.
• Other risk factors — volatile anaesthetics and nitrous oxide, long surgery, type of surgery (laparoscopic, gynaecological, ENT, strabismus, breast), younger age.
• Prevention — reduce baseline risk (TIVA with propofol, regional anaesthesia, minimise opioids, avoid nitrous oxide, adequate hydration); multimodal prophylaxis by risk — dexamethasone plus ondansetron (plus a third agent — droperidol, cyclizine, aprepitant — in high risk).
• Treatment — use an antiemetic from a different class from the prophylaxis given; exclude causes (hypotension, hypoxia, pain, opioids, ileus, bowel obstruction, raised ICP, hyponatraemia).
• Parkinson's disease — avoid metoclopramide and prochlorperazine (dopamine antagonists) — use domperidone (peripheral), ondansetron (caution with apomorphine) or cyclizine.

Airway and Respiratory Complications

• Airway obstruction in recovery — tongue and soft tissue (jaw thrust, adjuncts), laryngospasm, secretions or blood, neck haematoma after thyroid or carotid surgery (SCOOP — Skin exposure, Cut sutures, Open skin, Open muscles, Pack — remove clips at the bedside if airway compromise), laryngeal oedema, vocal cord palsy (bilateral recurrent laryngeal nerve injury).
• Residual neuromuscular blockade — weakness, hypoventilation, hypoxia, aspiration — check TOF; reverse.
• Hypoventilation — opioids, residual anaesthetic, residual paralysis, OSA, obesity — high CO₂ (check ABG), sedation — naloxone if opioid-induced, NIV.
• Bronchospasm — asthma, anaphylaxis, airway irritation, aspiration — salbutamol, deepen anaesthesia, adrenaline if severe.
• Atelectasis — the commonest postoperative pulmonary complication (day 1–2 fever, low saturations, reduced basal breath sounds) — analgesia, sitting up, early mobilisation, physiotherapy, incentive spirometry, CPAP.
• Postoperative pneumonia — hospital-acquired — antibiotics per local policy.
• Pulmonary embolism — sudden breathlessness, pleuritic pain, tachycardia, hypoxia — CTPA; anticoagulation (balance against bleeding risk — discuss with surgeons); thrombolysis or embolectomy for massive PE.
• Pulmonary oedema — fluid overload (common after surgery), MI, TACO, negative pressure pulmonary oedema (after laryngospasm — patient inspires against a closed glottis).
• Pneumothorax — after central lines, nerve blocks (supraclavicular, interscalene), thoracic and upper abdominal surgery, high airway pressures.

Cardiovascular Complications

• Perioperative myocardial injury and infarction — often silent (masked by analgesia and sedation) — rising troponin (MINS — myocardial injury after non-cardiac surgery — associated with 30-day mortality); type 2 MI (supply–demand mismatch — tachycardia, hypotension, anaemia, hypoxia) is common; manage with cardiology — treat the cause, aspirin and statin if safe; PCI and full anticoagulation are limited by bleeding risk.
• Postoperative AF — common after cardiac and thoracic surgery (and major abdominal surgery) — triggers: sepsis, hypovolaemia, electrolyte disturbance (potassium, magnesium), pain, hypoxia, fluid overload — correct triggers; rate control (beta-blocker); amiodarone; cardioversion if unstable; anticoagulation decisions balanced against bleeding.
• Hypertension — pain, urinary retention, hypoxia, hypercapnia, missed medications, fluid overload — treat the cause first.
• Bradycardia — opioids, neostigmine, high spinal, vagal stimulation, hypoxia — atropine or glycopyrronium.
• Haemorrhage:
  • Primary — during surgery.
  • Reactionary — within 24 hours — slipped ligature or opened vessels as BP rises.
  • Secondary — 7–14 days — infection eroding vessels.
  • Management — ABCDE, IV access, cross-match, blood, correct coagulopathy (reverse anticoagulants), tranexamic acid, return to theatre or interventional radiology.
• Fat embolism syndrome — after long bone (femur) and pelvic fractures and intramedullary nailing — hypoxia, confusion and petechial rash (axillae, conjunctivae) at 24–72 hours — supportive care.
• Bone cement implantation syndrome — hypotension, hypoxia and arrhythmias (or arrest) when cement is inserted during hemiarthroplasty — high-risk older patients — warn the team, optimise filling, vasopressors ready.
• Venous air embolism — sitting neurosurgery, central line insertion or removal — sudden fall in ETCO₂, hypotension, hypoxia — left lateral head-down position, 100% oxygen, aspirate air from a central line.

