Pulmonary Flashcards
Upper airways
nose or mouth: entry point into respiratory system
pharynx: common area used for both respiratory and digestive systems
larynx: connects the pharynx to the trachea, including the epiglottis and vocal cords
lower airways
the conducting airways, trachea to terminal bronchioles, transport air only. No gas exchange occurs.
The respiratory unit: respiratory bronchioles, alveolar ducts, alveolar savs and alveoli. Diffusion of gas occurs through all these structures
R lung
divided into 3 lobes by the oblique and horizontal fissures; each lobe divides into segments- total of 10
L lung
divided into 2 lobes by the oblique fissure; each lobe divides into segments- total of 8
pleura
Parietal pleura covers the inner surface of the thoracic cage, diaphragm and mediastinal border of the lung
visceral pleura: wraps the outside surface of the lung, including the fissure lines
Intracellular space is the potential space between the 2 pleurae that maintains the approximation of the rib cage and lungs, allowing forces to be transmitted from 1 structure to another
primary muscles of inspiration
Primary muscle: diaphragm
- made up of 2 hemidiaphragms, each with a central tendon.
- at rest, the hemidiaphragms are arched high into the thorax
- when the muscle contracts, the central tendon is pulled down, flattening the dome resulting in a protrusion of the abdominal wall during inhalation
Additional primary muscles: portions of the intercostals
Accessory muscles of inspiration
used when a more rapid or deeper inhalation is required or in disease states
upper 2 ribs are raised by the scalenes and SCM
rest of the ribs are are raised by the elevator costar and serrates
by fixing the shoulder girdle- the trap, pecs and serratus can become muscles of inspiration
expiratory muscles of ventilation
resting expiration results from a passive relaxation of the inspiratory muscles and the elastic recoil tendency of the lung
-normal abdominal tone holds the abdominal contents directly under the diaphragm, assisting the return of the diaphragm to the normal high domed position
expiratory muscles are used when a quicker/fuller expiration is desired
-QL, portions of the intercostals, muscles of the abdomen and triangularis sterni
ventilation with patients who lack abdominal musculature (SCI)
have a lower resting position of the diaphragm, decreasing inspiratory reserve
the more upright the body position, the lower the diaphragm and the lower the inspiratory capacity
the more suing the more advantageous the position of the diaphragm
an abdominal binder may be helpful in providing support to the abdominal viscera, assisting ventilation. Care must be taken not to constrict the thorax
Resting end expiratory pressure (REEP)
the point of equilibrium where inspiratory/expiratory forces are balanced
-occurs at end tidal expiration
Forces on the rib cage/breathing mechanics:
- elastic recoil of the lung parenchyma pulls lungs, and bony thorax into a position of exhalation (inward pull)
- bony thorax pulls into a position of inspiration (outward pull)
Tidal volume (TV)
volume of gas inhaled (or exhaled) during a normal resting breath
normal adult: 500mL
normal infant: 20 mL
inspiratory reserve volume (IRV)
volume of gas that can be inhaled beyond a normal resting tidal inhalation
Expiratory reserve volume (ERV)
volume of has that can be exhaled beyond a normal resting tidal expiration
Residual volume (RV)
volume of gas that remains in the lungs after ERV has been exhaled
Inspiratory capacity (IC)
IRV + TV
the amount of air that can be inhaled from REEP
Vital capacity (VC)
IRV + TV + ERV
the amount of air that is under volitional control; conventionally measured as forced expiratory vital capacity (FVC)
Functional residual capacity
ERV + RV
the amount of air that resides in the lungs after a normal resting tidal exhalation
Total lung capacity
IRV + TV + FRV + RV
the total amount of air that is contained within the thorax during a maximum inspiratory effort
Forced expiratory volume (FEV1)
the amount of air exhaled during the 1st second of FVC
in the healthy person, at least 70% of FVC is exhaled within the first second
FEV1/FVC x100 — >70%
ventilation vs. respiration
ventilation= movement of gas in and out of the pulmonary system
respiration= diffusion of gas across the alveolar capillary membrane
arterial oxygenation
=the ability of arterial blood to carry oxygen
PaO2 in the arterial blood
Partial pressure of oxygen in the arterial blood
depends on the integrity of the pulmonary system, the circulatory system and the atmosphere.
95-100% in a young, health person
decreases with age
Hypoxemia 100%
alveolar ventilation
ability to remove CO2 from the pulmonary circulation and maintain pH
pH
indicates the concentration of free floating hydrogen ions within the body
normal range: 7.35-7.45
PaCO2
the partial pressure of CO2 within the arterial blood
normal: 35-45 mmHg
removal or retention of CO2 by the respiratory system alters the pH of the body in an inverse relationship
- increase in the PaCO2 decreases the body’s pH
- decrease in PaCO2 increases pH
hypercapnea
PaCO2 >45 mmHg
increase in the PaCO2 decreases the body’s pH
hypocapnea
PaCO2
HCO3-
amount of bicarbonate ions within the arterial blood
normal: 22-28 mEq/mL
removal or retention of HCI3- alters the pH of the body in a direct relationship
- increase in HCO3- increases body’s pH
- decrease in HCO3- decreases body’s pH
optimal respiration occurs when:
ventilation and perfusion (BF to the lungs) are matched
different ventilation and perfuse relationships exist
dead space
anatomical (conducting airways) or physiological (diseases such as PE)
space that is well ventilated but in which no respiration (gas exchange) occurs
“gravity independent areas”
shunt
no respiration occurs because of a ventilation abnormality
complete atelectasis of a respiratory unit allows the blood to travel through the pulmonary capillary without gas diffusion
“gravity dependent areas”
effects of body position on the ventilation/perfusion relationship:
UPRIGHT POSITION:
- perfusion (Q) is gravity dependent- most pulmonary blood is found at the base of the lung
- ventilation: at the static point of REEP, the apical alveoli are fuller than those at the base. During the dynamic phase of inspiration, more air will be delivered to the less filled alveoli at the bases causing a greater change in Ve at the bases
- V/Q ratio: apices are gravity independent with the lowest blood flow (Q). Although relatively low, there is still more air than blood, resulting in a high V/Q ratio (dead space).
