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The primary functions of the pulmonary system are?
- Ventilation and Respiration
- To deliver and remove gases
What area of the brain regulates involuntary ventilation?
In the brainstem, the medulla oblongata and the pons are involved in ventilation
The movement of air in and out of the lungs is called?
The process of gas exchange by means of movement of oxygen from the atmosphere into the blood and movement of carbon dioxide from the blood into the atmosphere is called?
Describe the differences in the right and left lung lobes
The right lung is larger and heavier than the left because it has an upper, middle, and lower lobe
The left lung only has an upper and lower lobe
A thin membrane that lines the outside of the lungs and the inside of the chest wall
There are two pleural surfaces separated by an airtight space taht contains a thin layer of lubricating fluid
This lubricating fluid allows the two pleural membranes to glide against each other during inhalation and exhalation
Describe the importance of intrapleural pressure
The pleural space has a pressure within it called intrapleural pressure that differs from the pressure in the lungs and atmospher pressure
The constant pull of the two pleural membranes in opposite directions causes the pressure within the space to be below atmosphere...this negative pressure in the pleural space keeps the lungs inflated
If atmosphere pressure enters the pleural space, all or part of a lung will collapse, producing a pneumothorax
Describe the intrapleural pressure under normal conditions
- The intrapleural pressure is less than lung and atmosphere pressure
- The constant pull of the two pleural membranes in opposite directions during ventilation is what causes this subatmospheric or negative pressure
What keeps the lungs inflated?
The negative pressure in the pleural space
What happens if atmospheric pressure enters the pleural space?
All or part of a lung will collapse, producing a pneumothorax
The muscles of ventilation are governed by the regulatory activity of the CNS, which sends messages to the muscles to stimulate contraction and relaxation.
This muscular activity controls inhalation and exhalation.
Muscles that increase the size of the chest are called_____?
Muscles that decrease the size of the chest are called_____?
Muscles that increase the size of the chest are called muscles of inhalation
Muscles that decrease the size of the chest are called muscles of exhalation
The main muscle of inhalation is?
- The diaphragm
- The diaphragm separates the thoracic and abdominal cavities
- Because it does most of the work of inhalation, trauma involving levels C3 to C5 causes ventilatory dysfunction
During normal, quiet breathing, the diaphragm does approximately 80% of the work of breathing.
Describe the diaphragm on inhalation
On inhalation, the diaphragm contracts and flattens, pushes down on the viscera, and displaces the abdomen outward
Although the diaphragm is the main muscle of inhalation and does about 80% of the work of breathing, what are the other important muscles of inhalation?
- The intercostal muscles
- These muscles elevate the ribs and expand the chest cage outward
Exhalation in the healthy lung is a passive event requiring very little energy. Exhalation occurs when?
- The diaphragm relaxes and moves back up toward the lungs
- Because exhalation is a passive act, there are no true muscles of exhalation.
- However, during exercise exhalation becomes a more active event, requiring some participation of the accessory muscles of ventilation.
The accessory muscles of ventilation are those that enhance chest expansion during exercise but are not active during normal, quiet breathing.
These accessory muscles include?
- Other chest and back muscles such as the trapezius and pectoralis major
The conducting airways consist of?
- The upper airways
- The trachea
- Bronchial tree
What is the purposes of the conducting airways?
- To warm and humidigy the inhaled air
- To act as a protective mechanism that prevents the entrance of foreign matter into the gas exchange areas
- To serve as a passageway for air entering and leaving the gas exchange regions of the lungs
The upper airways consist of?
- Nasal and oral cavities
The upper airways main contribution to ventilation is?
- Conditioning of inspired air
- *Conditioned air is air that has been warmed, humidified, and cleansed of some irritants
- *Warming and humidifying, which are essential to prevent irritation of the lower airways, occur mainly within the nose by means of a dense vascular network that lines the nasal passages
- *The air is cleaned by the coarse hairs that line the nasal passages and filter large inhaled particles
What is located in the upper airways and protects the lower airways by closing the opening to the trachea during swallowing so that food and liquid passes into the esophagus not the trachea?