Delirium, Awareness and Nerve Injury

• Postoperative delirium:
  • Common in older people (up to 50% after hip fracture surgery) — linked to longer stay, falls, institutionalisation, dementia and death.
  • Risk factors — age over 65, dementia and cognitive impairment, frailty, hip fracture, severe illness, sensory impairment, polypharmacy.
  • Precipitants — pain, hypoxia, infection, dehydration, urinary retention, constipation, electrolyte disturbance, drugs (opioids, benzodiazepines, anticholinergics), alcohol withdrawal, environment change, sleep deprivation.
  • Assessment — 4AT screening tool; look for causes ("PINCH ME" — Pain, Infection, Nutrition, Constipation, Hydration, Medication, Environment).
  • Prevention and management (NICE CG103) — orientation, glasses and hearing aids, sleep, mobilisation, hydration, avoid catheters and restraints, treat causes; haloperidol only short term for severe distress or risk (avoid in Parkinson's and Lewy body dementia).
• Postoperative cognitive dysfunction — decline in cognitive function weeks to months after surgery — older people.
• Accidental awareness under general anaesthesia (AAGA — NAP5 — about 1 in 19,000):
  • Risk factors — neuromuscular blockade, TIVA, caesarean section under GA, cardiac surgery, obesity, emergency surgery, RSI with thiopental, drug errors, interruption of volatile delivery (transfers).
  • Consequences — distress, PTSD.
  • Prevention — depth of anaesthesia monitoring (processed EEG) with TIVA and neuromuscular blockade; agent monitoring; checks.
  • If reported — believe the patient, take a detailed history, apologise, explain, offer psychological support (NAP5 Awareness Support Pathway).
• Peripheral nerve injury — positioning (ulnar, peroneal), regional blocks (usually temporary — most recover within weeks), tourniquets, surgical injury — document, refer to neurology or the block service; nerve conduction studies if persisting.
• Dental damage — the commonest anaesthetic claim — document preoperative dentition; consent.

Postoperative Oliguria and AKI

• Oliguria — urine output under 0.5 mL/kg/hour for 6 hours or more (KDIGO AKI criterion); expected briefly after surgery (ADH release) but must be assessed.
• Causes:
  • Pre-renal (commonest) — hypovolaemia (bleeding, under-replacement, third-space losses), hypotension (epidural, sepsis, cardiac).
  • Renal — acute tubular necrosis (prolonged hypotension), nephrotoxins (NSAIDs, aminoglycosides, contrast, ACE inhibitors and ARBs), rhabdomyolysis, abdominal compartment syndrome.
  • Post-renal — blocked catheter (flush or change first), urinary retention, ureteric injury (pelvic surgery).
• Assessment — check the catheter and bladder scan; fluid balance and weight; observations; examine (abdomen — distension, tense abdomen); U&E (compare with baseline), potassium, VBG and lactate, urinalysis, CK if risk; ultrasound if obstruction suspected.
• Management — fluid challenge if hypovolaemic (500 mL crystalloid and reassess — avoid repeated boluses in a euvolaemic or overloaded patient), restore BP (vasopressors if needed), stop nephrotoxins, adjust drug doses, treat hyperkalaemia, critical care if refractory (renal replacement therapy).
• Abdominal compartment syndrome — intra-abdominal pressure (via bladder) over 20 mmHg with new organ dysfunction (oliguria, high ventilatory pressures) after laparotomy, pancreatitis, massive fluid resuscitation — decompressive laparotomy.
• Urinary retention — common after spinal and epidural anaesthesia, opioids, anticholinergics, hernia and pelvic surgery, older men — bladder scan; catheter.

Aspiration and Other Emergencies in Theatre

• Pulmonary aspiration — the leading cause of airway-related death in NAP4:
  • Risk factors — full stomach, emergency surgery, bowel obstruction, pregnancy, obesity, reflux, diabetes, GLP-1 agonists, SAD use in high-risk patients, light anaesthesia.
  • Management — head down and lateral, suction, 100% oxygen, intubate (cuffed tube) and suction the trachea before ventilating, bronchoscopy if particulate matter, bronchodilators; antibiotics if pneumonia develops (not routinely); ICU if severe (ARDS — Mendelson's syndrome).
• Intraoperative crises — use the Quick Reference Handbook (QRH) (Association of Anaesthetists) — cognitive aids for:
  • Hypoxia, high airway pressure, hypotension, bradycardia, tachycardia.
  • Anaphylaxis, LAST, malignant hyperthermia, massive haemorrhage.
  • Cardiac arrest (consider the 4 Hs and 4 Ts, plus anaesthetic causes — drug errors, high spinal, anaphylaxis, LAST, gas embolism, tension pneumothorax).
  • Fire in theatre (oxygen, alcohol prep, diathermy, laser — airway fire: stop gases, remove tube, saline).
• Drug errors — syringe swaps (colour-coded labels), wrong route (intrathecal — non-Luer connectors — NRFit), ampoule confusion — label all syringes.
• Human factors — situational awareness, communication (closed-loop), leadership and followership, fatigue, checklists, simulation training, debriefing.

