Ventilation-Perfusion (V/Q), Asthma, and COPD (Typed)

Vocabulary flashcards covering ventilation-perfusion ratios, pulmonary function measurements, asthma pathophysiology and pharmacology, and chronic obstructive pulmonary disease (COPD).

Hypercapnia

The presence of excess $CO_2$ in the arterial blood.

Hypoxemia

Abnormally low $O_2$ content in the blood.

Ventilation-Perfusion (V/Q) Ratio

A clinical ratio used to assess the efficiency and adequacy of ventilation (V) and perfusion (Q).

Normal V/Q

The physiological state in which equal amounts of air and blood enter the respiratory portion of the lungs.

Low V/Q (Shunt)

A ventilation-perfusion mismatch characterized by decreased ventilation despite normal perfusion (e.g., seen in asthma or lung injury), carrying a risk of respiratory acidosis.

High V/Q (Dead Space)

A ventilation-perfusion mismatch characterized by normal or high ventilation paired with decreased or impaired perfusion at the alveolar sacs (e.g., seen in pulmonary embolism).

Forced Expiratory Volume in 1 second ($FEV_1$)

A spirometry parameter measuring the volume of air forcefully exhaled during the first second after a full inhalation; values of $75\%+$ (approximately $4\,L$) are considered normal.

Forced Vital Capacity (FVC)

The total volume of air exhaled quickly and forcefully following a complete inhalation, typically measuring around $5\,L$ over $4\text{ to }6\text{ seconds}$.

Asthma

A chronic inflammatory airway disease characterized by bronchial hyperresponsiveness, bronchospasm, thick mucus production, and long-term scar tissue formation.

Bronchial Hyperresponsiveness

An abnormal closure and narrowing of the small airways leading to symptoms such as wheezing and chest tightness.

Bronchodilators

A class of medications that cause the smooth muscle in the lungs to relax.

SABA (Short-Acting Beta-2 Agonist)

A fast-acting bronchodilator (such as albuterol) that opens up the bronchioles.

SAMA (Short-Acting Muscarinic Antagonist)

An inhaled anticholinergic medication (such as ipratropium) that acts on the parasympathetic nervous system to prevent bronchioles from shutting.

LABA (Long-Acting Beta-2 Agonist)

A long-acting bronchodilator (such as formoterol) that stimulates smooth muscle relaxation to keep the airways open over time.

LAMA (Long-Acting Muscarinic Antagonist)

A long-acting bronchodilator that blocks bronchoconstriction and excessive mucus production.

Inhaled Corticosteroids

Maintenance therapy inhaled over time to decrease and prevent lung inflammation; per GINA guidelines, they must be combined with bronchodilators.

Eosinophils

A type of white blood cell identified on a complete blood count (CBC) that increases during allergic reactions and asthma exacerbations.

Signs of Impending Death in Asthma

Critical physical and laboratory signs of respiratory failure consisting of a silent chest and a $P_{CO_2} > 70\,mmHg$.

Chronic Obstructive Pulmonary Disease (COPD)

A progressive disease characterized by chronic inflammation and airflow obstruction resulting from inhalation of toxic substances or occupational pollutants.

Alpha-1 Antitrypsin Deficiency

A genetic condition characterized by the inability to produce anti-elastase, leading to the unchecked enzymatic breakdown of alveoli.

Elastase

An enzyme that protects against infection but breaks down lung tissue, cells, and proteins when left unchecked by anti-elastase.

Chronic Bronchitis

A component of COPD characterized by long-term inflammation of the bronchiole tubes where excess mucus plugs the airways.

Emphysema

A component of COPD characterized by the progressive breakdown and destruction of the alveoli.

Cor Pulmonale

Right-sided heart failure resulting from chronic hypoxemia-induced pulmonary vessel constriction and pulmonary hypertension.

$FEV_1 / FVC$ Ratio

A diagnostic spirometric ratio used to evaluate lung obstruction; a value under $70\%$ indicates an obstructive pattern.

Supplemental Oxygen Target in COPD

The recommended arterial oxygen saturation range of $88-92\%$; exceeding this range can trigger decompensation.