OMSB Emergency Medicine (OEEM) cheat sheet

ACLS cardiac arrest: compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions <10 s; shock VF/pVT at 200 J biphasic (or max device energy), resume compressions immediately, adrenaline 1 mg IV every 3-5 min, amiodarone 300 mg after the third shock.

Adult tachycardia with pulse: unstable (hypotension, ischemic chest pain, acute heart failure, altered mental status, shock) requires synchronized cardioversion; narrow regular SVT is treated with vagal maneuvers then adenosine 6 mg IV push, then 12 mg.

Adult bradycardia with pulse: treat if hypotension, altered mentation, ischemic chest pain, or acute heart failure; atropine 1 mg IV every 3-5 min (max 3 mg), then transcutaneous pacing or dopamine 5-20 mcg/kg/min or adrenaline infusion.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh, repeat every 5 min as needed; adjuncts (H1 antihistamine, corticosteroid, inhaled beta-agonist) never replace adrenaline; observe for biphasic reaction.

Sepsis: infection plus qSOFA (RR >=22, SBP <=100, altered mentation) or organ dysfunction; draw cultures before antibiotics, give broad-spectrum antibiotics within 1 hour for septic shock, 30 mL/kg crystalloid for hypotension or lactate >=4 mmol/L.

Acute ischemic stroke: non-contrast CT to exclude hemorrhage; IV thrombolysis (alteplase 0.9 mg/kg, max 90 mg, 10% bolus) within 4.5 h of last known well; thrombectomy up to 24 h in selected large-vessel occlusion; target BP <185/110 before thrombolysis and <180/105 after.

Status epilepticus: benzodiazepine first line (IV lorazepam 0.1 mg/kg, max 4 mg, repeat once; or IM midazolam 10 mg if no IV access), then second-line IV loading with levetiracetam, valproate, or phenytoin; refractory cases need intubation and continuous infusion.

Acute coronary syndrome: 12-lead ECG within 10 min of arrival; STEMI needs reperfusion (primary PCI within 90 min of first medical contact, or fibrinolysis within 30 min if PCI unavailable); aspirin 300 mg chewed plus P2Y12 inhibitor and anticoagulation; avoid nitrates in inferior MI with RV involvement or recent PDE5 inhibitor use.

Airway: predict difficulty with LEMON (Look, Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility) or MOANS; rapid sequence intubation uses a sedative (ketamine 1-2 mg/kg or etomidate 0.3 mg/kg) plus a paralytic (rocuronium 1.2 mg/kg or suxamethonium 1.5 mg/kg); confirm with continuous waveform capnography.

Trauma: primary survey ABCDE with cervical spine protection; massive transfusion protocol for hemorrhagic shock, permissive hypotension (SBP ~90 mmHg) until hemorrhage control in penetrating trauma; TXA 1 g within 3 h of injury; FAST exam for free intraperitoneal fluid.

Head injury: GCS <=8 requires intubation; avoid hypotension and hypoxia (each worsens outcome); hypertonic saline or mannitol for signs of herniation; reverse anticoagulation; neurosurgical consultation for extradural/subdural hematoma with mass effect.

Burns: estimate TBSA with Wallace rule of nines (head 9%, each arm 9%, each leg 18%, trunk front 18%, back 18%, perineum 1%); Parkland formula 4 mL/kg/%TBSA lactated Ringer's in first 24 h, half in first 8 h; intubate for inhalation injury, escharotomy for circumferential full-thickness burns.

Poisoning: activated charcoal 1 g/kg within 1 h of ingestion if airway protected; naloxone for opioid toxicity (0.04-0.4 mg IV titrated); N-acetylcysteine for paracetamol; sodium bicarbonate for salicylate or tricyclic toxicity; fomepizole or ethanol for methanol/ethylene glycol; do not induce vomiting.

Environmental: heat stroke needs rapid cooling to <39 C core within 30 min plus IV fluids; hypothermia uses active rewarming and ECMO for severe cases; high-altitude pulmonary edema is treated with descent, oxygen, and nifedipine; decompression illness needs recompression.

Electrolytes: hyperkalaemia with ECG changes gets IV calcium first (calcium gluconate 10 mL 10% or calcium chloride), then insulin-dextrose, salbutamol, and bicarbonate if acidotic; dialysis for refractory cases; hyponatraemia with seizures gets hypertonic 3% saline bolus.

Paediatric emergencies: weight estimate (age + 4) x 2 kg; paediatric dose of adrenaline for anaphylaxis is 0.01 mg/kg IM (max 0.5 mg); fluid bolus 10-20 mL/kg for shock; PALS arrest ratio 15:2 for two rescuers; consider non-accidental injury when mechanism is inconsistent.

Toxicology antidote pairs: organophosphate (atropine plus pralidoxime), beta-blocker (glucagon, high-dose insulin), calcium channel blocker (calcium, high-dose insulin, vasopressors), digoxin (digoxin-specific antibody), carbon monoxide (high-flow oxygen, hyperbaric for severe), cyanide (hydroxocobalamin).

Respiratory: acute severe asthma gives salbutamol and ipratropium nebulised, systemic corticosteroid, and magnesium sulphate 2 g IV for refractory cases; tension pneumothorax is a clinical diagnosis treated with immediate needle decompression then chest drain; COPD exacerbation uses controlled oxygen targeting SpO2 88-92%.

Abdominal emergencies: appendicitis, cholecystitis, pancreatitis (diagnosis needs 2 of 3: typical pain, lipase >3x upper limit, imaging), and ruptured AAA (pain plus hypotension plus pulsatile mass) all require early surgical or specialist referral; give analgesia early, as it does not mask diagnosis.

Obstetric emergencies: postpartum haemorrhage is treated with uterine massage, oxytocin, tranexamic acid 1 g IV, and balloon or surgical escalation; eclampsia gets magnesium sulphate 4 g IV loading then infusion; shoulder dystocia is managed with McRoberts manoeuvre plus suprapubic pressure.

Sepsis and meningitis: do not delay antibiotics for lumbar puncture in suspected bacterial meningitis; give dexamethasone with or before the first antibiotic dose in adults with suspected pneumococcal meningitis; use ceftriaxone 2 g IV plus vancomycin where pneumococcal resistance is a concern.

Renal and metabolic: diabetic ketoacidosis is treated with isotonic saline, insulin infusion 0.1 units/kg/h after potassium is above 3.3 mmol/L, and potassium replacement; add dextrose when glucose falls below ~14 mmol/L; watch for cerebral oedema in children.

Diagnostic decision rules: Ottawa ankle rules (tenderness at posterior malleolus or navicular base, or inability to bear weight) guide radiography; Wells score and D-dimer for pulmonary embolism; PERC rule to rule out PE in low-risk patients; HEART score for chest pain risk stratification.

Disposition and documentation: document time-critical decisions (door-to-needle, door-to-balloon, antibiotic time), reassess after every intervention, and use structured handover (SBAR); high-risk complaints (chest pain, headache, abdominal pain) require documented reassessment or safety-netting before discharge.