CCRN Mnemonics: 12 Memory Tricks for Critical Care Nurses

Reading a hemodynamic profile

“Pressures fill, resistance squeezes, index pumps”

Sort every PA-catheter number into one of three jobs. Filling pressures are preload: CVP/RAP for the right heart, PAOP (wedge) for the left. Resistance is afterload: SVR for the left ventricle, PVR for the right. Cardiac output and cardiac index show how well the pump is working. Read the three together before naming the problem.

Use it when: When a stem gives CVP, PAOP, CI and SVR and asks what is wrong or which drug fixes it: raise preload with volume, cut afterload with a vasodilator, boost the pump with an inotrope.

Careful: Use cardiac index, not raw cardiac output, because CI corrects for body size. A 'normal' CVP does not prove the patient is full, and static pressures predict fluid responsiveness poorly, so pair them with the trend and the clinical picture.

Initial ACS management (why MONA is outdated)

“MONA retired: give A and N, make O and M earn it”

1. AAspirin: chewed loading dose (162-325 mg) as soon as ACS is suspected, unless truly allergic
2. NNitroglycerin: sublingual for ongoing ischemic pain, if no hypotension, RV infarct or recent PDE-5 inhibitor
3. OOxygen: only if SpO2 is below 90% or the patient is in respiratory distress
4. MMorphine: only for pain that persists despite nitrates; it slows absorption of oral P2Y12 inhibitors

Use it when: When an item lists MONA-style orders and asks which is appropriate, or what to give first, to a patient with chest pain and ST changes.

Careful: MONA (morphine, oxygen, nitro, aspirin for every MI) is still taught but is outdated. Routine oxygen for a normoxemic patient is not recommended. Hold nitrates in an inferior MI with right ventricular involvement (hypotension, clear lungs, raised JVP) and give fluids instead.

Cardiac tamponade (Beck's triad)

“The three Ds”

1. DDistant (muffled) heart sounds
2. DDistended neck veins (raised JVP/CVP)
3. DDecreased blood pressure (hypotension)

Use it when: When a post-cardiac-surgery, post-cath or chest-trauma patient becomes hypotensive and the item asks for the cause or the next step (prepare for pericardiocentesis or return to the OR).

Careful: The full triad is often absent. Look for pulsus paradoxus over 10 mmHg, equalization of CVP, PA diastolic and wedge pressures, and, after cardiac surgery, chest tube output that suddenly stops. Fluids buy time; vasodilators and diuretics make it worse.

Lung-protective ventilation in ARDS

“Six and thirty, then turn them over”

Six: tidal volume about 6 mL/kg of predicted body weight (range 4-8). Thirty: keep plateau pressure at or below 30 cmH2O. Then turn them over: prone positioning for at least 12-16 hours a day in moderate-to-severe ARDS (PaO2/FiO2 below 150). Use enough PEEP to hold oxygenation and accept some hypercapnia rather than raise the volume.

Use it when: When an item gives vent settings for an ARDS patient and asks which change is right, or why the plateau pressure matters.

Careful: The weight is PREDICTED body weight from height and sex, not actual weight; using actual weight in an obese patient over-ventilates. Peak pressure reflects airway resistance; plateau pressure reflects the lungs, so a high peak with a normal plateau points to the airway (secretions, bronchospasm, kinked tube).

Sudden deterioration on the ventilator

“DOPE”

1. DDisplacement of the tube (right mainstem, out of the trachea)
2. OObstruction (secretions, mucus plug, kinked or bitten tube)
3. PPneumothorax (tension: absent breath sounds, tracheal shift, hypotension)
4. EEquipment failure (ventilator, circuit, oxygen supply)

Use it when: When an intubated patient suddenly desaturates or the high-pressure alarm sounds and the item asks for the first action or the likely cause.

Careful: The first move is to disconnect from the ventilator and bag with 100% oxygen: if bagging fixes it, the problem is the machine. Some versions add S (DOPES) for stacked breaths, the auto-PEEP of asthma and COPD, which is treated by lengthening expiratory time, not by more volume.

DKA vs HHS (2024 ADA consensus)

“DKA is spelled by its criteria; HHS is thick and dry”

1. DDiabetes or glucose of 200 mg/dL or more (lower than the old 250 cut-off)
2. KKetones: beta-hydroxybutyrate 3.0 mmol/L or more, or urine ketones 2+ or more
3. AAcidosis: pH below 7.3 and/or bicarbonate below 18 mEq/L
4. HHHS instead: glucose 600 or more, effective osmolality above 300, pH 7.3 or above, bicarbonate 15 or above, little ketosis

Use it when: When a stem gives glucose, pH, bicarbonate, ketones and osmolality and asks which crisis it is, or what to give first.

Careful: Euglycemic DKA (often on an SGLT2 inhibitor) can present with glucose under 200, which is why the threshold dropped. Start fluids first and check potassium before insulin: hold insulin if K is below 3.5 mEq/L. Mixed DKA-HHS pictures are common.

