Respiratory Abbreviations
109 abbreviations · part of Medical Abbreviations
Abbreviations for lung and airway diseases, breathing symptoms, pulmonary function and sleep tests, oxygen delivery devices, mechanical ventilation settings and inhaled medicines, as used by pulmonologists, respiratory therapists, intensivists, sleep physicians and nurses. Ventilator and oxygen abbreviations such as FiO2, PEEP and HFNC appear in orders that are acted on minute to minute, so units and settings should always be written alongside them. Several short forms are shared with other fields (PE also means physical examination, RV right ventricle, Vt is distinct from VT), so the clinical setting decides the meaning.
| Abbreviation | Stands for | Description |
|---|---|---|
| A-a gradient | Alveolar-arterial oxygen gradient | Difference between the oxygen pressure in the air sacs, calculated with the alveolar gas equation, and in arterial blood measured by a blood gas. |
| AATD | Alpha-1 antitrypsin deficiency | Inherited deficiency of a protein that protects the lungs from enzyme damage, causing early-onset emphysema, often in the lower lobes, and liver disease. |
| ABPA | Allergic bronchopulmonary aspergillosis | Allergic reaction to the fungus Aspergillus fumigatus colonizing the airways, occurring mainly in people with asthma or cystic fibrosis. |
| AC | Assist-control ventilation | Mechanical ventilation mode in which the ventilator delivers a full set breath, either a set volume or set pressure, every time the patient triggers a breath, plus… |
| AECOPD | Acute exacerbation of chronic obstructive pulmonary disease | Flare-up of COPD with worsening breathlessness, cough and sputum beyond normal day-to-day variation, usually triggered by viral or bacterial infection or air pollution. |
| AERD | Aspirin-exacerbated respiratory disease | Chronic condition combining asthma, recurrent nasal polyps with chronic sinusitis, and respiratory reactions such as wheezing and congestion after taking aspirin or… |
| AHI | Apnea-hypopnea index | Average number of apneas (breathing pauses) and hypopneas (shallow breathing with oxygen drop or arousal) per hour of sleep, the main measure of sleep apnea severity. |
| AHRF | Acute hypoxemic respiratory failure | Respiratory failure characterized mainly by low blood oxygen despite supplemental oxygen, commonly from pneumonia, ARDS, pulmonary edema or pulmonary embolism. |
| APAP | Automatic positive airway pressure | Sleep apnea machine that automatically adjusts pressure within a set range, breath by breath, in response to detected airway narrowing, snoring or apneas. |
| APRV | Airway pressure release ventilation | Ventilator mode that holds a high continuous pressure for most of the breathing cycle, with brief, timed releases to a low pressure that allow carbon dioxide to escape… |
| ARDS | Acute respiratory distress syndrome | Severe, rapidly developing lung injury in which inflammation makes the lungs leaky, filling air sacs with fluid and causing profound low oxygen and stiff lungs. |
| ARF | Acute respiratory failure | Sudden inability of the lungs to maintain adequate oxygen levels (type 1, hypoxemic, PaO2 below 60 mmHg) or to remove carbon dioxide (type 2, hypercapnic, PaCO2 above… |
| ATS | American Thoracic Society | Medical society for pulmonary, critical care and sleep medicine, publishing clinical practice guidelines and technical standards, including spirometry standards written… |
| BAL | Bronchoalveolar lavage | Procedure during bronchoscopy in which sterile saline is instilled into a lung segment and suctioned back, collecting cells and organisms from the alveoli for analysis. |
| BiPAP | Bilevel positive airway pressure | Noninvasive ventilation that delivers a higher pressure when the patient breathes in (IPAP) and a lower pressure when breathing out (EPAP), assisting ventilation and… |
| BOOP | Bronchiolitis obliterans organizing pneumonia | Former name for cryptogenic organizing pneumonia, a steroid-responsive condition in which granulation tissue fills small airways and alveoli. |
| BPD | Bronchopulmonary dysplasia | Chronic lung disease of premature infants, especially those born before 28 weeks, resulting from lung immaturity combined with injury from ventilation, oxygen and… |
