CRT (IJCAHPO) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ideal body weight formula

Male: 50 + 2.3 × (height in inches − 60). Female: 45.5 + 2.3 × (height in inches − 60). Used to set lung-protective tidal volumes.

Static compliance equation

Static compliance equals tidal volume divided by (plateau pressure minus PEEP). Normal adult values are roughly 60 to 100 mL per cm H2O.

Airway resistance equation

Airway resistance equals (peak pressure minus plateau pressure) divided by inspiratory flow. A pressure gradient above 10 cm H2O suggests increased resistive load.

Alveolar oxygen equation

PAO2 = FiO2 × (barometric pressure − 47) − (PaCO2 ÷ 0.8). It estimates alveolar oxygen tension and supports calculation of the A-a gradient.

Oxygen content formula

CaO2 = (1.34 × hemoglobin × SaO2) + (0.003 × PaO2). Most arterial oxygen content is bound to hemoglobin rather than dissolved in plasma.

Oxygen delivery equation

Oxygen delivery equals cardiac output multiplied by arterial oxygen content multiplied by 10. It quantifies oxygen transported to tissues per minute.

Bohr effect definition

A rightward shift of the oxyhemoglobin dissociation curve caused by increased PaCO2, decreased pH, or increased temperature, which reduces hemoglobin oxygen affinity.

Minute ventilation calculation

Minute ventilation equals respiratory rate multiplied by tidal volume. Normal resting adult values are approximately 5 to 6 liters per minute.

Heliox therapeutic effect

Helium-oxygen mixtures have lower density than air, reducing turbulent flow and work of breathing in large-airway obstruction such as post-extubation stridor.

Tracheal cuff pressure range

Endotracheal and tracheostomy cuff pressure should be maintained at 20 to 30 cm H2O to prevent aspiration while avoiding tracheal mucosal ischemia.

HEPA filter efficiency

High-efficiency particulate air filters remove at least 99.97 percent of airborne particles 0.3 micrometers or larger, protecting circuits and the environment.

MDI with valved holding chamber

Adding a valved holding chamber to a metered-dose inhaler improves lung deposition and reduces oropharyngeal impaction and systemic absorption of drug.

Small-volume nebulizer fill

Adult small-volume nebulizer treatments typically use 3 to 5 mL of solution driven at 6 to 8 L/min to produce adequate respirable aerosol output.

Closed suction system benefit

Closed suctioning maintains PEEP and oxygenation during the procedure and reduces environmental contamination and caregiver exposure compared with open suctioning.

C. difficile hand hygiene

Alcohol-based hand rub does not reliably kill Clostridioides difficile spores; soap and water handwashing is required when this organism is suspected.

Endotracheal tube depth

Average adult insertion depth is about 21 cm at the incisors for women and 23 cm for men, confirmed by chest radiograph showing tip above the carina.

Lung-protective ventilation settings

For ARDS, deliver 4 to 6 mL/kg predicted body weight with plateau pressure at or below 30 cm H2O to limit ventilator-induced lung injury.

Permissive hypercapnia rationale

Accepting elevated PaCO2 to limit tidal volume and plateau pressure is tolerated in ARDS when pH remains about 7.20 or higher and hemodynamics are stable.

Auto-PEEP correction strategies

Reduce auto-PEEP by lengthening expiratory time, lowering respiratory rate, treating bronchospasm, and reducing tidal volume or minute ventilation.

Volume versus pressure control

Volume control delivers a set tidal volume with variable airway pressure; pressure control delivers a set pressure with variable tidal volume.

Pressure support ventilation

Pressure support augments each spontaneous breath with a set pressure boost; because breaths are patient-triggered, it does not guarantee minute ventilation.

PEEP physiologic effects

Positive end-expiratory pressure recruits and stabilizes alveoli, improving oxygenation, but can decrease venous return and cardiac output at high levels.

Rapid shallow breathing index

RSBI equals respiratory rate divided by tidal volume in liters. A value below 105 breaths per minute per liter suggests readiness for weaning trials.

Aerosol delivery on ventilator

In-line nebulizer efficiency improves with dry circuit gas, adequate inspiratory time, and placement of the device near the patient wye.

Asthma first-line therapy

Short-acting beta-2 agonists are first-line for acute asthma; ipratropium is added for severe exacerbations along with systemic corticosteroids.

COPD oxygen target

In COPD patients at risk for hypercapnia, titrate oxygen to an SpO2 of roughly 88 to 92 percent while treating with bronchodilators and corticosteroids.

Croup treatment

Croup causes barking cough and inspiratory stridor; nebulized epinephrine and dexamethasone are standard therapies for moderate to severe presentations.

Epiglottitis management

Epiglottitis presents with drooling, tripod posture, and muffled voice; avoid agitating the patient and secure the airway in a controlled setting.

ARDS Berlin definition

ARDS is defined by onset within one week, bilateral opacities, and PaO2/FiO2 of 300 or less with PEEP of at least 5 cm H2O.

Pulmonary embolism presentation

Pulmonary embolism commonly causes sudden dyspnea and hypoxemia that appears out of proportion to physical findings; D-dimer and CT angiography aid diagnosis.

Flail chest management

Flail chest with pulmonary contusion is managed with analgesia, aggressive pulmonary hygiene, and ventilatory support; fluid overload worsens oxygenation.

Status asthmaticus adjuncts

When severe asthma fails bronchodilators and steroids, magnesium sulfate, heliox, and noninvasive ventilation may be considered as adjunctive therapies.