PHTH 521 Flashcards
1
Q
What is the Upper respiratory tract ?
A
It is the region of conduct between the atmosphere and lungs. It includes :
a. Nasal passage
b. Turbinates
c. Paranasal sinuses
d. Nasopharynx
e. Oropharynx
f. Laryngopharynx.
2
Q
What is the role of the Respiratory System?
A
- To transport oxygen from the atmosphere into the blood (necessary for cell metabolism)
- Remove carbon dioxide from the blood (waste product)
3
Q
What is the function of the Nasal passage, Turbinate and Paranasal sinuses?
A
- Nasal passage - opening to the respiratory system
- Turbinates : Warm, moistens and filters air
- Paranasal sinuses = Small cavities which add resonance to voice. (FEMS)
- Frontal
- Ethmoid
*Maxillary - Sphenoid
4
Q
What makes up the pharynx?
A
Pharynx connects nasal/oral cavities to the larynx and esophagus
- Nasopharynx - passage for air
- Oropharynx = contains tonsils, connects oral cavity
- Laryngopharynx = joins larynx and esophagus.
5
Q
What makes up the Larynx?
A
Consists of cartilage and muscles
- Hyoid, thyroid and cricoid
- Involved in breathing, producing voice and preventing aspiration
- Contains Epiglottis and vocal chords
{All lined by respiratory mucosa}
6
Q
What is the Significance of the Nasopharynx?
A
It is used to perform Nasopharyngeal suction = whereby a catheter is put down the naso-pharynx and stimulates a cough reflex to empty the phlegm.
7
Q
What is the significance of the Larynx?
A
Influences position of epiglottis in :
- Breathing = open
- Swallowing = closed to prevent aspiration
- Coughing = closed to build up pressure behind it.
8
Q
What is a part of the lower respiratory tract?
A
- Trachea
- Right and left primary bronchi
- Secondary and tertiary bronchi
- Bronchioles
- Alveoli
9
Q
What is the Anatomy of the Trachea?
A
- It connects the Larynx to the Bronchi
- Starts at the cricoid cartilage and ends at the sternal angle anteriorly and T5 posteriorly where it divides into left and right primary bronchi
- It is 12 cm long and 1.8cm in diameter
10
Q
What is the Trachea made of and how is it’s structure helpful?
A
Made of smooth muscle and elastic tissue shaped into C-shaped cartilage
- Open side allows esophagus to expand
- Cartilage supports the airway wall to prevent collapse.
11
Q
What is the clinical significance of the Trachea?
A
TRACHEOSTOMY
- It is a surgical procedure to create an opening in the anterior trachea to create an airway to facilitate breathing
- The cartilaginous rings of the Trachea create ridges which can be damaged by a suction catheter
NO SUCTION ON WAY DOWN only on WAY UP.
12
Q
What is the clinical significance of the Trachea dividing at T5?
A
The trachea divides into the left and right pulmonary bronchus at T5 (BIFURCATION is called Carina)
- During suction, the catheter comes into contact with the Carina which triggers the cough reflux
13
Q
What is the clinical significance of a larger right bronchus?
A
- The right bronchus is larger and branches at 20-30 degrees
- Aspirated material more likely to go to right lung as the bronchi is straighter.
14
Q
Describe the left bronchi
A
Left bronchi is smaller and branches from trachea at 45-55 degrees
15
Q
Describe the Bronchial tree and clinical significance of anatomical structure
A
- Each primary bronchus divides into secondary bronchi and then tertiary/segmental bronchi
- As bronchii become smaller cartilage decreases and smooth muscle increases
Clinical significance : smooth muscle is essential to allow the bronchiole to contract/adjust its size.
16
Q
Describe the Alveolar Ducts and Alveoli
A
- Bronchioles terminate in alveoli
- Alveoli are formed by EPITHELIAL Tissue which allows gas diffusion into blood
- Alveolar and capillary wall make up the respiratory membrane where gas exchange occurs
- Large number of alveoli and extensive capillary beds provide a large surface area for gas exchange.