| CAP | Community-acquired pneumonia | Pneumonia that develops outside the hospital in people without recent significant healthcare exposure. |
| CF | Cystic fibrosis | Inherited disease caused by variants in both copies of the CFTR gene, producing thick, sticky secretions that damage the lungs, pancreas, liver, intestines and… |
| COP | Cryptogenic organizing pneumonia | Inflammatory lung disease of unknown cause in which plugs of granulation tissue fill the small airways and air sacs, producing a flu-like illness, cough and… |
| COPD | Chronic obstructive pulmonary disease | Progressive lung disease with persistent airflow limitation, encompassing emphysema and chronic bronchitis, causing breathlessness, chronic cough, sputum and flare-ups. |
| CPAP | Continuous positive airway pressure | Therapy that delivers a constant stream of pressurized air through a nasal, nasal-pillow or full-face mask, splinting the upper airway open during sleep. |
| CPET | Cardiopulmonary exercise test | Exercise test on a bicycle or treadmill with breath-by-breath gas analysis, ECG and blood pressure monitoring, measuring peak oxygen uptake (VO2 peak) and identifying… |
| CPT | Chest physiotherapy | Group of airway clearance techniques, including percussion (clapping on the chest), vibration and postural drainage, used to loosen and move mucus from the lungs. |
| CSA | Central sleep apnea | Sleep-related breathing disorder in which breathing stops because the brain temporarily fails to signal the breathing muscles, rather than because the airway is blocked. |
| CSR | Cheyne-Stokes respiration | Breathing pattern of gradually increasing then decreasing depth (crescendo-decrescendo), alternating with pauses (central apneas), typically in cycles of about a minute. |
| CTEPH | Chronic thromboembolic pulmonary hypertension | Pulmonary hypertension caused by old blood clots that have organized into scar tissue inside the pulmonary arteries, usually after one or more pulmonary embolisms. |
| DIB | Difficulty in breathing | Charting and triage shorthand for breathlessness, used mainly in British, Irish, Indian and other Commonwealth health systems. |
| DLCO | Diffusing capacity of the lungs for carbon monoxide | Pulmonary function measurement of how efficiently gas transfers from the air sacs into the blood, obtained by inhaling a small, safe amount of carbon monoxide and… |
| EBUS | Endobronchial ultrasound | Bronchoscopy technique using an ultrasound probe on the bronchoscope tip to see and sample lymph nodes and masses next to the airways, usually by transbronchial needle… |
| EIB | Exercise-induced bronchoconstriction | Temporary narrowing of the airways triggered by vigorous exercise, typically peaking 5 to 15 minutes after exertion and causing cough, wheeze, chest tightness or… |
| ESS | Epworth Sleepiness Scale | Eight-item questionnaire in which people rate their chance of dozing in situations such as reading, watching TV, sitting in traffic or after lunch, each scored 0 to 3… |
| FeNO | Fractional exhaled nitric oxide | Breath test measuring nitric oxide in exhaled air, in parts per billion, a marker of type 2 (eosinophilic) airway inflammation. |
| FEV1 | Forced expiratory volume in 1 second | Volume of air a person can forcefully exhale in the first second after a full breath in, the most important single number from spirometry. |
| FEV1/FVC | Ratio of forced expiratory volume in 1 second to forced vital capacity | Proportion of the total exhaled breath that is blown out in the first second, the key spirometric value for detecting airflow obstruction. |
| FiO2 | Fraction of inspired oxygen | Proportion of oxygen in the gas a patient breathes, expressed as a decimal or percentage: room air is 0.21 (21 percent), and ventilators can deliver up to 1.0 (100… |
| FRC | Functional residual capacity | Volume of air remaining in the lungs at the end of a normal, relaxed exhalation, when the inward pull of the lungs balances the outward spring of the chest wall. |
| FVC | Forced vital capacity | Total volume of air a person can forcefully exhale after taking the deepest possible breath, measured in liters during spirometry. |
| GGO | Ground-glass opacity | Hazy area of increased density on CT through which underlying vessels and airways remain visible, reflecting partial filling of air spaces or thickening of the… |
