CMMU Medicina de Urgencias common mistakes
CMMU Medicina de Urgencias · Understand the traps and how to avoid them.
In a shockable rhythm (VF/pVT) during ACLS, pausing chest compressions to re-check the rhythm or pulse for more than a brief window, or delaying the first defibrillation while obtaining IV access or intubating.
Candidates treat rhythm/pulse checks and procedures as the priority under time pressure and forget that compression fraction and time-to-shock drive survival; the algorithm's order gets inverted in the heat of the scenario.
What to do instead
Drill a fixed script: compressions continuous, rhythm check limited to ~5 seconds every 2 minutes, shock delivered as soon as the defibrillator is charged with immediate resumption of compressions. Practice stating aloud 'charging, clear, shock, resume compressions' so the sequence becomes automatic.
Choosing the wrong reperfusion strategy or misapplying the ECG criteria for STEMI: calling a STEMI in the presence of LBBB or LVH without applying Sgarbossa/appropriate criteria, or failing to recognise an inferior STEMI that needs right-sided leads and avoids nitrates.
Pattern-recognition shortcuts learned from classic tracings break down with confounders, and candidates underweight the clinical context (ongoing pain, hemodynamics) when the ECG is ambiguous.
What to do instead
Before committing, systematically apply the criteria: measure ST elevation against the J-point in contiguous leads, apply Sgarbossa in LBBB, and in any inferior STEMI actively look for hypotension and RV involvement before giving nitroglycerin. Verbalise the reasoning step by step.
In a patient with severe respiratory distress or a predicted difficult airway, proceeding straight to rapid-sequence intubation without a pre-oxygenation and failed-airway plan, or using a paralytic in a patient who cannot be ventilated.
Candidates anchor on 'intubate' as the answer and skip the airway assessment, backup plan, and haemodynamic optimisation that the scenario is actually testing.
What to do instead
Memorise and recite a pre-intubation checklist (pre-oxygenation, suction, positioning, drugs and doses, backup device, surgical airway plan) and contraindications to paralysis before answering. In questions, always identify the failed-airway rescue plan as part of the correct option.
Missing the time-critical diagnosis in acute stroke: attributing focal deficits to hypoglycaemia or intoxication without checking glucose, or failing to establish last-known-well time and the thrombolysis/thrombectomy window.
Candidates jump to the most familiar cause and the exam rewards recognising that glucose is the mandatory first test and that time defines eligibility.
What to do instead
For any focal neurological deficit, first state 'check capillary glucose', then establish last-known-well and calculate the window explicitly. Practise classifying deficits by vascular territory so posterior-circulation strokes (vertigo, diplopia, ataxia) are not dismissed.
In major trauma, following ABCDE out of order (e.g., assessing the abdomen or ordering CT before controlling catastrophic haemorrhage and airway), or missing the need for massive transfusion and permissive hypotension in hemorrhagic shock.
Candidates default to a medical model of assessment and underestimate that exsanguinating hemorrhage kills before airway problems in many trauma scenarios.
What to do instead
Apply ABCDE with catastrophic haemorrhage control first, and rehearse the shock index and triggers for massive transfusion. For each trauma stem, explicitly rank threats by lethality before choosing the next action.
Failing to give the specific antidote or decontamination step at the right time in poisoning: e.g., not giving naloxone for opioid-induced respiratory depression, N-acetylcysteine for paracetamol, or sodium bicarbonate for TCA cardiotoxicity with widened QRS.
Candidates focus on supportive care and forget the toxidrome-to-antidote mapping, or hesitate because they are unsure of the indication threshold.
What to do instead
Build a one-page toxidrome/antidote table (opioid-naloxone, paracetamol-NAC, TCA-bicarbonate, benzodiazepine-flumazenil caution, organophosphate-atropine/pralidoxime, methanol-fomepizole) and rehearse the decision thresholds (e.g., QRS >100 ms for bicarbonate).
Mismanaging severe hyperglycaemic emergencies or electrolyte crises: giving insulin before fluids in DKA/HHS, or correcting severe hyponatraemia or hyperkalaemia too fast without addressing the underlying cause and monitoring.
Candidates memorise 'give insulin' but not the sequence, and underestimate the harm of rapid osmotic or electrolyte shifts.
What to do instead
Anchor on sequence: fluids first, then insulin, then potassium replacement, with explicit rate limits (e.g., sodium correction ≤8–10 mmol/L per 24 h). For hyperkalaemia, state the membrane-stabilising step (calcium) before shifting and eliminating potassium.
Delaying antibiotics and source control in sepsis while waiting for cultures or for confirmatory results, or failing to recognise septic shock requiring vasopressors after adequate fluid resuscitation.
Candidates want diagnostic certainty before treating and forget that each hour of delay increases mortality; they also misclassify hypotension as purely hypovolaemic.
What to do instead
Commit to 'cultures then antibiotics within the first hour' as the default, and identify the lactate, fluid challenge, and vasopressor threshold explicitly. Rehearse the definition of septic shock (vasopressor requirement plus elevated lactate after fluids).
In obstetric emergencies, failing to recognise pregnancy-related causes of shock (ectopic, abruption, postpartum haemorrhage) and neglecting left lateral tilt/uterine displacement in a hypotensive pregnant patient; in paediatrics, using adult drug doses or missing compensated shock.
Candidates apply adult templates to pregnant and paediatric patients and overlook the physiological differences (supine hypotension, larger circulating volume, compensatory tachycardia).
What to do instead
For any reproductive-age woman with abdominal pain or shock, make pregnancy test and ectopic part of the first step. For paediatrics, memorise weight-based dosing and the compensated-shock picture (tachycardia with normal BP). Rehearse lateral tilt and PPH bundle steps.
In agitated or suicidal patients, jumping to chemical restraint or disposition without first excluding a medical cause of delirium and without a structured risk assessment; or failing to address the safety of the patient and staff.
Candidates interpret agitation as purely psychiatric and skip the glucose, oxygen, toxidrome, and head-injury screen; they also under-document risk assessment.
What to do instead
Apply a fixed sequence: safety first, then rule out reversible medical causes (glucose, hypoxia, intoxication/withdrawal, head injury, sepsis), then structured suicide/violence risk assessment, then least-restrictive management. Practise stating the medical mimics aloud.
Misusing point-of-care ultrasound: treating a single view or a technically poor image as definitive, or failing to integrate POCUS findings into the clinical question (e.g., calling cardiac standstill from a poor window, or missing free fluid in trauma).
Candidates over-trust the image and lack a structured protocol, so they neither confirm nor exclude the diagnosis they were actually asking about.
What to do instead
Tie every POCUS answer to a specific clinical question and a protocol (e.g., FAST, RUSH, lung sliding for pneumothorax), state the limitations and the need for a repeat or confirmatory study, and never act on an inadequate window alone.