Obstructive Lung Disease '24 Flashcards
What do obstructive respiratory diseases contribute to in the perioperative setting?
Risk of pulmonary complications
What role do pulmonary complications play in long-term postoperative mortality?
Major role
How can the incidence of perioperative pulmonary complications be decreased?
Pt optimization before surgery
How can obstructive respiratory diseases be classified in terms of anesthetic management?
4 groups
What percentage of people aged 25-44 experience the common cold per year?
19%
Delete card. What fraction of scheduled surgery patients may have an active URI?
Consequently, a fraction
What accounts for approximately 95% of all URIs?
Infectious nasopharyngitis
What are the most common viral pathogens associated with URIs?
Rhinovirus, coronavirus, influenza, parainfluenza, RSV
Why are viral cultures and lab tests impractical in a busy clinical setting for diagnosing URI?
Lack sensitivity, time-consuming, expensive
What are some respiratory adverse events children with URI’s are at a higher risk for?
Transient hypoxemia, laryngospasm, breath holding, coughing
Is data on how adults with URI’s fare under anesthesia readily available?
Limited data
How long should surgery be postponed if cancelled due to an acute URI?
Not be rescheduled within 6 weeks
What does the COLDS scoring system assess in relation to proceeding with surgery?
Current symptoms, onset, lung disease, airway device, type of surgery
What should be included in the anesthetic management of patients with upper respiratory infections (URIs)?
Adequate hydration, reducing secretions, limiting airway manipulation
How can upper airway sensitivity be reduced in patients with URIs?
Nebulized or topical local anesthetic on vocal cords
Which airway device may reduce the risk of laryngospasm in patients with URIs?
LMA (laryngeal mask airway)
What is a consideration for induction and maintenance in patients with URIs?
Similar to asthma
When may deep extubation be considered in patients with URIs?
No contraindications, for smoother emergence
What adverse respiratory events can occur in patients with URIs?
Bronchospasm, laryngospasm, airway obstruction, postintubation croup, desaturation, atelectasis
How can intraoperative and postoperative hypoxemia be treated in patients with URIs?
Supplemental O2
What is asthma?
Chronic inflammation of lower airways
What leads to infiltration of airway mucosa in asthma?
Activation of inflammatory cascade
What results in airway edema in asthma?
Inflammation
What leads to thickening of basement membrane and smooth muscle mass in asthma?
Airway remodeling
What are the main inflammatory mediators implicated in asthma?
Histamine, prostaglandin D2, leukotrienes
What are some symptoms of asthma?
Expiratory wheezing, cough, dyspnea, chest tightness, eosinophilia
What is status asthmaticus?
Life-threatening bronchospasm
What should be focused on when obtaining history from an asthma patient?
Previous intubations, ICU admissions, hospitalizations, coexisting diseases
How is asthma diagnosed?
Clinical history, symptoms, airway obstruction
What symptoms are reported by patients with asthma?
Wheezing, chest tightness, SOB
How is asthma severity classified?
Symptoms, PFTs, medication usage
What is Forced Expiratory Volume in 1 sec (FEV1)?
Volume of air exhaled in 1 sec
What is the normal range for FEV1?
80%-120% of predicted value
What is Forced Vital Capacity (FVC)?
Volume exhaled after deep inhalation
What are the normal FVC values for females and males?
3.7 L (females) and = 4.8 L (males)
What is the normal range for the FEV1/FVC ratio in healthy adults?
75%-80%
What is Maximum Voluntary Ventilation (MVV)?
Max air in/out in 1 min
How is MVV measured?
Over 15 sec extrapolated
What are the average MVV values for males and females?
140-180 L/min, 80-120 L/min
What is Diffusing Capacity (DLCO)?
CO transfer to blood
How is DLCO measured?
CO breath held 20 sec
What is the normal DLCO value?
17-25 mL/min/mm Hg
What are direct measures of the severity of expiratory obstruction in asthma?