| GINA | Global Initiative for Asthma | International organization that publishes the annually updated Global Strategy for Asthma Management and Prevention, used by clinicians and health systems around the… |
| GOLD | Global Initiative for Chronic Obstructive Lung Disease | International collaboration that publishes the annually updated Global Strategy for the diagnosis, management and prevention of COPD. |
| HCAP | Healthcare-associated pneumonia | Former category for pneumonia in nonhospitalized patients with healthcare contact, such as nursing home residents, dialysis patients and those recently hospitalized… |
| HFNC | High-flow nasal cannula | Oxygen system delivering heated, humidified gas through wide nasal prongs at flows up to about 60 liters per minute in adults, with oxygen concentration adjustable up… |
| HP | Hypersensitivity pneumonitis | Immune-mediated lung disease caused by repeatedly inhaling organic particles, such as bird proteins, molds in hay or hot tubs, and some chemicals, to which a person has… |
| HSAT | Home sleep apnea test | Simplified sleep study done in the patient's own bed with a portable device recording airflow, breathing effort, oxygen saturation and heart rate, used to diagnose… |
| HTX | Hemothorax | Collection of blood in the pleural space, most often from chest trauma such as rib fractures or penetrating injury, and occasionally from surgery, anticoagulation or… |
| ICS | Inhaled corticosteroid | Anti-inflammatory steroid delivered to the airways by inhaler, including fluticasone, budesonide, beclomethasone, mometasone and ciclesonide. |
| ILD | Interstitial lung disease | Umbrella term for more than 200 disorders that inflame or scar the lung interstitium, the tissue around the air sacs, causing progressive breathlessness, dry cough and… |
| iNO | Inhaled nitric oxide | Gas delivered through a ventilator or nasal cannula that relaxes blood vessels only in ventilated parts of the lung, lowering pulmonary pressures and improving… |
| IPF | Idiopathic pulmonary fibrosis | Chronic, progressive scarring of the lungs of unknown cause, occurring mainly in adults over 60, particularly men with a smoking history. |
| LABA | Long-acting beta2-agonist | Inhaled bronchodilator that relaxes airway muscle for 12 to 24 hours, including salmeterol, formoterol, vilanterol and olodaterol. |
| LAMA | Long-acting muscarinic antagonist | Inhaled bronchodilator that blocks acetylcholine receptors in airway muscle for about 24 hours, including tiotropium, umeclidinium, glycopyrronium and aclidinium. |
| LLL | Left lower lobe | Lower lobe of the left lung, much of which lies behind the heart on a frontal chest x-ray. |
| LPM | Liters per minute | Unit of flow rate used for supplemental oxygen and ventilator gas delivery, as set on a flowmeter or oxygen concentrator. |
| LRTI | Lower respiratory tract infection | Infection below the larynx, including acute bronchitis, bronchiolitis, pneumonia and infective exacerbations of chronic lung disease. |
| LTOT | Long-term oxygen therapy | Home oxygen used for at least 15 hours a day, and ideally continuously, in patients with chronic lung disease and severe resting hypoxemia. |
| LUL | Left upper lobe | Upper lobe of the left lung, which includes the lingula, a tongue-shaped portion that corresponds to the right middle lobe. |
| MART | Maintenance and reliever therapy | Asthma treatment strategy using a single inhaler containing an inhaled corticosteroid and formoterol, typically budesonide-formoterol, both every day as maintenance and… |
| MV | Mechanical ventilation | Use of a machine to move air in and out of the lungs through an endotracheal or tracheostomy tube in patients who cannot breathe adequately on their own, from… |
| NC | Nasal cannula | Lightweight tube with two prongs placed in the nostrils to deliver supplemental oxygen, usually at 1 to 6 liters per minute. |
| NIPPV | Noninvasive positive pressure ventilation | Mask-delivered ventilation with positive pressure, the term common in US charts and neuromuscular and home ventilation practice. |
| NIV | Noninvasive ventilation | Breathing support delivered through a mask rather than a tube in the trachea, usually bilevel positive pressure. |
| NRB | Nonrebreather mask | Face mask with an attached reservoir bag and one-way valves that delivers a high concentration of oxygen, typically at 10 to 15 liters per minute. |