17
Q
What is the significance of Alveoli surfactant?
A
- The inside of alveoli are coated with surfactant produced by the alveolar wall
- Surfactant reduces surface tension and allows inspiration while preventing collapse.
18
Q
What is Collateral ventilation?
A
Process of airflow occurring between adjacent alveoli or bronchioles through alternative pathways that bypass normal airways
19
Q
What is the Interbronchiolar channel of martin ?
A
Pathways connecting neighboring bronchioles.
20
Q
What is the Bronchiole-Alveolar Channel of Lambert?
A
Channels connecting bronchioles to adjacent alveoli
21
Q
What is the Interalveolar Pore of Kohn?
A
Pores that connect adjacent alveoli.
22
Q
What is the Interlobar Pathways via Fissures?
A
Airflow pathways between lobes through natural fissures in the lung.
23
Q
What are features of the Lungs?
A
- Cone shaped structures on either side of the heart
- Mediastinum sits between the lungs (has the heart, blood vessels, esophagus and trachea)
- Right lung has 3 lobes and 15% LARGER than the left (2 lobes)
24
Q
What divides the lungs into lobes?
A
Fissures divide the lung into lobes and each lobe is divided into broncho- pulmonary segments
1. Horizontal fissure = divides right upper and middle lobes (ONLY ON RIGHT Lung)
2. Oblique fissure :
Right : divides middle lobe from inferior lobe.
Left : divides upper and lower lobes
25
What is the Surface Anatomy of the Right Lung?
- Starts 3 cm above the clavicle in the mid-clavicular line
- Follows right para-sternal line
- Ends at 6th rib in midclavicular line anteriorly, 8th rib in midaxillary line and 10th rib posteriorly to the lateral border of vertebral line
- 15% LARGER THAN LEFT due to position of the heart
26
Which hemidiaphragm is higher and why?
Right sits 1-2 widths HIGHER than the left due to the position of the LIVER.
27
What is the Surface Anatomy of the Left lung?
- Starts 3 centimeters above clavicle in midclavicular line
- Down and follows left parasternal line
- Joins with 6th rib in midclavicular line, 8th rib in mid-axillary line, 10th rib posteriorly and lateral border of vertebral line posteriorly.
28
What is the Oblique Fissure?
From spinous process of T2 (posteriorly) to 6th costal cartilage (anteriorly)
Separates right middle and lower lobes and left upper and lower lobes.
29
What is the Horizontal/Transverse fissure?
- Extends from the oblique fissure along border of the 3rd and 4th rib.
- Separates right upper and middle lobes
30
What are the bronchopulmonary segments of the Right Upper Lobe?
All Animals Play
- Anterior
- Apical
- Posterior
31
What are the bronchopulmonary segments of the Right Middle Lobe?
My Love
- Medial
- Lateral
32
What are the bronchopulmonary segments of the Right Lower Lobe?
Some Men Like A Party
- Superior
- Medial
- Lateral
- Anterior
- Posterior
33
What are the bronchopulmonary segments of the Left Upper Lobe?
All Animals Play Ludo
- Anterior
- Apical
- Posterior
- Lingula
34
What are the bronchopulmonary segments of the Left Lower Lobe?
Some Like A Party
- Superior
- Lateral
- Anterior
- Posterior
35
Why are the Bronchopulmonary segments important?
Important for airway clearance so that the patient can be positioned and gravity can assist with drainage.
36
What is Pleura and 2 types of it?
Each lung is covered by a double walled membrane called the pleural membrane (SITE FOR LUNG PATHOLOGY)
1. Visceral pleura = Attached to outer surface of lung
2. Parietal pleura = lines inside of the thoracic cavity and diaphragm.
- The layers sit close together separated by a small amount of pleural fluid.
- It provides lubrication during respiratory movements
37
What is the relevance of Slight negative pressure in Pleural Cavity?