FEV1, FEF, midexpiratory phase flow
What is a typical FEV1 percentage in a symptomatic asthmatic patient coming to the hospital?
<35%
What do flow-volume loops show in asthma?
Downward scooping of expiratory limb
What happens to the functional residual capacity (FRC) during moderate or severe asthma attacks?
May increase substantially
What happens to total lung capacity (TLC) during moderate or severe asthma attacks?
Usually remains normal
What is not changed in asthma patients regarding lung capacity for carbon monoxide?
Diffusing lung capacity
What does relief of obstruction after a bronchodilator suggest in patients with expiratory obstruction?
Diagnosis of asthma
Do abnormalities in pulmonary function tests (PFTs) persist after an asthma attack despite the absence of symptoms?
Yes
What is B in FEV1 <80% of VC?
bronchospasm
Inspiratory flow normal
Volume increasing
Restrictive (expiratory)
R(E)
Restrictive (parenchymal)
R(P)
Normal flow-volume curve of expiration
TLC to RV
What ABG findings are common in symptomatic asthma?
Hypocarbia and respiratory alkalosis
What may result in a PaO2 of <60 mmHg in asthma?
Increasing severity of expiratory obstruction
When does PaCO2 likely increase in asthma?
When FEV1 is <25% of predicted
What contributes to the development of hypercarbia in asthma?
Fatigue of skeletal muscles
What findings may be seen in the CXR of patients with severe asthma?
Hyperinflation, hilar vascular congestion
How can CXRs be helpful in asthma exacerbations?
Determining cause, ruling out other causes
What EKG findings may be present during an asthma attack?
RV strain, ventricular irritability
What are some differential diagnoses for asthma?
Viral tracheobronchitis, sarcoidosis, COPD, foreign body aspiration
What is the aim of asthma treatments?
Control symptoms and reduce exacerbations
What is the first-line treatment for patients with mild asthma?
Short-acting inhaled β2 agonist
What is recommended for those with less than 2 exacerbations per month?
Short-acting inhaled β2 agonist
What can be added if symptoms remain uncontrolled despite initial treatment?
Daily inhaled β2 agonist
What other therapies can be considered for asthma treatment?
Inhaled muscarinic antagonists, leukotriene modifiers, mast cell stabilizers
When are systemic corticosteroids used in asthma treatment?
Severe asthma uncontrolled with inhalational medications
What does SQ immunotherapy show in asthma treatment studies?
Decreases long-term medication use, may improve quality of life
What is bronchial thermoplasty (BT)?
Radiofrequency ablation of airway smooth muscles
How is bronchial thermoplasty (BT) performed?
Through bronchoscopy in three sessions
What can be a risk of bronchial thermoplasty (BT)?
Airway fire due to intense heat
How does the loss of airway smooth muscle mass help in asthma treatment?
Reduces bronchoconstriction
Why are serial PFTs important during treatment?
To monitor response
At what % of normal FEV1 do patients usually have minimal or no symptoms?
50%
What is acute severe asthma defined as?
Bronchospasm not resolving with usual treatment
Why is acute severe asthma considered life-threatening?
Emergency situation
What is the emergency treatment for acute severe asthma?
High-dose, short-acting β2 agonists and systemic corticosteroids
How often can inhaled β2 agonists be administered in acute severe asthma?
Every 15-20 minutes for several doses
Why are IV corticosteroids administered early in acute severe asthma?
Onset takes several hours
What are the two corticosteroids commonly used in acute severe asthma?
Hydrocortisone & methylprednisolone
Why is supplemental oxygen given in acute severe asthma?
To maintain oxygen saturation >90%
What other drugs can be used in more severe cases of acute severe asthma?
Magnesium and oral leukotriene inhibitors
What is the recommended oxygen saturation level to maintain in acute severe asthma?
