EHPLE Anesthesia common mistakes
EHPLE Anesthesia · Understand the traps and how to avoid them.
When a question gives arterial blood gas values, the candidate labels the primary disorder from the pH and PaCO2 alone and stops, without computing the expected compensatory response (e.g., Winter's formula for metabolic acidosis) to decide whether a second, mixed disorder is present.
Training emphasizes pattern recognition of the four primary disorders, and candidates memorize pH/CO2 arrows rather than the compensation formulas. Under time pressure, the calculation feels optional, so mixed acid-base states are missed and the answer chosen reflects only the dominant process.
What to do instead
Before answering any blood gas item, write the three-step routine on scratch paper: (1) pH direction, (2) primary driver (PaCO2 vs HCO3), (3) compare measured compensation with the expected value (Winter's: expected PaCO2 = 1.5 x HCO3 + 8 +/- 2; expected HCO3 change of 1 per 10 mmHg acute CO2 change, 3-4 per 10 mmHg chronic). Practise 15 mixed-disorder vignettes until the calculation is automatic within 60 seconds.
The candidate answers pharmacology items by recalling a drug's class and typical use but cannot state the mechanism at the receptor or ion-channel level, the onset/offset determinants (redistribution, context-sensitive half-time), or the active metabolite, so items asking 'why does effect prolong in renal failure' or 'why is offset fast after a short infusion but slow after a long one' are answered by guesswork.
Study tends to be organized around clinical indications and dose tables rather than pharmacokinetic principles. Candidates recognize drug names and pass on familiar stems but have not built a model that lets them predict behaviour in an altered patient.
What to do instead
For each core agent (propofol, thiopental, etomidate, ketamine, succinylcholine, rocuronium, neostigmine, remifentanil, morphine, lidocaine, bupivacaine), write a one-page card covering receptor target, physicochemical determinants of onset, metabolism and active metabolites, context-sensitive half-time behaviour, and the specific comorbidity that changes it. Test yourself by predicting the answer before reading options.
On preoperative items the candidate clears the patient for anesthesia based on the absence of an acute complaint, without systematically working through the functional-capacity assessment, the specific comorbidity that changes management (undiagnosed murmur, untreated anemia, poorly controlled asthma, recent MI or stent, obstructive sleep apnea), and the planned anesthetic technique.
Preoperative questions look like general medicine questions, so candidates answer them with general medical knowledge and skip the anesthesia-specific step: how this finding changes induction agent, airway plan, monitoring, or postoperative disposition.
What to do instead
Use a fixed checklist for every preoperative stem: exercise tolerance in metabolic equivalents, active cardiac symptoms, pulmonary status and recent exacerbation, airway predictors, aspiration risk, renal/hepatic function affecting drug choice, anticoagulant/antiplatelet status and neuraxial timing, and NPO status. Then explicitly state which element of the anesthetic plan changes.
When an airway item describes a difficult mask ventilation or failed intubation scenario, the candidate jumps to a single rescue device (often a supraglottic airway or cricothyrotomy) instead of following a staged algorithm and stating the trigger point at which each step is abandoned.
Rescue devices are studied as a list rather than as an ordered sequence with decision thresholds. Candidates recognize the device name in an option and select it without checking whether earlier steps were completed or whether the patient is in a 'cannot intubate, cannot oxygenate' state.
What to do instead
Memorize one airway algorithm as an explicit ladder with time or attempt limits: optimize position and preoxygenation, limited laryngoscopy attempts with a changed first step each time, supraglottic rescue, then front-of-neck access when oxygenation fails. For each rung, write the finding that mandates moving up. Answer scenario items by locating the stem on the ladder before reading options.
The candidate treats monitoring questions as 'which number is abnormal' rather than 'what does this signal physically represent and how does it fail', so items on pulse oximetry in low perfusion, methemoglobinemia, capnography waveform changes, or noninvasive blood pressure cuff size are answered from the displayed value alone.
Monitors are learned in the operating room as displays, not as instruments with failure modes. Candidates have not connected the physics (light absorbance, infrared absorption, oscillometry) to the artifact patterns tested.
