Characteristics of asthma:
Chronic airway inflammation
Airway wall thickening (severe cases)
Reversible expiratory airflow obstruction
Causes of asthma exacerbations:
Allergens Exercise Nighttime/sleep Chemicals (ASA/NSAIDs, VAs, irritants) Cold Infection
S/s of asthma:
Wheezing
Middle-sized airways narrowed by bronchospasm & further narrowed by forced exhalation
Cough - can be mucoid
Dyspnea/air hunger
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 –> bronchospasm)
H2 antagonists (unopposed H1 antagonism –> bronchospasm)
Bronchodilators (albuterol)
Pre-op steroids (if FEV1 is
Overall goal for induction in asthmatics:
Blunt airway reflexes and bronchoconstriction response during airway instrumentation
Induction in asthmatics:
EDTA-preserved propofol + ketamine (+/- glyco for secretions) Opioids (non-histamine) Lidocaine VA w/ mask prior to laryngoscopy LMA if possible
Maintenance in asthmatics:
High concentration VA
Sevo/halo are least pungent/irritating
Avoid histamine releasers (sux, atra, miva)
Ventilation goals for asthmatics:
Avoid PEEP - they are prone to air trapping
Low RR, high TV, long I:E ratio
Keep peak airway pressure volume control
Liberal hydration of pt and circuit
Tx of intra-op bronchospasm:
FiO2 to 100% Deepen VA If no air movement: ketamine, propofol, lido B2 agonists IV epi in severe cases or SQ terbutaline IV corticosteroids
Emergence/post-op care for asthma:
Pre-emptive albuterol, IV lido
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 Mucus/inflammation obstruction Moderate dyspnea PaO2 45 Pulmonary hypertension d/t HPV Cough and diminished breath sounds Marked cor pulmonale Tend to be obese Poor prognosis CXR: increased bronchovascular markings
“Pink puffers”:
Emphysema Obstruction due to loss of recoil Severe dyspnea PaO2 > 60, normal PaCO2 Very diminished breath sounds Better prognosis Tend to be thin CXR: hyperinflation with a low diaphragm
Smoking cessation timeline:
12-24 hours: decreased carbon monoxide and nicotine levels
48-72 hours: decreased carboxyhemoglobin, ciliary function improves, increased airway secretions, hyperreactivity
1-2 weeks: decreased secretions/sputum
4-6 weeks: PFTs improve
6-8 weeks: immune, metabolic function normalizes
8-12 weeks: decreased overall postop M&M
Induction in COPD patients:
Caution with pre-medication
Hold opioids under monitored and with oxygen on
Ketamine is good for pts who tolerate the CV effects, otherwise propofol
Short-acting NMB
Stay away from histamine releasers
Maintenance in COPD patients:
Cautious with N2O; can cause rupture of bullae from emphysema
VAs bronchodilate but also attentuate HPV reflex
Increased gradient between PaCO2 and ETCO2
Ventilation goals in COPD patients:
No PEEP
Large TVs (10-15ml/kg) and low RR (6-10 bpm)
Humidifier in circuit
Consider patient’s baseline CO2 and tolerate hypercarbia based on it
Monitor for air trapping
Emergence and post-op management in COPD patients:
May need to stay intubated/ventilated for prolonged period, esp. after abdominal/thoracic surgeries
Good pain control to avoid splinting
Causes of reduced lung compliance:
Normal compliance = 100-200ml/cmH2O Increased fibrous tissue Alveolar edema Low lung volumes/atalectasis Increased pulm venous pressure
Four types of restrictive lung disorders with examples:
Acute intrinsic (pulm edema, ARDS, aspiration pneumonitis) Chronic intrinsic (pulm fibrosis, sarcoidosis) Chronic extrinsic (chest wall/ab/neuromusc diseases, obesity, kyphosis) D/o of pleura/mediastinum (tumors, pneumothorax, pleural effusions)
Describe re-expansion pulm edema:
After rapid evacuation of > 1L from pneumothorax/effusion that’s > 24 hours old, due to enhanced capillary membrane permeability
O2, PEEP, no diuretics unless volume overload is primary issue
Describe negative pressure pulmonary edema:
Minutes to 2-3 hours after acute upper airway obstruction, due to highly negative intrapleural pressure caused by attempting to breath against closed airway
Most often post-extubation laryngospasm; self-limiting in 12-24 hours; tx with O2, airway monitoring, mechanical ventilation + PEEP if needed
Tx for aspiration pneumonitis:
Increase FiO2
PEEP
B2 agonists for bronchodilation
Bronchoscopy for suspected solid material
Describe sarcoidosis:
Systemic granulomas
Can be in airway (difficult intubation) and myocardium (CV effects)
Liver, spleen, optic and facial nerves too
Pulm HTN and RH failure
Often on chronic steroids
Prone to hypercalcemia
Describe chronic extrinsic lung disease effects:
RH dysfunction d/t chronic compression of pulm vasculature
Impaired cough –> chronic infections and obstructive component
S/s of pneumothorax:
Acute dyspnea Decreased PaO2, increased PaCO2 Hypotension Tachycardia Uneven/decreased chest wall movement Hyperresonant percussion
Regional anesthesia in restrictive lung disease:
> T10 level means loss of accessory muscles which may put patients at risk, plus they don’t tolerate sedation well; not a bad idea for post-op pain though
Induction in restrictive lung disease:
Titrated pre-meds carefully d/t respiratory depression
Pre-oxygenation critical d/t reduced FRC
May need etomidate if CV comorbidities
Maintenance in restrictive lung disease:
VA uptake will be faster d/t reduced FRC
Need ETT, not LMA; will need higher pressures
Low TV (4-8ml/kg) and high RR (14-18 bpm)
Avoid excessive FiO2
