Restrictive Lung Diseases Flashcards
Restrictive Lung Disease
RLD
Any condition that interferes w/ normal lung expansion during inspiration
↓total lung capacity (TLC)
↓ALL lung volumes & capacities
Normal FEV1/FVC ratio
Reduced diffusing capacity of carbon monoxide
TLC % in RLD
Mild 65-80% TLC
Moderate 50-65% TLC
Severe <50% TLC
Acute INtrinsic Causes
Pulmonary edema
- Cardiogenic
- Non-cardiogenic
Starling’s Law
Capillary hydrostatic pressure
Interstitial fluid hydrostatic pressure
Blood colloid osmotic pressure
Interstitial fluid colloid osmotic pressure
Arterial - net positive outflow
Venous - net negative inflow
Excess enters lymphatic system
Cardiogenic Pulmonary Edema
Acute INtrinsic RLD
L-sided heart incompetence or failure ↑pulmonary capillary pressure until fluid transudation exceeds lymph drainage → alveolar flooding
Cardiogenic Pulmonary Edema S/S
Rapid, shallow breathing not relieved by O2 Sympathetic stimulation S/S - Hypertension - Tachycardia - Diaphoresis
NON-Cardiogenic Pulmonary Edema
Acute INtrinsic RLD ↑capillary hydrostatic pressure w/ change in fluid filtration coefficient Causes: - Neurogenic - Uremic - High altitude - Upper airway obstruction Lymph system overload → alveoli
Negative Pressure Pulmonary Edema
Acute INtrinsic RLD
Caused by prolonged, forceful inspiratory effort against an obstructed upper airway in spontaneously breathing patients
*Most common cause = laryngospasm
Intense sympathetic stimulation
↑afterload
Hypertension
Central volume displacement
Negative Pressure Pulmonary Edema
Risk Factors
Male Young age Long obstruction period Over zealous fluid admin History cardiac or pulmonary disease
Negative Pressure Pulmonary Edema
Onset
Minutes to several hours
Negative Pressure Pulmonary Edema
S/S
Rapid and shallow breathing
See-saw breathing
Pulmonary Edema Management
Medical emergency
Early recognition = key
- Oxygen
- PEEP or CPAP
- Pharmacologic therapy (vasodilator to ↓preload)
- Fluid balance (goal-directed fluid therapy)
Pulmonary Edema S/S
Tachypnea - sympathetic stress stimulation Hypoxemia (low PaCO2 initially) ↑CVP Jugular vein distension Lung auscultation CXR = most reliable
NON-Cardiogenic Pulmonary Edema
Causes
Aspiration pneumonitis
Pneumonia
ARDS
TRALI
*Not typically anesthesia patients
Aspiration Pneumonitis
NON-cardiogenic acute INtrinsic RLD Three syndromes: - Chemical (Mendelson's syndrome) - Mechanical obstruction - Bacterial infection
Mendelson’s Syndrome
NON-cardiogenic acute INtrinsic RLD *Anesthesia caused Pneumonitis from periop aspiration Produces an asthma-like syndrome pH <2.5 Volume 25mL
Mendelson’s Risk Factors
Abdominal pathology, obesity, diabetes, neurologic deficit, lithotomy position, difficult intubation, reflux, hiatal hernia, inadequate anesthesia, cesarean section
→ Pharmacologic prophylaxis minimal impact
→ Most frequently occurs during induction/intubation & emergence
Mendelson’s Pathophysiology
Aspirated substance (acidic gastric contents) causes lung parenchyma injury, inflammatory reaction, & secondary injury in 24hr
→ Arterial hypoxemia
Mendelson’s Considerations
Risk factors NPO standards Pharmacologic prophylaxis Cricoid pressure (?) Awake intubation Regional anesthetic
Mendelson’s Treatment
Head down or lateral
Suction mouth or pharynx (tracheal suction NOT indicated)
Minimal supplemental O2
PEEP or bag-mask w/ APL
Antibiotics (not recommended)
