Arterial Blood Gases, Chest Trauma, Pneumothorax, and Pulmonary Embolism Vocabulary

Comprehensive vocabulary flashcard set reviewing arterial blood gas interpretation, acid-base disorders, chest trauma mechanisms, pneumothorax types, chest tube drainage systems, and pulmonary embolism pathophysiology and diagnostics.

Pulse Oximetry

A noninvasive diagnostic monitor used to measure arterial oxygen saturation ($SpO_2$), with normal values ranging from $94\%$ to $99\%$.

Arterial Blood Gases (ABGs)

A diagnostic arterial blood sample evaluating oxygenation and acid-base balance by measuring $PaO_2$, $PaCO_2$, $pH$, $HCO_3^-$; requiring no oxygen concentration changes for $15\,min$ prior to collection and drawn using a heparinized syringe.

Acidosis

An acid-base imbalance characterized by a blood $pH < 7.35$, resulting in central nervous system depression, drowsiness, confusion, slow weak heart rate, muscle weakness, hyperkalemia, and Kussmaul respirations.

Alkalosis

An acid-base imbalance characterized by a blood $pH > 7.45$, resulting in central nervous system irritability, restlessness, anxiety, fast racing heart rate, muscle twitching or cramps, hypocalcemia, hypokalemia, and slow shallow breathing.

Carbonic Acid-Bicarbonate Buffer System

The primary chemical buffer system maintaining a $1:20$ ratio of carbonic acid ($H_2CO_3$) to base bicarbonate ($HCO_3^-$) that converts strong acids into weak acids via the chemical reaction $HCl + NaHCO_3 \rightarrow NaCl + H_2CO_3$.

Respiratory Acid-Base Regulation

An acid-base regulation mechanism controlled by the respiratory center in the medulla using the chemical process $CO_2 + H_2O \rightarrow H_2CO_3 \rightarrow H^+ + HCO_3^-$, where increased respirations eliminate $CO_2$ to increase $pH$, and decreased respirations retain $CO_2$ to lower $pH$.

Renal Acid-Base Regulation

The renal system's acid-base mechanism that conserves bicarbonate ($HCO_3^-$) and excretes acid by secreting free hydrogen ions ($H^+$), combining $H^+$ with ammonia ($NH_3$), and excreting weak acids.

Respiratory Acidosis

An acid-base imbalance caused by carbonic acid excess ($CO_2$ retention) leading to $pH < 7.35$ and $PaCO_2 > 45\,mmHg$, commonly caused by COPD, pneumonia, and respiratory failure.

Respiratory Alkalosis

An acid-base imbalance caused by carbonic acid deficit ($CO_2$ elimination) leading to $pH > 7.45$ and $PaCO_2 < 35\,mmHg$, commonly caused by hyperventilation, anxiety, and severe pain.

Metabolic Acidosis

An acid-base imbalance caused by base bicarbonate deficit leading to $pH < 7.35$ and $HCO_3^- < 22\,mEq\,L^{-1}$, commonly caused by diabetic ketoacidosis (DKA), renal failure, and severe diarrhea.

Metabolic Alkalosis

An acid-base imbalance caused by base bicarbonate excess leading to $pH > 7.45$ and $HCO_3^- > 26\,mEq\,L^{-1}$, commonly caused by vomiting, nasogastric (NG) suctioning, and diuretic therapy.

Kussmaul Respirations

Abnormally deep and rapid respiratory patterns that act as a compensatory mechanism to blow off excess carbon dioxide during metabolic acidosis.

ROME Mnemonic

An acid-base diagnostic rule standing for Respiratory Opposite ($pH$ and $PaCO_2$ move in opposite directions) and Metabolic Equal ($pH$ and $HCO_3^-$ move in the same direction).

Blunt Chest Trauma

Chest wall injury produced by shearing and compression forces where external physical appearance may be minor despite severe internal organ damage.