It holds the pleura together and promotes lung expansion.
38
What is the importance of the Thorax?
- Consists of Ribs, Vertebrae and Sternum
- Provides a rigid protective wall for lungs
Ribs 1-7 = true ribs
Ribs 8-10 = false ribs
Ribs 11 and 12 - floating ribs
- External and Internal intercostals muscles are located between ribs and assist with ventilation.
39
What is the Diaphragm and its location?
- It is a dome shaped muscle below the heart and lungs
- In upright relaxed position it sits at T8-T10.
40
What are the roles of the Diaphragm?
1. Primary Muscle of Inspiration
2. Postural stability
3. Role in vascular and lymphatic systems
4. Supports gastroesophageal functions.
41
What are the 3 openings in Diaphgram and what passes through?
- T8 = Inferior Vena Cava, Phrenic Nerve (Right)
- T10 = esophagus, ant and posterior vagal trunks
- T12 = thoracic duct and aorta.
42
What are the respiratory defense mechanisms of our body?
Inspired O2 can be a source of pathogens. But upper and lower airways protect the lung via anatomical barriers (RMC)
1. Respiratory Mucosa
2. Mucociliary transport
3. Cough Reflex.
43
What is the Respiratory Mucosa?
- Made up of Epithelial Cells, including Ciliated Columnar Cells and Mucus secreting goblet cells.
2 layers of mucus
1. Gel (outer) = Traps inhaled particles
2. Sol layer (periciliary) = thinner watery layer under the gel which allows cilia to beat effectively.
44
What is the Function of Mucus?
Keeps the airway surfaces moist and traps contaminants which are cleared via muco-ciliary transport mechanisms.
45
What is Muco-ciliary transport?
- Cilia are present on the surface of the epithelial cells and beat in a wave like motion
- FAST Forward stroke, slower back stroke
- This moves the mucus layer towards the pharynx where it is either swallowed or coughed out.
46
What factors affect muco-ciliary transport?
1. Temperature and humidity
2. Ciliary health
3. Pathological conditions.
* Cystic fibrosis is when the mucus is really thick and cilia cannot beat properly to clear it.
47
What is the Cough Reflex?
- Excessive amount of mucus or particles stimulate a sneeze or cough to clear the foreign materials from lungs
--> Cough is by Large Maximal Inspiration, Glottis Closure, Increased Abdominal pressure, Glottis Opening and Expelling Air forcefully.
--> Creates TURBULENCE and SHEARING force to expel foreign material and mucus.
48
What influences Airflow (L/min)?
1. Airway resistance = Airflow is inversely proportional to airway resistance. As airway resistance increases, airflow decreases
2. Pressure difference = Airflow is proportional to pressure difference. As pressure gradient increases, airflow also increases
(higher pressure --> Lower pressure)
49
How is inspiration and expiration related to size of thoracic cavity?
Airflow during inspiration and expiration can be created by changing the size/volume of the thoracic cavity which causes a change in pressure
1. When size of thoracic cavity increases, the pressure decreases = When atmospheric pressure is higher than air pressure in lungs air flows in = Inspiration
2. When size of thoracic cavity decreases, pressure increases = When lung air pressure is higher than the atmosphere, air will flow out = expiration.
50
What is Boyle's Law?
Volume of a gas and pressure are inversely proportional at a given temperature. When the pressure increases , the volume decreases and vice versa
51
What is the normal sequence of events for Inspiration?
1. Normal quiet respiration begins with contraction of the Diaphragm and External Intercostal Muscles
2. Diaphragm flattens and descends while the external intercostals raise ribs up and outwards = Increases size of thoracic cavity.
3. Increased size causes decreased pressure in the pleural cavity, alveoli and airways.
4. As ribs and diaphragm move, the attached parietal pleura moves the visceral pleura and lungs with it
5. As atmospheric pressure is > than intra-alveolar pressure, air flows into the lungs.
52
What is the sequence of events in Expiration?