Perioperative Care at a Glance

Spot the Diagnosis

Exam-style Scenarios

1. Six hours after an open right hemicolectomy, a 70-year-old man has HR 120, BP 85/50 and a urine output of 10 mL/hour for 3 hours. His abdomen is distended. Hb is 78 g/L (preoperative 125).
Answer: Reactionary haemorrhage with hypovolaemic shock.

• ABCDE, oxygen, two large-bore cannulas, crystalloid bolus while blood is obtained; major haemorrhage protocol if ongoing.
• Cross-match, clotting, fibrinogen, lactate; correct coagulopathy; tranexamic acid.
• Urgent surgical senior review — return to theatre (or interventional radiology).

2. An 80-year-old woman with CKD stage 4 is on a morphine PCA after a laparotomy. On day 2 she is drowsy, RR 8, SpO₂ 88% on air, with pinpoint pupils.
Answer: Opioid toxicity from accumulation of morphine metabolites in renal impairment.

• Stop the PCA; oxygen; airway support.
• Naloxone 100–200 microgram IV increments (repeat or infusion — longer-acting metabolites); monitor closely.
• Switch to an opioid safe in renal failure (oxycodone at reduced dose, fentanyl) with regional and non-opioid analgesia; acute pain team.

3. One hour after a total thyroidectomy, a patient becomes agitated with stridor and a tense swelling in the neck.
Answer: Postoperative neck haematoma compressing the airway.

• Call for help (anaesthetist and surgeon); 100% oxygen; sit up.
• SCOOP — open the wound at the bedside (cut sutures, open skin and muscle layers) to release the haematoma.
• Return to theatre for haemostasis; anticipate a difficult intubation (airway oedema).

4. A 35-year-old non-smoking woman with a history of motion sickness is having a laparoscopic cholecystectomy. She will need opioids afterwards.
Answer: High PONV risk (Apfel 4 — about 80%).

• Reduce baseline risk — TIVA (propofol), avoid nitrous oxide, opioid-sparing analgesia (paracetamol, NSAID, port-site local anaesthetic).
• Prophylaxis with dexamethasone and ondansetron, plus a third agent (e.g. droperidol or cyclizine).
• Rescue with an antiemetic from a different class; adequate hydration.

5. On day 2 after a hip fracture repair, an 86-year-old man with mild dementia is agitated, pulling at his cannula and hasn't opened his bowels since admission.
Answer: Postoperative delirium.

• 4AT; look for causes — pain, urinary retention (bladder scan), constipation, infection, hypoxia, electrolytes, drugs (opioids, anticholinergics).
• Non-drug measures — family, orientation, glasses and hearing aids, sleep, mobilise, fluids and laxatives.
• Short-term low-dose haloperidol only if severe distress or risk (not in Parkinson's or Lewy body dementia); orthogeriatric review.

Key Points

• IV fluids follow the 5 Rs — 500 mL boluses for resuscitation; 25–30 mL/kg/day for maintenance; switch to oral early.
• Large volumes of 0.9% saline cause hyperchloraemic acidosis; hypotonic fluids cause hyponatraemia.
• Transfuse at Hb under 70 g/L (80 with ACS) — one unit at a time; TACO is the commonest serious harm.
• Prevent hypothermia — warm air and warmed fluids.
• Haemorrhage is primary, reactionary (under 24 hours) or secondary (7–14 days).
• Postoperative fever — atelectasis early; UTI, wound, VTE and anastomotic leak later.
• Multimodal, opioid-sparing analgesia; pain controlled enough to breathe, cough and mobilise.
• Avoid morphine and codeine in renal failure; only the patient presses the PCA button.
• New leg weakness with an epidural — stop the infusion and get an urgent MRI.
• Apfel score predicts PONV — combine prophylactic antiemetics in high risk.
• Neck haematoma after thyroid surgery — SCOOP at the bedside.
• Delirium — 4AT, treat the cause, non-drug measures first.
• Oliguria — check the catheter first, then volume status; stop nephrotoxins.

Guidelines and Further Reading

• NICE CG174: Intravenous fluid therapy in adults in hospital; NICE NG29: IV fluid therapy in children
• NICE NG24: Blood transfusion; SHOT annual reports; BSH guidelines on massive haemorrhage
• NICE CG65: Hypothermia — prevention and management in adults having surgery
• Faculty of Pain Medicine: Opioids Aware; Core Standards for Pain Management Services; Surgery and Opioids (2021)
• NICE NG193: Chronic pain; NICE CG173: Neuropathic pain in adults
• Fourth Consensus Guidelines for the Management of PONV (2020)
• NICE CG103: Delirium — prevention, diagnosis and management; 4AT
• Royal College of Anaesthetists: NAP4, NAP5; Association of Anaesthetists Quick Reference Handbook
• BNF — for current doses