> 90%
What is the interval for administering 2 agonists via metered-dose inhaler or continuous nebulizer in acute severe asthma?
every 15-20 min
What type of corticosteroids are recommended for intravenous administration in acute severe asthma?
hydrocortisone or methylprednisolone
When is tracheal intubation and mechanical ventilation recommended in acute severe asthma?
when Paco₂ >50 mm Hg
What medication can be administered by inhalation as an anticholinergic in acute severe asthma?
ipratropium
What can be considered as a last resort in acute severe asthma?
Extracorporeal membrane oxygenation (ECMO)
What is the purpose of high gas flows in mechanical ventilation for acute severe asthma?
permit short inspiration times and longer expiration times
Percentage range of asthmatics experiencing bronchospasm under GA
0.2-4.2%
Factors increasing risk of bronchospasm in asthmatics
Type of surgery, recency of last asthma attack
GA mechanisms increasing airway resistance
Depression of reflexes/functions, increased fluid in airway wall
Roll of intubation in asthma patients under GA
Stimulates airway, contributing to bronchospasm
Substances contributing to bronchospasm in asthmatics under GA
Substance P, neurokinins
What does preoperative evaluation of patients with asthma involve?
Disease severity, current treatment effectiveness, need for additional therapy
What aspects of a patient’s history should be noted in preoperative assessment of asthma?
Symptom control, exacerbation frequency, hospitalizations, anesthesia tolerance
Why is auscultation of the chest important in asthma preoperative assessment?
To detect wheezing or crepitations
What do eosinophil counts often reflect in asthma management?
Degree of airway inflammation
What pulmonary function tests may be indicated in preoperative assessment of asthma?
(esp FEV1) before and after bronchodilator
What reduction in FEV1 or FVC poses a risk for perioperative respiratory complications?
<70% of predicted, or FEV1:FVC ratio <65% of predicted
How can reversible components of asthma be improved preoperatively?
Chest physiotherapy, antibiotics, bronchodilators
When are ABGs indicated in preoperative assessment for asthma?
If there is a question about ventilation or oxygenation
What medications should be continued until induction in a preoperative asthma assessment?
Anti-inflammatories, bronchodilators
What is indicated if the patient has been on systemic corticosteroids within the past 6 months?
Stress-dose hydrocortisone or methylprednisolone
What criteria should be met regarding wheezing and PEFR before surgery in asthma patients?
Free of wheezing, PEFR >80% predicted/personal best value
What is COPD?
Chronic airflow obstruction
What are the symptoms of emphysema in COPD?
Lung parenchymal destruction
What risks factors contribute to COPD?
Cigarette smoking, dust exposure, genetic factors
What is the worldwide prevalence of COPD?
10%
How does COPD rank among causes of death globally?
3rd leading cause of death
What is one of the pathologic effects of COPD?
Destruction of lung parenchyma, enlarged air sacs, and development of emphysema
How does COPD impact bronchiolar wall structure?
Decreases structure, allowing collapse during exhalation
What happens to intrabronchial pressure in COPD?
Lowers and favors airway collapse
What are the symptoms of COPD?
Dyspnea, chronic cough, chronic sputum
What characterizes COPD exacerbations?
Acute worsening in airflow obstructions
How do tachypnea and prolonged expiratory times manifest as COPD worsens?
Evident with increasing expiratory obstruction
What are common breath sounds in COPD?
Decreased sounds, expiratory wheezes
What triggers exacerbations in COPD as the disease progresses?
Bacterial respiratory infections
How is the definitive diagnosis of COPD made?
Spirometry
What do PFTs show in patients with COPD?
Decrease in FEV1:FVC ratio and FEF 25-75%
What are common findings in COPD?
FEV1:FVC <70%, increased FRC & TLC, reduced DLCO
Why is there an increase in residual volume in COPD?
Slow expiratory airflow and gas trapping
What does the compensated increase in RV and FRC in COPD lead to?
Enlarged airway diameter
GOLD Spirometric Criteria for Mild COPD Severity
FEV1 ≥ 80% predicted
GOLD Spirometric Criteria for Moderate COPD Severity
50% ≤ FEV1 < 80% predicted
GOLD Spirometric Criteria for Severe COPD Severity
30% ≤ FEV1 < 50% predicted
GOLD Spirometric Criteria for Very Severe COPD Severity
FEV1 < 30% predicted
What imaging technique is much more sensitive at diagnosing COPD than CXR?