- After inspiration the diaphragm and external intercostals relax, which decreases thoracic size
- This along with the natural elastic recoil of the alveoli causes increased intra-alveolar pressure (greater than atmospheric pressure) and air flows out.
QUIET EXPIRATION IS A PASSIVE PROCESS
53
What muscles are involved in Forced inspiration?
SPSS = SCM, Scalenes, Pec Minor and Serratus Anterior contract to increase elevation of Ribs and Sternum.
54
What muscles are involved in Forced Expiration?
Abdominal muscles (internal and external obliques, rectus and transverse abdominus) contract to increase upward pressure on diaphragm and internal intercostals contract pulling the ribs and sternum down and inwards.
55
What is Compliance and what factors influence it?
Compliance = Ability of the lungs to expand
- Depends on the elasticity of the tissues
- Alveolar surface tension and shape
- Size and flexibility of the thorax.
56
What influences the Rate and Depth of Breathing set by the medullary centre?
CHEMICAL Factors are most important in respiratory control.
* Higher brain centres = voluntary control but limited by CO2 in blood, pain, temperature, emotion
* Peripheral chemoreceptors
* Central chemoreceptors
* Muscle/joint receptors = stimulated by exercise
* Stretch and irritant receptors in lungs = protective reflex to avoid over expansion
* External factors like drugs
57
How are Central and Peripheral Chemoreceptors impacting Control of Ventilation?
Peripheral = located in carotid and aortic bodies, respond to decreased O2 in arterial blood or low pH
Central = Located in medulla, respond to elevated PCO2 or decrease in pH of CSF.
58
What normally triggers Respiration?
HYPERCAPNIA - elevated CO2
- When CO2 levels increase in the blood, it diffuses into the CSF
- This lowers the pH and stimulates the respiratory center resulting in an increased RATE and DEPTH of breathing.
59
When to chemoreceptors respond to Hypoxemia?
Normal O2 levels provide a reserve of O2 in venous blood so a marked decrease of O2 is needed.
60
What is the Clinical Relevance of Control of Ventilation?
- The mechanism of responding to low O2 may be important in individuals with chronic lung disease who adapt to increased levels of CO2
- The elevated levels of CO2 mean their respiration is no longer triggered by elevated by CO2 but a HYPOXIC drive to breath
- This means their stimulus for respiration is now dependant on low O2 levels rather than increase in CO2.
** Important to not give these patients excessive O2 or it can blunt their drive to breathe.
- Give them sufficient O2 (SpO2 88-92%)
61
What is a normal cycle of ventilation control look like?
1. When CO2 levels in blood increases, gas diffuses into CSF and lowers pH
2. This stimulates the Central chemoreceptors in the medulla
3. Which stimulates the inspiratory muscles
4. Causes an increased respiratory rate
5. This removes more CO2 from body
6. Which decreases PCO2
7. Thus the chemoreceptor activation decreases
8. Respiration slows down and more CO2 is retained.
62
What happens with Ventilator Control - Hypoxic Drive to breathe with chronically elevated PCO2?
- Chronic elevation of CO2 levels
- Medullary chemoreceptors become insensitive to high PCO2
- PCO2 increases and PO2 decreases slightly
- There is no change in inspiration
- Then there is a marked decrease in O2 and at very low PO2 it stimulates the peripheral chemoreceptors
- This in turn stimulates the inspiratory muscles which increases respiration
- This removes CO2 and takes O2 which increases PO2 and decreases PCO2 and respiration slows down again.
63
Why are Pulmonary Volumes important?
They are a measure of VENTILATORY Capacity
- They measure the air moving in and out of the lungs with either normal or forced inspiration and expiration.
64
What is Residual Volume?
The volume of air remaining in the lungs after maximal expiration.
- This provides gas exchange and maintain partial inflation of lungs.
65
What is Vital Capacity ?
Maximal amount of air that can be moved in and out of the lungs.
- Can be altered by lung disease
- Size of thorax
- Amount of blood in lungs and body position.
