Respiratory pathophysiology 3 Flashcards
Asthma is defined by an
acute, reversible airway obstruction that is accompanied by chronic airway inflammation and bronchial hyperreactivity
____________ is the greatest risk factor for developing asthma
Atopy (the condition of being “hyper-allergic”)
Asthma has a __________ component
reversible!- bronchodilator therapy helps to improve
With asthma, ______________ are reduced but improve following bronchodilator therapy
FEV1
FEV1/FVC
FEF 25-75%
The most common ABG finding with asthma is
respiratory alkalosis with hypocarbia
With asthma, an elevated PaCO2 suggests
air trapping
respiratory muscle fatigue
impending respiratory failure
Key signs and symptoms of asthma include
wheezing
dyspnea
chest discomfort and/or tightness
productive or non-productive cough
prolonged expiratory phase
eosinophilia
What kind of extubation is preferred for asthmatics?
deep if not contraindicated
Ways to avoid triggering asthma include:
suppressing airway reflexes during airway instrumentation (consider an LMA or regional technique instead of tracheal intubation if possible)
What types of drugs should be avoided with asthmatics?
non-selective beta blockers (use beta 1 selective agents instead)
avoid histamine-releasing drugs (succinylcholine, atracurium, morphine, meperidine)
What should be done intraoperatively for asthmatics?
limit inspiratory time
prolong expiratory time
tolerate moderate permissive hypercapnia
Anesthetic agents that promote bronchodilation include
sevo
iso
ketamine
propofol
and lidocaine (IV or tracheal)
Stimuli that provoke s/sx of asthma include
allergens- environmental
drugs- aspirin, NSAIDs, beta antagonists, sulfites
infection-resp. virus
stress- vagal stimulation, cold air
exercise- usually following physical activity
With asthma, tachypnea and hyperventilation are the result of __________________ NOT ___________.
neural reflexes; NOT hypoxemia
A _________ retains airway humidity and may benefit patients with exercise-induced asthma.
heat-moisture exchanger
___________ can increase airway resistance and should be avoided in patients with aspirin-intolerant asthma.
Ketorolac
This obstetric drug can cause bronchoconstriction in asthmatic patients
Carboprost (hemabate)
____________ reduces the viscosity of airway secretions
Intravenous hydration
Although anticholinesterases could precipitate bronchospasm, co-administration of ______ negates the risk.
anticholinergics
_________ is the best choice beta blocker in asthmatics
esmolol because of its short 1/2 life and beta-1 selectivity
Presynaptic H2 receptor stimulation reduces ________
histamine release; can cause bronchospasm but risk is low
Which drug is LEAST likely to be effective in relieving symptoms of acute bronchospasm?
a. ketamine 1 mg/kg IV
b. epinephrine 1 mcg/kg IV
c. hydrocortisone 2 mg/kg IV
d. lidocaine 1.5 mg/kg IV
c. hydrocortisone 2 mg/kg- won’t help in acute phase b/c it takes several hours to take effect
Not all wheezing is asthma, so you must consider other etiologies in your differential diagnosis including
a kinked ETT
end-bronchial intubation
& pulmonary aspiration
pneumothorax
pulmonary edema
pulmonary embolus
light anesthesia leads to coughing and straining and reduced FRC
Intraoperative bronchospasm presents as
wheezing
decreased breath sounds
increased peak inspiratory pressure (decreased dynamic compliance)
increased alpha angle on the EtCO2 waveform
Treatment for acute bronchospasm includes
100% FiO2
deepen anesthetic
short-acting inhaled beta 2 agonist
inhaled ipratropium
epinephrine 1 mcg/kg IV
hydrocortisone 2-4 mg/kg IV
aminophylline
helium-oxygen gas mixture
Mechanical obstruction of ETT can be a result of
kinking
patient biting down
secretions
cuff overinflation
_______________ is NOT used in the treatment of acute bronchospasm.
Montelukast
Alpha-1 antitrypsin deficiency: (select 2)
a. increases the risk of bronchospasm
b. causes panlobular emphysema
c. can be treated with IgG
d. is the most common metabolic disease affecting the liver
b. causes panlobular emphysema
d. is the most common metabolic disease affecting the liver
COPD is characterized by a reduction in
maximal expiratory flow and a slower forced emptying of the lungs
Unlike asthma, air flow obstruction with COPD is
not fully reversible
The name COPD is really an umbrella term for
chronic bronchitis and emphysema
Chronic bronchitis is associated with
hypertrophied bronchial mucus glands and chronic inflammation
Emphysema is associated with
enlargement and destruction of the airways distal to the terminal bronchioles
Etiologies of COPD include
smoking
respiratory infection
exposure to environmental pollutants such as coal mining, gold mining, and textile industries
alpha 1 antitrypsin deficiency
Inability to fully exhale leads to
gas trapping (increased residual volume)
Chronically elevated PaCO2 causes
respiratory acidosis
With COPD, the kidneys reabsorb bicarbonate which provides a
compensatory metabolic alkalosis
Administering supplemental oxygen to the patient with severe COPD does
not inhibit the “hypoxic drive”
Administering supplemental oxygen to the patient with severe COPD can cause
oxygen-induced hypercapnia due to inhibition of hypoxic pulmonary vasoconstriction
The Haldane effect
To minimize the risk of oxygen-induced hypercapnia in the patient with severe COPD, you should titrate the FiO2 to maintain the SaO2 between
88-92%
Common findings in patients with COPD include
flattened diaphragm
increased AP diameter
pulmonary bullae
increased work of breathing
______________ removes over distended tissue and allows normal lung tissue to function in a more regular way for patients with COPD
Lung reduction surgery
Chronic bronchitis is defined by the presence of
cough and sputum production for more than three months for two consecutive years
The common cause of chronic bronchitis is
cigarette smoking
What happens to the heart in chronic bronchitis?
left heart function is normal (normal PAOP)
a weak right heart creates a back pressure on the liver–> liver congestion and ascites
_________________ is more efficacious than any drug in terms of improving pulmonary hypertension and preventing erythrocytosis in chronic bronchitis.
Oxygen therapy
With chronic bronchitis, RBCs are
overproduced to compensate for V/Q mismatch and hypoxemia
leads to increased blood viscosity and myocardial work
With chronic bronchitis, chronic hypoxemia and hypercarbia increase PVR leading to
pulmonary hypertension–> RV strain–> cor pulmonale
Emphysema is associated with
enlargement and destruction of the airways distal to the terminal bronchioles
Emphysema results in
increased dead space & destruction of the pulmonary capillary bed leading to pHTN
_______ can cause emphysema
Alpha-1 antitrypsin deficeincy
The patient with emphysema generally has a normal or slightly reduced
PaO2
PaCO2 is usually normal or decreased (as a result of hyperventilation)
Late in emphysema, hypoxemia and hypercarbia further
increase PVR leading to RHF
Alpha 1 antitrypsin is an enzyme produced by
the liver
Alpha-1 antitrypsin deficiency is a disease where
an abnormal variant of the enzyme is produced
Alpha 1 antitryspin deficiency allows a relative overactivity of
alveolar elastase activity resulting in destruction of pulmonary connective tissue and the development of panlobular emphysema
What spirometry values are increased in COPD?
RV, FRC, TLC
What spirometry values are decreased in COPD?
FEV1, FEV1/FVC ratio, FEF 25-75%
An FEV1/FVC ratio of <70% after bronchodilator therapy is diagnostic of
COPD
