Dasgupta - Respiratory Mechanics Flashcards by Dylan Weaver

Venous blood gas tells you ____ about respiratory function

Nothing

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The volume of air that you cannot get out of the lung at zero pressure

Residual volume

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Flow in large airways is _____

Fast and turbulent

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Lesions inside the thoracic cage will be affected to a greater extent by?

Expiration

Trachea tumor is example

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destroys the entire alveolus uniformly and is predominant in the lower half of the lungs. generally is observed in patients with homozygous alpha1-antitrypsin (AAT) deficiency or Ritalin-induced lung emphysema. This condition called the Ritalin lung is seen in people who abuse Ritalin. They crush the pills and then inject them intravenously. This pills contain fillers which are insoluble particles. These particles block the fine blood vessels of the lung. Although the lung has millions of blood vessels, routine intravenous administration of Ritalin can block sufficient blood vessels to cause pulmonary hypertension and damage lung tissue to cause _____ emphysema. This is also observed in people who Ritalin by inhalation. In people who smoke, focal ____ emphysema at the lung bases may accompany centrilobular emphysema.

Panacinar emphysema

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Normal spontaneous breathing

Eupnea

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Low pO2 in ABG

Hypoxemia

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The volume of air present in the lungs at the end of passive expiration. At _____ the opposing elastic recoil forces of the lungs and chest wall are in equilibrium and there is no exertion by the diaphragm or other respiratory muscles

Functional residual capacity

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A complex mixture of phospholipids (90%) and protein (10%) secreted by type II alveolar cells.

Functions to lower surface tension by inserting itself between water molecules along surface

Pulmonary surfactant

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What are the two kinds of dead space?

Anatomical dead space (large airways w/o alveoli)

Physiological dead space (alveoli that are ventilated but not perfused and the anatomical dead space values combined)

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If alveolar ventilation is doubled (hyperventilation) but CO2 production remains the same, the alveolar and arterial PCO2 will be _____

Halved

This raises blood pH and causes respiratory alkalosis

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In the absence of surfactant (premature infants) lung recoil forces are —______

Very high

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The compliance measurements made by spirometry measure ?

Both lung and chest wall compliance (Total compliance)

[if dx can assume chest wall is normal, then you can assume this measure is lung compliance]

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The pressure in the lung due to gravity is more negative at the ____

Top

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The chest wall exerts and elastic recoil force to _____

Expand the lung

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Decrease of respiratory rate

Bradypnea

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Expiration is low and prolonged because of high compliance and dynamic collapse in

Obstructive disease

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Normal venous blood gas bicarb

24-30meq / mL

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Obstructive disease is characterized by?

High airway resistance

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Amount of air in lungs which can’t be exhaled or pushed out of lungs

Residual volume (RV)

In adults; 1-2 liters

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Obtructions not effected by inspiratory or expiratory effort

Fixed obstructions

[caused by foreign bodies or scarring which makes region of airway too stiff to be affected by transmural pressure gradient]

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Bernoulli’s effect:

The faster the airflow, the lower the pressure

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The greatest airway resistance is in the ____ airways

Largest

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Lung compliance alone can be measured by using ?

Esophageal balloon

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Normal ABG bicarb

22-26 meq/mL

_____ % of barometric pressure is exerted by oxygen and ____ % is exerted by N2 Molecules

21 79

Inflammation of the pleural cavity

Pleuritis

Compliance:

Change in volume _______________ Change in pressure

Normal venous blood gas PO2

38-42mmHg

Restrictive lung diseases are characterized by :

Low lung compliance or increased stiffness of the lung and increased lung recoil

The pattern for FEV1 in restrictive lung disease is described as?

Witch hat shaped

Amount of air that can be exhaled as quickly during a forced exhalation Normal 4600mL

Forced vital capacity (FVC)

Greatest flow velocities of air are observed in ________ airways

Large

If alveolar ventilation is halved (Hypoventilation) but CO2 production remains the same, the alveolar and arterial PCO2 will ____

Double This lowers blood pH and causes respiratory acidosis

Main contributor to lung recoil is ?

Surface tension

A rapid rate of breathing

Tachypnea

Reasons for a decrease in compliance of a lung

Interstitial lung disease (fibrosis) Loss of surfactant [remember this is things making it harder to fill] {right shift on PV curve and TLC is reduced}

High pCO2 in ABG

Hypercapnia

Increased depth (volume) of breathing w/ or w/o increased frequency

Hyperpnea

“Accessory muscles” of the shoulder girdle are not involved in quiet breathing, but are involved in ______

Breathing during exercise Coughing Sneezing

Volume of air in the lung when the lung and chest wall have equal recoil force

Functional residual capacity (FRC) Normal: 2300mL

The lungs elastic recoil forces act to -____

Collapse the lung

Dead space Volume =

150mL

Primary surface tension lowering pulmonary surfactant

DPPC Dipamitoyl phosphatidyl choline

FEV1 should be about _____ % of FVC

80-100%

When room air is drawn into airways, what other species of gas is added to the mix to change the partial pressure?