The trachea begins at the cricoid cartilage and ends athe the?
The two main stem bronchi arise from the carina
The two main stem bronchi arise from the?
- The carina is an important landmark during endoscopy of the bronchial tree
How are the two main stem bronchi structurally different?
- The left bronchus is smaller and narrower than the right because the heart needs room, it angles directly toward the left lung
- The right bronchus is wider and has a sharper angle. This position along with the forces of gravity is the reason the right side is the most common site of aspiration of foreign objects
Which bronchus is the most common site of aspiration of foreign objects due to its position?
Through the right main stem bronchus into the lower lobe of the right lung
The conducting airways consist of?
The respiratory airways consist of?
- Respiratory bronchioles
- Gas exchange takes place in these areas of the lungs
The main defense system within the airways is the?
- Mucous blanket which is a combination of mucus and cilia
- The mucus floats on top of the cilia and traps foreign particles
- Ciliary movement then propels the entire mucous blanket and any trapped particles upward toward the pharynx to be swallowed or cleared
- The cough reflex is another protective mechanism in the lungs. Excessive amounts of foreign particles in the trachea and bronchi can initiate the cough reflex
Each respiratory bronchiole gives rise to several alveolar ducts, which terminate in clusters of?
- The alveoli are the primary site of gas exchange and the end of the respiratory tract
Cells within the alveoli secrete what important phospholipid composed of fatty acids?
- Surfactant lowers surface tension of the alveoli
- Within the lungs, surfactant stabilizes the alveoli, increases lung compliance, and eases the work of breathing
Surfactant functions to?
- Lower surface tension of the alveoli
- Increases lung compliance
- Eases the work of breathing
What happens when pulmonary disease disrupts the normal synthesis and storage of surfactant?
- Lungs become less compliant and the work of breathing increases
- Severe loss of surfactant results in alveolar instability and collapse and impairment of gas exchange
The trachea and bronchus contain what cells that produce sticky mucous that trap inhaled debris?
Where are cilia located?
In the bronchioles
Where does gas exchange begin?
In the respiratory bronchioles
Anything that causes the pressure within the pleural space to rise to atmospheric pressure or above will cause?
The lung will collapse, also called a pneumothorax
Why are the bronchioles sensitive to constriction?
- Their walls are made up of smooth muscle instead of connective tissue and cartilage
- When constriction occurs, these airways may close completely because of the lack of structural support
What is the normal pH of the lungs?
Oxygen and carbon dioxide traverse easily across the alveolar capillary membrane because?
Alveoli are only one cell membrane thich which presents no barrier to diffusion
Air moves into and out of the lungs because of?
- The difference between intrapulmonary pressure (pressure inside the lungs) and atmospheric pressure
- When the pressure falls below atmospheric pressure, air enters the lungs (inhalation)
- At the end of inhalation, the muscles of ventilation relax, the thorax contracts and the lungs are compressed, and intrapulmonary pressure rises
- When the pressure rises above atmospheric pressure, air exits the lungs (exhalation)
The work of breathing is the amount of work that must be performed to overcome the elastic and resistive properties of the lungs.
What are the elastic and resistive properties of the lungs?
- *Elastic properties are determined by:
- Lung recoil
- Chest wall recoil
- Surface tension of the alveoli
- *Resistive properties are determined by:
- Airway resistance
*Normally, the work of breathing occurs during inhalation, but even exhalation can be a strain when lung recoil, chest wall recoil, or airway resistance is abnormal
During normal, quiet ventilation a very small amount of basal oxygen consumption is required by the pulmonary system.
The amount of energy required by the pulmonary system can be greater during heavy exercise.
How does pathologic conditions of the pulmonary system drastically change the energy requirement for ventilation?
Pulmonary diseases that decrease lung compliance (ex:atelectases, pulmonary edema), decrease chest wall compliance (ex:kyphoscoliosis), increase airway resistance (ex:bronchitis, asthma), or decrease lung recoil (ex:emphysema) can increase the work of breathing so much that one third or more of the total body energy is used for ventilation. Nutrition is important to maintain energy. We supplement oxygen so patients do not have to work so hard to breath
Pulmonary diseases can be categorized as?