Penetrating Chest Trauma

Chest wall injury occurring when a foreign object impales or passes through thoracic tissues, creating an open chest wound.

Sucking Chest Wound Dressing

An emergency nonporous dressing applied over an open chest wound and taped on three sides to pull shut during inspiration (preventing air entry) and push open during expiration (allowing air to escape).

Pneumothorax

A condition in which air enters the pleural space, converting negative intrapleural pressure into positive pressure and causing partial or complete lung collapse.

Spontaneous Pneumothorax

A type of pneumothorax caused by the rupture of small air-filled blebs on the lung surface, occurring in healthy or chronically ill individuals (e.g., COPD, asthma, cystic fibrosis) with risk factors including tall, thin stature, male gender, and family history.

Iatrogenic Pneumothorax

A pneumothorax caused by medical procedures or invasive interventions, such as lung biopsies, subclavian catheter insertions, mechanical ventilation, or esophageal trauma.

Tension Pneumothorax

A life-threatening emergency where air continually accumulates in the pleural space without escaping, leading to severe intrapleural pressure, mediastinal shift, tracheal deviation, neck vein distention, and hemodynamic collapse from impaired venous return and cardiac output.

Needle Decompression

An immediate emergency procedure performed to vent trapped pleural air and decompress the chest cavity in a patient experiencing a tension pneumothorax.

Chest Tube

A $20\,inch$ long catheter inserted into the pleural space to drain air, fluid, or blood and reestablish normal negative pressure required for lung reexpansion.

Water-Seal Chamber

The second compartment of a chest drainage system filled with $2\,cm$ of water that acts as a one-way valve, allowing air to escape from the pleural cavity while preventing outside air from reentering.

Collection Chamber

The first compartment of a chest drainage unit designed to collect and retain fluid, blood, or exudate while allowing air to pass into the adjacent water-seal chamber.

Suction Control Chamber

The third compartment of a chest drainage unit that regulates applied suction pressure, utilizing either a prescribed column of water (wet suction, commonly $-20\,cm\,H_2O$) or a mechanical regulator control dial (dry suction).

Tidaling

The normal upward and downward fluctuation of water in the water-seal chamber corresponding to intrapleural pressure changes during respiration, which disappears as the lung fully reexpands.

Subcutaneous Emphysema

A clinical condition resulting from air escaping into the subcutaneous tissues of the chest and neck, producing a characteristic crackling or crepitus feeling upon palpation.

Pulmonary Embolism (PE)

The occlusion of one or more pulmonary arteries by a thrombus, fat or air embolus, or tumor tissue, most commonly originating from deep vein thrombosis (DVT) in the lower extremities and affecting the lower lung lobes.

Saddle Embolus

A large, massive thrombus lodged directly at the bifurcation of the main pulmonary artery, causing severe hemodynamic instability and high mortality.

Pulmonary Infarction

A complication of pulmonary embolism where occlusion of medium or large pulmonary vessels combined with inadequate collateral blood supply leads to alveolar necrosis, hemorrhage, pleural effusion, and potential abscess formation.

Pulmonary Hypertension

A complication of PE resulting from chronic hypoxemia associated with recurrent or massive emboli obstructing greater than $50\%$ of the pulmonary vascular bed, leading to right ventricular hypertrophy.

D-Dimer

A laboratory blood test measuring cross-linked fibrin degradation products that increases with clot breakdown, though false-negative results can occur with small pulmonary emboli.

Spiral CT Scan (CTA)

The primary diagnostic test for pulmonary embolism that utilizes intravenous contrast media to produce three-dimensional visualization of the pulmonary blood vessels.

Ventilation-Perfusion (V/Q) Scan

A nuclear diagnostic study combining perfusion scanning (via intravenous radioisotope injection) and ventilation scanning (via inhaled radioactive gas), utilized to identify pulmonary embolism in patients unable to tolerate intravenous contrast media.