| NSIP | Nonspecific interstitial pneumonia | Pattern of interstitial lung disease with fairly uniform inflammation or fibrosis of the alveolar walls, often associated with connective tissue diseases such as… |
| OHS | Obesity hypoventilation syndrome | Combination of obesity (BMI 30 or more) and elevated daytime carbon dioxide (PaCO2 of 45 mmHg or more) not explained by another lung, neuromuscular or metabolic disorder. |
| OSA | Obstructive sleep apnea | Sleep disorder in which the upper airway repeatedly collapses during sleep, causing pauses in breathing, oxygen drops and frequent awakenings. |
| P/F | PaO2/FiO2 ratio | Ratio of arterial oxygen pressure (from a blood gas) to the fraction of inspired oxygen, a quick measure of how well the lungs oxygenate the blood regardless of how… |
| PAH | Pulmonary arterial hypertension | Group 1 pulmonary hypertension, in which the small pulmonary arteries narrow and stiffen, raising resistance to blood flow and eventually causing right heart failure. |
| PAP | Positive airway pressure | Generic term for therapies that deliver pressurized air through a mask to keep the airway open or assist breathing, including CPAP, BiPAP and auto-titrating devices. |
| PE | Pulmonary embolism | Blockage of a pulmonary artery, usually by a blood clot that has traveled from the deep veins of the legs or pelvis. |
| PEEP | Positive end-expiratory pressure | Pressure maintained in the airways at the end of each exhalation during mechanical or noninvasive ventilation, preventing the air sacs from collapsing and improving… |
| PEF | Peak expiratory flow | Fastest speed of air a person can blow out in a single forceful breath, measured in liters per minute with a simple handheld peak flow meter. |
| PEFR | Peak expiratory flow rate | Measurement of maximal exhalation speed, in liters per minute, that is the traditional British and older clinical name for peak flow. |
| PF | Pulmonary fibrosis | Scarring and stiffening of lung tissue that makes breathing progressively harder and reduces oxygen transfer to the blood. |
| PFT | Pulmonary function test | Group of breathing tests that measure how much air the lungs hold, how quickly air can be blown out and how well oxygen passes into the blood. |
| PH | Pulmonary hypertension | Raised blood pressure in the pulmonary arteries, defined since 2022 by a mean pulmonary artery pressure above 20 mmHg at rest on right heart catheterization. |
| PIP | Peak inspiratory pressure | Highest pressure reached in the airways during a ventilator breath, reflecting both airway resistance and the stiffness of the lungs and chest wall. |
| PNA | Pneumonia | Charting shorthand for pneumonia, an infection of the lung's air sacs that fill with fluid or pus, causing cough, fever, breathlessness and chest pain. |
| PND | Paroxysmal nocturnal dyspnea | Sudden episodes of severe breathlessness that wake a person from sleep, typically one to two hours after lying down, relieved by sitting upright or standing. |
| Pplat | Plateau pressure | Airway pressure measured during a brief pause at the end of inspiration on a ventilator, when airflow stops, reflecting the pressure in the alveoli and the stiffness of… |
| PRVC | Pressure-regulated volume control | Adaptive ventilator mode that delivers a target tidal volume using the lowest pressure needed, adjusting the inspiratory pressure breath by breath as lung compliance… |
| PSG | Polysomnography | Overnight in-laboratory sleep study recording brain waves, eye movements, muscle activity, airflow, breathing effort, oxygen saturation, heart rhythm and leg movements. |
| PSV | Pressure support ventilation | Spontaneous ventilator mode in which every breath is started by the patient and boosted by a set inspiratory pressure, with the patient controlling breathing rate… |
| PTX | Pneumothorax | Air in the pleural space between the lung and chest wall, causing part or all of the lung to collapse, with sudden one-sided chest pain and breathlessness. |
| RAD | Reactive airway disease | Loose clinical label for episodes of wheezing, cough and bronchospasm, often used for young children before a firm asthma diagnosis can be made or for adults with… |
| RDI | Respiratory disturbance index | Number of apneas, hypopneas and respiratory effort-related arousals per hour of sleep, a broader measure than the apnea-hypopnea index that captures subtler airway… |
