Obstructive Lung Diseases Flashcards
Obstructive Lung Disease
Obstructive sleep apnea
Asthma
COPD
Miscellaneous
Obstructive Sleep Apnea
Not technically an obstructive lung disease
Mechanical breathing obstruction occurs during sleep when pharyngeal muscles relax → chronic hypoxemia ↑CO2 ↓FRC
Obesity = most significant precipitating factor
Risk factor ↑morbidity
STOPBANG
○ Snoring ○ Tired ○ Observed apnea ○ Pressure HTN ○ BMI >35kg/m2 ○ Age >50yo ○ Neck circumference >40cm ○ Gender M
OSA S/S
Habitual snoring, fragmented sleep, daytime somnolence Comorbidities r/t obesity & hypoxemia - Systemic & pulmonary HTN - Ischemic heart disease - Congestive heart failure
OSA Diagnosis
Polysomnography - records # abnormal respiratory events STOPBANG Apnea-hypopnea index AHI Normal <5 Mild 5-15 Moderate 15-30 Severe >30
FEV1
Forced expiratory volume in 1 second
TLC 5L
Normal FEV1 = 4L
80-120%
FVC
Forced vital capacity
Volume air forcefully exhaled after deep inhalation
Females 3.7L
Males 4.8L
FEV1:FVC Ratio
Normal 75-80%
FEV 25-75%
Air flow measurement at midpoint forced exhalation
Maximum Voluntary Ventilation
MVV
Maximum amount air inhaled & exhaled in 1 minute
Females 80-120L/min
Males 140-180L/min
DLCO
Diffusion capacity
Patient inhales helium & carbon monoxide
Measures volume CO transferred across the alveoli into the blood per minute per unit alveolar partial pressure
Single breath 0.3% CO + 10% helium held for 20 seconds
Normal value 17-25mL/min/mmHg
Acute Upper Respiratory Infection
Common cold
Infectious (viral or bacterial) nasopharyngitis 95%
S/S:
- Non-productive cough
- Sneezing
- Rhinorrhea
- Bacterial include fever, purulent nasal discharge, productive cough, & malaise
Acute Upper Respiratory Infection
Anesthetic Management
Hydration
↓secretions
Limit airway manipulation
LMA vs. ETT
Asthma
REVERSIBLE airway obstruction - Bronchial hyperreactivity - Bronchoconstriction - Lower airways chronic inflammation Genetic & environmental
Asthma Pathophysiology
Inflammatory pathway activation → airway mucosa infiltration w/ eosinophils, neutrophils, mast cells, T/B cells, & inflammatory mediators
→ EDEMA
Asthma S/S
Wheezing, productive/non-productive cough, dyspnea, chest tightness, SOB, airflow obstruction
FEV1 <35% ↑FRC
TLC = WNL
DLCO unchanged
CXR hyperinflation d/t air trapping
R ventricle strain T wave inversion V1-4 & II, III, aVF
Asthma Treatment
Corticosteroids Long-acting bronchodilators Leukotriene modifiers Anti-IgE Methylxanthines Mast cell stabilizer
Status Asthmaticus
Life-threatening emergency Bronchospasm does not respond to treatment β2 agonists IV corticosteroids Supplemental O2 IV magnesium sulfate
Asthma Anesthetic Considerations
Regional vs. general anesthesia ↓airway manipulation Propofol & Ketamine - bronchodilation IV or transtracheal Lidocaine Sevoflurane less pungent Light anesthetic potential bronchospasm Avoid histamine releasing drugs
COPD
Chronic obstructive pulmonary disease
NONREVERSIBLE loss alveolar tissues & progressive airway obstruction
Type A - Emphysema (pink puffers)
Type B - Chronic bronchitis (blue bloaters)
COPD Risk Factors
Cigarette smoking Occupational exposures Pollution Recurrent respiratory infections Low birth weight Antitrypsin deficiency
Chronic Bronchitis
Type B
Characterized by excessive sputum production
- Mucus gland hypertrophy
- Small airway inflammatory changes
- Tissue granulation
- Peri bronchial fibrosis
Clinical S/S indicate pulmonary complications
COPD Spirometry
Normal lung volumes ↓FEV1/FVC ratio ↓FEV 25-75 ↑FRC & TLC Severity determined by GOLD criteria
COPD Treatment
Designed to relieve symptoms & slow disease progression
- Smoking cessation
- Oxygen
- Long-acting β2 agonists
- Inhaled corticosteroids
- Long-acting anticholinergic
- Lung volume reduction surgery
Lung Volume Reduction Surgery
Remove worse lung portion to optimize remaining Severe COPD ↓V/Q mismatch Double-lumen ETT Avoid N2O One lung ventilation VT 3-4mL/kg IBW
