Chapter 13 Altered Ventilation and Diffusion

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Exam 2

conducting airways

Move air into lungs
Warm and humidify air
Trap inhaled particles

respiratory airways

Bronchioles
Alveoli
Gas is exchanged with the blood

ventilation

Involves both acquiring oxygen (inspiration) and removing carbon dioxide (expiration) from the blood
Neuronal impulses are directed by lung receptors, which map the current state of breathing and lung function
Uses the intercostal muscles, diaphragm, and sternocleidomastoid muscles

inspiration

Breathing in to acquire oxygen

Unidirectional from high pressure to low pressure.

Chest cavity size changes to alter the pressure gradient

expiration

Removing carbon dioxide out of the body through the lungs

The diaphragm and external intercostal muscles relax

Lungs compress and increase the pressure inside the airways

diffusion

Oxygen and carbon dioxide are exchanged at alveolar capillary junctions

Two major process occur:
Oxygen is trying to get to all the cells
Carbon dioxide is trying to escape the body through the lungs

gas exchange

Oxygen moves from alveolar air into blood
Carbon dioxide moves from blood into alveolar air

partial pressure

The collision of oxygen and carbon dioxide creates pressure
PaO2
PaCO2

blood gases- oxygen

Dissolved oxygen = PaO2 or PO2
Normal value >80 mm Hg
Oxygen bound to hemoglobin = oxyhemoglobin
Normal value 95% to 97% saturation
Below 90% needs oxygen

impaired ventilation

A problem of blocking airflow in and out of the lungs
Two major mechanisms implicated:
Compression or narrowing of the airways
Disruption of the neuronal transmissions needed to stimulate the mechanics of the airways

ventilation perfusion mismatching

Blood goes to parts of the lung that do not have oxygen to give it
Blood does not go to parts of the lung that have oxygen
Perfusion without ventilation is a blocked airway.
Ventilation without perfusion is a blocked capillary

impaired diffusion

Restricted transfer of oxygen and/or carbon dioxide across the alveolar capillary junction
Dependent upon:
solubility and partial pressure of the gas
surface area and thickness of the membrane

hypoxemia

PO2 <60 mm Hg
Cyanosis
Impaired function of vital centers
Agitated or combative behavior, euphoria, impaired judgment, convulsions, delirium, stupor, coma
Retinal hemorrhage
Hypotension and bradycardia
Activation of compensatory mechanisms
Sympathetic system activation
Measured with arterial blood gas

hypoxia

lack of oxygen at the tissue level. O2 Sat

hypercapnia

PCO2 >50 mm Hg
Respiratory acidosis
Increased respiration
Decreased nerve firing
Carbon dioxide narcosis
Disorientation, somnolence, coma
Decreased muscle contraction
Vasodilation
Headache; conjunctival hyperemia; warm, flushed skin

treating impaired ventilation and diffusion

Remove obstruction and restore physical integrity of airways, lung tissues
Decrease inflammation and mucus; treat infection
Supplemental oxygen
Mechanical ventilation

pneumonia patho

Infectious process
Respiratory droplet spread
Causes inflammation of the lungs
Occurs commonly in the bronchioles, interstitial lung tissue and/or the alveoli
Products of inflammation accumulate and cause consolidation

pneumonia manifestations

Sudden onset of fever
Chills
Cough
Sputum production
Fatigue
Loss of appetite
Dyspnea
Tachypnea
Tachycardia
Pleuritic pain
Crackles in lungs

pneumonia diagnostic criteria

History and physical examination
Complete blood cell count
Chest X-ray
Thoracic CT scan

pneumonia treatment

Restore optimal ventilation and diffusion
Identify pathogen and target with appropriate pharmacologic treatment
Supplemental oxygen

TB patho

Mycobacterium tuberculosis

Airborne droplet nuclei travel directly to the terminal bronchioles and alveoli of the lung