| RDS | Respiratory distress syndrome | Breathing disorder of premature newborns caused by insufficient surfactant, the substance that keeps air sacs open, leading to collapsed alveoli, grunting, retractions… |
| RLL | Right lower lobe | Largest lobe of the right lung, at the base of the chest, with five segments. |
| RML | Right middle lobe | Smallest lobe of the right lung, found only on the right side, lying against the right border of the heart between the horizontal and oblique fissures. |
| RSBI | Rapid shallow breathing index | Breathing rate divided by tidal volume in liters, measured during a brief period of unsupported breathing to predict whether a patient can be weaned from the ventilator. |
| RUL | Right upper lobe | Top lobe of the right lung, divided into apical, posterior and anterior segments and separated from the middle lobe by the horizontal fissure. |
| RV | Residual volume | Air remaining in the lungs after a complete forced exhalation, which cannot be blown out and keeps the airways and alveoli from collapsing. |
| SABA | Short-acting beta2-agonist | Rescue bronchodilators, mainly albuterol (salbutamol) and levalbuterol, that open the airways within minutes and last about 4 to 6 hours. |
| SAMA | Short-acting muscarinic antagonist | Inhaled anticholinergic bronchodilator with a short duration of action, mainly ipratropium bromide, used as an add-on rescue treatment in acute asthma and COPD… |
| SaO2 | Arterial oxygen saturation | Percentage of hemoglobin in arterial blood carrying oxygen, measured directly by co-oximetry on an arterial blood gas sample. |
| SBT | Spontaneous breathing trial | Test of readiness to come off the ventilator, in which support is reduced to minimal pressure support or a T-piece for 30 to 120 minutes while breathing rate… |
| SDB | Sleep-disordered breathing | Umbrella term for abnormal breathing during sleep, covering snoring, upper airway resistance, obstructive and central sleep apnea, and sleep-related hypoventilation. |
| SIMV | Synchronized intermittent mandatory ventilation | Ventilator mode that delivers a set number of mandatory breaths per minute, timed to coincide with the patient's own efforts, while allowing spontaneous breaths in… |
| SOBOE | Shortness of breath on exertion | Breathlessness that occurs with physical activity, such as climbing stairs or walking uphill, and eases with rest; common in British and Commonwealth clinical notes. |
| SPN | Solitary pulmonary nodule | Single round opacity in the lung measuring 3 cm or less, surrounded by normal lung, with no associated collapse or enlarged lymph nodes. |
| TLC | Total lung capacity | Volume of air in the lungs after the deepest possible breath in, normally about 6 liters in an average adult man. |
| trach | Tracheostomy | Surgical or percutaneous opening in the front of the neck into the trachea, with a tube inserted to provide an airway. |
| UIP | Usual interstitial pneumonia | Pattern of lung scarring seen on CT and biopsy, with patchy fibrosis concentrated at the bases and under the pleura, honeycombing and traction bronchiectasis. |
| URI | Upper respiratory infection | Infection of the nose, sinuses, throat or larynx, most often the common cold, caused mainly by rhinoviruses and other respiratory viruses. |
| URTI | Upper respiratory tract infection | Infection affecting any part of the upper airway, including colds, pharyngitis, sinusitis, laryngitis and otitis media in some classifications. |
| V/Q | Ventilation-perfusion ratio | Relationship between airflow reaching the air sacs and blood flow reaching the lung capillaries; an overall ratio of about 0.8 is normal. |
| VATS | Video-assisted thoracoscopic surgery | Minimally invasive chest surgery performed through small incisions using a camera and long instruments, used for lung biopsy, wedge resection, lobectomy, pleural… |
| VM | Venturi mask | Oxygen mask with a color-coded adapter that entrains room air at a fixed ratio, delivering a precise oxygen concentration, typically from 24 to 60 percent, regardless… |
| Vt | Tidal volume | Volume of air moved into or out of the lungs with each normal breath, about 500 mL (roughly 7 mL/kg) in a resting adult. |
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