Compliancy in Lungs

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Questions and Answers

What does high compliance in the lungs indicate?

Lungs have normal elastic properties.

Lungs cannot expand easily.

Lungs are stiff and have high elastic recoil.

Lungs are stretchy and have low elastic recoil. (correct)

How is static compliance defined?

Pressure applied to small airways during a pause. (correct)

Change in lung volume during inhalation.

Pressure in the lungs at the end of expiration.

Lungs in movement and flexibility.

What is the formula for calculating dynamic compliance?

VT / (PEEP + Plateau)

VT / (Plateau - PEEP)

VT / (PIP - PEEP) (correct)

VT / (PIP - Plateau)

What ventilation strategy is recommended for patients with compliance issues?

Use low tidal volumes and high rates. Signup and view all the answers

What does a low volume change in the volume pressure curve indicate?

Low compliance in the lungs. Signup and view all the answers

What is PEEP in the context of lung mechanics?

Pressure in the lungs at the end of expiration. Signup and view all the answers

How does compliance relate to the volume pressure curve in normal lungs?

Normal amounts of pressure lead to normal volume changes. Signup and view all the answers

Which of the following lung conditions is associated with high compliance?

COPD. Signup and view all the answers

What happens to compliance when the volume and pressure in the lungs increase?

Compliance decreases. Signup and view all the answers

What is a common clinical sign associated with positive pressure ventilation hazards?

Tachycardia Signup and view all the answers

Which condition is a known cause of decreased lung compliance?

Atelectasis Signup and view all the answers

According to Laplace's Law, which factor requires higher pressure for inflation?

Higher surface tension Signup and view all the answers

Which of the following correctly describes Hooke's Law?

The strain of an elastic object is proportional to the stress. Signup and view all the answers

What is a potential risk of forcing too much gas into a patient's lungs?

Damage or death Signup and view all the answers

What happens to the thoracic cavity during diaphragm contraction?

Increases in size, decreasing intrapulmonary pressure Signup and view all the answers

Which of the following statements is true regarding surface tension?

Surface tension causes molecules on the surface to be pushed together. Signup and view all the answers

What is the effect of diaphragm relaxation on lung pressure?

It increases lung pressure and allows exhalation Signup and view all the answers

What does the use of accessory muscles during breathing indicate?

The patient is experiencing respiratory distress Signup and view all the answers

What is driving pressure?

Pressure difference between two points in a vessel or tube Signup and view all the answers

When are intercostal retractions most commonly observed?

During inspiration, indicating respiratory stress Signup and view all the answers

What happens to intrapleural pressure when the diaphragm lowers?

It decreases, allowing air to flow in Signup and view all the answers

What occurs when CO2 levels in the body become excessively high?

Breathing rate increases, leading to hyperventilation Signup and view all the answers

Transthoracic pressure is defined as the pressure difference between which two areas?

Alveolar space and body surface Signup and view all the answers

What is a common sign of severe respiratory stress in newborns?

Intercostal retractions and accessory muscle use Signup and view all the answers

What is the main function of ventilation in the respiratory system?

To move gases between the external environment and the vascular line Signup and view all the answers

What happens to atmospheric pressure as altitude increases?

It decreases Signup and view all the answers

What is the typical barometric pressure at sea level?

760 mmHg Signup and view all the answers

When climbing to high altitudes, what primarily causes altitude sickness?

Decreased barometric pressure affecting oxygen availability Signup and view all the answers

How is fraction of inspired oxygen (FiO2) affected by altitude?

It remains constant at 21% regardless of altitude Signup and view all the answers

Which example illustrates the effects of altitude on a person?

A person sleeping at altitudes without previous exposure Signup and view all the answers

What effect does altitude have on the availability of air molecules?

It decreases the number of air molecules available Signup and view all the answers

What measurement tool is commonly used to evaluate atmospheric pressure?

Mercury barometer Signup and view all the answers

How does altitude sickness manifest in unacclimated individuals?

Severe headaches and fatigue Signup and view all the answers

What is a potential metric for changes in ventilation mechanics?

Breathing rate fluctuations Signup and view all the answers

What is the definition of transpulmonary pressure?

Pressure difference between the alveolar space and the pleural cavity. Signup and view all the answers

Which pressure refers to the difference between the alveolar space and the body's surface?

Trans thoracic Pressure Signup and view all the answers

What characterizes flail chest?

