Respiratory System 4 Flashcards by Jhaunte Braithwaite

What is spirometry?

This is a test used to assess pulmonary function

It provides information about lung volumes and capacities

This information can be used to identify patients with obstructive diseases, restrictive diseases or normal lung function

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What is tidal volume?

The volume of air inhaled or exhaled with each normal breath

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What is inspiration reserve volume(IRV)?

The volume of air inhaled at the end of a normal tidal inspiration

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What is expiratory reserve volume(ERV)?

The volume of air within the lungs that can be exhaled after the end of a tidal exhalation

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What is the residual volume?

The air remaining in the lungs after a maximal expiration (this volume of gas cannot be expelled, and cannot be measured by spirometry)

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What are functional Residual Capacity( FRC)?

The total volume of air remaining in the lungs at the end of a tidal exhalation

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What is the function of total lung capacity(TLC) ?

The volume of air in the lungs at the end of a maximal inspiration

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What is a vital capacity(VC)?

The volume of air exhaled from maximal inspiration to maximal exhalation; maximum expiration. When done with force this volume is termed the forced vital capacity (FVC)

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What is forced expiratory volume in 1 second (FEV1)?

The volume of air exhaled in the first second of a FVC second

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What is an obstructive disorder?

Expiratory flow rate is significantly decreased resulting in decreased FEV 1 and FVC
The FEV1/FVC ratio is low

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What is a restrictive diso4der?

Lung inflation is decreased resulting in decreased FEV 1 and FVC
The FEV1/FVC ratio is normal or increased

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What is Forced expiratory flow (FEF25-75)?

Forced expiratory flow

Represents the expiratory flow rate over the middle half of the FVC (between 25% and 75%)
Small airway obstruction may be present even when the FEV1/FVC % is above the lower limit of normal
FEF25-75 has the greatest sensitivity for the detection of early airflow obstruction

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How much is FEV 1 normally?

Normally FEV 1 should be about 80% of total volume expired(FVC)

FEV1/FVC ratio= 4.5 L/5.5 L*100= 80%

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Differentiate restrictive and obstructive in the flow/volume loop

Obstructive loop- scooped out appearance common in emphysema

Restrictive loop- steep expiratory limb

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Differentiate restrictive and obstructive pulmonary diseases

Obstructive- expiratory flow rate is decreased,
Restrictive- lung inflation is decreased

Obstructive- airway occlusion, air trapping
Restrictive- intrinsic- lung tissue, extrinsic- chest wall, pleura or neuromuscular

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Give examples of obstructive diseases

Obstructive Bronchitis
Emphysema
Asthma

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Give examples of restrictive disease

pulmonary fibrosis
IRDS
Scoliosis

What is COPD?

Chronic obstructive pulmonary disease (COPD)

Combination of chronic bronchitis, emphysema and asthma
The most common chronic lung disease in the United States
Commonly caused by cigarette smoking
The classical feature is decreased airflow due to chronic obstruction of the small airways
Results in a decrease in FVC, FEV1 and FEV1/FVC ratio
In severe cases of air is trapped in the lungs during forced expiration

What is the partial pressure?

Atmospheric air= mixture of gases

Dalton’s law: total pressure exerted by gas mixtures is equal to the sum of partial pressures all the component gases

The pressure exerted by an individual gas in a mixture of known gases

Expressed in terms of its dry gas concentration

What is fractional concentration?

The percentage or concentration of a gas in a mixture of gases

Why is partial pressure of water vapor taken into consideration when calculating partial pressure in trachea?

Air is humidified in the conducting zone therefore, the partial pressure of water vapor (Ph2o) must be taken into consideration

Inspired Ph2o is not altered by altitude

What is Henry’s law and partial pressure?

in venous blood the drop in PO2 is greater than the rise in PCO2
Water vapor pressure depends on temperature, at 37 degrees Celsius max 47 mm Hg

How does air composition of air change with altitude?

With increasing altitude the composition of air remains the same but the barometric pressure decreases

Mount Everest is 8848 m high

The barometric is 253 mm Hg

PO2- 53 mm Hg

The fractional concentration of oxygen doesn’t change but, the PO2 decreases

What is minute ventilation?

Volume of air moved in or out lungs per unit time
Minute ventilate= total ventilation

Ve= Vt x f

Vt= tidal volume- typically~500 ml
f- breathing frequency -vtypically 12/min

Therefore minute ventilation= (0.5 liters)x12/min= 6 liters per minute

Air is distributed into two compartments...

1. Dead space (VD) in which gas exchange cannot occur 2. Alveolar space where there is gas exchange Wasted air: air that does participates in gas exchange

What is dead space( Vd)

Volume 0f inhaled air that does not participate in gas exchange Regions of no gas exchange include: 1. Conducting airways: an atomic dead space 2. Alveoli with no perfusion - alveolar dead space Physiological dead space= anatomical dead space+ alveolar dead space

What is pulmonary embolism?

Emboli is lodged in a branch of the pulmonary artery - Inadequate pulmonary blood flow (poor perfusion) - Inadequate perfusion leads to inadequate exchange of gas (ventilation in excess of perfusion) - Increased I; the physiological dead space

What is alveolar ventilation?

Volume of air delivered to the respiratory zone per minute - The fraction of inspired air that participates in gas exchange - Alveolar ventilation is dependent on depth of breathing (tidal volume) and rate of breathing(frequency) - Increasing the depth of breathing is far more effective in elevating alveolar ventilation than is increasing the frequency or rate of breathing

How gas partial pressures and ventilation related?

Alveolar ventilation is usually evaluated in terms of arterial PCO2 - Increased alveolar ventilation beyond that required to meet metabolic needs is termed hyperventilation - Hyperventillation leads to hypocapia (PaCO2 is below normal) - Decreased alveolar ventilation below that required to meet metabolic needs is termed hypoventilation - Hypoventilation leads to decrease in PaO2 and hypercapnia (e”levated in PaCO2)

What are the factors determining alveolar oxygen partial pressure( PAO2)?

Altitude- the fractional concentration of oxygen doesn’t change but, the PO2 decreases with an increase in altitude Supplemental oxygen- providing a high PO2 increases PAO2 Metabolic activity- high metabolic activity uses oxygen and would push PAO2 down Ventilation- increasing ventilation keeps PAO2 elevated

What are the factors affecting PACO2?

PACO2- alveolar partial pressure of CO2 PaCO2- arterial partial pressure of carbon dioxide Carbon dioxide is a highly diffusable gas, alveolar PCO2 is assumed to be equal to arterial PCO2 -In the steady state, carbon dioxide excreted by the lungs equals that produced from metabolism Therefore, PACO2 is inversely proportional to alveolar ventilation (PaCO2 is also inversely proportional to alveolar ventilation/VA)

What is hypocentilation?

Decreased alveolar ventilation with increased PaCO2

What is hyperventilation?

Increased alveolar ventilation with decreased PaCO2

What is hypercapnia?

Increased carbon dioxide in blood

What is Eupnia?

Normal breathing

What is hypopnea?

Decreased ventilation in response to lowered metabolic CO2 production

What is hyperpnea?

Increased ventilation in response to increased metabolic CO2 production

What is tachypnea?

Increased frequency of breathing. Ventilation may or may not change depending on tidal volume

What is Dyspnea?

Shortness of breath/ labored breathing (ill breathing)

What is apnea ?

‘A’ prefix= without Temporary cessation of breathing