CEN cheat sheet

STEMI: new ST elevation at the J-point of at least 1 mm in two contiguous limb leads, or at least 2 mm in two contiguous precordial leads (1.5 mm in V2-V3 for women).

Right ventricular infarction: inferior ST elevation plus hypotension, JVD, and clear lungs - give a fluid bolus and withhold nitrates.

Cardiac tamponade: Beck triad (hypotension, JVD, muffled heart sounds) with pulsus paradoxus; treat with pericardiocentesis.

Aortic dissection: sudden tearing chest or back pain, pulse deficit, or interarm systolic pressure difference greater than 20 mmHg - control heart rate with a beta-blocker before vasodilator.

Symptomatic bradycardia: atropine 1 mg IV every 3-5 minutes to a maximum of 3 mg; transcutaneous pacing or dopamine if atropine fails.

Stable SVT: adenosine 6 mg rapid IV push, then 12 mg; avoid in asthma and in pre-excited atrial fibrillation (WPW).

Refractory VF/pulseless VT: defibrillate (120-200 J biphasic), epinephrine 1 mg every 3-5 minutes, amiodarone 300 mg then 150 mg.

Nitroglycerin is contraindicated with sildenafil use within 24 hours or tadalafil within 48 hours, and with systolic BP below 90 mmHg.

Acute decompensated heart failure: dyspnea, crackles, JVD, S3, elevated BNP - sit upright, give oxygen or NIV, nitroglycerin, and loop diuretic.

Severe asthma: continuous albuterol, ipratropium, systemic corticosteroid, and magnesium sulfate 2 g IV over 20 minutes; a silent chest signals impending respiratory arrest.

COPD with suspected CO2 retention: titrate oxygen to SpO2 88-92% and monitor for somnolence and worsening acidosis rather than withholding oxygen.

Tension pneumothorax: absent breath sounds, hyperresonance, hypotension, and tracheal deviation away from the affected side - decompress before imaging.

Pulmonary embolism: sudden dyspnea, pleuritic chest pain, tachycardia, and hypoxemia; risk stratify with Wells criteria, obtain D-dimer or CT angiography, and give anticoagulation.

ARDS (Berlin criteria): acute onset within 1 week, bilateral opacities, not explained by cardiac failure, and PaO2/FiO2 ratio of 300 mmHg or less.

ABG normal values: pH 7.35-7.45, PaCO2 35-45 mmHg, HCO3 22-26 mEq/L, PaO2 80-100 mmHg.

Respiratory acidosis = pH low with PaCO2 high; metabolic alkalosis = pH high with HCO3 high; use the direction of pH change to name the primary disorder.

Flail chest: paradoxical inward movement of the flail segment during inspiration, with underlying pulmonary contusion; provide analgesia, oxygen, and positive pressure as needed.

Spontaneous pneumothorax most often occurs in tall, thin young males and presents with abrupt unilateral pleuritic pain and diminished breath sounds.

Acute stroke: check glucose, activate stroke team, obtain noncontrast CT to exclude hemorrhage before thrombolysis; alteplase window 0-4.5 hours from last known well.

Alteplase eligibility requires BP below 185/110 mmHg, no anticoagulation or recent surgery, and glucose above 50 mg/dL.

Cushing triad - hypertension with widened pulse pressure, bradycardia, and irregular respirations - signals rising intracranial pressure and herniation.

Cerebral perfusion pressure = mean arterial pressure - intracranial pressure; normal ICP 5-15 mmHg, target CPP 60-80 mmHg.

Status epilepticus: seizure lasting longer than 5 minutes or repeated without recovery; first-line lorazepam 4 mg IV, then fosphenytoin, levetiracetam, or valproate.

Subarachnoid hemorrhage: sudden thunderclap headache, photophobia, nuchal rigidity; CT may be negative early, and xanthochromia in CSF supports the diagnosis.

Bacterial meningitis: fever, headache, nuchal rigidity, positive Kernig and Brudzinski signs; place on droplet precautions and give dexamethasone with antibiotics.

Unilateral fixed and dilated pupil after head injury indicates ipsilateral uncal herniation and requires immediate neurosurgical consultation.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; a score of 8 or less generally indicates need for airway protection.

Primary survey sequence: catastrophic hemorrhage control, airway with cervical spine protection, breathing, circulation, disability, exposure with prevention of hypothermia.

Immediately life-threatening chest injuries: airway obstruction, tension pneumothorax, massive hemothorax, open pneumothorax, flail chest, and cardiac tamponade.

Hemorrhagic shock classes: class II 15-30% loss with tachycardia; class III 30-40% with systolic hypotension and altered mentation; class IV over 40% with marked hypotension.

Traumatic hypotension is hemorrhage until proven otherwise; use large-bore IVs, blood products over crystalloid, and permissive hypotension (SBP ~90 mmHg) before surgical control.

Lethal triad of trauma: hypothermia, acidosis, and coagulopathy - prevent heat loss with warm fluids, blankets, and forced-air warming.

