pulmonary pa tho physiology

8/2/2019 Pulmonary Pa Tho Physiology

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Pulmonary Pathophysiology


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Reduction of Pulmonary Function

1. Inadequate blood flow to the lungshypoperfusion

2. Inadequate air flow to the alveoli -hypoventilation


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Signs and Symptoms of PulmonaryDisease

Dyspnea subjective sensation ofuncomfortable breathing, feeling short of

breath

Ranges from mild discomfort after exertionto extreme difficulty breathing at rest.

Usually caused by diffuse and extensiverather than focal pulmonary disease.


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Dyspnea cont. Due to:

Airway obstruction

Greater force needed to provide adequateventilation

Wheezing sound due to air being forcedthrough airways narrowed due toconstriction or fluid accumulation

Decreased compliance of lung tissue


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Dyspnea

Causes

1-Pulmonary embolism

2-Pulmonary edema

3-COPD 4-Pneumonia

5-Large pleural effusion

6-Obesity 7-Sever anemia

8-Malgnancy


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Signs of dyspnea:

Flaring nostrils

Use of accessory muscles in breathing

Retraction (pulling back) of intercostalspaces


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Cough

Attempt to clear the lower respiratorypassages by abrupt and forceful expulsionof air

Most common when fluid accumulates inlower airways


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Cough may result from:

Inflammation of lung tissue

Increased secretion in response tomucosal irritation

Inhalation of irritants

Intrinsic source of mucosal disruption suchas tumor invasion of bronchial wall

Excessive blood hydrostatic pressure inpulmonary capillaries Pulmonary edema excess fluid passes into

airways


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Cyanosis When blood contains a large amount of

unoxygenated hemoglobin, it has a dark red-blue color which gives skin a characteristicbluish appearance.

Most cases arise as a result of peripheralvasoconstriction result is reduced blood flow,which allows hemoglobin to give up more of its

oxygen to tissues- peripheral cyanosis. Best seen in nail beds


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Pain Originates in pleurae, airways or chest

wall Inflammation of the parietal pleura causes

sharp or stabbing pain when pleura

stretches during inspiration Usually localized to an area of the chest wall,

where a pleural friction rub can be heard

Laughing or coughing makes pain worse Common with pulmonary infarction due to

embolism


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Chest Pain

Other Causes

1-Cardiac

2-Osphageal 3-Trauma

4-Local infection


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Pleural Effusion

Causes

1-TB

2-Pnumonia 3-Cardiac Failure

4-Pulmonary infarction

5-Malgnent disease


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Hemoptysis

1-TB

2-Carcinoma

3-Pulmonary infarction

4-Pneumonia

Causes

5-Acute left ventricular failure

6-Leukemia and hemophilia

7-Mitral stenosis

8-Anticoagulant

9-Acute bronchitis

10-Foreign body


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Pneumothorax

Causes

1-Primary

2-Secondary:Tb,COPD,Pulmonaryinfarction, Carcinoma

3-Trauma


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Tests of Pulmonary Function


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Chest radiographs are among the

most common examinations of thepulmonary system.

Chest x-ray

Heart sizeLung mass

Pleural effusion

FibrosisPneumonia


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SpirometryThe diagnosis of COPD is confirmed by spirometry, a test that

measures breathing.

Spirometry measures the forced expiratory volume in one second

(FEV1) which is the greatest volume of air that can be breathedout in the first second of a large breath and the forced vital

capacity (FVC) which is the greatest volume of air that can be

breathed out in a whole large breath. Normally at least 70% of

the FVC comes out in the first second (i.e. the FEV1/FVC ratio is>70%).
http://en.wikipedia.org/wiki/Spirometryhttp://en.wikipedia.org/wiki/Spirometry


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In COPD, this ratio is less than normal, (i.e.

FEV1/FVC ratio is


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Severity of

COPDFEV1 % predicted

Mild Less than 80

Moderate 50-69

Severe 30-49

Very severe


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Ventilation/perfusion ratio (or V/Q ratio) : It is

defined as: the ratio of the amount of air reaching

the alveoli to the amount of blood reaching the

alveoli.

"V" - ventilation - the air which reaches the

alveoli

"Q" - perfusion - the blood which reaches thealveoli

These two variables constitute the main

determinants of the blood oxygen concentration.

In fact since V determines the quantity of oxygenmass reaching the alveoli per minute (g/min) and

Q expresses the flow of blood in the lungs (l/min),

the V/Q ratio refers to a concentration (g/l).
http://en.wikipedia.org/wiki/Ventilation_(physiology)http://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Pulmonary_alveolushttp://en.wikipedia.org/wiki/Perfusionhttp://en.wikipedia.org/wiki/Bloodhttp://en.wikipedia.org/wiki/Bloodhttp://en.wikipedia.org/wiki/Perfusionhttp://en.wikipedia.org/wiki/Pulmonary_alveolushttp://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Ventilation_(physiology)


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Pathophysiology

A lower V/Q ratio usually seen in chronic

bronchitis, asthma and acute pulmonaryedema.