66
What is Dead Space?
The volume of air in the respiratory tract segments which is responsible for conducting air to alveoli and bronchioles but does NOT take part in gas exchange
--> Can be increased by obstruction or destruction of Alveoli.
67
What is Tidal Volume?
Amount of Air entering the lungs with each normal breath - 500mL
68
What is inspiratory reserve volume (IRV)
Max volume of air inspired in excess of normal quiet inspiration (tidal volume)
69
What is expiratory reserve volume?
Maximal volume of air expired following a passive expiration.
70
What is total lung capacity?
Total volume of air in lungs after maximal inspiration (5800mL)
71
What is Gas exchange?
Flow of gas between air in alveoli and blood in the pulmonary capillaries
CO2 and O2 diffusion depends on the Relative concentration or Partial pressure of gases.
72
What is Dalton's Law
- Movement of O2 and CO2 occurs from high pressure to low pressure and is independent of other gases
73
What is Pulmonary Circulation composed of ?
Pulmonary arteries = Bring venous blood from right side of heart to be oxygenated
Pulmonary veins = Bring oxygenated blood to left side of heart to be pumped into circulation
Pulmonary capillaries = site of gas exchange.
74
Alveolar air has different concentration of gases than atmospheric air or blood. TRUE OR FALSE
TRUE
75
What factors affect Gas Diffusion? --> PTT
1. Partial pressure gradient
2. Thickness of the respiratory membrane (Accumulation of fluid in alveoli)
3. Total surface area available for gas exchange (if alveolar wall is destroyed by emphysema)
** The imbalance is called Ventilation/Perfusion ratio
** The lungs have an auto-regulatory mechanism to adjust ventilation and blood flow to produce a good match.
76
What is Ventilation?
Process of moving air in and out of the lungs to facilitate gas exchange.
77
Why is Pleural pressure usually negative?
1. Due to recoil of chest wall and lungs
2. Due to negative pressure from lymphatic system.
78
What is the Pleural pressure gradient like, and why is it like that and what does it cause?
In upright position it is MORE negative in Apices and LESS negative in Base (vertical pressure gradient)
- Due to gravity and pressure from mediastinal and abdominal contents
This results in :
1. TOP of lung - alveoli Larger and more inflated = flat/non compliant part of the volume-compliance curve and change little in tidal respiration
2. DEPENDENT Lung = alveoli small and compressed = steep/compliant portion of volume-compliance curve and GREATER alveolar ventilation
79
What is Perfusion?
Passage of blood to or through organs
-Pulmonary arterial blood carries CO2 to the alveoli for exhalation and removal
- Pulmonary venous blood provides filling of oxygen to left heart to support systemic perfusion
Pulmonary perfusion pressures LOWER than systemic perfusion pressure, and are further reduced the higher above heart the blood flows.
80
Are pulmonary perfusion pressures uniform?
- Pulmonary perfusion pressures are NOT uniform across the lung
- as both pulmonary arterial pressure and pulmonary venous pressure are dependant on the elevation above the heart
- whereas alveoli pressure is relatively constant c
81
What are the WEST Zones?
These zones describe how blood flow varies in the lung due to gravity and the relationship between pressures:
Zone 1 : PA> Pa> Pv (Top of Lung)
Alveolar pressure quite high, which collapses the capillaries and reduces blood flow. This causes alveolar dead space as Ventilation occurs but no perfusion
Zone 2 : Upper mid zone - Pa> PA> Pv
Blood flow depends on the gradient between alveolar and pulmonary artery pressure. Greater perfusion than Zone 1 (BEST PERFUSION)
Zone 3 : Lower mid zone - Pa>Pv>PA
Blood flow is highest here, depends on the gradient between pulmonary arterial and venous pressure. Ventilation/perfusion exchange does happen in the dependant part of the lung just because of large amounts of blood flow.
82
What does efficient gas flow rely on?
Ventilation perfusion matching.
83
What does the following V/Q mean?