What to do instead
For each monitor, learn three things: the physical principle, the two most common artifacts, and the clinical condition that mimics a real change. Specifically rehearse the capnography waveform for esophageal intubation, bronchospasm, circuit disconnect, and exhausted absorbent, and the oximetry pitfalls of poor perfusion, nail polish, and dyshemoglobins.
On regional anesthesia items the candidate selects a block by name and dermatome but cannot state the relevant anatomy, the expected sensory and motor coverage, the specific complication to warn about, and the safe dose of local anesthetic by weight with additive adjustment.
Block coverage is memorized as a map rather than as a three-dimensional anatomical relationship, and maximum local anesthetic dose is recalled as a single number without the weight-based calculation or the epinephrine and patient-factor adjustments.
What to do instead
For each block on the exam list, draw the nerve pathway from plexus to target, list the landmarks and the structures at risk, state the motor and sensory territory, and compute the maximum milligram dose for a 70 kg and a 50 kg patient including the additive. Rehearse the calculation until it is done before reading options.
Faced with an intraoperative crisis stem (sudden hypotension, desaturation, rising airway pressure, hyperthermia, wide-complex rhythm), the candidate picks the treatment that matches the most prominent sign rather than first committing to a differential generated from the event timing and the anesthetic agents in use.
Crisis items are written to reward a structured differential, but candidates read the last sentence and answer the symptom. The timing cue (at induction, at incision, after tourniquet release, during emergence) that discriminates the diagnosis is overlooked.
What to do instead
Practise a fixed opening move for every crisis stem: note the timing, the agent just given, the ventilator and circuit findings, and the hemodynamic pattern, then list three candidate causes ranked. Only then read the options and eliminate any that treat a sign rather than the leading cause. Drill malignant hyperthermia, anaphylaxis, local anesthetic systemic toxicity, tension pneumothorax, and bronchospasm this way.
Postoperative and pain items are answered by naming an analgesic or antiemetic without addressing multimodal strategy, the transition from intraoperative to postoperative analgesia, opioid tolerance and opioid-induced hyperalgesia, or the specific red flag (new severe pain after neuraxial technique suggesting epidural hematoma or abscess, respiratory depression with neuraxial opioid).
Postoperative care is studied last and thinly, so candidates rely on drug-name recognition. They also conflate 'treat the symptom' with 'investigate the complication', which the exam deliberately separates.
What to do instead
Build a postoperative template: multimodal analgesia layers (regional, non-opioid adjuncts, opioid as rescue), antiemetic prophylaxis by mechanism, and a red-flag list with the time window and the immediate action for each. For any new neurologic symptom after neuraxial block, rehearse the imaging and decompression timeline rather than an analgesic adjustment.
On obstetric, pediatric, and geriatric items the candidate applies adult dosing, adult monitoring thresholds, and adult physiology, ignoring the altered pharmacokinetics and the specific contraindication that defines the population (e.g., left uterine displacement and aspiration prophylaxis in obstetrics, weight-based dosing and altered MAC in pediatrics, reduced clearance and increased sensitivity in the elderly).
Adult anesthesia is the default mental model, and special-population facts are memorized as isolated trivia rather than as deviations from that default. Candidates answer the adult version of the question.
What to do instead
For each special population, write the three or four ways it departs from the adult baseline: body composition and volume of distribution, protein binding and clearance, MAC or sensitivity change, airway and aspiration differences, and the drug or technique to avoid. Then answer the item by first stating which departure is being tested.
Ethics and safety items are answered by choosing the option that sounds most reassuring or most deferential, rather than applying the specific principle (informed consent elements and capacity assessment, disclosure of a complication, conflict of interest, reporting a safety event, duty when a colleague is impaired) and the correct escalation pathway.
Candidates treat professionalism as common sense and do not study it, so they select the polite-sounding answer. They also miss that some items test the mandatory reporting or disclosure obligation rather than the interpersonal response.
What to do instead
Learn a short framework: identify the principle at stake, identify who holds the decision, identify the required disclosure or report and to whom, and identify the documentation step. Practise distinguishing capacity from refusal, near-miss from harm, and institutional from regulatory reporting, and choose the option that names the obligation rather than the one that preserves comfort.