Pulmonary System

Pulmonary system:

Two lungs 3 lobes on right 2 lobes on left

Their airways Blood vessels that serve them Chest wall (thoracic cage)

Conducting airways

allows air into and out of the gas exchange structures of the lung

upper airway nasorpharynx oropharynx

lined with ciliated mucosa that warms and humidifies inspired air and removes foreign particles

nose breathing more effective in warming and humidifying

Pulmonary Defense Mechanisms

Upper respiratory tract mucosa Nasal hairs Mucus Cilia Alveolar macrophages Irritant receptors in the nose Irritant receptors in the trachea and

large airways

Impaired Defense Mechanisms Any nursing or medical intervention

that interferes with the airways will impair the defense mechanisms Risk for infection Ineffective breathing patterns Ineffective airway clearance

larynx connects upper and lower airways Vocal cords, supporting cartilage, muscles

that help with swallowing Trachea- connects larynx to bronchus bronchi- carina where bronchi branch

Gas Exchange airways

respiratory bronchioles- 3 layers: epithelial lining, smooth muscle lining and the connective tissue layer

Epithelial lining consists of the mucus secreting goblet cells and the ciliated cells

alveolar ducts alveoli- primary gas-exchange units of

the lung where oxygen enters the blood and carbon dioxide is removed.

Alveoli Type 1 provide structure Type 2 secretes surfactant

Surfactant- a lipoprotein that coats the inner surface of the alveolus and lowers alveolar surface tension at the end-expiration preventing lung collapse.

Blood Flow Through the Heart

Pulmonary and bronchial circulation The pulmonary circulation

1. facilitate gas exchange 2. delivers nutrients to lung tissue 3. acts as a reservoir for the left ventricle 4. serves as a filtering system that removes clots, air, and other

debris from the circulation

Pulmonary Circulation

Entire cardiac output from the right ventricle goes into the lung

Pulmonary circulation has a lower pressure and resistance

Each pulmonary vein drains several pulmonary capillaries

Pulmonary veins have no valves in them

There is also deep and superficial lymphatic's in this system

pulmonary circulation has a lower pressure and resistance than the systemic circulation

about 1/3 of the pulmonary vessels are filled with blood at any given time-

gas exchange occurs at the alveolocapillary membrane

lymphatic system keeps the lung free of fluid

Chest wall and Pleura

protects muscles, along with the diaphragm

perform the muscular work of breathing the pleura is a serous membrane that

adheres firmly to the lungs and then folds over itself and attaches firmly to the chest wall. Visceral pleura- membrane covering the lung Parietal pleura- lining of the thoracic cavity Pleural space

Function of pulmonary system Ventilation Breathing Diffusion Perfusion compliance

Ventilation- is the mechanical movement of gas or air into and out of the lungs

Adequate ventilation is necessary to maintain normal PaCO2 levels, diseases that limit ventilation result in CO2 retention

Oxygen Transport

Consist of Lungs and CV system

Ventilation

Perfusion

Carrying Capacity

Pulmonary Function Tests

Measure lung volumes and flow rates

Used to diagnose lung disease, effective treatment, not done that often in each client, maybe one time a year

Ventilation Continued

CO2 is the gaseous form of carbonic acid H2CO3 that is produced by cellular metabolism

This is eliminated to maintain a normal arterial CO2 of about 40 mmHg and normal acid base balance

You need adequate ventilation to maintain this

Chemo receptors

Help to monitor pH, PaCO2, PaO2 of arterial blood Central chemo receptors monitor pH by sensing

changes of pH in CSF If alveolar ventilation is inadequate, PaCO2

increases and diffuses across the BBB until PCO2 in the blood and CSF reach equilibrium

Central receptors stimulate the respiratory center to increase the depth and rate of ventilation, this causes the CO2 to return to normal, if possible

Over time and in the presence of long term disease processes, the receptors become insensitive to changes

Neurochemical control of Ventilation

breathing is usually involuntary

voluntary breathing is necessary for certain things

respiratory center in the brain stem controls respiration

pattern of breathing can be influenced by what?

Peripheral Chemo receptors Not as sensitive to changes in CO2

and pH

Primarily sensitive to oxygen levels in the blood

PO2 must drop well below normal before the peripheral sensors act

Ventilation

Centrally controlled by the medulla

The phrenic nerve, innervates the diaphragm and intercostal muscles

Chemo receptors are in the carotid and aortic bodies, the brainstem.