V/Q = 1 --> lung unit with well matched gas and blood flow
V/Q >1 --> excellent ventilation, poor blood flow (Zone 1)
V/Q < 1 --> poor ventilation, excellent blood flow (Zone 3)
V/Q infinite --> alveoli units receive no blood flow (Pulmonary embolism)
V/Q = 0 --> alveoli units with no airflow (severe obstruction
84
Which zone has the ideal V/Q match?
Zone 2 - 1.0
Overall in lung there is 4l/min of ventilation and 5l/min of perfusion with V/Q of 0.8
--> Ventilation and perfusion increase progressively from NON DEPENDENT to Dependent portion of lung but change in perfusion is more extreme.
85
How is O2 transported?
* Most O2 is reversibly bound to Hb as oxyhemoglobin (When all 4 heme molecules have O2 attached = fully saturated)
* Only 1 % of total O2 is dissolved in plasma (as it is relatively insoluble)
86
What is the procedure for oxygen transport?
- As O2 diffuses out of the blood into the cells, Hb releases O2 to replace it so dissolved O2 is always available in plasma to diffuse into cells
- 25% dissolved O2 is released into the cells for metabolism during circulation, leaving 75% bound to Hb as a safety margin so that O2 can meet all cell demands
87
What influences Hemoglobin binding or releasing O2.
1. Partial pressure of O2
2. Partial pressure of CO2
3. Temperature
4. Plasma pH
88
What does the O2 dissociation curve show?
Relation between partial pressure of O2 and hemoglobin saturation with O2. It shows how readily hemoglobin binds to and releases O2.
- The steep portion of the curve shows O2 unloading in tissues, where small changes in PO2 leads to large O2 release
- The flat portion of curve shows O2 loading in lungs, whereby Hemoglobin remains saturated even if oxygen decreases.
89
What factors cause a right shift- Decreased affinity of hemoglobin for O2?
- Acute acidosis
- High PCO2
- Increased temperature
- Abnormal hemoglobin
- High level of 2,3 - DPG
90
What factors cause a left shift - Increased affinity?
This means that Hemoglobin holds onto O2 more tightly.
Acute alkalosis
- Decreased PCO2
- Decreased temperature
- Low levels of 2,3DPG
- Carboxyhemoglobin ad Methemoglobin
91
How is CO2 transported?
- 7% is dissolved in plasma and diffuses through cell membranes
- 20% loosely and reversibly bound to HB attached to an amino group = Carbaminoglobin
Majority of CO2 from cell metabolism diffuses into RBC where its acted upon by CARBONIC Anhydrase and converted to carbonic acid and bicarbonate ions which act as a blood buffer.
92
What are 2 main types of Lung disease and their subtypes?
1. Time
- Acute
- Chronic
2. Type
- Obstructive
- Restrictive
- Other
93
What are Time based respiratory pathologies?
These are based on the onset of pathology and how long it lasts for.
94
What is Acute respiratory pathology?
- Generally has a sudden onset
- May resolve or become chronic
95
What is Chronic respiratory pathology?
- Develops over an extended period of time or stems from an acute pathology
- Symptoms typically worsen over time
- Can have acute on chronic.
96
What are Type Based respiratory pathologies?
Refers to the pathophysiology of the disease and what is occurring at the cellular level.
97
What is Obstructive respiratory Pathology?
- Reduction in AIRFLOW
- Can get Air IN but difficulty exhaling, not all OUT
Example : COPD, Asthma
98
What is Restrictive respiratory Pathology?
- Reduction in LUNG VOLUME
- Difficulty inhaling due to reduced lung compliance due to lung or chest stiffness
- Can get all air out but less volume as couldn't get much air in.
Example: Interstitial lung disease
99
What are the different types of Diagnostic tests? --> ACOBE
They test pulmonary volumes, and airflow time.
