Oral Review: Pulm Flashcards
Characteristics COPD and asthma:
Chronic Obstructive diseases characterized by:
- Chronic airway inflammation
- Airway wall thickening (epithelial, submucosa and smooth muscle) → impairs gas exchange
-
Expiratory airflow obstruction
- Asthma = reversible
- COPD = not reversible or incompletely reversible
- Airway hyperreactivity
Causes of asthma exacerbations:
- Allergens
- Exercise
- Nightime/sleep
- Chemicals (ASA/NSAIDs, VAs, irritants)
- Cold
- Infection
S/s of asthma:
- Wheezing
- Breathlessness/Air Hunger
- Chest tightness
- Early AM or nighttime cough
- Reversible airflow obstruction
- Tachypnea
- Prolonged expiratory phase
- Fatigue
Pre-op assessment of asthma:
- Triggers
- Severity (med requirements)
- Degree of reversibility w/ tx
- Current status, symptoms
- Prior anesthesia history
- Breath sounds
- general appearance, etc
Pre-op labs for asthma:
- PFTs
- ABG
- ECG (RH failure)
- CBC (eosinophils)
- CXR (hyperinflation of lungs)
Pre-op meds for asthmatics:
-
Benzos
- anxiety can precipitate bronchospasm bronchospasm)
-
Opioids
- be sure to titrate carfully
-
H2 antagonists
- unopposed H1 antagonism may cause bronchoconstriction- Use Caution!
-
Bronchodilators
- albuterol) - 15-30 min before
-
Pre-op steroids - prohylaxis
- Hydrocortizone 100 mg q8h if FEV1 <80% predicted
Overall goal for induction of anesthesia in asthmatics
GOAL= Blunt airway reflexes and avoid bronchoconstriction during airway instrumentation
- Consider Regional (good choice)
-
GA should:
-
depress airway reflexes
- Lidocaine 1-1.5 mg/kg IV (consider LTA)
- Opioids -judiciously (fentanyl and analogues)
- (Higher end of induction doses)
- Propofol and ketamine is best for induction - avoid Sodium metabisulfite prep
-
Avoid hyperreactivity
- Use High MAC >1.5 for bronchodilation and bronchial reflex inhibition (Sevo and halothane are the least irritating)
- AVOID desfluane/isoflurane - airway irritant
- Ketamine will increase secretions which may irritate the airway, but does bronchodilate - maybe give some glyco?
- Maybe AVOID ketoralac/NSAIDS - increased leukotrienes via lipooxygenase pathway
-
Treat bronchoconstriction
- albuterol
- sevoflurane
-
AVOID histamine realease
- Sux, atricurium, mivicurium, D-tubo, morphine, demerol, thopental
- Neostigmine is ok for reversal, but MUST be given with anticholinergic - glycopyrolate
-
depress airway reflexes
Maintenance of anesthesthesia in asthmatics:
-
High concentration VA
- Sevo/halo are least pungent/irritating
- Avoid histamine releasers (sux, atra, miva)
- Avoid bronchospasm
Ventilation goals for asthmatics:
Ventilation
- Avoid PEEP →prone to air trapping
- Decrease RR (8-10 bpm) - allows for adequate exhalation
-
Increase TV - to maintain Normal PaCO2
- TV and inspiritory flow rates are limited by excessive peak airway pressures
- Upper Limit - 40 cm H2O
- Longer I:E ratio
- Liberal hydration of pt and circuit
Treatment of intra-op bronchospasm:
- FiO2 to 100%
- Deepen anesthesia with VA or drugs
- Give a ß-agonist
-
If no air movement:
- Epinephrine IV: 2-8 mcg/min (SQ 0.3-0.5mg q20-30min)
- Terbutaline (SQ)
- Corticosteroids: 1-2 mg of cortisol
-
Other IV broncholilators
- Ketamine
- Propofol
- Lidocaine
Emergence/post-op care for asthma:
- Smooth emergence - ETT promotes bronchoconstriction and airway resistence
- Pre-emptive albuterol, IV lido 10-15 minutes prior to wake up
- Deep extubation if possible
- If not, try to get patient to SV as early as possible
Characteristics of COPD:
Progressive airway obstruction Chronic bronchitis and/or emphysema Smoking #1 risk factor
COPD staging:
- Stage 1: FEV1 > 50% predicted
- Stage 2: FEV1 35-49%
- Stage 3: FEV 1
“Blue bloaters”:
- Chronic bronchitis
- Copious secretions cause obstruction
- Cough
- Diminshed breath sounds
- PaO2 < 60 →cyanosis and dusky appearance
- PaCO2 > 45
- Pulmonary hypertension d/t HPV
- Marked cor pulmonale/righ sided heart failure
- Overweight
- CXR: increased bronchovascular markings
“Pink puffers”:
- Emphysema
- Obstruction due to loss of recoil
- Severe dyspnea
- PaO2 > 60
- Normal PaCO2
- Very diminished breath sounds
- Tend to be thin
- anxious, pursed lips
- CXR: hyperinflation with a low diaphragm