A high V/Q ratio increases paO2 and decreases

paCO2. This finding is typically associatedwith pulmonary embolism (where blood

circulation is impaired by an embolus), but can

also be observed in COPD as a maladaptiveventilatory overwork of the undamaged lung

parenchyma.
http://en.wikipedia.org/wiki/Chronic_bronchitishttp://en.wikipedia.org/wiki/Chronic_bronchitishttp://en.wikipedia.org/wiki/Asthmahttp://en.wikipedia.org/wiki/Acute_pulmonary_edemahttp://en.wikipedia.org/wiki/Acute_pulmonary_edemahttp://en.wikipedia.org/wiki/Pulmonary_embolismhttp://en.wikipedia.org/wiki/COPDhttp://en.wikipedia.org/wiki/COPDhttp://en.wikipedia.org/wiki/Pulmonary_embolismhttp://en.wikipedia.org/wiki/Acute_pulmonary_edemahttp://en.wikipedia.org/wiki/Acute_pulmonary_edemahttp://en.wikipedia.org/wiki/Asthmahttp://en.wikipedia.org/wiki/Chronic_bronchitishttp://en.wikipedia.org/wiki/Chronic_bronchitis


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Sputum : It is usually in air passages

in diseased lungs, bronchi,

pneumonia It can be associate with

blood (hemoptysis) if a chronic

cough is present, possibly fromsevere cases of tuberculosis.


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ABG Arterial blood gas analysis

commonly performed for

individuals with suggested or

diagnosed pulmonary disease.

Provides valuable information aboutan individuals gas exchange & acid-

base status.


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Upper Respiratory Tract Infection

1-Common cold

2-Acute laryngitis

3-Acute Bronchitis 4-Infeunza


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Obstructive Pulmonary Disease

Definition


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Obstructive Pulmonary Disease

Characterized by airway obstruction that is

worse with expiration. More force is required toexpire a given volume of air, or emptying oflungs is slowed, or both.

The most common obstructive diseases areasthma, chronic bronchitis, and emphysema.

Many people have both chronic bronchitis and

emphysema, and together these are oftencalled chronic obstructive pulmonarydisease - COPD


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Major symptom of obstructive pulmonarydisease is dyspnea, and the unifying sign

is wheezing.

Individuals have increased work ofbreathing, V/Q mismatching, and a

decreased forced expiratory volume.

A h


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Asthma More intermittent and acute than COPD,

even though it can be chronic Factor that sets it apart from COPD is its

reversibility

Occurs at all ages, approx. half of allcases develop during childhood, andanother 1/3 develop before age 40

5 % of Adults and 7-10 % of children inU.S. have asthma


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.

Runs in families, so evidence genetics plays a

role. Environmental factors interact with inherited

factors to increase the risk of asthma and

attacks of bronchospasm Childhood exposure to high levels of allergens,

cigarette smoke and/or respiratory viruses

increases chances of developing asthma.


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Clinical manifestions

During remission individual isasymptomatic and pulmonary functiontests are normal

Dyspnea Often severe cough

Wheezing exhalation

Attacks usually of one to two hoursduration, but may be severe and continuefor days or even weeks.


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If bronchospam is not reversed by usual

measures, the individual is considered tohave severe bronchospasm or statusasthmaticus

If continues can be life threatening.

M t


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Management

Avoid triggers (allergens and irritants)

Patient education Acute attacks treated with corticosteroids

,oxygen and bronchodilator

Chronic management based on severity ofasthma and includes regular use of inhaledantiinflammatory medications corticosteroids,

Inhaled bronchodilators *** Immunotherapy allergy shots, etc.

COPD


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COPD

Pathological changes that cause reduced

expiratory air flow Does not change markedly over time

Does not show major reversibility in

response to pharmacological agents

Progressive


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Primary cause is cigarette smoking

Both active and passive smoking havebeen implicated

Other risks are occupational exposures

and air pollution

Genetic susceptibilities identified

Ch i B hiti


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Chronic Bronchitis Hypersecretion of mucus and chronic

productive cough for at least 3 months(usually winter) of the year for at least twoconsecutive years.

Incidence may be increased up to 20times in persons who smoke and more inpersons exposed to air pollution.

T t t


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Treatment Best treatment is PREVENTION because

changes are not reversible. Cessation of smoking halts progression of

the disease

Bronchodilators, expectorants, and chestphysical therapy are used as needed.

Acute attacks may require antibiotics,steroids and possibly mechanical

ventilation. Chronic oral steroids as a last resort.

Home oxygen therapy

E h


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Emphysema Abnormal, permanent enlargement of the

gas-exchange airways and destruction ofthe alveolar walls.

Obstruction results from changes in lung

tissue rather than mucus production andinflammation.

Major mechanism is loss of elastic recoil


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Major cause is cigarette smoking

Other causes are air pollution and

childhood respiratory infections


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Clinical manifestations

Dyspnea

Barrel chest

Minimal wheezing Prolonged expiration

Hypoventilation and polycythemia late in

the progression of the disease

Treatment


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Treatment Similar to chronic bronchitis

Stop smoking Bronchodilating drugs

Breathing retraining

Relaxation exercises

Antibiotics for acute infections

Severe COPD may require inhaled or oralsteroids, and home oxygen

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