RESTRICTIVE LUNG DISEASE Flashcards
structures of the thoracic cage that surrounds the lungs
- parietal pleura
- skeleton
- muscles (intercostals, diaphragm, accessory muscles of respiration)
restrictive disease & lung volumes
proportional decrease in all lung volumes w/ preservation of flow
PFTs in restrictive lung disease
decrease in: - total lung volume - FRC - reserve volume - VC <70mL/kg - FEV1 - FVC no change in: - FEV1/FVC ratio
does arterial hypoxemia occur in restrictive lung disease?
it can, due to V/Q mismatch NOT due to gas exchange issues
breathing pattern in restrictive lung disease
rapid & shallow in attempts to maintain adequate MV
- reduction in lung compliance
classification & examples of restrictive lung diseases
acute intrinsic = pulmonary edema, ARDS
chronic intrinsic = diseased lung parenchyma (sarcoidosis)
chronic extrinsic = chest wall, intraabdominal, neuromuscular diseases
disorders of the pleura & mediastinum
what is pulmonary edema
leakage of intravascular fluid into the lung interstitium & alveoli
causes of pulmonary edema
- increased capillary/hydrostatic pressure (ie cardiogenic)
2. increased capillary permeability (ie inflammatory process)
CXR pulmonary edema
bilateral symmetrical opacity
s/s cardiogenic pulmonary edema
dyspnea
tachypnea
SNS activation = hypertension, tachycardia, diaphoresis
what is aspiration pneumonitis
aspirate into the lungs that is rapidly distributed throughout; acidic nature = destruction of surfactant producing cells, injury of the endothelium & capillaries
–> capillary permeability w/ resultant atelectasis & edema (like ARDS)
clinical findings w/ aspiration pneumonitis
- arterial hypoxia
- tachypnea
- bronchospasm
- pulmonary vascular constriction –> pulmonary HTN
- CXR = RLL
tx of aspiration pneumonitis
increase FiO2!
- PEEP
- B2 agonists
- no prophylactic abx
- steroid controversial
what is negative pressure pulmonary edema
2-3hrs after acute upper airway obstruction in spontaneously breathing patient
–> negative pressure generation against obstructed airway pulls fluid from vasculature, interstitial spaces into lungs
causes of negative pressure pulmonary edema
- post extubation laryngospasm
- OSA
- hiccups
- epiglottitis
- tumors
physiologic results of highly negative intrapleural pressures
- decreased interstitial hydrostatic pressure
- increased venous return (preload)
- increased afterload on LV
- increased SNS outflow
s/s negative pressure pulmonary edema
tachypnea
cough
failure to maintain SaO2 >95%
treatment of negative pressure pulmonary edema
usually self-limited 12-24hr duration
supportive care: supplemental O2, maintenance of patent upper airway, occasionally require mechanical ventilation briefly
what is sarcoidosis
systemic granulomatous disorder that changes the intrinsic properties of the lung due to pulmonary fibrosis
- -> pulmonary HTN & cor pulmonale
- -> more fibrosis & loss of pulmonary vasculature
areas affected by sarcoids
OFTEN: thoracic lymph nodes & lungs
Other areas:
- laryngeal - ETT issues
- myocardial (rare) - conduction defects
- liver
- spleen
- optic
- unilateral facial nerve
presentation of sarcoidosis patient
dyspnea cough rapid shallow breathing often present for mediastinoscopy (diagnosis) often on corticosteroids (stress dose)
cardiac implications of chronic extrinsic restrictive lung disease
chronic compression of pulmonary vasculature –> right ventricular dysfunction
neuromuscular disorders that can prevent the generation of normal respiratory pressures
- diaphragmatic paralysis
- spinal cord transection
- guillian-barre
- myasthenia gravis
- myasthenic syndrome
- muscular dystrophy
pulmonary implications of neuromuscular disorders that can prevent the generation fo normal respiratory pressures
- impaired clearance of secretions
- impaired cough –> chronic infection –> COPD
- impaired ability to swallow –> aspiration
- PNA
- respiratory failure may result
- very sensitive pulm system to CNS depressants
physiologic implications of mediastinal tumors
- progressive airway obstruction
- loss of lung volumes
- compression of pulmonary artery, myocardium, or SVC
- **may occlude in supine position and/or obstruct airway if muscle relaxant given during induction
- -> review imaging
preop assessment of the patient w/ restrictive lung disease
- exercise tolerance
- baseline dyspnea
- PFTs, flow volume loops, ABG may be helpful
Factors that signal increased risk:
- decrease in VC<15mL/kg
- resting hypercarbia
optimization preop of the patient with restrictive lung disease
treat pulmonary infection improve sputum clearance treat cardiac dysfunction attempt to improve resp muscle strength smoking cessation
mechanical ventilation guidelines for restrictive lung dz
lower Tv
higher rr
PPV = high airway pressures
anesthestic management considerations for restrictive lung dz
- caution w/ respiratory depressant medications = very little reserve
- caution w/ regional anesthesia >T10 = loss of accessory muscles
- caution w/ N2O = pneumothorax
- shorter acting IV/maintenance agents preferred to minimize postop respiratory depression
- volatile agents have accelerated uptake
- low FRC = less safe apnea time after preoxygenation
- expect high PIP
extubation criteria for restrictive lung dz
adequate PaO2 >60 PaCo2 <50 rr <30 Tv >300 VC >10-15mL/kg adequate consciousness & muscle strength full NMB reversal
critically ill patients w/ restrictive lung disease & anesthetic management
cancel elective surgery w/ ARDS, pulmonary edema
if emergency surgery:
- diuretics
- vasodilators/inotropes for cardiac failure
- consider pleural effusion/ascites drainage preop
- may require ICU w/ ventilator
- aggressive hemodynamic monitoring (artline, CVP, PA cath)
