Page 9 of 11
AS10.1-4 | Patient Safety in Anaesthesiology — Graded Quiz
Click any question card to reveal the correct answer.
A patient is positioned prone for lumbar spine surgery. Thirty minutes into the procedure, the circulating nurse notes that the right eye is directly resting on the headrest foam with visible compression of the globe. The anaesthetist immediately repositions the head. Which complication was MOST likely being averted by this intervention?
Direct compression of the globe in the prone position raises intraocular pressure and can occlude the central retinal artery (normal perfusion pressure approximately 25 mmHg; IOP can exceed 40 mmHg with direct compression). Central retinal artery occlusion causes irreversible monocular blindness. This is the MOST serious and preventable complication of inadequate globe offloading in the prone position.
In the prone position, a horseshoe headrest or dedicated prone frame must offload the orbit completely — NEVER allow the globe to contact the headrest. Direct compression raises IOP and occludes the central retinal artery, causing permanent monocular blindness — one of the most devastating preventable anaesthetic complications.
Anterior ischaemic optic neuropathy (AION) is caused by prolonged systemic hypotension and anaemia reducing optic nerve perfusion — not direct eye compression. Corneal abrasion is caused by inadequate eyelid taping, not globe compression. Orbital compartment syndrome is linked to Trendelenburg plus prolonged massive fluid infusion, not direct compression. The direct mechanism here is central retinal artery occlusion.
Click to reveal answer
A patient undergoing prolonged surgery in the Trendelenburg position develops wrist drop postoperatively. Which nerve was most likely injured, and what was the mechanism?
Wrist drop (inability to extend the wrist and fingers) is the clinical signature of radial nerve injury at the spiral groove of the humerus. In surgical positioning, this occurs when the arm is unsupported and hangs over the edge of the operating table, compressing the nerve against the hard surface or the lateral edge of the table at the spiral groove level.
Radial nerve injury at the spiral groove causes wrist drop; prevention requires the arm to be fully supported on a padded arm board at no more than 90° abduction, with the elbow never hanging unsupported over the table edge during prolonged procedures.
Ulnar nerve injury at the medial epicondyle produces sensory loss in the ring and little finger with weakness of intrinsic hand muscles — not wrist drop. Median nerve compression causes thenar wasting and loss of thumb opposition (carpal tunnel presentation). Musculocutaneous nerve injury causes loss of elbow flexion and forearm sensation. Wrist drop is the hallmark of radial nerve injury at the spiral groove.
Click to reveal answer
A 45-year-old patient with no previous lung disease has a baseline SpO₂ of 99% on air. After induction of general anaesthesia with propofol and tracheal intubation, the SpO₂ falls to 94% despite ventilating with 100% oxygen. The chest X-ray taken intraoperatively shows bilateral basal density. PEEP is increased to 8 cmH₂O and SpO₂ recovers to 98%. Which pathophysiological mechanism BEST explains the initial desaturation?
General anaesthesia reduces FRC by approximately 15-20%, predominantly from cephalad shift of the diaphragm and reduced chest wall muscle tone. This falls below closing capacity in many patients, causing airway closure and alveolar collapse (atelectasis) in dependent lung zones, creating a true intrapulmonary shunt. Shunt is characterised by poor response to supplemental O₂ alone; PEEP recruits collapsed alveoli and reverses the shunt — explaining the clinical scenario.
Anaesthesia-induced atelectasis (shunt physiology) is the commonest cause of intraoperative hypoxaemia — caused by FRC reduction, diaphragm shift, and absorption atelectasis. It responds to PEEP, recruitment manoeuvres, and inspired oxygen titration — not just increasing FiO₂ alone.
Bronchospasm causes V/Q mismatch with wheeze and raised airway pressures — not bilateral basal density. Pulmonary oedema from fluid overload would require substantial fluid volumes and shows diffuse bilateral opacities, not just basal. PFO-related shunt is fixed and would not respond to PEEP. The basal density responding to PEEP is the hallmark of anaesthesia-induced atelectasis.
Click to reveal answer
A 35-year-old woman with no known allergies develops sudden cardiovascular collapse (BP 50/30 mmHg, HR 140/min, SpO₂ 85%) within 90 seconds of receiving suxamethonium 100 mg IV during rapid-sequence induction. She also develops diffuse urticaria. What is the MOST likely diagnosis and first-line treatment?