Pelvic fracture: apply a pelvic binder at the level of the greater trochanters; assess for blood at the urethral meatus before catheter placement.

Tourniquet: place 2-3 inches proximal to the wound, not directly over a joint, tighten until bleeding stops, and record the time.

Neurogenic shock from cervical or high thoracic cord injury: hypotension with bradycardia and warm, dry skin; treat with fluids, vasopressors, and atropine.

Burns: estimate TBSA with the rule of nines (each arm 9%, each leg 18%, anterior trunk 18%, posterior trunk 18%, head 9%); Parkland formula = 4 mL x kg x %TBSA over 24 hours, half in the first 8 hours.

DKA: glucose above 250 mg/dL, arterial pH below 7.3, bicarbonate below 18 mEq/L, anion gap, and ketones; give isotonic fluids, then insulin infusion - hold insulin if potassium is below 3.3 mEq/L.

HHS: glucose above 600 mg/dL, minimal ketones, serum osmolality above 320 mOsm/kg, and profound dehydration; treat with aggressive fluid resuscitation and insulin.

Hypoglycemia: glucose below 70 mg/dL with symptoms; give oral glucose if awake, D50 IV or glucagon IM if not, and recheck in 15 minutes.

Anaphylaxis: epinephrine 0.3-0.5 mg IM (1:1000) into the anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamines, corticosteroids, and fluids.

Sepsis bundle: measure lactate, obtain cultures, give broad-spectrum antibiotics and 30 mL/kg crystalloid for hypotension or lactate of 4 mmol/L or higher.

Adrenal crisis: refractory hypotension with hyponatremia, hyperkalemia, and hypoglycemia; give hydrocortisone 100 mg IV and isotonic fluids.

Thyroid storm: fever, tachycardia, agitation, and heart failure; treat with a beta-blocker, propylthiouracil, iodine after PTU, and glucocorticoids.

Severe hyperkalemia with ECG changes: give calcium chloride or gluconate first to stabilize the myocardium, then insulin with glucose, albuterol, and bicarbonate as indicated.

Sickle cell vaso-occlusive crisis: aggressive hydration, oxygen for hypoxemia, and prompt opioid analgesia; fever warrants cultures and antibiotics for possible infection.

Anticholinergic toxidrome: hot, dry, flushed skin, mydriasis, urinary retention, and delirium ('blind as a bat, mad as a hatter'); give physostigmine only in selected cases.

Cholinergic toxidrome (SLUDGE plus bradycardia, bronchorrhea, miosis): organophosphate exposure - atropine titrated to drying of secretions plus pralidoxime.

Opioid toxidrome: pinpoint pupils, respiratory depression, and coma; give naloxone 0.04-2 mg IV titrated to adequate respiration, repeat as needed.

Acetaminophen overdose: N-acetylcysteine is the antidote; plot the level drawn at least 4 hours after ingestion on the Rumack-Matthew nomogram.

Salicylate toxicity: tinnitus, hyperventilation, mixed respiratory alkalosis with metabolic acidosis; give bicarbonate to alkalinize urine and serum.

Carbon monoxide poisoning: cherry-red skin is uncommon, pulse oximetry is falsely normal, and treatment is 100% oxygen with hyperbaric therapy for severe or neurologic symptoms and pregnancy.

Beta-blocker overdose: glucagon is first-line for bradycardia and hypotension; high-dose insulin with glucose and calcium are alternatives.

Calcium channel blocker overdose: IV calcium, glucagon, and high-dose insulin with glucose; vasopressors for refractory shock.

Heat stroke: core temperature above 40 degrees C with altered mental status; initiate immediate cold-water immersion or evaporative cooling - antipyretics are ineffective.

Upper GI bleeding (above the ligament of Treitz) presents with hematemesis or melena; lower bleeding typically presents with hematochezia.

Acute GI bleed management: two large-bore IVs, type and crossmatch, volume and blood product replacement, PPI infusion, and urgent endoscopy.

Suspected esophageal varices: add octreotide infusion and prophylactic antibiotics (e.g., ceftriaxone); balloon tamponade is a temporizing rescue measure.

Pancreatitis: severe epigastric pain radiating to the back, lipase elevated more than three times normal; treat with NPO status, isotonic fluids, and analgesia.

Small bowel obstruction: colicky pain, vomiting, distension, and high-pitched then absent bowel sounds; place a nasogastric tube and give fluids.

Appendicitis: periumbilical pain migrating to the right lower quadrant with McBurney point tenderness, Rovsing sign, and low-grade fever.

Cholecystitis: right upper quadrant pain, fever, positive Murphy sign, and leukocytosis; obtain right upper quadrant ultrasound.

Mesenteric ischemia: pain out of proportion to examination findings in an older patient with atrial fibrillation; treat with fluids, anticoagulation, and surgical consultation.

Perforated viscus: sudden severe pain with a rigid, board-like abdomen and free air on radiograph - surgical emergency requiring antibiotics and laparotomy.