Inward movement during inhalation and outward during exhalation. Signup and view all the answers

What is the primary treatment for a patient with flail chest?

Positive pressure ventilation to stabilize breathing. Signup and view all the answers

What is the breathing pattern observed in flail chest known as?

Seesaw breathing Signup and view all the answers

Which condition involves the presence of air in the pleural cavity?

Pneumothorax Signup and view all the answers

What does subcutaneous emphysema feel like upon examination?

Like bubble wrap. Signup and view all the answers

In a case of flail chest, the effect of positive pressure ventilation is to?

Eliminate negative pressure changes. Signup and view all the answers

What is the primary cause of paradoxical breathing in flail chest?

Broken ribs leading to disrupted normal movement. Signup and view all the answers

What typically accompanies the condition of flail chest?

Pneumothorax Signup and view all the answers

Study Notes

Compliance in Lungs

High compliance indicates stretchy lungs with low elastic recoil; low compliance indicates stiff lungs with high elastic recoil.

Static Compliance

Measured when lungs are still; involves inspiratory hold.
Definition: Pressure applied to small airways and alveoli during a pause.

Dynamic Compliance

Measured during lung movement; assesses inhalation.
Definition: Change in lung volume per unit change in pressure during inhalation.

Key Terms

Tidal Volume (Vt): Volume of gas in one breath.
Plateau Pressure: Pressure during inspiratory hold measured at small airways and alveoli.
PEEP (Positive End-Expiratory Pressure): Pressure in lungs at the end of expiration.
Peak Inspiratory Pressure (PIP): Highest pressure during inhalation.

Calculating Compliance

Static Compliance: VT / (Plateau - PEEP).
Dynamic Compliance: VT / (PIP - PEEP).

Importance of Compliance

Higher lung volume and pressure can lead to decreased compliance.

Low Tidal Volume Ventilation Strategy

Employ low tidal volumes (e.g., 250-300 ml) and high rates to protect lungs with compliance issues.

Compliance and Volume Pressure Curve

Normal lungs show a normal pressure-volume relationship (4-5 liters).
High compliance (e.g., emphysema, COPD) displays rapid volume increase with pressure.
Low compliance (e.g., pneumonia, COVID-19) shows reduced volume change with pressure.

Ventilation Definition

Movement of gases between the external environment and the bloodstream via airways and alveoli.

Mechanisms of Ventilation

Atmospheric Pressure: Measured with a mercury barometer, typically 760 mmHg at sea level, varies with weather.
Higher altitudes decrease atmospheric pressure, leading to fewer air molecules.

Real-Life Example: Altitude Sickness

Occurs when individuals fail to acclimate to high altitudes; reduced barometric pressure leads to impaired oxygen absorption.

Respiratory Pressures

Transpulmonary Pressure: Difference between alveolar space and pleural cavity pressure.
Transmural Pressure: Difference across airway walls.
TransThoracic Pressure: Difference between thoracic cavity and outside pressure.

Flail Chest Definition

Condition where broken ribs cause paradoxical chest movement during breathing, leading to unstable respiratory mechanics.

Flail Chest Treatment

Positive pressure ventilation counteracts negative pressure changes during inhalation.

Complications of Flail Chest

Pneumothorax: Air in pleural cavity can occur.
Subcutaneous Emphysema: Air in the subcutaneous tissue that may feel like bubble wrap.

Effects of Low Compliance

Results in low oxygen levels, decreased chest rise, and diminished aeration on imaging.

Functional Residual Capacity (FRC)

Volume when the lung and chest wall recoil returns to a resting state; disruptions affect compliance.

Causes of Decreased Compliance

Conditions like pneumonia, ARDs, atelectasis, and pulmonary fibrosis increase lung stiffness.

Hooke's Law

Describes elasticity; strain of elastic object is proportional to applied stress.

Hazards of Positive Pressure Ventilation

Can cause severe complications such as tension pneumothorax and decreased cardiac function.

Clinical Signs of Tension Pneumothorax

Tachycardia, diminished breath sounds, tracheal deviation, and decreased blood pressure.

Surface Tension

Force that causes liquid molecules to form a cohesive layer; essential for alveolar stability.

Laplace's Law

Higher surface tension necessitates increased pressure for inflation; smaller radii require higher pressure.

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Description

Explore the concepts of lung compliancy through static and dynamic measurements. Understand the implications of high and low compliance on lung function as well as the methods used for measurement. This quiz will help clarify how these factors affect respiratory health.