NBRC CRT cheat sheet

Minute ventilation = respiratory rate × tidal volume; normal adult tidal volume is 6–8 mL/kg predicted body weight.

IBW (kg): male = 50 + 2.3 × (height in inches − 60); female = 45.5 + 2.3 × (height in inches − 60).

Normal ABG: pH 7.35–7.45, PaCO2 35–45 mm Hg, HCO3− 22–26 mEq/L, PaO2 80–100 mm Hg on room air.

Acid-base rule: pH and PaCO2 move opposite in respiratory disorders; pH and HCO3− move same in metabolic disorders.

Winter's formula for metabolic acidosis: expected PaCO2 = (1.5 × HCO3−) + 8 ± 2.

P/F ratio = PaO2 ÷ FiO2; values <300 indicate impaired oxygenation and <200 indicate severe impairment.

A-a gradient = PAO2 − PaO2; PAO2 = FiO2 × (Patm − 47) − (PaCO2 ÷ 0.8).

SpO2 88–92% is the typical target for a patient with COPD and chronic hypercapnia to avoid oxygen-induced hypercapnia.

Capnography: normal end-tidal CO2 is 35–45 mm Hg; a sudden drop suggests disconnection, leak, or cardiac arrest.

Thorpe-tube flowmeter: read the center of the ball; it must be upright and not used with a restrictor that exceeds its calibrated flow.

Oxygen cylinder duration (min) = (gauge pressure in psi × cylinder factor) ÷ oxygen flow in L/min; E cylinder factor is 0.28, H cylinder 3.14.

Low-pressure ventilator alarm: suspect disconnection, circuit leak, or inadequate gas source; high-pressure alarm: suspect secretions, kinking, biting, or bronchospasm.

Before use, perform a ventilator leak test by occluding the patient Y-piece; a sustained set pressure indicates an intact circuit.

Adult suction pressure is generally −80 to −120 mm Hg; higher negative pressure increases mucosal trauma and atelectasis risk.

Airborne precautions: N95 or higher respirator and negative-pressure room for tuberculosis, measles, and varicella.

Droplet precautions: surgical mask and eye protection for influenza, pertussis, and meningococcal disease; contact precautions for C. difficile and MRSA.

High-level disinfection is required for bronchoscopes and other semicritical devices; ethylene oxide is used for heat-sensitive equipment.

Change ventilator circuits only when visibly soiled or malfunctioning; drain condensate away from the patient to prevent contamination.

Nasal cannula at 1–6 L/min delivers approximately 24–44% FiO2; a simple mask at 5–10 L/min delivers approximately 35–50%.

Venturi mask provides precise low FiO2 (24–50%) and is preferred when controlled oxygen is needed.

Nonrebreather mask at 10–15 L/min delivers approximately 80–95% FiO2; ensure reservoir bag is inflated before placement.

Initial invasive ventilation for adults: tidal volume 6–8 mL/kg IBW, respiratory rate 12–20/min, PEEP 5 cm H2O, and FiO2 to target SpO2.

ARDS lung-protective ventilation: tidal volume 4–6 mL/kg IBW and plateau pressure ≤30 cm H2O.

Weaning readiness: RSBI = respiratory rate ÷ tidal volume in liters <105; vital capacity >10–15 mL/kg; MIP more negative than −20 to −30 cm H2O.

For COPD, titrate oxygen to SpO2 88–92%; for most other adults, target SpO2 92–96%.

Aerosolized bronchodilator: administer beta-2 agonist before anticholinergic if both ordered; monitor heart rate, tremor, and paradoxical bronchospasm.

Humidification: heated humidifier or HME for ventilator circuits; avoid HME in patients with thick secretions, hemoptysis, or low tidal volumes.