COMPLIANCE AND RESISTANCE IN MECHANICAL VENTILATION

A set of flashcards covering key vocabulary and concepts related to compliance and resistance in mechanical ventilation, essential for understanding respiratory mechanics.

Compliance

A measure of lung distensibility, defined as change in volume per unit change in pressure.

Static Compliance

Compliance measured during no-flow conditions, reflecting the elastic properties of lungs and chest wall.

Dynamic Compliance

Compliance measured during active breathing, influenced by both elastic and resistive forces.

Specific Compliance

Compliance per unit of lung volume, useful for comparing patients of different sizes.

Resistance

Opposition to airflow in the respiratory system, defined as change in pressure per unit flow rate.

Airway Resistance

Opposition to airflow in conducting airways; a major component of total respiratory resistance.

Tissue Resistance

Resistance due to lung and chest wall tissue deformation.

Endotracheal Tube Resistance

Additional resistance encountered by mechanically ventilated patients due to the presence of the tube.

Poiseuille's Law

A law stating that a reduction in airway lumen by 50% results in a fourfold increase in airway resistance.

Time Constant (τ)

The product of compliance and resistance, representing the time required to fill or empty lung units.

Low Compliance

Characterized by stiff lungs, resulting in increased work of breathing and risk of barotrauma.

High Compliance

Characterized by overly distensible lungs, associated with risks such as dynamic hyperinflation.

Factors Affecting Compliance

Includes lung tissue elasticity, chest wall elasticity, surfactant function, and patient positioning.

Factors Affecting Resistance

Includes airway diameter, length of airways, gas density and viscosity, among others.

Clinical Implications of Altered Resistance

Increased resistance is seen in obstructive lung diseases and can increase work of breathing.

Monitoring Compliance and Resistance

Regular assessment of trends is crucial for detecting patient-ventilator asynchrony and other issues.