CT
What does hyperlucency in the lung periphery suggest in COPD diagnosis?
Emphysema
What confirms emphysema in COPD diagnosis?
Bullae
What is the multiorgan loss of tissue phenotype of COPD associated with?
Airspace enlargement, alveolar destruction, loss of bone, muscle, and fat tissues, higher rates of lung cancer
What is the bronchitic phenotype of COPD associated with?
Bronchiolar narrowing, wall thickening, metabolic syndrome, cardiac disease
What is the BODE index used for in COPD diagnosis?
Assess prognosis
What do higher BODE scores indicate?
Greater risk of exacerbations, hospitalizations, and pulmonary death
What does α1-antitrypsin deficiency associate with in COPD?
Inherited disorder
What is required for low α1-antitrypsin levels in COPD?
Lifelong replacement therapy
What should be measured in COPD patients with uncontrolled disease despite bronchodilator treatment?
Eosinophils
What does high eosinophil levels indicate the need for in COPD treatment?
Inhaled glucocorticoids
When do ABGs in COPD patients often remain normal?
Until COPD is severe
When does PaO2 usually decrease in relation to FEV1 in COPD?
When FEV1 is <50% of predicted
When may PaCO2 not increase significantly in COPD?
Until FEV1 is even lower
What is the first step in COPD treatment?
Reducing exposure to smoke and environmental pollutants
How much can smoking cessation decrease disease progression and mortality by?
Up to 18%
What is the initial treatment in COPD?
Long-acting inhaled muscarinic antagonists
What can be added if dyspnea persists despite initial treatment?
Long-acting β2 agonist
When are inhaled glucocorticoids most effective in COPD patients?
Associated asthma, rhinitis, elevated eosinophils, and history of exacerbations
What can inhaled treatments improve in COPD?
Symptoms, FEV1
What are other treatments recommended for COPD?
Flu & pneumonia vaccines
What are helpful for COPD if right heart failure (RHF) or congestive heart failure (CHF) develop?
Diuretics
What treatments may be necessary during COPD exacerbations?
Abx, corticosteroids, theophylline
What can pulmonary rehab programs do for individuals with COPD?
Increase exercise capacity
When is long-term home oxygen recommended in COPD treatment?
PaO2 <55mmHg, HCT >55%, evidence of cor-pulmonale
What is the goal PaO2 with supplemental oxygen in COPD treatment?
> 60 mmHg
How can supplemental O2 flow rate be titrated in COPD treatment?
According to ABG or SpO2
Why is supplemental O2 more effective than drug therapy in COPD treatment?
Decreases pulmonary vascular resistance, pulmonary hypertension, prevents erythrocytosis
What non-pharmacological interventions should be advised for COPD patients?
Deep breathing exercises or incentive spirometry
What is the capital of France?
Paris
What is the largest planet in our solar system?
Jupiter
What is lung volume reduction surgery indicated for in COPD patients?
severe refractory COPD and overdistended lung tissue
How does lung volume reduction surgery improve lung function?
increases elastic recoil, decreases hyperinflation, decreases ventilation/perfusion mismatch
What are the common surgical approaches for lung volume reduction surgery?
median sternotomy or video-assisted thoracoscopic surgery (VATS)
What is the recommended anesthesia management for lung-volume reduction surgery?
double-lumen ETT, avoidance of nitrous oxide, minimize excessive airway pressure
Why is CVP an unreliable guide for fluid management during lung-volume reduction surgery?
surgical alterations affecting intrathoracic pressures
What should be investigated in the history of a patient with COPD?
Causes, course, severity
Why is it important to note the patient’s smoking history and current medications?
Impact on anesthesia management
What should be determined regarding previous ventilation support in COPD patients?
Need for NIPPV or mechanical ventilation
Why should patients with COPD be questioned about comorbidities?