1. Arterial blood gases = Check O2, CO2 and bicarbonate levels
2. Chest X-ray = provide diagnosis and check disease progression
3. Oximeter = measures O2 saturation (SaO2)
4. Exercise tolerance tests
5. Bronchoscopy = thin rigid bronchoscope is inserted into the airways to visualize respiratory system.
100
What are Pulmonary Function Tests (PFTs)?
- Non invasive tests which show how well the lungs are working
- Results are based on predictive values (Age, sex, rate, and disease specific)
- Part of a respiratory assessment
101
What is the purpose of PFTs?
1. Help to diagnose and monitor a broad range of respiratory disease including severity
2. Assist with medication prescription and titration
3. Determines the patient's ability to tolerate anesthetic or surgery
4. Measure disability of environmental or chemical exposure.
5. Research.
102
Who performs PFTs?
- Respiratory therapists
- Clinical Nurse specialist
- Physician
- Ocassionally Physiotherapists.
103
What are different types of PFTs?
1. Spirometry = Measures ventilated gas
- Cannot measure = Residual volume, total lung capacity and functional residual volume.
- Done before/after bronchodilators
2. Plethysmography
- Performed under pressure in closed room
= Measures Residual volume and Functional residual capacity.
104
What does FEV1 mean?
Forced expiratory volume in 1 s - total volume of air a patient can exhale in the first second during maximal effort
105
What is FVC?
Forced vital capacity = total volume of air a patient is able to exhale for the total duration of the test during maximal effort.
106
What is FEV1/FVC ratio?
The percentage of FVC expired in 1 second.
Normal = 80% or 0.8
107
What are the steps to interpreting results of a Pulmonary function test?
1. Determine if FEV1/FVC ratio is LOW (<70%) = Obstructive defect
2. If FVC is low (less than lower end of normal) = Restrictive pattern.
3. Confirm the restrictive pattern but referring the patient for DLCO test (diffusion capacity for Carbon monoxide)
- Include total lung capacity, if <80% = restrictive
- Diseases which REDUCE blood flow to lungs or damage alveoli = less efficient gas exchange and lower DLCO
4. Grade the obstructive abnormality - GOLD or ATS criteria
- GOLD more sensitive to COPD related obstructive disease
5. Determine the reversibility of the Obstructive deficit - give bronchodilator and see if there is an increase in FEV1 or FVC
6. Bronchoprovocation = if tests normal but medics suspect exercise induced asthma then Methacholine or Mannitol inhalation challenge, Exercise test.
7. Establish differential diagnosis
8. Compare current and prior PFT results.
108
What does the FEV1/FVC Ratio look like for Obstructive - COPD and ASTHMA?
* FEV1 is significantly reduced due to airway narrowing or obstruction.
* FVC may also be reduced, but not as much as FEV1.
* FEV1/FVC ratio < 70%, indicating obstructed airflow.
* The curve shows a slower rise in exhaled volume, with a prolonged time to reach FVC.
109
What does the FEV1/FVC Ratio look like for Restrictive diseases?
- Both FEV1 and FVC are reduced due to reduced lung compliance or lung volume.
- FEV1/FVC ratio ≥ 70% or normal, because both FEV1 and FVC are proportionately reduced.
- The curve shows a rapid rise but reaches a lower overall FVC.
110
What are the major changes with Obstructive pattern?
FVC = Decreased/normal
FEV1 = Decreased
FEV1/FVC ratio = Decreased
Total lung capacity = Normal or Increased
FEV1 decreased > than FVC
111
What are the major changes with Restrictive pattern?
FVC = Decreased
FEV 1 = Normal or decreased
FEV1/FVC ratio = normal
Total lung capacity = decreased
FEV1 and FVC decrease in proportion
112
How to classify airflow limitation severity in COPD patient with GOLD scale
Gold 1 = Mild (FEV1> 80% predicted)
Gold 2 = Moderate (50% < FEV1< 80% predicted)
Gold 3 = Severe (30% < FEV 1 < 50% predicted)
Gold 4 = Very severe ( FEV1 < 30% predicted)
113