This is perioperative anaphylaxis — the triad of cardiovascular collapse, bronchospasm (SpO₂ drop), and urticaria within seconds of drug exposure is diagnostic. First-line treatment is adrenaline (epinephrine) 0.5 mg IM into the lateral thigh (1:1000 solution, i.e., 0.5 mL of 1 mg/mL). Adrenaline is the only drug that simultaneously reverses vasodilation, bronchospasm, and histamine release. Corticosteroids and antihistamines are adjuncts, not first-line.
Perioperative anaphylaxis: treat with adrenaline 0.5 mg IM (1:1000) as the immediate first-line drug — NOT antihistamines or steroids first. Suxamethonium is the most common trigger. Call for help, stop the agent, give IV fluids 500-1000 mL, and administer IM adrenaline without delay.
Suxamethonium apnoea causes prolonged paralysis without cardiovascular collapse or urticaria. Malignant hyperthermia causes rising temperature, rigidity, and hypercarbia — not urticaria or immediate hypotension. Hydrocortisone has a slow onset (hours) and is never first-line for anaphylaxis; it is an adjunct to adrenaline. Adrenaline 0.5 mg IM is the life-saving first step.
Click to reveal answer
After a ward round, the surgical registrar tells the anaesthetic resident: 'Mr Patel in bed 4 needs his postoperative analgesia reviewed — I think his pain is not controlled.' The resident acknowledges with 'okay' and walks away. Forty minutes later the nurse finds Mr Patel in severe pain — the resident had forgotten the instruction. Which communication failure does this BEST illustrate?
Closed-loop communication requires three steps: (1) sender transmits message, (2) receiver repeats back the specific action they will take, and (3) sender confirms. The resident's 'okay' was an acknowledgement without a read-back of the specific action, and no follow-up occurred. The loop was never closed — the resident had no committed action statement and subsequently forgot. This is the definition of broken closed-loop communication.
Closed-loop communication requires read-back of the specific action: e.g., 'I will review Mr Patel's analgesic prescription in the next 10 minutes and call you if I need guidance.' A verbal 'okay' without a committed action read-back is not closed-loop and does not create accountability.
Faulty handover refers to structural deficiencies in shift-to-shift or team-to-team communication. Cognitive overload involves the receiver being overwhelmed by information volume or complexity — the message here was simple. Situation awareness failure means being unaware of what is happening clinically. This scenario specifically illustrates the absence of closed-loop confirmation — the sender and receiver never jointly confirmed a specific committed action.
Click to reveal answer
An operating theatre team completes a difficult 6-hour vascular reconstruction. Before the patient is transferred to ICU, which structured communication action MOST effectively prevents information loss at this critical handover point?
The OR-to-ICU handover is a high-risk transition where critical information (intraoperative events, vasopressor requirements, blood loss, antifibrinolytics given, ventilatory settings, family communication) must transfer reliably. A formal face-to-face SBAR handover with both the ICU nurse and intensivist present ensures the information is received, understood, and can be questioned — far superior to written records read later or unstructured verbal summary.
OR-to-ICU handover is one of the highest-risk care transitions. Best practice is a structured SBAR handover with the anaesthetist present, receiver read-back, and confirmation — not a written record alone. All major intraoperative events (haemodynamic instability, difficult airway, drug reactions) must be verbally communicated.
An unstructured verbal summary relies on the receiver guessing what is important — structured SBAR guides complete, systematic information transfer. Written records alone are inadequate because they cannot be questioned in real time and may be read after the patient is already unstable. The anaesthetist is the primary holder of intraoperative information and must participate in the handover — surgical handover does not substitute.
Click to reveal answer
A patient scheduled for elective thyroidectomy has documented iodine contrast allergy in their chart. During induction, the anaesthetist administers providone-iodine skin prep without checking the allergy alert. The patient develops anaphylaxis. Which type of medical error does this represent according to the IOM classification?
James Reason's Swiss Cheese Model distinguishes active failures (unsafe acts by front-line staff — the anaesthetist not checking the allergy chart) from latent failures (organisational/system deficiencies that allow active failures to cause harm — no automated allergy alert integrated into the drug administration workflow). Most anaesthetic adverse events involve both layers. Near miss requires that the error was detected and intercepted before reaching the patient — here it caused harm.
Perioperative adverse drug events involve both active failures (individual unsafe acts) and latent failures (system gaps). Root cause analysis must address both layers — individual feedback AND system redesign (allergy alerts at point-of-care, colour-coded wristbands, mandatory allergy check on anaesthetic chart before any drug administration).