Association with smoking & COPD
How should right ventricular function be assessed in patients with pulmonary disease?
Clinical exam, echocardiogram
What preoperative therapies should be continued until the morning of surgery for COPD patients?
Inhalation therapies
How can postoperative pulmonary complications be reduced in COPD patients?
Chest physiotherapy
Which clinical findings are more predictive of pulmonary complications in COPD patients?
Smoking, wheezing, productive cough
Is the value of routine preoperative PFTs accepted in COPD patients?
Controversial
What are some indications for preoperative pulmonary evaluation?
Hypoxemia on room air, history of respiratory failure, planned pneumonectomy
What can be a sign of the need for preop pulmonary evaluation?
Severe shortness of breath from respiratory disease
Do patients with COPD undergoing peripheral surgery need preop PFTs?
No
What can be sufficient to assess lung disease if in doubt?
Spirometry with FEV1
What can be assessed by measuring airflow related to lung volume?
Ventilatory function
What is produced by plotting expiratory flow rates against lung volumes?
Flow-volume curves
What are flow-volume loops obtained from?
Adding flow rates during inspiration to flow-volume curves
When is the flow rate zero in relation to lung capacity?
At TLC before the start of expiration
When is the peak flow rate achieved during expiration?
Rapidly after forced expiration begins
How does the flow rate change as volume decreases to RV?
Falls in a linear fashion
What causes a U shaped inspiratory curve during maximal inspiration from RV to TLC?
Most rapid inspiratory flow at midpoint of inspiration
In COPD, what is observed in terms of expiratory flow rate at any given lung volume?
Lower expiratory flow rate
What shape is the expiratory curve in COPD due to uniform emptying of the airways?
Concave
Why is RV increased in COPD?
Air trapping
What are some major patient-related risk factors for the development of postoperative pulmonary complications?
Age >60 yr, ASA class >II, CHF, Preexisting pulmonary disease, Cigarette smoking
What are some procedure-related risk factors for the development of postoperative pulmonary complications?
Emergency surgery, Abdominal/thoracic/head and neck/neurovascular/aortic aneurysm surgery, Prolonged anesthesia, General anesthesia
What test predictor is associated with an increased risk of postoperative pulmonary complications?
Albumin level <3.5 g/dL
What strategies should be encouraged preoperatively to reduce post-op complications?
Smoking cessation, treat airflow obstruction and respiratory infection, initiate patient education on lung volume expansion maneuvers.
What intraoperative strategies can help reduce post-op complications?
Minimally invasive surgery, regional anesthesia, avoid lengthy procedures.
What postoperative interventions are recommended to reduce complications?
Lung volume expansion maneuvers, maximize analgesia.
What percentage of smokers undergo general anesthesia annually?
5-10%
When is the maximum benefit of smoking cessation seen in relation to surgery?
at least 8 weeks prior
What is the single-most important risk factor for developing COPD and death caused by lung disease?
Smoking
What does the American Society of Anesthesiologists provide to help encourage smoking cessation?
resources
How long do the sympathomimetic effects of nicotine on the heart last?
20-30 minutes
What is the elimination half-life of carbon monoxide?
4-6 hrs
Within 12 hours of smoking cessation, how much does P50 increase from?
22.9 to 26.4 mmHg
What happens to plasma levels of carboxyhemoglobin 12 hours after smoking cessation?
decrease from 6.5% to 1%
Does short-term abstinence from cigarettes decrease postop pulmonary complications?
No
How long does it take to see improved ciliary and small airway function after quitting smoking?
Weeks
What effect does smoking have on immune responses and response to pulmonary infection following surgery?
Interfere
How long does it take for normal immune function to return after quitting smoking?
At least 6 weeks
How long may it take for hepatic enzyme activity to return to normal after quitting smoking?
6 weeks or longer
What is the optimal timing of smoking cessation before surgery to reduce postop pulmonary complications?
6-8 weeks
What interventions should be offered to smokers scheduled for surgery in less than 4 weeks?