- V/Q of the middle zone of the lung are evenly matched.
- V/Q of the bases are gravity dependent and therefore, have the most Q. Although Ve is relatively high, there is more blood than air, resulting in a (relatively) low V/Q ratio (shunt)
OTHER POSITIONS:
- gravity independent area– dead space
- gravity dependent area– shunt
Ventilation/perfusion ratio (V/Q ratio):
the ratio of pulmonary alveolar ventilation to pulmonary capillary perfusion
central control centers for ventilation
cortex, pons, medulla and ANS
patient interview:
chief complaint
-usually loss of function, ADLs
present illness
- initial onset
- progression
- worsens of improves
history
- occupation and exposures
- PMH- heart disease? long term steroid?
- current meds that can mask (steroids) or alter (BB, bronchodilators) VS
- social habits: smoking, alcohol, drugs
- exercise
- cough/sputum
- family history
tachypnea
RR > 20 bpm
key observations during examine
peripheral edema seen in gravity dependent areas and jugular venous distention indicates possible heart failure
-RV hypertophy and dilation (cor pulmonale) are common sequelae to chronic lung disease
body positions: stabilizing the shoulder girdle places the thorax in the inspiratory position and allows the additional recruitment of muscles for inspiration (pectorals)
color: cyanosis (sign of hypoxemia)
digital clubbing (sign of chronic hypoxemia)
Neck:
- observe the trachea- should be midline
- use of accessory muscles of ventilation
Thorax:
- changes in body thorax- pectus excavate, cranium
- ant-post:lat dimension– 1:2 ratio (With obstructive pulmonary disease, the lung recoil force is decreased, resulting in a barreled chest and increased AP dimension)
- R and L thorax should be symmetrical
- healthy thoracic excursion should be 2-3 inches
lung auscultation: normal lung sounds
intensity of inspiration and expiration is quieter at the bases than the apex
vesicular- normal breath sound: a soft rustling sound heard t/out all of inspiration and the beginning of expiration
Bronchial: a more hollow, echoing sound normally found only over the R superior anterior thorax- corresponds to an area over the R main stem bronchus.
-all of inspiration and most of expiration are heard with bronchial breath sounds
*Decreased: a very distant sound not normally heard over a healthy thorax; allows only some of the inspiration to be heard. often associated with obstructive lung diseases
adventitious (extra) lung sounds:
Crackles: “rales, crepitations”
- crackling sound heard usually during inspiration that indicates pathology
- could be result of air bubbles in secretions or movement of fibrotic tissue during breathing
- atelectasis, fibrosis, pulmonary edema, LV CHF
Wheezes/rhonci: a musically pitched sound, usually heard during expiration, caused by airway obstruction (asthma, COPD, foreign body aspiration)
-with severe airway constriction, as with croup, wheezes may be heard on inspiration as well
vocal sounds
normal:
- loudest near trachea and main stem bronchi
- softer and less clear at more distal areas
abnormal:
- may be heard through fluid-filled areas of consolidation, cavitation lesions or pleural effusions
- Egophony
- bronchopony
- whispered pectoriloquy
egophony
nasal or bleating sound heard during auscultation
“E” sounds are transmitted to sound like “A”
-may be heard through fluid-filled areas of consolidation, cavitation lesions or pleural effusions
Bronchophony
characterized by an intense, clear sound during auscultation, even at the lung bases
“99” “66”
-may be heard through fluid-filled areas of consolidation, cavitation lesions or pleural effusions
Whispered pectoriloquy
occurs when whispered sounds are heard clearly during auscultation
-may be heard through fluid-filled areas of consolidation, cavitation lesions or pleural effusions
pulmonary radiographic exam
chest x-ray: 2D radiographic film to detect presence of abnormal material (exudate, blood) or a change in pulmonary parenchyma (fibrosis, collapse)
CT: cross sectional plane
MRI
Ventilation perfusion (V/Q) scan: matches the ventilation pattern of the lung to the perfusion pattern to identify the presence of PE
Fluroscopy: continuous x ray beam allows observation of diaphragmatic excursion
Respiratory alkalosis
high pH
low PaCO2
normal HCO3-
causes: alveolar hyperventilation
S&S:
- dizzy
- syncope
- tingling
- numbness
- early tetany
respiratory acidosis
low pH
high PaCO2
normal HCO3-
causes: alveolar hypoventilation
S&S
- Early: anxiety, restless, SOB, HA
- Late: confusion, drowsy, coma