Classifying this as active failure only ignores the system vulnerability (no allergy alert at the point of drug preparation). Latent failure only ignores the anaesthetist's direct unsafe act. A near miss by definition is intercepted before it causes harm to the patient — anaphylaxis occurred, so this was not a near miss. The Swiss Cheese model correctly identifies both active and latent failure layers.
Click to reveal answer
An anaesthetic trainee draws up rocuronium 50 mg (5 mL from a 10 mg/mL vial) into a 5-mL syringe but forgets to label it. She then draws up neostigmine 2.5 mg into an identical 5-mL syringe, also unlabelled, and places both syringes on the drug tray side by side. At reversal, she picks up the wrong syringe and administers rocuronium instead of neostigmine. Which prevention strategy would MOST directly have prevented this error?
Immediate syringe labelling at preparation is the single most effective intervention against this category of error. A labelled syringe is inspectable — the administering clinician can verify the drug, dose, and concentration before injection. The error in this scenario occurred specifically because the syringes were unlabelled and visually identical. Labelling immediately (not 'I'll label it in a moment') is the international patient safety standard.
The unlabelled syringe is the highest-risk object in the operating theatre. ALWAYS label each syringe immediately upon preparation with drug name, concentration, dose, and preparation time — before the syringe leaves your hand. This is non-negotiable international patient safety standard for all anaesthetic drug administration.
Preparing one drug at a time reduces concurrent confusion but does not address the core risk of an unlabelled syringe being picked up later. Syringe size differentiation is not standardised and would not reliably prevent confusion. Separate storage rooms is impractical and addresses a different risk (LASA proximity storage). The most direct, actionable, and evidence-based prevention is immediate labelling of every syringe upon preparation.
Click to reveal answer
A 62-year-old patient undergoing 5-hour hip arthroplasty in the lateral decubitus position is found to have a new facial nerve palsy on the contralateral (down) side postoperatively. On reviewing the operative notes, the axillary roll had been placed directly in the axilla rather than 5 cm distal to it. Which complication would ADDITIONALLY be expected from axillary roll misplacement in this position?
The axillary roll must be placed 5 cm distal to the axilla — its purpose is to offload the weight of the thorax from the axilla by resting it on the chest wall, thereby preventing compression of the neurovascular bundle (brachial plexus and axillary vessels) by the body weight. An incorrectly placed roll directly in the axilla instead compresses the brachial plexus and axillary artery, potentially causing brachial plexus palsy and vascular compromise of the down arm. The facial nerve palsy was from the head resting directly on the table.
In the lateral decubitus position: (1) axillary roll goes 5 cm DISTAL to the axilla to protect the brachial plexus; (2) head on a pillow to prevent facial/ear pressure; (3) dependent knee flexed, padded; (4) check the down arm pulseoximetry remains present throughout. Review all pressure points at 2-hourly intervals for long cases.
Ulnar nerve compression in the lateral position affects the down arm elbow but is a different positioning issue unrelated to the axillary roll. Femoral nerve and common peroneal nerve injuries involve the lower limbs and are unrelated to the axillary roll position. The axillary roll protects the brachial plexus — its misplacement causes brachial plexus compression.
Click to reveal answer
A consultant anaesthetist retrospectively reviews 100 anaesthetic charts and finds that in 23 cases, the intended muscle relaxant dose was half the weight-based dose (a systematic 2-fold dosing underestimate). On investigation, the drug calculator software was using the patient's weight in pounds instead of kilograms. This is BEST classified as which type of medication error?
A systematic error affecting 23% of cases is not a random slip or individual knowledge failure — it is a latent system error embedded in the software design. The drug calculator's failure to clearly distinguish pounds from kilograms (or to default to kilograms as the standard clinical unit) is a design flaw that created a recurrent trap. This is the prototypical latent failure: invisible to individual users, causing harm across multiple patients until revealed by audit.
Systematic medication errors revealed by audit almost always have a latent system root cause (software design, labelling, storage, workflow). Individual retraining addresses the person, not the system. The correct response is system redesign: configure the calculator to accept kg only, flag pound entries, and require weight-unit confirmation — so the safe action becomes the default.
A slip is an individual error of execution — not a systematic 23/100 pattern. A knowledge-based mistake would imply the anaesthetists didn't know mg/kg dosing — but they correctly applied the calculator's output; the calculator was wrong. A violation requires deliberate rule-breaking. The systematic nature and software root cause clearly identify this as a latent system design error requiring a software fix, not individual retraining.
Click to reveal answer