Inflammatory and immune responses
Containment- asymptomatic, granuloma may form
Multiplication- progressive primary TB
Dormancy-

tb manifestations

Many of those infected are symptomatic
In the presence of chronic inflammation:
Malaise
Weight loss
Fatigue
Anorexia
Low-grade fever
Possibly night sweats

tb diagnostic criteria

Tuberculin skin tests
Chest X-ray
Sputum culture
Sputum nucleic acid amplification

emphysema pathophysiology

Irreversible enlargement of the air spaces beyond terminal bronchioles
destruction of the alveolar walls
obstruction of airflow
Chronic smoking most often implicated

emphysema clinical manifestations

Persistent cough
Dyspnea
Wheezing
Barrel chest
Pursed lip breathing

emphysema diagnostic

History and physical examination
Pulmonary function tests
Chest x-ray
Hypercapnia/hypoxemia

emphysema treatment

Maintain optimal lung function in order to allow the individual to perform the desired activities of daily life
Smoking cessation
Pharmacologic therapy
Lung volume reduction or transplant

chronic bronchitis patho

Persistent, productive cough lasting three months or greater, for two or more consecutive years
Result of:
Chronic inflammation and edema of the airways
Hyperplasia of the bronchial mucous glands and smooth muscles
Destruction of cilia
Squamous cell metaplasia
Bronchial wall thickening and development of fibrosis

chronic bronchitis manifestations

Cough
Purulent sputum
Dyspnea
Adventitious lung sounds
Cyanosis

chronic bronchitis diagnostic criteria

History and physical examination
Arterial blood gases
Pulmonary function tests
Pulse oximetry
Sputum analysis

chronic bronchitis treatment

Smoking cessation
Pulmonary rehabilitation
Pharmacologic therapy
Supplemental oxygen

asthma patho

Intermittent or persistent airway obstruction due to:
Bronchial hyperresponsiveness
Chronic inflammation
Bronchoconstriction
Excess mucous production

asthma manifestations

Wheezing and tachypnea
Dyspnea and coughing
Chest tightness
Excessive sputum production
Anxiety

asthma diagnostic criteria

History and physical examination
Pulmonary function tests
Laboratory studies
Chest x-ray

asthma treatment

Monitor lung function
Control environmental triggers
Pharmacologic therapy
Patient and family education; action plan

cystic fibrosis patho

Autosomal recessive disorder of electrolyte and water transport affecting certain epithelial cells (respiratory, digestive, and reproductive lining)

Mutation of the CF gene

Associated with mucus plugging, inflammation, and infection in the lungs; also affects other body systems

Respiratory failure is most common cause of death

cf manifestations

Respiratory

Gastrointestinal

Reproductive

cf diagnostic criteria

History and physical examination
Sweat test
Genetic testing
Chest x-ray
Sputum analysis

cf treatment

Respiratory
Chest physiotherapy
Pharmacologic treatment
Lung transplant
Gastrointestinal
Optimal nutrition
Pancreatic enzymes

ARDS patho

Lung injury to respiratory distress within 24-48 hours
Severe acute inflammation and pulmonary edema without evidence of fluid overload or impaired cardiac function
Mortality rate 30%-40% from multi-system organ failure in those untreated

ARDS clinical manifestations

Tachypnea
Dyspnea
Retractions
Crackles due to fluid accumulation
Restlessness, anxiety

ARDS diagnostic criteria

History and physical examination
Laboratory studies
Imaging studies

ARDS treatment

Remove causative factors
Administration of 100% oxygen
Mechanical ventilation

pleural disorders decreased ventilation

Parietal pleura lines the thoracic wall and superior aspect of the diaphragm
Visceral pleura covers the lung
Pleural cavity or space between the two layers contains a thin layer of serous fluid

pneumothorax

Air enters the pleural cavity
Air takes up space, restricting lung expansion
Partial or complete collapse of the affected lung
Spontaneous: an air-filled blister on the lung ruptures
Traumatic: air enters through chest injuries
Tension: air enters pleural cavity through the wound on inhalation but cannot leave on exhalation
Open: air enters pleural cavity through the wound on inhalation and leaves on exhalation

open pneumothorax

lung collapse but air can still go in and out

tension pneumothorax

lung collase and air can go in but not out, not allowing the lung to expand.

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