L5: Swallowing and the Resp System Flashcards
conducting zone =
“ventilation”
resp passageways
nasal cavity, oral cavity, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
respiratory zone =
“respiration”
site of gas exchange
resp bronchioles, alveolar ducts, alveoli
what 2 things does the ease of ventilation depend on?
integrity of the ventilatory pump - mechanism which air moves into the lungs (musculature/nerves)
compliance of the alveoli and chest wall (recoil pressure - elasticity; resistance to recoil pressure by connection to chest wall) ….partly inflated all the time inc compliance + surfactant
what can damage the ventilatory pump?
kyphosis, scoliosis
paralysis
pain
alveolar compliance is altered by…
fibrosis, inflammation (thickened/damaged alveoli)
ARDS/Pneumonitis (loss of surfactant)
Atelectasis, pneumothorax (damaged chest wall coupling)
so ventilation needs…
an intact pump
compliant alveolar system (elastic alveolar membrane + surfactant to maintain surface tension)
respiration involves…
a thin membrane
needs blood in the capillary bed (to exchange gas w atmosphere)
alveolar and capillary gas concentration diff (allows for diffusion to occur)
external resp =
gas exchanged bw alveolar air and pulmonary capillaries
internal resp =
gas exchanged bw arterial blood and working tissues
O2 and CO2 concentrations are balanced by…
the resp system
hypoxemia =
poor O2 conc in the alveoli, so poor movement of O2 into blood – relates to external resp
hypoxia =
low O2 getting to muscles for example or to brain, related to internal resp
hypercapnia =
too much CO2 in the system (those who are hypoxemic are hypercapnia)
external resp can be disrupted by…
changes to the resp membrane
inflammation, excess mucous
insufficient clearance of infiltrates
resp failure can be caused by gas concentration being…
insufficient for diffusion
build up of CO2 in the lungs (due to insufficient expiratory airflow) [lung fibrosis, emphysema]
respiration needs…
porous resp thin membrane
intact capillary perfusion (blood to alveolar air interface, no obstructions)
gas gradient bw air and blood
intact perfusion at organ level
COPD =
group of diseases that are characterized by irreversible airway obstruction caused by destruction of lung tissue
to diagnose COPD it involves what symps, risk factors, spirometry?
symps= cough + sputum, dyspnea
risk factors = tobacco, occupation, indoor/outdoor pollution
spirometry = FEV1 (forced exp volume across 1 sec) and FVC (forced vital capacity)
chronic bronchitis =
productive cough for a min of 3 months/year, for 2 consecutive years
excessive mucous production, narrowing of small airways secondary to edema
eventually dev of tissue fibrosis due to repeated episodes of irritation and inflammation
cyanotic due to inadequate gas exchange - low levels of oxygen in blood trigger inc resp efforts
emphysema =
deterioration of alveolar walls; loss of elastic recoil properties
air remains trapped in lungs
diaphragm becomes less efficient as it is flattened by hyperinflated lungs
inc use of accessory muscles of resp to ventilate alveoli (rapid shallow breathing; weight loss)
thin. barrel-chested appearance
gas exchange requires…
near constant, predictable cycle of ventilation cycle
resp rate approx 16/min in young and 20/min in old
resp cycle = insp 40% and exp 60%
is swallowing cycle less or more predictable than gas exchange?
alimentary swallow?
saliva swallow?
total swallow duration?
swallow apnea duration?
less predictable
alimentary swallowing = unpredictable; > 1 sw/min
saliva swallowing = more preditable; approx 1 sw/min (based on saliva flow rate and vallecular volume)
total swallow duration = inc w age
swallow apnea duration = inc w age, dec w lower lung volumes
describe the set up for the Martin et all (2005) study
healthy volunteers across aging continuum
2trials of 5 ml thin liquid (most likely to aspirate on this)
looked at onset of 11 breathing and swallowing events
identified phases of breathing bf and after swallowing
presence, depth, and response to airway penetration was recorded
result of the martin harris et al (2005) study
4 resp-phase patterns which change w advanced age
Ex-sw-ex, in-sw-ex, ex-sw-in, in-sw-in
EX-SW-EX = most common/safe
non dominant patterns inc w advancing age
apnea onset and duration were highly variable (apnea offset sig later in oldest group; tendency for total swallow duration to inc w age)
no diffs in penetration/asp scores bw patterns
disease can alter…
ultimately leads…
ventilation +/- resp… changes how a patient breathes
to change in coordination bw breathing and swallowing (and speech)
pulomary disease leads to altered…
ventilation +/- gas exchange
ex. COPD = effortful airflow; dec permeability of resp mem
neurological disease can lead to altered …
resp control coordination
ex. stroke= smaller lung volumes, shorter cycle duration at rest; direction of airflow after swallow (60% expire after swallow vs 95% in health)
what are the two airway clearance methods for proximal LRT?