- Restrictive diseases
- Obstructive diseases
- *Depends on how the underlying cause affects normal ventilation
- *Some people may have both types
- *Normal muscular action of the diaphragm, flexibility of the rib cage, elasticity of the lungs, and airway diameter are key in allowing easy inhalation and exhalation. Any interference with these actions impairs normal ventilation
Which category of lung disease limit lung or chest wall movement and include diffuse interstitial lung fibrosis, atelectasis, kyphoscoliosis, and severe chest wall pain?
- Restrictive diseases
- Can be acute or chronic
- Because they restrict lung or chest wall expansion, or both, patients have smaller tidal volumes but an increased ventilatory rate to maintain minute ventilation
Which category of lung disease impede normal airflow?
- Obstructive disease
- Classic examples are emphysema and asthma
- In emphysema, airflow is decreased because of a decrease in lung recoil which results in lungs that inflate easily but, do not compress to assist with exhalation because the normal elastic recoil is not there
- So patients with emphysema may have no trouble inhaling, but struggle to exhale
- In asthma, airflow is decreased because of diffuse airway narrowing
Pulmonary ventilation can be described in terms of?
- Volumes and Capacities:
- Tidal volume
- Inspiratory reserve volume
- Expiratory reserve volume
- Residual volume
- Inspiratory capacity
- Functional residual capacity
- Vital capacity
- Total lung capacity
The amount of air inhaled and exhaled with each breath is called?
Tidal volume (VT)
The maximum amount of air that can be inhaled over and above the normal tidal volume is called?
- Inspiratory reserve volume (IRV)
- So when you breath in as far as you can, then force more air in the lungs is the IRV
The maximum amount of air that can be exhaled beyond the normal tidal volume is called?
- Expiratory reserve volume (ERV)
- So when you exhale as much as you can, then force more air out of the lungs is the ERV
The amount of air left in the lungs after a complete exhalation is called?
Residual volume (RV)
Expiratory reserve volume + Residual volume=?
- Funtional residual capacity (FRC)
- So when you take the maximum amount of air that can be exhaled + the amount of air left in the lungs after, you get the FRC
Inspiratory reserve volume + Tidal volume + Expiratory reserve volume =?
- Vital capacity (VC)
- So when you take the maximum amount of air inhaled + the amount of air inhaled and exhaled with each breath + the maximum amount of air exhaled =VC
What represents the maximal amount of air that can be inhaled?
Total lung capacity (TLC)
Tidal volume + Inspiratory reserve volume + Expiratory reserve volume + Residual volume =?
Total lung capacity (TLC)
The portion of total ventilation that participates in gas exchange is known as alveolar ventilation.
The portion of ventilation that does not participate in gas exchange is called wasted ventilation.
The areas in the lungs that are ventilated but have no gas exchange is known as?
- Dead space regions
- So air is getting into the areas (ventilated), but the alveoli are not being perfused with blood.
- Without perfusion, gas exchange cannot take place, and the ventilation is wasted
The basic dumbed down reason for breathing problems is?
Air cant get in or out
Oxygen and carbon dioxide move throughout the body by?
- Diffusion moves molecules from an area of high concentration to an area of low concentration
- The difference in the concentrations of the gases is referred to as the driving pressure
- The greater the driving pressure of the gas through the membrane, the greater the rate of diffusion
Within the lungs, diffusion occurs because of the difference in the driving pressure between the?
- Pulmonary capillaries and the alveoli
- Oxygen is in high concentration within the alveoli and moves by diffusion from the alveoli into the pulmonary capillaries
- Carbon dioxide is in higher concentration within the pulmonary capillaries; therefore, carbon dioxide diffuses out of the capillaries into the alveoli where it is exhaled
In addition to the driving pressure of oxygen and carbon dioxide, what other factors affect the rate of diffusion?