Behavioral support, pharmacotherapy
What are some options for nicotine replacement therapy?
Patches, inhalers, nasal sprays, lozenges, gum
When should sustained release bupropion be started in relation to smoking cessation?
1-2 weeks before
What are some disadvantages that can be experienced in the immediate preop period due to smoking cessation?
Sputum production, stress handling issues, withdrawal symptoms
What is bronchiectasis associated with?
Irreversible airway dilation, inflammation, chronic bacterial infection
Who is the prevalence of bronchiectasis highest in?
Pts >60 with chronic pulmonary dz and in women
What are the symptoms of bronchiectasis?
Chronic productive cough, purulent sputum, hemoptysis, clubbing
What leads to a vicious cycle in bronchiectasis?
Poor mucociliary activity and mucous pooling
Why is it nearly impossible to eradicate bacterial superinfection in bronchiectasis?
Recurrent bacterial infections causing further inflammation
What baseline tests should be obtained for all suspected patients of bronchiectasis?
CXR and PFT
What does CT usually show in bronchiectasis?
Dilated bronchi
What are key treatments for bronchiectasis?
Abx and chest physiotherapy
What guides antibiotic selection in bronchiectasis?
Results of sputum cultures
When is surgery considered in bronchiectasis?
Severe symptoms persist or recurrent complications occur
What is cystic fibrosis?
Autosomal recessive disorder of chloride channels
How many people does cystic fibrosis affect in the US?
30,000
What gene mutation causes cystic fibrosis?
Gene on chromosome 7 encoding CFTR
How does mutated CFTR gene affect mucus production?
Abnormally thick mucus
What is the primary cause of morbidity and mortality in cystic fibrosis?
Chronic pulmonary infection
What can the end result of cystic fibrosis lead to?
Severe organ damage
What are the diagnostic criteria for cystic fibrosis?
Sweat chloride concentration >60 mEq/L with clinical sx or family history
How can DNA analysis contribute to diagnosing cystic fibrosis?
Identifies >90% of pts with CFTR mutation
What is almost universal in individuals with cystic fibrosis?
Chronic pansinusitis
What type of evidence indicates pancreatic exocrine insufficiency associated with cystic fibrosis?
Malabsorption with response to pancreatic enzyme tx
What is a sign of airway inflammation seen in bronchoalveolar lavage of cystic fibrosis patients?
High percentage of neutrophils
What condition is virtually present in all adult cystic fibrosis patients?
COPD
What is a potential treatment for cystic fibrosis that is currently being investigated?
Gene therapy
What is the main nonpharmacologic approach to enhancing clearance of secretions in cystic fibrosis?
Chest physiotherapy with postural drainage
What is a possible alternative method of physiotherapy for cystic fibrosis patients?
High-frequency chest compression with an inflatable vest and airway oscillation devices
When can bronchodilators be considered for cystic fibrosis patients?
If pts have a beneficial response to inhaled bronchodilators
How is a beneficial response to bronchodilators defined in cystic fibrosis patients?
Increase of 10% or more in FEV1 after administration
What contributes to the thick viscosity of secretions in cystic fibrosis?
Neutrophils and degradation products
How can DNA released from neutrophils be cleaved to increase sputum clearance in CF?
Recombinant human deoxyribonuclease
How are antibiotics selected for patients with CF?
Based on identification of bacteria from sputum cultures
When bronchoscopy may be indicated for CF patients with no pathogens identified in sputum cultures?
To remove lower airway secretions
What is often prescribed for many cystic fibrosis patients to suppress chronic infection?
Long-term maintenance antibiotics
When should elective surgery be delayed in relation to pulmonary function?
Until optimal pulmonary function is ensured by controlling infection and facilitating removal of airway secretions
In what situations may Vitamin K be necessary for anesthesia?
If hepatic function is poor or exocrine pancreatic function is impaired
What are important steps in maintaining less-viscous secretions during anesthesia?