Ectopic pregnancy: amenorrhea, unilateral pelvic pain, and vaginal bleeding with a positive hCG but no intrauterine sac; rupture causes shoulder pain, syncope, and shock - treat with surgery or methotrexate.

Preeclampsia: BP of 140/90 mmHg or higher after 20 weeks gestation plus proteinuria or end-organ dysfunction; give magnesium sulfate for seizure prophylaxis in severe disease.

Magnesium toxicity: loss of deep tendon reflexes, respiratory depression, and oliguria - stop the infusion and give calcium gluconate 1 g IV.

Placenta previa: painless bright red vaginal bleeding with a soft uterus; no digital or speculum examination until ultrasound localizes the placenta.

Abruptio placentae: painful vaginal bleeding with a firm, board-like uterus and concealed hemorrhage; monitor for fetal distress and coagulopathy.

Postpartum hemorrhage: uterine atony is the most common cause - perform fundal massage, give oxytocin, and escalate to other uterotonics or surgery.

Testicular torsion: sudden severe scrotal pain, high-riding testis, and absent cremasteric reflex; surgical detorsion is needed within about 6 hours to save the testis.

Renal colic: flank pain radiating to the groin with hematuria; NSAIDs are first-line analgesia, and CT confirms the stone.

Pyelonephritis: fever, flank pain, and costovertebral angle tenderness with urinary symptoms; obtain urine culture and start antibiotics with fluids.

Fracture assessment: pain, pallor, pulselessness, paresthesia, paralysis, and pressure; document distal neurovascular status before and after splinting.

Compartment syndrome: pain out of proportion and pain with passive stretch are early signs; pulselessness and paralysis are late - treatment is urgent fasciotomy.

Open fracture: control bleeding, irrigate, cover with sterile dressing, give antibiotics and tetanus prophylaxis, and splint before imaging.

Hip fracture: shortened, externally rotated leg after a fall; posterior hip dislocation presents shortened and internally rotated.

Anterior shoulder dislocation is the most common type; assess axillary nerve function (deltoid sensation) before and after reduction.

Fat embolism syndrome after long bone fracture: hypoxemia, petechiae over the chest and axillae, and confusion appearing 24-72 hours after injury.

Crush injury and rhabdomyolysis: dark tea-colored urine, elevated creatine kinase, and hyperkalemia; treat with aggressive isotonic fluids.

Wound irrigation: sterile saline at 8-12 psi removes debris and bacteria without driving contaminants deeper; irrigate before closure.

Animal bites: irrigate thoroughly, do not routinely close, and give amoxicillin-clavulanate plus rabies and tetanus prophylaxis as indicated.

Suicide risk assessment: ask directly about ideation, plan, intent, and access to lethal means; higher risk warrants one-to-one observation and removal of ligature and sharp items.

Alcohol withdrawal timeline: tremor and autonomic hyperactivity at 6-24 hours, withdrawal seizures at 12-48 hours, and delirium tremens at 48-96 hours.

Delirium tremens: agitation, hallucinations, tachycardia, hypertension, fever, and diaphoresis; treat with benzodiazepines and fluid/electrolyte correction.

De-escalation is first-line for agitation; verbal engagement, reduced stimulation, and offering choices precede chemical or physical restraint.

Restraint use requires a time-limited physician order, monitoring every 15 minutes for circulation, skin integrity, and needs, and documentation of less restrictive alternatives tried.

Excited delirium: extreme agitation, hyperthermia, profuse sweating, and superhuman strength - a medical emergency requiring sedation and cooling.

Hyperventilation from anxiety produces respiratory alkalosis with perioral numbness and carpopedal spasm; treat with reassurance and paced breathing, not a paper bag.

Acute dystonia from antipsychotics: sustained muscle spasm, often of the neck or eyes; treat with diphenhydramine or benztropine.

Serotonin syndrome: clonus, hyperreflexia, agitation, and hyperthermia after serotonergic drugs; stop the agent and give benzodiazepines and supportive care.

Emergency Severity Index triage: ESI 1 requires immediate life-saving intervention, ESI 2 is high risk or unstable, ESI 3 needs two or more resources, ESI 4 one resource, ESI 5 none.

SBAR handoff: Situation, Background, Assessment, Recommendation - a structured format that reduces omission of critical information during transitions of care.

Two patient identifiers (e.g., name and date of birth) are verified before medication administration, procedures, blood transfusion, and specimen labeling.

Medication safety: right patient, drug, dose, route, and time, plus documentation and reason; independent double-check for high-alert drugs such as insulin and heparin.

Time-out immediately before any invasive procedure confirms patient, site/side, procedure, and consent with the whole team present.

EMTALA requires a medical screening examination and stabilization of any patient presenting with an emergency condition regardless of ability to pay.

Needlestick injury: wash with soap and water, report immediately, and start HIV postexposure prophylaxis within hours when indicated.

Sentinel events trigger a root cause analysis; a just culture distinguishes system failures from reckless behavior while encouraging error reporting.

Mandatory reporting includes suspected abuse or neglect, communicable diseases, and certain injuries such as gunshot wounds per state law.