- The thickness of the alveolar capillary membrane (ex:pulmonary edema, fibrosis)
- The surface area of the membrane (ex:pneumonectomy, lobectomy, pulmonary embolus, emphysema all decrease the rate of diffusion)
- The diffusion coefficient of the gas (is determined by its solubility and carbon dioxide diffuses more rapidly than oxygen)
Ventilation (V) and perfusion (Q) should be equally matched at the alveolar capillary membrane level for optimal gas exchang to take place, but because of normal regional variations in the distribution of ventilation and perfusion this is not the case.
What is the normal ventilation/perfusion (V/Q) ratio?
- Normally, alveolar ventilation is about 4L/min and pulmonary capillary perfusion is about 4 L/min
- So the normal ventilation/perfusion ratio (V/Q) is 4:5
- The distribution of ventilation throughout the lungs is not even as a result of factors such as the shape of the thorax and the effects of gravity on intrapleural pressure.
- The distribution of perfusion through the lungs is related to gravity and intraalveolar pressures
A variety of factors can affect the matching of ventilation to perfusion in the lungs, and their relationship can be considered as a continuum.
Describe both ends of the continuum when it comes to ventilation/perfusion mismatch
- At one end of the continuum, the alveolus is receiving ventilation but is not receiving any perfusion and is unable to participate in gas exchange (alveolar dead space)
- On the other end of the continuum, the alveolus is receiving perfusion but is not receiving any ventilation and is unable to participate in gas exchange (intrapulmonary shunting) in this case, the blood is returned to the left side of the heart unoxygenated
- In between the two there are an infinite number of ventilation/perfusion mismatches
- Although minor mismatching of ventilation may not significantly affect gas exchange, significant alterations in the relationship results in hypoxemia
Although minor mismatching of ventilation and perfusion may not significantly affect gas exchange, significant alterations in the relationship results in?
Situations in which ventilation exceeds perfusion are considered to be?
Dead space producing
Situations in which perfusion exceeds ventilation are considered to be?
- Intrapulmonary shunting
- In this case, the blood is returned to the left side of the heart unoxygenated
The distribution of perfusion is affected by the amount of oxygen in the alveoli. Although most blood vessels in the body dilate in response to hypoxia, the pulmonary vessels constrict when the Pao2 is less than 60 This is known as?
- Hypoxic vasoconstriction
- This event is thought to be a compensatory response used to limit the return of unoxygenated blood to the left side of the heart.
- If the response is prolonged and generalized throughout the lungs, pulmonary hypertension will result
What can result from prolonged hypoxic vasoconstriction?
What is the normal lung pH?
Effects of smoking
- Inhale CO instead of O2
- CO clings to hemoglobin for a long time
- Decreases cilla action
- Mast cells are stimulated
- The break down and release of mediators cause an inflammatory response which causes edema and contraction of smooth muscles
- There is a decrease in surfactant secretion which is important to keep alveoli open
- There is an increased release of protease which eventually exhausts the release of antiprotease
- Alveolar destruction causes inflammation and they loose elasticity
What can happen with overuse of nasal spray?
Using more than q48 hrs can cause rebound inflammation
How much oxygen is in the air we breath?
Assessing acid base balance determines?
The adequacy oxygenation/ventilation and circulation
- Decreases with aging from 60-90yrs the normal is 7.31-7.42
Normal pH for 60-90 year olds
In order to maintain pH balance, what responds in seconds?
In order to maintain pH balance, what responds in minutes?
In order to maintain pH balance, what responds in Days?
AlKalosis ___ ___ pH
AlKalosis Kicks up pH
AciDosis ___ ___ pH
AciDosis kicks Down pH
Normal level PCO2
- PCO2 increases with aging
- Co2 travels in the blood as carbonic acid to the lungs where it is exhaled
- So when pH is up, Respirations increase
Easy way to remember pH and PCO2 normals
- pH is 7.35-7.45
- PCo2 is 35-45
Normal level PA02/PO2
- Decreases with age
- The partial pressure O2 in blood is the amound of oxygen dissolved in plasma
- It is the amount of O2 waiting in line to attach to hemoglobin
- Oxygen can only be carried by hemoglobin
What always holds hands with HCO3?