SIADH vs diabetes insipidus

“SIADH soaks, DI dries”

SIADH soaks: too much ADH holds water, so urine output falls, urine is concentrated, and serum sodium and osmolality drop (dilutional hyponatremia). DI dries: too little ADH (central) or no kidney response (nephrogenic) means large volumes of dilute urine with low specific gravity, rising serum sodium and osmolality, and dehydration.

Use it when: When a neuro, head-injury or post-pituitary-surgery patient has abnormal urine output and sodium and the item asks for the diagnosis or the treatment (fluid restriction for SIADH, desmopressin and fluids for central DI).

Careful: Correct chronic hyponatremia slowly; most guidance caps the rise at about 8-10 mEq/L in 24 hours (the lower figure for high-risk patients) to avoid osmotic demyelination. Hypertonic saline is reserved for severe or symptomatic hyponatremia such as seizures.

Treating hyperkalemia

“C BIG K”

1. CCalcium gluconate IV: stabilizes the cardiac membrane first when there are ECG changes
2. BBeta-2 agonist (nebulized albuterol) and, if acidotic, bicarbonate: shift potassium into cells
3. IInsulin (regular, IV): shifts potassium into cells
4. GGlucose with the insulin, unless glucose is already high, to prevent hypoglycemia
5. KK out of the body: potassium binders, loop diuretics, or dialysis

Use it when: When a renal, crush-injury or tumor lysis patient has peaked T waves or a high potassium and the item asks for the first or the definitive treatment.

Careful: Calcium protects the heart but does not lower potassium, and insulin and albuterol only move it into cells for a few hours. Only removal (binders, diuretics, dialysis) lowers total body potassium. Sodium polystyrene sulfonate acts slowly and is not an emergency fix.

Raised ICP: Cushing's triad

“Wide, Slow, Irregular”

1. WWidening pulse pressure (rising systolic pressure)
2. SSlow heart rate (bradycardia)
3. IIrregular respirations (e.g. Cheyne-Stokes, ataxic)

Use it when: When a head-injury or stroke patient's vital signs change and the item asks what is happening (impending herniation) or what to do first.

Careful: Cushing's triad is a late sign; a falling level of consciousness and a new pupil change come earlier. Do not confuse it with Cushing syndrome or with the hypotension and bradycardia of neurogenic shock. Protect perfusion with CPP = MAP minus ICP, kept at about 60-70 mmHg.

ICU Liberation (ABCDEF) bundle for delirium

“ABCDEF”

1. AAssess, prevent and manage pain
2. BBoth spontaneous awakening and spontaneous breathing trials
3. CChoice of analgesia and sedation (light sedation, avoid benzodiazepines when possible)
4. DDelirium: assess, prevent and manage (CAM-ICU or ICDSC)
5. EEarly mobility and exercise
6. FFamily engagement and empowerment

Use it when: When an item asks how to prevent or manage ICU delirium, which sedation practice is best, or what reduces post-intensive care syndrome.

Careful: Hypoactive delirium (quiet, withdrawn) is the type most often missed. CAM-ICU can only be scored when the patient is rousable (RASS of -3 or lighter). Routine antipsychotics are not recommended to prevent or treat ICU delirium, and benzodiazepines raise its risk.

Sepsis first hour (Surviving Sepsis Campaign)

“Lactate, Cultures, Antibiotics, Fluids, Pressors”

1. LLactate: measure it, and re-measure if raised to guide resuscitation
2. CCultures: blood cultures before antibiotics, if this causes no delay
3. AAntibiotics: broad-spectrum within 1 hour for shock or probable sepsis; within 3 hours for possible sepsis without shock
4. FFluids: 30 mL/kg balanced crystalloid within 3 hours for hypotension or hypoperfusion
5. PPressors: norepinephrine first line if MAP stays below 65 mmHg during or after fluids

Use it when: When an item asks what to do first, or which order is wrong, for a patient with suspected sepsis and hypotension or a raised lactate.

Careful: The 2026 guidelines suggest a MAP of 60-65 mmHg for patients 65 or older, recommend NEWS, MEWS or SIRS over qSOFA as a single screening tool, and say not to give fluids reflexively just because lactate is high. Steroids are suggested for septic shock. Never delay antibiotics to get cultures.

Shock states by hemodynamic signature

“Empty tank, failed pump, leaky pipes, blocked pipe”

1. EEmpty tank, hypovolemic: low CVP and PAOP, low CI, high SVR
2. FFailed pump, cardiogenic: high PAOP, low CI, high SVR
3. LLeaky pipes, distributive (septic, anaphylactic, neurogenic): low SVR; CI often normal or high early in sepsis
4. BBlocked pipe, obstructive (tamponade, tension pneumothorax, massive PE): low CI with a high CVP, high SVR

Use it when: When a stem gives a hemodynamic profile and asks which shock it is, or why a drug (fluid, inotrope, vasopressor) is the right or wrong choice.

Careful: Neurogenic shock is the distributive exception: bradycardia and warm, dry skin instead of tachycardia. Obstructive shock does not respond to inotropes or pressors for long; the obstruction must be relieved.