If additional O2 is needed, what happens?

Successful ventilation involves the mechanics of breathing The interaction of forces and

counterforces involving the muscles of inspiration and expiration

Alveolar surface tension Elastic properties of the lungs and chest

wall resistance to air flow through the

conducting airways

major muscle of inspiration is the diaphragm

when the diaphragm contracts, it moves downward in the thoracic cavity, creating a vacuum that causes air to flow into the lungs

- no major muscle of expiration

The Alveoli

Represent Type 1 and Type II epithelial cells Type I form the alveolar walls, where gas

exchange occurs

Type II are the cells that produce surfactant which allows alveoli to expand uniformly and prevents collapse during expiration

Alveolar Surface Tension

In a sphere such as the alveoli, surface tension makes expansion difficult

Alveolar ventilation is made possible by surfactant

Surfactant has a detergent like effect

Surfactant is missing in premature infants and becomes deleted in severe lung damage in adults

Gas Transport

There are four steps Ventilation of the lungs Diffusion of O2 from the alveoli Perfusion of the systemic capillary with

oxygenated blood Diffusion of the CO2 from the cells into

the systemic capillaries

Transport of carbon dioxide

diffusion of carbon dioxide from the cells into the systemic capillaries

perfusion of the pulmonary capillary bed by venous blood

diffusion of carbon dioxide into the alveoli

removal of the carbon dioxide from the lung by ventilation

Carbon dioxide

is more soluble in plasma than oxygen

diffuses readily from tissue cells into plasma

Compliance is the ease with which the lungs and chest wall expand during inspiration lung compliance is based on adequate surfactant

- chest wall expansion depends on flexibility

Elastic recoil is the lungs returning to the resting state after inspiration Accessory muscles The elastic recoil forces of the lungs and chest

wall are in opposition and pull on each other creating the negative pressure of the pleural space

Ventilation and Perfusion The amount of gas exchange depends on the

amount of air in the alveoli and the amount of blood in the capillaries

The amount of air refers to ventilation

The amount of blood refers to perfusion

The ratio of ventilation to perfusion is called the V/Q ratio, the effectiveness of gas exchange

In the normal lung, the alveoli receive air at about 4L/minute

The capillaries supply blood to the alveoli at a rate of 5L / minute

This creates a V/Q ratio of 4:5

V/Q mismatch

This occurs from V/Q dysfunction or altered lung mechanics

It accounts for most of the impaired gas exchange in respiratory disorders

Ineffective gas exchange can affect multiple body systems as a result of impaired tissue perfusion

Outcomes of ineffective gas exchange Shunting

Reduced ventilation to a lung unit Unoxygenated blood reaches the left side of

the heart Dead-space ventilation

Reduced perfusion to a lung unit Pulmonary embolism, pulmonary infarct,

cardiogenic shock

Conditions Affecting Chest Wall Movement Pregnancy Obesity Musculoskeletal Abnormalities Trauma Muscle Disease Nervous System Disease Burns

Developmental Factors

Prematurity – insufficient Surfactant Infants and Toddlers – Increase in

URI, 2nd hand smoke, aspiration School Age / Adolescents – Smoking Young Middle Adult – Unhealthy diet,

poor lifestyle, stress, drugs, smoking Older Adults – normal aging process

Behavioral Factors

Nutrition Exercise Smoking Environmental Anxiety

Atelectasis

The collapse of the alveoli that prevents normal respiratory exchange of CO2. As alveoli collapse, less of the lung can be ventilated

Alt. Respiratory Patterns Tachypnea Bradypnea Apnea Kussmal Cheyne-Stokes Biot’s

Signs and Symptoms

Hyperventilation

Hypoventilation

Hypoxia

Tachycardia Headache *Restless

SOB Lethargy Cyanosis

Chest Pain Disorientation Dyspnea

Dizziness Cardiac Dysrhythmias

* ↑ HR

Blurred Vision Coma *Anxiety

Lab Tests

CBC Chemistry Arterial Blood Gas

Provides information about diffusion of gas across the alveolar-capillary membrane and adequacy of tissue oxygenation.