Normal level HCO3
- It is the bicarbonate ion concentration in the blood
- It is the renal response to acid base balance that takes days to correct
Normal level of Base Excess
- -2 to +2
- It is the nonrespiratory contribution to acid base balance
The nonrespiratory contribution to acid base balance is?
- Base excess and Base deficit
- This is the amount of blood buffers in the blood and is a non-respiratory response to acid base balance
A negative base level -2 is reported as a base deficit, which means?
A positive base level +2 is reported as a base excess, which means?
Normal level SaO2 (Pulse Ox)
- 95% or higher
- It is the % of oxygen bound to hemoglobin
SaO2 (pulse ox) is the % of oxygen bound to hemoglobin and can be affected by?
Hypoventilation leads to?
Hypoventilation leads to respiratory acidosis, what are conditions that cause hypoventilation/respiratory acidosis?
- Pulmonary Emboli/Edema
- Opiate Overdose
Hyperventilation leads to?
Hyperventilation leads to respiratory alkalosis, what are conditions that cause hyperventilation/respiratory alkalosis?
What should a person do if they are hyperventilating?
Rebreath CO2 in a bag
ABG's that go in opposite directions indicating the problem is respiratory?
ABG's that go in the same direction indicating the problem is metabolic?
pH and HCO3
What are the implications for a thoracentesis?
- Done at the bedside for the removal of fluid or air from the pleural space
- Can be used as a diagnostic tool or may also be performed therapeutically for the drainage of a pleural effusion or empyema
- Patient is placed in a sitting position with legs over the side of bed with hands and arms supported on a table
PFTs are used for a variety of purposes, including?
- Preoperative assessment
- Evaluating lung mechanics
- Diagnosing and tracking pulmonary diseases
- Monitoring therapy
- Results are individualized according to age, gender, and body size
What are the indications for a Ventilation/Perfusion Scan (V/Q)?
- When a serious alteration of the normal V/Q relationship is suspected
- It consists of a ventilation scan and a perfusion scan
- Helps determine if the problem is heart or lung related
- Ordered most often to diagnose and follow a suspected PE
- Only 90% accurate diagnosing PE so use clinical assessment
How is the ventilation portion of the V/Q scan done?
How is the perfusion portion of the V/Q scan done?
- The ventilation scan is done by having the patient inhale a gas and air mixture
- The perfusion scan is done by injecting the patient with a radioisotope
What areas are assessed on a chest xray?
- Thoracic cage: there should be no evidence of fractures, etc
- Mediastinum:trachea should be midline
- Diaphragm: should be clearly visible at the 10th rib
- Pleural Space: Should not be visible at all
- Lung Tissue: viewed for any areas of increased density
- Wires etc: assessed for proper placement of tubes, wires, and lines
What is the indication for Pulse Oximetry?
In any situation that requires continuous observation
What is the pathophysiology of ARDS?
- ARDs is usually caused by another disorder that has altered the normal function of the pulmonary system such as smoke inhalation, oxygen toxicity, chemicals, trauma, etc
- Because these disorders damage the alveolar capillary membrane, the lungs cannot exchange gas sufficiently to oxygenate the blood
Easy way to remember COPD and Bronchitis: blue bloater vs. pink puffer diseases
- emPhysema has the letter P
- Bronchitis has the letter B
COPD: 4 types and hallmark sign
- Chronic bronchitis
- Dyspnea or Decreased FEV/FVC
For a patient on mechanical ventilation, total collapse of the alveoli can be prevented by?
Which ventilator mode delivers gas at a preset rate and tidal volume or pressure regardless of inspiratory effort?
What should always be kept at the bedside of a patient on mechanical ventilation?
- Manual resuscitation bag and mask
How often is incentive spirometer used?
If a patient coughs while changing the tape of a tracheostomy tube and it dislodges, what is the initial nursing action?
If the tube is dislodged accidentally, the initial nursing action is to grasp the retention sutures and spread the opening