Humidification of inspired gases, hydration, and avoidance of anticholinergic drugs
When may frequent tracheal suctioning be necessary during anesthesia?
Maintaining less-viscous secretions
What conditions should patients meet before extubation?
Regain full airway reflexes, adequate TV & RR
Why is postop pain control important during anesthesia recovery?
To allow for deep breathing, coughing, and early ambulation to minimize pulmonary complications
What is Primary Ciliary Dyskinesia?
Impaired ciliary activity in respiratory tract and other areas
What are the consequences of impaired ciliary activity in Primary Ciliary Dyskinesia?
Chronic sinusitis, recurrent respiratory infections, bronchiectasis, infertility
What is Kartagener syndrome?
Chronic sinusitis, bronchiectasis, situs inversus
What is the association between cilia function and situs inversus?
Approximately half exhibit situs inversus
What is the association between isolated dextrocardia and congenital heart disease?
Almost always associated
What is the preferred vein for central venous catheterization in the presence of significant organ inversion?
Left IJ vein preferred due to inversion of the great vessels
How should uterine displacement be done in pregnant women?
Displacement to the right side
What is implemented to avoid vena cava syndrome in pregnant women?
Left uterine displacement (LUD)
What is the reason for selecting the right internal jugular vein for CVC insertion in typical cases?
Right IJ leads straight to the SVC
Why may a left double-lumen endotracheal tube be preferred over a right one?
RUL more easily obstructed in cases of pulmonary inversion
What positioning adjustments are needed for EKG interpretation in the presence of dextrocardia?
Reverse placement for accurate interpretation
How can postoperative pulmonary complications be decreased in patients with Primary Ciliary Dyskinesia?
Regional anesthesia preferable to general anesthesia
Why should nasopharyngeal airways be avoided in patients with Primary Ciliary Dyskinesia?
High incidence of sinusitis
What is Bronchiolitis Obliterans?
Epithelial and subepithelial inflammation
What are the risk factors for Bronchiolitis Obliterans?
Viral infections, environmental exposures, transplants
What are the symptoms of Bronchiolitis Obliterans?
Dyspnea, nonproductive cough
What do PFTs show in Bronchiolitis Obliterans?
Obstructive disease, reduced FEV1
What finding on high-resolution CT indicates severe Bronchiolitis Obliterans?
Air trapping, bronchiectasis
What does Central Airway Obstruction include?
Tracheal and mainstem bronchi obstruction
What percentage of lung cancer patients can be affected by airflow obstruction?
20-30%
What can cause central airway obstruction?
Tumors, chronic infection granulation, cartilage destruction
What can develop after prolonged intubation with ETT or tracheostomy tube?
Tracheal stenosis
How can tracheal mucosal ischemia progress?
To destruction of cartilaginous rings and scar formation
How can the risk of tracheal mucosal ischemia be minimized?
Use high-volume, low-pressure cuffs on ETTs
What diameter does tracheal stenosis become symptomatic?
<5mm
When may symptoms of tracheal stenosis develop after extubation?
several weeks
What symptom is prominent even at rest in central airway obstruction?
dyspnea
What is usually audible in central airway obstruction?
stridor
What do flow-volume loops typically show in central airway obstruction?
flattened curves
What muscles are utilized throughout all phases of the breathing cycle in central airway obstruction?
accessory muscles
What will a CT illustrate in central airway obstruction?
tracheal narrowing
What can be used as a temporizing measure to treat tracheal stenosis?
Tracheal dilation
What methods can be used for tracheal dilation in tracheal stenosis?
Balloon dilators, surgical dilators, laser resection
What is considered the most successful treatment for tracheal stenosis?
Surgical resection & reconstruction with primary re-anastomosis
What is necessary for the surgical procedure of tracheal resection and reconstruction?
Translaryngeal intubation
What is useful for ensuring maximal FiO2 during maintenance of anesthesia for tracheal resection?
Volatile anesthetics
What may be facilitated by the addition of helium to the inspired gases during anesthesia for tracheal resection?
Tracheal ventilation