Water vapor

The pressure difference inside and outside of a given system

Transmural pressure (Ptm)

During gas exchange, the oxygen consumption is _____ mL/min and the CO2 production is ____ mL / min

250 200

Lungs are stiffer and only a small volume is inhaled and expired quickly in

Restrictive disease

Specific compliance =

Compliance / functional residual capacity

The air which a person breathes but is not used for gas exchange. It fills respiratory passages like the nose pharynx and trachea

Dead space volume (Vd) Normal adult value (150mL)

Dyspnea which occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair

Orthopnea

Normalizes compliance value to the FRC

Specific compliance

Volume of air inspired or expired with each breath

Tidal volume Normal adult (500mL)

Pneumothorax will cause a mediastinum shift to the

Side opposite the collapse

Partial or total collapse of the lung without air entering the pleural space

Atelectasis

Amount exhaled in the first second. | Should be 80% of FVC

FEV1 Forced expiratory volume in 1 second Normal: 3800 liters

The lowest part of the lung is ventilated _____ than the uppermost part

More (This holds true whether standing or supine, and does not refer to the apex of the lung, but the part of the lung that is lower to earth)

Increases in age lead to a ______ in FRC

Increase in FRC because there is a decrease in elastic recoil of lung and an increase in compliance leading to increase in FRC

Obstructions in which the cross-sectional area of the obstruction is dependent on inspiratory or expiratory effort

Variable obstructions

As airway size decreases, velocity of flow is ___________

Increased

What is the methacholine challenge test used to detect?

Hyperactive airways. It is a sensitive test for asthma

Lying down decreases functional residual capacity by _____

10-15%

Forced exhalation uses what extra muscles?

Abdominal muscles (internal oblique, rectus abdominus, and transverse abdominus these push gut into the diaphragm) Internal intercostals (move ribs down and back

Difficulty breathing that the individual is aware of

Dyspnea

Respiratory problems associated with kyphoscoliosis?

Underventilation of the lungs —> FRC and RV lower

Laplace’s Law states that Pressure is inversely proportional to _______

Radius

Normal arterial blood pH

7.35 - 7.45

Factors involved in lung elastic recoil forces.

Lung tissue elastic recoil (from collagen and elastin) Surface tension forces (each alveolus is water lined and surface tension forces reduce size of surface)

What is a shunt through the lung?

A vascular pathway in which there is no gas exchange

Normal arterial blood gas PO2

80-100mmHg

Volume of air left in unperfused alveoli which is a measure of lung disease or ventilation-perfusion mismatch

Alveolar dead space

Alveolar ventilation is always ______ than total ventilation

Less Because it subtracts the volume of dead space in the lung and therefore considers only the volume of air actually participating in gas exchange.

is the most common morphological subtype of emphysema This affects the central portion of secondary pulmonary lobules, around the central respiratory bronchioles, typically involving the superior part of the lungs or lobes. It begins in the respiratory bronchioles and spreads peripherally. this form is associated with long-standing cigarette smoking, occupational exposure to chemicals, dust etc. and predominantly involves the upper half of the lungs.

Centrilobar emphysema

Flow in small airways is ____-

Slow and laminar

Type of pneumothorax in which there is air in the pleural cavity but it does not accumulate with every breath

Non-tension pneumothorax

Complete absence of spontaneous ventilation

Apnea

Doubling radius increases surface tension of alveoli by a factor of _

Normal ABG PCO2

35-45mmHg

The measurement of physiological dead space with Bohr’s method is based on which 3 assumptions:

The content of CO2 in atmosphere is 0.04% and negligible All expired CO2 comes from alveoli All CO2 comes from the ventilated and perfused alveoli and not from dead space

Complete atelectasis is accompanied with a mediatinum shift to the

Side of the collapse

Why is tension pneumothorax a medical emergency?

Because the air that accumulates with each breath puts pressure on the organs of the chest

The intrapleural pressure is ______

Negative [subatmospheric]

Type of pneumothorax due to medical procedure

Iatrogenic pneumothorax

Volume of air in lungs after the maximum inspiratory effort

TLC Total lung capacity

What molecules that make up the physical lung will cause lung tissue elastic recoil forces which act to deflate the lung

Elastin and collagen

Surfactant has a hydrophilic and hydrophobic region, allowing it to reside _________

At the air-water interface

Venous blood gas pH | Normal

7.34 - 7.37

O2 exchange takes place where?

Alveolar sacs | Alveolar ducts These are the last 4 divisions of the airways

Forced exhalation in emphysema patients can cause

Airway collapse Which leads to increased resistance and decreased exhalaltion

Type of pneumothorax in which air accumulates within the chest with every breath

Tension pneumothorax

The reduced area in a PEF graph suggests

Some ventilatory limitation

Airways or alveoli being attached to their neighbors

Tethering

Rate of alveolar ventilation depends on:

Respiratory rate Tidal volume Dead space volume

What do surgical removal of a lobe, obesity, pulmonary vascular congestion, and decreased pulmonary surfactant do to the pressure - volume curves ? (PV curve, pressure on x axis)

Right shift

Examples of variable extrathoracic lesions:

Vocal cord paralysis, fat deposits, obstructive sleep apnea

Normal venous blood gas PCO2

44-46mmHg

Reasons for an increase in compliance

Emphysema Loss of elastic fibers (w/ age sometimes) Lung becomes easier to inflate PV curve shifts left and TLC is increased

Sitting or standing leaning forward in respiratory distress. With upper body with hands on knees for support

Tripod stance

An abnormally low FEV1 is highly diagnostic of a patient with

Obstructive pulmonary disease | FEV1 basically tells you airway resistance, because max expiratory flow rates are largely effort INdependent

Compared to a person who is standing, the FRC of a supine person is ______

Less | Gut is pushing into diaphragm in supine

What happens to FRC as a person grows older?

FRC increases

Obstructions in which the cross-sectional area of the obstruction is dependent on inspiratory and expiratory effort

Variable obstructions

Variable intrathoracic lesions will be affected to a greater extent by _________

Expiration

Dasgupta - Respiratory Mechanics Flashcards

(104 cards)