Obstructive and Restrictive Lung Disease Flashcards
what is Respirtory Lung Dysfunction: aka Restrictive Lung exspanison diminshed
RLD: an abnormal reduction in pulmonary ventilation. Lung expansion is diminished. The volume of gas moving in and out of the lungs is decreased.
What things physilogically affect the Respiratory Lung Dysfunction
Aspects of ventilation contributing to RLD
Compliance of the lung and the chest wall
Alteration in lung volumes and capacities
Work of breathing
What is Compliance and what happens if it is reduced???
Physiological link that establishes a relationship between the pressure exerted by the chest wall and/or the lungs and the volume of air that can be contained within the lungs
In RLD, chest wall and/or lung compliance is reduced.
ranspulmonary gradient needed just to expand the lungs.
Decreased chest wall compliance limits thoracic expansion and therefore, lung inflation, even if lung compliance is normal.
What is diminshed when Respiratory lung dysfunction occurs???
ERV goes up or down
Tidal volume - goes up or down
IRV- up or down
RLD eventually causes all lung volumes and capacities to be reduced.
When the lung becomes less compliant, the IRV is diminished
Tidal volume also decreases as the work of breathing increases
ERV is reduced, this reduction is particularly pronounced if lung compliance is the principle etiology of the RLD.
What the most two common measures used to ID RLD while using spirometer? and What is indicated by a decrease in TLC and FRC ?
Total lung capacity: the volume in the lungs at maximal inflation, the sum of VC and RV.
Vital capacity: the volume of air breathed in after the deepest inhalation
http://en.wikipedia.org/wiki/Lung_volumes
Total Lung Capacity and Vital Capacity are the two most common measures used to identify RLD
Decreases in TLC and FRC are a direct result of a decrease in lung compliance
What is the 3 ways that work of breathing increases
In RLD, work of breathing is increased.
Work of breathing is increased by:
Increased airway resistance
Increases in flow rates
Decreases in lung or chest wall compliance
Compensatory mechanism
How does the lungs deal with a decreased breathing compliance.
To overcome the decrease in pulmonary compliance, the respiratory rate is usually increased
Accessory muscles of inspiration are recruited either at rest or at a lower activity level, in order to assist with chest wall expansion.
How much does a normal person use of VO2 at rest vs. Someone with RLD how much VO2 do they use???
In normal persons at rest, the body uses less than 5% of the VO2 (ie 3-14 ml O2/min) to support the work of breathing
With RLD the % of VO2 required to support the work of breathing can be 25% or more
What are the six classic signs of Respiratory Lung Dysfunction
Six classic signs often indicate and are consistent with RLD
Tachypnea
Hypoxemia
Alteration in breath sounds on auscultation
Decrease in lung volumes/capacities
Decreased diffusing capacity
Cor Pulmonale
What is tachypnea???
Tidal Volume- by the way is the NORMAL lung volume without any extra effort being made amount of air inhaled and exhaled.
An involuntary adjustment is made to increase the respiratory rate to compensate for the decrease in tidal volume thereby maintaining the same minute ventilation
Early in RLD, overcompensation may occur which results in alveolar hyperventilation
What is hypoxemia? How does it come about
Ventilation-Perfusion Mismatching
May occur as a result of:
Changes in the collagenous framework of the lung
Scarring of capillary channels
Distortion or narrowing of the small airways
Compression from tumors in the lung
Bony abnormalities of the chest wall
Decreased oxygen in the blood.
What happens with Tidal voulme, IRV, ERV,
Decrease in Tidal volume
Decrease in inspiratory reserve volume
Decrease in expiratory reserve volume
Residual volume is decreased, but degree of decrease may not be as dramatic as that seen in the IRV and ERV
Why does the diffusion capacity decrease with RLD? think scarring
DLCO is decreased as a result of a widening of the interstitial spaces due to scar tissue, fibrosis of the capillaries, and ventilation-perfusion abnormalities.
In RLD DLCO has been measured at less than 50% of predicted.
What is Cor Pulmonale?
Right sided heart failure resulting from hypoxemia, fibrosis, and compression of the pulmonary capillariespulmonary hypertension.
Because the pulmonary capillaries are fibrotic, they are less capable of distending to handle the ordinary increase in cardiac output expected with exercise
Symptoms associated with RLD
Dyspnea
Dry non productive cough
Wasted, emaciated appearance
What is the treatment typically for RLD
If etiological factors are permanent or progressive, supportive measures are mostly utilized:
Antibiotic therapy
Measures to promote adequate ventilation
Supplemental oxygen
Prevention of accumulation of pulmonary secretions
Nutritional support
What is obstructive lung dysfunction
Diseases of the respiratory tract that produce an obstruction to airflow. This obstruction to airflow can ultimately affect both the mechanical and gas exchanging capability of the lungs.
Typical changes seen with Obstructive lung disease
Increased mucus production/impaired mucus secretion
Inflammation of the mucosal lining of the bronchi and bronchioles
Mucosal thickening
Spasm of the bronchial smooth muscle
Two ways that the bronchioles shutdown.
Narrowing of the bronchial lumen
Increased resistance to airflow
Loss of normal elastic recoil of lung tissuetendency for the airways to collapse
hyperinflation
What does the work rate of breathing increase
Respiratory muscles must work harder to overcome the increased airway resistance
Diaphragm excursion may be limited due to hyperinflation of the lungs
Alveolar ventilation is reduced
Alveolar-capillary membrane surface area may be reduced.
To determine the diaphargmatic distance you can tap on the chest to hear the hollowness upon tapping on it. Also in an X-ray if the lungs are flat then then they are pushing down on the diapharggm and the diaphragm is not expanded
Clinical manisfestations or Signs of Obstructive Lung Disease or OLD
Signs Hypoxemia Increased production of mucus/impaired clearance Pulmonary Hypertension Polycythemia Cor Pulmonale
External signs of OLD
Chronic cough
Expectoration of mucus
Wheezing
Dyspnea on Exertion
Classfications of Obstruction
Bronchi or airways with cartilage in their walls (>2mm in diameter)
Bronchioles or airways without cartilage in their walls (<2mm in diameter)
Lung parenchyma (alveolar units): portion of the lung involved in gas exchange.
What are some enviormental factors that can lead to Obstructive Lung Disease and what decade of life does it usally come about???
Environmental factors Pollution Noxious gases Occupational exposures Cigarette smoking
Functionally, not notable until the sixth or seventh decade of life