CRN cheat sheet

Fasting before procedural sedation: clear liquids 2 hours, breast milk 4 hours, infant formula 6 hours, nonhuman milk and light meal 6 hours.

Moderate sedation monitoring: heart rate, blood pressure, respiratory rate, and SpO2 documented at least every 5-15 minutes, with continuous observation of ventilation, plus a pre-sedation and pre-discharge vital sign set.

ASA physical status: I healthy; II mild systemic disease; III severe systemic disease; IV constant threat to life; V moribund; VI brain-dead organ donor. ASA III and above warrant anesthesia-level planning.

Mallampati classes III and IV (only base of uvula or hard palate visible) predict a potentially difficult airway and require escalation before sedation.

Iodinated contrast and metformin: for eGFR 30-59, withhold metformin at the time of the study and for 48 hours afterward; restart only after renal function is confirmed stable.

Elective iodinated contrast is generally avoided when eGFR is below 30; group I linear gadolinium is contraindicated when eGFR is below 30 because of nephrogenic systemic fibrosis risk.

A reported shellfish or povidone-iodine allergy does not predict an iodinated contrast reaction; documented prior contrast reaction and asthma are the meaningful risk factors.

Typical premedication regimen for prior contrast reaction: prednisone 50 mg orally at 13, 7, and 1 hour before, plus diphenhydramine 50 mg orally 1 hour before.

Coagulation thresholds for arterial puncture or percutaneous intervention: INR 1.5-1.8 or less and platelet count 50,000/mcL or greater, per institutional protocol.

Osmolality: low-osmolar iodinated contrast is roughly 600-800 mOsm/kg water; high-osmolar contrast is roughly 1400-2000 mOsm/kg water and causes more pain and osmotic diuresis.

Contrast-induced acute kidney injury: serum creatinine rise of 0.3 mg/dL or more, or 50 percent or more above baseline, within 48-72 hours of intravascular contrast.

Reaction grading: mild (nausea, mild urticaria, flushing), moderate (vomiting, diffuse urticaria, mild bronchospasm), severe (hypotension, laryngeal edema, convulsions, cardiopulmonary arrest).

Epinephrine dosing for severe contrast reaction: adult 0.3-0.5 mg IM of 1:1000; pediatric 0.01 mg/kg IM; repeat every 5-15 minutes as needed while calling the emergency response team.

Vasovagal reaction (bradycardia, hypotension, pallor, diaphoresis) is treated with supine or Trendelenburg position, leg elevation, IV crystalloid, and atropine 0.5-1 mg IV if bradycardia persists.

Extravasation: stop injection, remove the cannula, elevate the limb, apply cold compresses, document volume and site; volumes above roughly 50 mL or severe symptoms warrant surgical consultation.

Barium sulfate is contraindicated when perforation or obstruction is suspected because extraperitoneal leakage causes barium peritonitis; water-soluble iodinated contrast is substituted.

Reversal agents: naloxone 0.04-0.4 mg IV titrated for opioid-induced respiratory depression; flumazenil 0.2 mg IV titrated to 1 mg for benzodiazepine oversedation.

After arterial sheath removal: hold pressure per protocol, keep the limb straight and the patient on bed rest, and check distal pulses, color, and sensation every 15 minutes for the first hour.

ALARA: dose is minimized using the three cardinal rules, time (shortest exposure), distance (greatest practical separation), and shielding (lead apron, thyroid shield, shields).

Inverse square law: intensity is inversely proportional to the square of the distance, so doubling distance from the source reduces exposure to one quarter.

Occupational dose limits: 50 mSv (5 rem) annual effective dose; 150 mSv lens; 500 mSv extremities and skin; general public 1 mSv per year.

Declared pregnancy: conceptus limit is 0.5 mSv in any month and 5 mSv over the entire gestation; the worker decides when to declare in writing.

A 0.5 mm lead-equivalent apron attenuates roughly 90-95 percent of scatter at typical fluoroscopic energies; aprons are inspected annually for cracks and stored flat on a rack.

Dose-reduction practices in fluoroscopy: pulsed fluoroscopy, last-image-hold instead of live imaging, tight collimation, minimal magnification, and keeping the image receptor close to the patient.

MRI safety zones I-IV: zone IV is the magnet room and admits only screened patients and personnel; any ferromagnetic implant requires documented device verification before entry.

Fire response: RACE (rescue, alarm, contain, extinguish or evacuate); extinguisher use follows PASS (pull, aim, squeeze, sweep). Oxygen is shut off before evacuating a room fire.

Dosimeter badges are worn at the collar outside the lead apron and exchanged monthly or quarterly; a badge worn under the apron under-reports the dose actually received.

Teach-back: the patient explains the plan or instructions in their own words; it is the preferred method for confirming comprehension and identifying gaps.

Written materials are prepared at a fifth- to sixth-grade reading level, use plain language, and include pictures or large fonts for low-literacy and visually impaired patients.

Informed consent elements: nature of the diagnosis, proposed procedure, risks, benefits, alternatives (including no treatment), and the right to refuse or withdraw.

Limited English proficiency requires a qualified medical interpreter; using family members, especially minor children, for consent or complex teaching is not acceptable practice.

Developmental preparation: infants and toddlers fear separation and intrusion; preschoolers fear bodily injury; school-age children need concrete explanations; adolescents fear loss of control and privacy.

Nonpharmacologic anxiety reduction includes procedural preparation, slow breathing, music, guided imagery, and controlled pacing of the exam; these lower heart rate and improve image quality.

Physical accessibility: hearing-impaired patients need qualified sign language interpreters or captioning; visually impaired patients need verbal orientation to the room and equipment.

Documentation of education includes the content taught, the teaching method, the patient's response or understanding, and any barriers identified, with who received the teaching.

Nursing scope of practice is set by the state Nurse Practice Act; facility policy may be more restrictive than the law but can never expand it.

The ANA Code of Ethics has nine provisions covering compassion and respect, primacy of the patient, patient rights, authority and accountability, self-care, safe practice environment, advancement of the profession, collaboration, and social justice.

Sentinel event: unexpected death, permanent harm, or severe temporary harm; the organization performs a root cause analysis and reports per Joint Commission requirements.

PDSA: Plan (define the change and prediction), Do (test on a small scale), Study (compare results to prediction), Act (adopt, adapt, or abandon).

Institute of Medicine six aims: care that is safe, effective, patient-centered, timely, efficient, and equitable.

Malpractice requires four elements proven together: duty owed, breach of the standard of care, causation, and damages.

An incident report is an internal, confidential quality document; it is completed promptly, written factually, and never placed in the medical record or referenced in charting.

HIPAA: minimum-necessary use and disclosure applies to all PHI; breaches of unsecured PHI require notification to affected individuals within 60 days of discovery.

SBAR handoff: Situation, Background, Assessment, Recommendation; it is the standard structure for transfer of care and escalation of a deteriorating patient.

ASA physical status: I healthy; II mild systemic disease; III severe systemic disease; IV constant threat to life; V moribund; VI brain-dead organ donor.

Fasting intervals before sedation: clear liquids 2 hours; breast milk 4 hours; infant formula, nonhuman milk, and light meal 6 hours.

Metformin: hold at the time of iodinated contrast and for 48 hours afterward when eGFR is 30-59, restarting after renal function is confirmed stable.

Reported shellfish or iodine allergy does not predict an iodinated contrast reaction; prior contrast reaction and asthma are the relevant risk factors.

Mallampati class III or IV predicts a difficult airway and requires airway escalation before sedation.