Acute Respiratory & Acid-Base Imbalances Flashcards

Vocabulary flashcards created from lecture notes on acute respiratory failure, ARDS, mechanical ventilation, ABG interpretation, chest trauma, and critical care pharmacology.

Normal Blood pH Scale Values

Standard arterial reference ranges consisting of pH $7.35-7.45$, $PaCO_2$ $45-35\,mmHg$, and $HCO_3^-$ $22-26\,mEq/L$.

Respiratory Acidosis

An acid-base imbalance defined by pH $< 7.35$ and $PaCO_2 > 45\,mmHg$, occurring when the lungs retain too much carbon dioxide ($CO_2$) while the kidneys compensate.

DEPRES

A mnemonic for causes of respiratory acidosis: Drugs, Edema, Pneumonia or fluid in lungs, Respiratory center damaged, Emboli, and Sac elasticity damage (COPD and emphysema).

Respiratory Alkalosis

An acid-base imbalance defined by pH $> 7.45$ and $PaCO_2 < 35\,mmHg$, occurring when a person exhales too much carbon dioxide due to hyperventilation while the kidneys compensate.

Metabolic Acidosis

A kidney-origin acid-base imbalance defined by pH $< 7.35$ and $HCO_3^- < 22\,mEq/L$, resulting from increased acid production or bicarbonate loss, compensated by the lungs blowing off $CO_2$.

Kussmaul Respirations

Deep, rapid breathing pattern performed by the lungs as a compensatory mechanism to blow off excess $CO_2$ during metabolic acidosis.

Metabolic Alkalosis

A kidney-origin acid-base imbalance defined by pH $> 7.45$ and $HCO_3^- > 26\,mEq/L$, resulting from conditions causing acid loss or bicarbonate retention, compensated by the lungs retaining $CO_2$.

PaO2

The partial pressure of oxygen dissolved in blood plasma, with a normal reference range of $80-100\,mmHg$.

Pulse Oximetry (SaO2)

The percentage of the capacity of hemoglobin to carry oxygen, with a normal reference range of $95-100\%$.

Mixed Venous Oxygen Saturation (SvO2)

A measurement of how much oxygen remains in the veins after tissues consume it, with a normal range of $60-80\%$.

V:Q Mismatch

Ventilation-perfusion imbalance where air and blood are not meeting correctly in the lungs, leading to decreased oxygen in the blood and tissue starvation.

Hypercapnic Respiratory Failure

A condition where carbon dioxide cannot get out and builds up in the blood, leading to respiratory acidosis, $CO_2$ narcosis, and CNS depression.

Acute Respiratory Distress Syndrome (ARDS)

A severe condition where the alveolar-capillary membrane becomes damaged and very leaky, causing fluid to move into alveoli and severely impairing gas exchange.

PaO2 to FiO2 Ratio

A diagnostic ratio used in ARDS criteria, classified as mild ($200-300$), moderate ($100-199$), or severe ($< 100$).

Prone Positioning

A intervention for ARDS where the patient is placed on their stomach to open posterior lung areas, recruit collapsed alveoli, redistribute fluid, and improve V/Q matching.

Positive End-Expiratory Pressure (PEEP)

Pressure left in the lungs at the end of exhalation to prevent alveoli from collapsing and to improve oxygenation.

Tidal Volume

The amount of air delivered with each breath by a mechanical ventilator, usually calculated based on ideal body weight to prevent overinflation injury.

Fraction of Inspired Oxygen (FiO2)

The percentage of oxygen delivered to a patient, ranging from room air ($21\%$) up to $100\%$ on a ventilator.

End-Tidal Carbon Dioxide (ETCO2)

The amount of $CO_2$ measured at the end of exhalation, with a normal range of $35-45\,mmHg$, used to assess patient ventilation.

Artificial Airways

Airway devices used for mechanical ventilation including endotracheal tubes, nasotracheal tubes, and cuffed, cuffless, or fenestrated tracheostomy tubes.

Richmond Agitation Sedation Scale (RASS)

An ICU scale measuring agitation and sedation ranging from $+4$ (combative, violent, danger) to $-5$ (unarousable to voice or touch), with $0$ being alert and calm.

CAM-ICU

Confusion Assessment Method for the ICU, a tool assessing altered mental status, inattention, level of consciousness, and disorganized thinking to diagnose ICU delirium.

Cuff-Leak Test

A procedure where the RT deflates the ET tube cuff to check for air flow around the tube; little or no leak indicates possible airway edema and risk for post-extubation stridor.

Stridor

A high-pitched wheezing sound indicating upper airway obstruction, which represents a medical emergency.

Spontaneous Awakening Trial (SAT)

A temporary pause in sedation prior to extubation to assess whether a patient can wake up, follow commands, and protect their airway.

Spontaneous Breathing Trial (SBT)

A trial prior to extubation where ventilator support is significantly reduced to assess if the patient can breathe independently.

Carbon Monoxide Poisoning

Toxicity resulting from carbon monoxide binding tightly to hemoglobin, preventing oxygen transport; causes confusion, headache, dizziness, and often presents with normal pulse oximetry.

Pneumothorax

A condition where air enters the pleural space between the lung and chest wall, causing partial or complete lung collapse.

Flail Chest

A chest injury where fractured rib segments move paradoxically (inward during inspiration and outward during expiration).

Thoracentesis

A bedside or imaging-guided procedure using a needle or catheter to remove air or fluid from the pleural space for diagnostic or therapeutic purposes.

Transudative Pleural Effusion

Pleural fluid accumulation caused by pressure imbalances rather than inflammation, classically due to heart failure.

Exudative Pleural Effusion

Pleural fluid accumulation caused by inflammation or tissue damage, commonly secondary to pneumonia, cancer, or infections.

Empyema

An accumulation of infected purulent fluid (pus) within the pleural space.

Cisatracurium

A neuromuscular blocking drug that paralyzes skeletal muscles to improve ventilator synchrony without providing sedation or analgesia.

Dexmedetomidine

A sedative used for mechanically ventilated patients that causes minimal respiratory depression, with primary risks of bradycardia and hypotension.

Propofol

A rapid-onset, short-acting anesthetic sedative used for ventilated patients that causes hypotension and respiratory depression and provides no analgesia.

Mean Arterial Pressure (MAP)

A metric calculated to evaluate tissue perfusion using the equation $\text{MAP} = \frac{2 \times \text{Diastolic} + \text{Systolic}}{3}$.