COPD Anesthetic Considerations
Preop pulmonary function test Hypoxemia ↑PaCO2 Baseline HCO3¯ (renal compensation) Determine response to bronchodilators CV involvement R ventricle function Desflurane → irritation Avoid N2O attenuates HPV ↑V/Q mismatch Limited opioid & benzodiazepine use (prolonged ventilatory depression)
Smoking Cessation
At least 6 weeks prior to surgery
Benefits seen w/in 4-6hr
Immediate cessation NOT recommended
Auto PEEP
Air trapping
Capnography - expiratory flow does not reach baseline before next breath
+ pressure ventilation PPV applied w/o adequate expiration ↑intrathoracic pressure ↓VR ↑pulmonary artery pressure → R heart strain
Bronchospasm Treatment
Deepen anesthetic Short-acting bronchodilator Suction secretions IV steroids Epinephrine
Expiratory Outflow Obstructions
Bronchiectasis Cystic Fibrosis Primary ciliary dyskinesia Bronchiolitis obliterans Tracheal stenosis
Bronchiectasis
Irreversible airway dilation & collapse resulting from inflammation d/t chronic infections
Significant hemoptysis 200mL over 24hr
Resultant airway collapse ↑recurrent infection risk
Bronchiectasis S/S
Chronic cough w/ purulent sputum CT imaging to confirm Hemoptysis Pleuritic chest pain Dyspnea Wheezing Finger clubbing
Bronchiectasis Anesthetic Considerations
Delay elective procedures until patient optimized
General anesthesia w/ ETT
- Frequent suctioning
- Avoid nasal intubation
- Double lumen tube prevent cross-contamination
Cystic Fibrosis
Autosomal recessive disorder
Chromosome 7
Prevents chloride transport & Na+/H2O movement in & out cells
→ abnormally thick sputum production outside epithelial cells
1° cause morbidity & mortality chronic pulmonary infection
Cystic Fibrosis Diagnosis
Sweat chloride >70mEq/L Chronic purulent sputum production Malabsorption (pancreatic enzyme therapy) Bronchoalveolar lavage ↑neutrophils COPD common in adult patients
Cystic Fibrosis Treatment
Directed toward symptom alleviation - Clear airway secretions - Correct organ dysfunction - Nutrition (impaired ability to absorb nutrients) - Prevent intestinal obstruction Gene therapy (?)
Cystic Fibrosis Anesthetic Considerations
Delay elective procedures until patient optimized
- Control infection & remove secretions
Vitamin K treatment (fat-soluble vitamins absorption)
General anesthesia w/ volatile agents
AVOID anticholinergic medications
Awake extubation
Adequate pain control
Primary Ciliary Dyskinesia
Congenital ciliary activity impairment in the respiratory tract & sperm cells
Pulmonary infections
Organ inversion
Kartagener’s Syndrome
Chronic sinusitis
Bronchiectasis
Situs inversus
Primary Ciliary Dyskinesia Anesthetic Considerations
Regional anesthesia preferred Dextrocardia - reverse EKG placement L IJ central line R uterine displacement (term mothers to prevent vena cava compression) Avoid NP airways d/t sinusitis risk
Bronchiolitis Obliterans
Small airways & alveoli disease in children d/t RSV
Lower bronchioles destruction
Adults d/t viral pneumonia, collagen vascular disease (RA), silo filler’s disease (NO2 inhalation), or graft vs. host disease
Bronchiolitis Obliterans Organizing Pneumonia
BOOP
Similar features as interstitial lung disease
Treatment typically ineffective S/S management
Corticosteroid ↓swelling
Bronchodilators to optimize the airway diameter
Tracheal Stenosis
Tracheal mucosa ischemia → scarring
Prolonged intubation or cuff over-inflation
Tracheal Stenosis S/S
Adult symptomatic when tracheal diameter <5mm
Dyspnea even at rest
Accessory muscle use during inspiration & expiration
Flow loops flattened inspiratory & expiratory curves
Tracheal Stenosis Treatment
Dilation = temporary measure - Balloon or surgical dilators - Laser scarred tissue Tracheobronchial stent Best treatment = tracheal resection w/ anastomosis
Tracheal Stenosis Anesthetic Considerations
Translaryngeal intubation
Volatile agents to ensure maximum inspired oxygen concentration
Helium ↓gas mixture density & improves flow