Looks at hydrogen ion concentration, PCO2, PO2, SAO2

Classifications of pulmonary disease

acute chronic obstructive restrictive infectious noninfectious

Terms

dyspnea- subjective sensation of uncomfortable breathing

feel like not able to get enough air breathlessness short of breath labored breathing

Orthopnea Dyspnea when lying down

S/S of Pulmonary Disease

Dyspnea- At rest On exertion Orthopnea Paraxsysmal nocturnal (PND)

paroxysmal nocturnal dyspnea (PND)- results from fluid in the lungs caused by the redistribution of body water when person is lying down. Can by seen in some individuals with left ventricular failure who wake up gasping for air.

Objective signs of dyspnea

Use of accessory muscles Retraction of the intercostal spaces Flaring of nostrils

Normal breathing

eupnea is rhythmic and effortless ventilatory rate is 12- 20 breaths

per minute

Abnormal breathing patterns kussmaul respiration (hyperpnea)

slightly increased ventilatory rate large tidal volumes no expiratory pause

Cheyne-stokes respirations Alternating periods of deep and shallow breathing Apnea (no breathing) lasts from 15 – 60 seconds This is followed by ventilations that increase in volume

until a peak is reached Then ventilation decreases again to apnea

Hypoventilation

is inadequate alveolar ventilation in relation to metabolic demands Build up of CO2 called hypercapnia

(PaCO2) Results in respiratory acidosis that can

affect the function of tissues in the body

hyperventilation

is alveolar ventilation exceeding metabolic demands lungs remove CO2 faster than it is

produced results in decreased PaCO2 or

hypocapnia. Occurs in anxiety and acute head

injuries

cough is a protective reflex that cleans the lower airways by an explosive expiration Need to consider cancer when patients

have chronic cough Hemoptysis is the coughing up of

blood or bloody secretions Infection or inflammation Tuberculosis Lung abscess Cancer

cyanosis

is a bluish discoloration of the skin and mucous membranes caused by increasing amounts of desaturated or reduced hemoglobin in the blood lack of cyanosis does not necessarily mean the

there is normal oxygenation in adults cyanosis is not evident until severe

hypoxemia is present and is not a good indication of respiratory failure (late sign)

clubbing is the selective bulbous enlargement of the distal segment of a digit

Hypercapnia-

increased carbon dioxide in the arterial blood ( increased PaCo2) caused by hypoventilation of the alveoli- drugs that depress the respiratory center- diseases of the medulla- abnormalities of the spinal conducting pathways- diseases of the neuromuscular junction or of the respiratory muscles themselves

- large airway obstructions, sleep apnea- increased work of breathing or physiologic

dead space ( emphysema)- acidosis can result

Hypoxemia

Decreased oxygen content (PO2) of inspired gas

Hypoventilation Diffusion abnormalities Abnormal ventilation-perfusion ratios Pulmonary right-to-left shunt (blood passes

through portions of the pulmonary capillary bed that receive no ventilation because of an obstruction)

an area where alveoli are ventilated but not perfused is termed alveolar dead space

Acute respiratory failure defined as inadequate gas exchange or

hypoxemia PaO2 <50 mm Hg and PaCO2>50 mm

Hg pH < 7.25 can result from direct injury to the

lungs, airways or chest wall indirectly from injury to another body

system such as the brain or spinal cord can result due to patient having

chronic pulmonary disease

if the respiratory failure is primarily hypercapnic, there is inadequate alveolar ventilation and the individual must receive ventilatory support – mechanical ventilator or bag-valve mask

if the respiratory failure is primarily hypoxemic, it is the result of inadequate exchange of oxygen between the alveoli and the capillaries and the individual will need supplemental oxygen therapy.

Many have combination

Pulmonary edema

excess water in the lung predisposing factors

heart disease (most common) acute respiratory distress syndrome inhalation of toxic gases (cellular injury) blockage in the lymphatic system --hydrostatic pressure push exceeds

oncotic pressure (which holds fluid in the capillary) fluid moves out into the interstitium or interstitial space

Clinical manifestations - dyspnea- hypoxemia- increased work of breathing- inspiratory crackles (rales) - pink frothy sputum

treatment is to find underlying cause and treat it

Pulmonary Edema

Pulmonary Edema

Treatment

Aspiration

is passage of fluid and solid particles into the lung

tends to occur in those whose normal swallowing mechanism and cough reflex are impaired

predisposing factorsaltered level of consciousness due to

substance abusesedationseizure disorderscerbrovascular accidentmyasthenia gravis (neuromuscular disease)Guillain -Barre syndrome (inflammation of

nerves)the rate of deaths resulting from aspiration-caused

pneumonitis (localized lung inflammation) is greater than 50%

Atelectasis

is the collapse of lung tissue Two types:

- compression atelectasis - Absorption atelectasis

Signs and symptoms- dyspnea- cough- fever- leukocytosis

tends to occur after surgery- don’t breath deep due to pain or change positions so viscous secretions pool in dependent portions of the lung

1. walk2. cough and deep breath3. Incentive spirometer

Pneumothorax

is the presence of air or gas in the pleural space

caused by rupture in the visceral pleuraor the parietal pleura and chest wall

destroys the negative pressure of the pleural space

lung collapses open pneumothorax (communicating

pneumothorax)

tension pneumothorax site acts a one-way valve permits air in on inspiration prevents its escape by closing up

during expiration more air moves in the pleural space,

air pressure in the pneumothorax begins to exceed barometric pressure

life threatening deterioration occurs quickly

Signs and symptoms - hypoxemia - dyspnea - hypotension Spontaneous pneumothroax - Sudden pleural pain - Tachypnea - Mild dyspnea

Pleural effusion

is the presence of fluid in the pleural space source of the fluid is usually blood or lymphatic

vessels can be an abscess or lesion draining into the space pleura is relatively permeable membrane and fluids

can cross into the pleural space does not cause the lung to collapse can be transudative (watery) or exudative (high

white cell count) small amounts can be drained by lymphatic system Thoracentesis (needle aspiration) may need to be

done for larger effusions

Empyema infected pleural effusion, usually pneumonia

first signs and symptoms

cyanosis, fever cough tachycardia pleural pain breath sounds decreased over the site of the

empyema Antibiotics Thoracentesis Chest tube Pleurisy (pleuritis) is inflammation of the pleura

Pulmonary fibrosis

is excessive amount of fibrous or connective tissue in the lung can be caused by healing after active

disease inhalation of harmful substance

causes marked loss of lung compliance lungs become stiff very poor prognosis

Acute Respiratory Distress Syndrome (ARDS)

characterized by acute lung inflammation diffuse alveolocapillary injury with

noncardiogenic pulmonary edema affects about 200,000 to 250,000 people per

year in the US most survivors have almost normal lung

function 1 year after the acute illness caused by lung injury

most common causes sepsis multiple trauma pneumonia burns aspiration pancreatitis drug overdose smoke inhalation

injure the alveolcapillary membrane and produce severe pulmonary edema, shunting and hypoxemia

Signs and symptoms

rapid shallow breathing respiratory alkalosis dyspnea decreased lung compliance hypoxemia unresponsive to oxygen therapy diffuse alveolar infiltrates seen on chest

radiographs

progressive symptoms: 1. hyperventilation 2. respiratory alkalosis 3. dyspnea and hypoxemia 4. metabolic acidosis 5. Respiratory acidosis 6. further hypoxemia 7. hypotension, decreased cardiac output,

death goal is to maintain adequate oxygenation

and ventilation while preventing infection smokers are at risk for postoperative

respiratory failure

Most common postoperative pulmonary problems are

- atelectasis- pneumonia- pulmonary emboli- pulmonary edema

Obstructive Pulmonary Disease

airway obstruction that is worse with expiration

more force needed for expiration most common are

asthma bronchitis emphysema

Asthma

is a chronic inflammatory disorder of the airways

- occurs at all ages- familial disorder- genetics may play a role

- environmental factors interact with inherited factors to increase the risk

Three phases 1. remission 2. partial remission 3. attacks

treatment- education- avoid triggers- oral steroids - inhalers (bronchodilators)

COPD (chronic obstructive pulmonary disease)

Defined as pathologic lung changes with airflow limitation that is not fully reversible

chronic bronchitis- hypersecretion of mucus and chronic productive cough for at least 3 months of the year for 2 consecutive years

incident increases with smokers those exposed to air pollution repeated infections are common major health problem for the elderly

