CRT (CREST) cheat sheet

The TMC Detailed Content Outline (effective January 2020–December 31, 2026) organizes the exam into three content areas: (1) Patient Data and Assessment, (2) Therapeutics and Diagnostics, and (3) Patient Safety and Quality Control.

Content Area 1 covers gathering the clinical information that drives every later decision: chart review, patient interview, physical assessment, and interpretation of laboratory and imaging data.

Vital-sign reference anchors: adult resting respiratory rate 12–20 breaths/min, heart rate 60–100 beats/min, SpO2 94–100% on room air at sea level, and core temperature 36.5–37.5 °C.

Arterial blood gas interpretation order: pH first (acidemia <7.35, alkalemia >7.65 is impossible; use 7.45), then PaCO2 (35–45 mm Hg) to identify respiratory component, then HCO3- (22–26 mEq/L) for metabolic component, then check compensation.

Expected compensation rules: acute respiratory acidosis raises HCO3- about 1 mEq/L per 10 mm Hg rise in PaCO2; chronic raises it 3–4 mEq/L per 10 mm Hg. Acute respiratory alkalosis lowers HCO3- about 2 mEq/L per 10 mm Hg fall in PaCO2; chronic lowers 4–5.

Oxygenation is judged by PaO2 and the P/F ratio (PaO2 ÷ FiO2); a P/F ratio under 300 suggests significant shunt or V/Q mismatch, and under 200 indicates severe impairment.

Normal chest radiograph interpretation sequence: technical quality (rotation, penetration, inspiration), then airways, bones, cardiac silhouette, diaphragm, effusion, fields (lung), gastric bubble, and hardware.

Spirometry decision rules: obstruction when FEV1/FVC is below the lower limit of normal (commonly <0.70); severity graded by FEV1 percent predicted; a post-bronchodilator FEV1 rise of ≥12% and ≥200 mL indicates significant reversibility.

Oxygen delivery devices and typical FiO2 ranges: nasal cannula 1–6 L/min (~24–44%), simple mask 5–10 L/min (~35–55%), air-entrainment (Venturi) mask delivers a fixed FiO2 (24–50%), partial and nonrebreather masks ~60–95%, and high-flow nasal cannula titrates FiO2 21–100% with heated humidification.

Humidified oxygen is indicated when flow exceeds about 4 L/min by nasal cannula or when the artificial airway bypasses the upper airway; heated humidification targets 32–37 °C and 100% relative humidity at the airway.

Aerosol drug delivery: a small-volume nebulizer with 6–8 L/min produces particles of 1–5 µm; a pressurized metered-dose inhaler with a valved holding chamber is preferred for most patients who can coordinate inhalation.

Mechanical ventilation basics: volume-control delivers a set tidal volume (often 6–8 mL/kg predicted body weight, lower in ARDS); pressure-control limits peak pressure; PEEP recruits alveoli and improves oxygenation but raises intrathoracic pressure.

Weaning readiness criteria include adequate oxygenation (PaO2/FiO2 >150–200 on PEEP ≤5–8), hemodynamic stability without vasopressors, ability to initiate breaths, and a rapid shallow breathing index (respiratory rate ÷ tidal volume in liters) under 105.

Noninvasive ventilation (CPAP/BiPAP) is indicated for acute hypercapnic respiratory failure in COPD exacerbation and for cardiogenic pulmonary edema; contraindications include inability to protect the airway, vomiting, and hemodynamic instability.

Chest physiotherapy techniques: postural drainage uses gravity with the affected lobe uppermost; percussion and vibration follow drainage positioning; airway clearance is timed before meals and before inhaled bronchodilators when possible.

Emergency drugs and actions: racemic epinephrine for post-extubation stridor, albuterol for bronchospasm, naloxone for opioid-induced hypoventilation, and immediate needle decompression for tension pneumothorax at the second intercostal space midclavicular line (or fifth space anterior axillary line).

Infection control hierarchy: standard precautions apply to all patients; transmission-based precautions add contact (MRSA, C. difficile), droplet (influenza, pertussis), and airborne (TB, measles, varicella) isolation with N95 or higher for airborne.

Oxygen safety rules: no smoking or open flame near oxygen, keep sources at least 5–10 feet from open flames, avoid oil or grease on regulators, and use cotton or synthetic fabrics rather than wool to reduce static.

Cylinder duration formula: duration (minutes) = (cylinder pressure in psig × cylinder factor) ÷ flow in L/min. Common factors: E cylinder 0.28, H/K cylinder 3.14, M cylinder 1.56.

Equipment cleaning levels: critical items (contacting mucosa or sterile areas) require sterilization; semicritical items (contacting intact mucous membranes, e.g., bronchoscopes) require high-level disinfection; noncritical items require low-level disinfection.

Quality control for blood gas analyzers: run two levels of control material at least every 8 hours and after electrode changes or maintenance; verify calibration, check for clots, and document results per policy.

Pulse oximeter quality control: verify probe placement and perfusion, recognize that carboxyhemoglobin reads falsely high and methemoglobin falsely low, and that anemia, motion, and nail polish can degrade the signal.

Ventilator alarm priorities: high-pressure alarms suggest secretions, biting, kinking, or bronchospasm; low-pressure alarms suggest disconnection or leak; low exhaled volume or apnea alarms require immediate assessment of the patient before the machine.

Patient safety and monitoring: verify patient identity and order before any therapy, confirm two identifiers, document device settings and patient response, and report critical values to the responsible clinician per protocol.