Cough
mucociliary action
pulmonary clearance is _____ in the superior portion of the lower resp tract
mechanical
cough =
reflex involving afferent inputs and forceful expulsion of air from lungs
what is involved with a cough?
inc lung volume
rise in subglottic pressure
abrupt opening of glottis causes narrowing of trachea and major conducting airways
rapidly accelerating expiratory airflow sweeps mucosal surface
cough reflex can be altered in
various disease states
mucociliary action =
Cilia?
mucous and foreign particles trapped w/i it are propelled toward major airways and trachea by beating of cilia
cilia extend from larynx to terminal bronchiole and adjacent cilia beat in coordination
ciliary action and mucous secretion can be altered in certain diseases
two ways to clear the airway in the distal LRT are…
clearance of particles
clearance of liquids
pulmonary clearance differs in the ….
distal LRT
clearance of particles involves…
pulmonary clearance of particles is cellular in distal part of LRT (i.e. beyond terminal bronchiole)
alveoli are protected by alveolar macrophages which provide phagocytosis (particle ingestion) and carry particles to lymph nodes
alveolar macrophages kill pathogens after phagocytosis
clearance of liquids involves…
pulmonary clearance for liquids is by lympathics which return fluid to lymph nodes where they are filtered
lung lymphatics begin as small vessels at level of resp bronchioles and join to form larger vessels that eventually empty via thoracic duct into the blood vessels
lymphatics normally clear 400-700 ml/day
persons w reduced lymphatic clearance are at inc risk of pneumonia
foreign material interferes w gas exchange in many ways:
block small airways, reduce surfactant concentration, causes inflammation that can inc distance bw airway and blood in pulmonary capillaries
atelectasis
atelectasis =
collapse of alveoli; may involve a single alveolus or a large part of the lung
actelctalsis of larger lung segments is detected as focal infiltrates on chest xray
atelectasis is a predisposing factor in pneumonia
pneumonia =
vs
pneumonitis =
pneumonia = lung infection + inflammation
pneumonitis = lung inflammation +/- infection
what are the predisposing events for pneumonitis?
chemical exposure
irritants, allergens
radiation therapy
medication
acidic aspirate (reflex, emesis) = aspiration pneumonitis
a predisposing event for pneumonitis leads to…
traumatizes lung tissue leading to acute injury
manifests as lung inflammation
bacterial infection may occur in later stage of lung injury
what are the signs, symps, and outcomes of pneumonitis?
signs = wheezing, dyspnea, cyanosis, coughing, gastric material in oropharynx
symps = pulmonary edema
outcomes = hypotension, hypoxemia, severe acute resp distress syndrome, death
2 types of pneumonia
community acquired pneumonia - ex. airborne, droplet airborne pathogen
hospital acquired pneumonia or nosocomial pneumonia - ex. airborne/droplet pathogen, ventilator associated pneumonia
2 types of aspiration pneumonia
dysphagia related aspiration pneumonia
non dysphagia related aspiration pneumonia
dysphagia related aspiration pneumonia =
features of pneumonia
infiltrates are in gravity dependent segments of lung (usually lower R lung)
pt has dysphagia
non dysphagia related aspiration pneumonia =
features of pneumonia
no dysphagia symps
can conceivably be related to gastroesophageal reflux or emesis
aspiration pneumonia has a predisposing event such as
bacterial or viral pathogens in oral cavity/pharynx
aspiration
during aspiration pneumonia after predisposing event….
what can it lead to?
pathogens colonize in the lungs (portion of lung affected depends on gravitational flow)
results in infection and inflammation - pathogens and their waste irritate lung tissue
if does not resolve, can spread systematically and lead to… sepsis, multi-organ failure, shock, death
signs, symps, outcomes or pneumonia?
signs = cough, sputum production, fever, resp distress
symps = leukocytosis (inc WBC count), infiltrates on chest x ray, insp crackles
outcomes = sepis, multi-organ failure, shock, death
how aspiration pneumonitis managed?
if event is witnesses, suctioning of upper airway
antibiotics not indicated unless pneumonitis does not resolve w/i 48 hours
may prescribe other meds, like steroids
how aspiration pneumonia managed?
if persistent fever (>24 hours), leukocytosis (elevated WBC), new infiltrate on chest xray, resp distress, productive cough
antiobiotics are unequivocally indicated (broad spectrum)
aspiration pneumonia is a major cause of…
morbidity and mortality among the elderly who are hospitalized or in nursing homes
mortality rate ranges from 20-80%
most freq infectious cause of death
aspiration pneumonia also the leading cause of mortality in …
children under 5
aspiration tolerance is related to 8 factors
nature of aspirate (freq, volume, acidity, depth)
status of immune sys
pulmonary status
nutritional status
level of consciousness
mobility
prior history of pneumonia
age
bottom line about factors related to aspiration tolerance…
not all aspirators dev aspiration pneumonia
what are some predictors of aspiration pneumonia?
advanced age
residing in institutional setting
predisposing medical conds
reduced mental status
reduced functional status
tube feeding
gastoresophageal reflux
poor nutritional status
oropharyngeal colonization of pathogenic bacteria, reduced pulmonary clearance, and immunocompromise
certainly ____ predisposes for aspiration pneumonia, but association not always found
dysphagia
across all pt groups best independent predictors of asp pneumonia were:
tube fed before AP
dependent for oral care
dependent for feeding
current smoking
number of meds
number of decayed teeth
multiple medical diagnoses
aspiration pneumonia results when…
critical threshold of INVASION and RESISTANCE is passed
to cause aspiration pneumonia, aspiration …
must occur, but aspiration will only lead to pneumonia if quantity of material is great, bacteria are pathogenic, and/or host resistance is compromised
dysphagia is an important risk factor for aspiration pneumonia, but…
not sufficient to cause pneumonia in absence of other risk factors
