RT (CRT/RRT) key terms

Measured indicators of basic body function, typically including heart rate, respiratory rate, blood pressure, temperature, and oxygen saturation. Therapists record them to detect change and guide treatment decisions.

A blood sample drawn from an artery and analyzed for pH, carbon dioxide, oxygen, and bicarbonate. It shows how well the lungs ventilate and oxygenate and how well the kidneys balance acid-base status.

A noninvasive method that shines light through tissue to estimate the percentage of hemoglobin carrying oxygen. Readings fall quickly when oxygenation drops but can be falsely normal in poor perfusion or abnormal hemoglobin.

Continuous measurement and display of exhaled carbon dioxide, usually reported as end-tidal CO2. The waveform confirms correct tube placement and reflects ventilation, circulation, and metabolism.

The process of explaining a procedure's purpose, risks, benefits, and alternatives so the patient can decide freely. The therapist verifies consent before treatment and documents the discussion.

The proportion of oxygen in the gas a patient breathes, expressed as a decimal or percent. Room air is 0.21; the therapist sets it to keep arterial oxygen adequate while limiting toxicity.

A low-flow device with prongs placed in the nostrils that delivers oxygen at 1 to 6 liters per minute. The actual inspired oxygen varies with the patient's breathing pattern.

An air-entrainment mask that mixes oxygen with room air through a calibrated jet to deliver a fixed, predictable FiO2, often 24 to 50 percent.

A high-concentration reservoir mask with a one-way valve that prevents exhaled gas from entering the bag, delivering roughly 60 to 90 percent oxygen when the seal is good.

A device that delivers heated, humidified gas at flows up to 60 liters per minute with a set FiO2, providing some positive pressure and washing out dead space.

Lung and airway damage from breathing high concentrations of oxygen for prolonged periods, causing cough, chest pain, and declining gas exchange. It is a reason to use the lowest effective FiO2.

Collapse of alveoli that occurs when high oxygen replaces nitrogen, which normally helps keep small airways open. It can develop during surgery or with prolonged high-FiO2 therapy.

A device that separates nitrogen from room air to produce oxygen-rich gas for home therapy. It requires electricity and delivers low flows, typically 1 to 5 liters per minute.

A flowmeter with a tapered tube and ball that indicates gas flow, calibrated for a specific gas and pressure. Accuracy depends on the tube being upright and unobstructed.

A hand-held device that encourages slow, sustained deep breaths to expand the lungs. Patients hold the breath a few seconds, and the visible target gives feedback.

A therapy in which the patient exhales against a fixed resistance through a mask or mouthpiece, splinting airways open and helping move mucus toward the upper airway for clearing.

A fitted vest rapidly inflates and deflates to create airflow pulses in the chest, loosening secretions independent of patient effort. Sessions are often combined with coughing or suctioning.

A breathing technique that moves mucus from small to large airways using slow, controlled breaths at three lung volumes, without equipment, guided by the feel of airflow.

A cycle of relaxed breathing, deep breaths, and huff coughs that clears secretions with less fatigue than continuous coughing. It is often combined with postural drainage positions.

Positioning the patient so gravity moves secretions from specific lung segments toward the trachea. Positions are matched to the affected lobe and often combined with percussion or vibration.

A device that delivers a deep breath and then quickly reverses flow to simulate a cough, helping patients with weak muscles clear secretions.

A curved plastic device inserted through the mouth to hold the tongue away from the throat. It is used only in unconscious patients because it can trigger gagging and laryngospasm.

A soft tube passed through the nostril to keep the upper airway open, tolerated by patients with intact reflexes. Correct sizing and lubrication reduce bleeding and injury.

Placement of a cuffed tube through the vocal cords into the trachea to secure the airway and allow positive-pressure ventilation, suctioning, and protection from aspiration.

A device such as a laryngeal mask that sits above the vocal cords and seals the upper airway without entering the trachea. It supports ventilation but does not protect against aspiration.

A surgically created opening in the neck into the trachea, fitted with a tube, that provides a long-term airway for ventilation, secretion clearance, or bypassing an obstruction.

Measuring the pressure in an artificial airway cuff, usually kept between about 20 and 30 cm H2O, to prevent air leaks while protecting tracheal blood flow.

Passing a catheter into an artificial airway to remove secretions, done with sterile technique and limited to short passes to avoid hypoxemia, bleeding, and atelectasis.

Manual delivery of breaths with a self-inflating bag and mask, used to ventilate a patient when breathing is inadequate. A good seal and airway opening determine effectiveness.

The amount of gas moved into or out of the lungs with each breath. In mechanical ventilation, it is set by the clinician, often based on predicted body weight.

Pressure held in the airways at the end of exhalation that keeps alveoli open, improves oxygenation, and reduces atelectasis. Excess PEEP can lower cardiac output and cause barotrauma.

The airway pressure measured during a brief pause at end-inspiration, reflecting alveolar pressure. It guides safe ventilator settings; values above about 30 cm H2O raise injury risk.

Air trapped in the lungs because exhalation does not finish before the next breath begins. It raises intrathoracic pressure, causes dyspnea, and can drop blood pressure.

A mode in which each breath delivers a set tidal volume at a set rate, with airway pressure varying. Pressure limits protect the lungs when compliance changes.

A mode that augments each patient-triggered breath with a set amount of inspiratory pressure, reducing the work of breathing. The patient controls rate, inspiratory time, and volume.

The relationship between inspiratory time and expiratory time during a breath. Normally about 1:2 to 1:3; shorter expiratory time in obstructive disease causes air trapping.

A period, often 30 to 120 minutes, during which a patient breathes with minimal ventilator support to test readiness for extubation. Success is judged by comfort, gas exchange, and stable vital signs.

Ventilatory support delivered through a tight-fitting mask instead of an artificial airway, commonly used for COPD exacerbation or acute heart failure to avoid intubation.