Treatment- stop smoking- bronchodilators- expectorants- chest physical therapy

Acute bronchitis

acute infection or inflammation of the airways or bronchi

commonly follows a viral illness and is usually self-limiting

Emphysema

abnormal permanent enlargement of the gas exchange airways with destruction of alveolar walls

obstruction is the result of changes in lung tissue

loss of elastic recoil smoking major cause primary emphysema linked to deficiency of

enzyme alpha 1-antitrypsin destruction of alveolar septa which

eliminates portions of the pulmonary capillary bed

because expiration becomes difficult of loss of elastic recoil reduces the volume of air that can be expired passively

hyperinflation of alveoli produce large air spaces (bullae) and air spaces adjacent to pleurae (blebs)

bullae and blebs are not effective in gas exchange and there is a ventilation/perfusion mismatch and hypoxemia

late disease develop hypercapnia

signs and symptoms- dyspnea- productive cough- smoking history- barrel chest

Treatment and evaluation- pulmonary function tests- chest x ray- CT scan- ABG (arterial blood gases)- may need home O2- respiratory inhalers- lung reduction or lung transplant

may be needed

Respiratory tract Infection

most common cause of short-term disability in the US

a. colds

b. pharyngitis

c. Laryngitis

- most infections are in the upper respiratory tract

- infections of the lower tract most often in individuals whose normal defense mechanisms are impaired

Pneumonia is an acute infection of the lower respiratory tract

caused by bacteria, viruses, fungi, protozoa or parasites

6th leading cause of death in the US elderly are more at risk risk factors

age immunocompromised lung disease alcoholism smoking endotracheal intubation malnutrition immobilization altered consciousness

Community acquired Nosocomial

High mortality rate More opportunistic infections

streptococcus pneumoniae most common community acquired pneumonia and has a low overall mortality

legionella- contaminates cooling systems and water supplies

pseudomonas aeruginosa and staphylococcus aureus most common nosocomial pneumonias

HIV and transplant patients susceptible to pneumocystis carinii, and fungal infections Hard to treat High mortality rate

Signs and symptoms - fever - chills - productive or dry cough- pleural pain- sometimes dyspnea- hemoptysis (sometimes)

Evaluation

elevated WBC Chest x-ray shows infiltrates Need sputum culture to identify the

organism May need bronchoscopy or lung biopsy Blood cultures

Treatment

Antibiotics for bacterial Viral is treated with supportive therapy Adequate hydration Supplemental oxygen Respiratory treatments Incentive spirameter

Tuberculosis (TB)

is an infection caused by Mycobacterium tuberculosis, an acid-fast bacillus that usually affects the lungs but can be in other body systems

risk factors emigration of infected individuals from

certain countries crowded institutional settings homelessness substance abuse lack of access to medical care all have

contributed to spread of TB

Transmitted via airborne droplets The body walls off the infection It can lay dormant in the body for

life If immune system is impaired,

however, or if live bacilli escape into the bronchi, active disease occurs and may spread in the body

Signs and Symptoms

may be asymptomatic if symptoms do appear, it can be

gradually fatigue weight loss lethargy hemoptysis dyspnea night sweats fever in afternoon chest pain

Evaluation and treatment

diagnosed with a positive tuberculin skin test

****sputum culture chest x ray

Treatment

Antibiotic therapy isoniazid rifampin pyrazinamide ethambutol streptomycin

recommended treatment is 9- 12 months

patient is considered safe when three sputum test come back negative for the bacilli

Pulmonary Hypertension

is high blood pressure in the pulmonary arteries

normal pressure is 15- 18 mm/Hg it is rare has no known cause usually occurs in women between the ages of 20

and 40 years of age may be hereditary primary pulmonary hypertension has a poor

prognosis most die within 5 years of diagnosis

secondary pulmonary hypertension- usually associated with cardiovascular disorder elevated left ventricular filling pressures

(CHF and Mitral valve disease) increased blood flow through the pulmonary

circulation ( obliteration or obstruction of the pulmonary

vascular bed by a pulmonary embolus or by chronic destruction of alveolar wall (emphysema)

vasoconstriction of the vascular bed (hypoxemia, acidosis or both)

other causes include obstructive sleep apnea, cystic fibrosis, cirrhosis with portal hypertension, use of appetite suppressants

Secondary pulmonary hypertension can be reversed if the primary disorder is resolved Oxygen Digoxin Diuretics Vasodilators Anticoagulants Lung transplant

damage can become irreversible if pulmonary hypertension continues long enough

Cor pulmonale- also called pulmonary heart disease right ventricular enlargement a. Hypertrophy

b. dilation develops as pulmonary hypertension produces chronic

pressure overload in the right ventricle

the right ventricle usually fails when pulmonary artery pressure equals systemic blood pressure

goal of treatment is to decrease the workload of the right ventricle and is same as primary pulmonary hypertension

Lung cancer- Tobacco smoke is responsible for

80 – 90 % of lung cancers- Believe there is an inherited

genetic predisposition to cancers