Discharge dependent on patient disposition - potentially longer PACU stay or admit overnight depending on severity
Acute Respiratory Failure
NON-cardiogenic acute INtrinsic RLD
Inability to provide adequate O2 & eliminate CO2
PaO2 <60mmHg despite supplemental O2
PaCO2 >50mmHg w/o respiratory compensation
ARDS → acute respiratory failure
Acute Respiratory Failure
Treatment
GOAL = support oxygenation & ventilation
- Patent upper airway
- Correct hypoxia
- Remove excess CO2
ARDS
NON-cardiogenic acute INtrinsic RLD
Insult to the alveolar-capillary membrane causing ↑capillary permeability → interstitial & alveolar edema
Severe damage & inflammation at alveolar-capillary membrane
ARDS Risk Factors
Sepsis
Pneumonia
Trauma
Aspiration pneumonitis
Factors are additive
HIGH mortality rate
ARDS Clinical S/S
Resembles pulmonary edema & aspiration pneumonitis
Dyspnea, hypoxia, hypovolemia, ↓lung compliance
NO definitive treatment
Identify & treat cause
Supportive care
ARDS Berlin Definition
Acute onset lung injury
Apparent clinical insult & progression pulmonary S/S
Bilateral opacities on imaging (not explained by other pathology)
Respiratory failure not explained by cardiac or volume overload
↓arterial PaO2/FiO2 ratio
PaO2/FiO2 Ratio
P:F ratio
Arterial PO2 / FiO2 (fraction inspired)
MILD 201-300
MODERATE 101-200
SEVERE <100
ARDS Anesthetic Implications
Protective lung ventilation
“Open lung” strategy + pressure to prevent atelectasis
Permissive hypercapnia (?)
+PEEP
Prone positioning ↑surface area available for gas exchange
Transfusion Related Acute Lung Injury
TRALI
NON-cardiogenic acute INtrinsic RLD
Acute lung injury associated w/ blood transfusion
Occurs 2° to interaction b/w transfused blood & patient WBCs
*Highest incidence after platelet transfusion
TRALI Risk Factors
Surgery Malignancy Sepsis Alcoholism Liver disease Donor risk factors
TRALI Pathophysiology
Activated neutrophils become trapped w/in pulmonary vasculature → non-cardiogenic pulmonary edema
Associated w/ blood transfusion r/o transfusion associated circulatory overload (TACO)
Acute onset hypoxemia
Supportive treatment w/ LPV
TRALI Anesthetic Implications
STOP transfusion immediately R/O incompatibility reaction or TACO IV fluids Diuretics (?) Ventilation support Lab findings
Chronic INtrinsic RLD
Disease characterized by pulmonary fibrosis (stiff rubber band)
- Idiopathic pulmonary fibrosis
- Radiation injury
- Cytotoxic & non-cytotoxic drug exposure
- O2 toxicity
- Autoimmune diseases (sarcoidosis)
Type 1 Epithelial Cell
Lung parenchyma
Structural - mechanical support, not active metabolically
Type 2 Epithelial Cell
Lung parenchyma
Globular cell - minimal support
Metabolically active - produce surfactant
Rapidly reproduce in response to injury
Alveolar Macrophage
Lung parenchyma
Scavenger cell - contains lysosomes that digest engulfed matter
Fibroblast
Lung parenchyma
Collagen & elastin synthesis cell
Interstitium
Thin - fused basement epithelial & endothelial layers
→ Gas exchange
Thick - includes type 1 collagen
→ Fluid exchange
Continuous w/ perivascular space
Route fluid drains from capillaries to lymph
Idiopathic Pulmonary Fibrosis
Chronic INtrinsic RLD
Presents as thickened alveolar wall interstitium
- Lymphocytes infiltration
- Fibroblasts ↑collagen bundles
- Cellular exudate w/in alveoli “desquamation”
Alveolar architecture destroyed & scarring results
Idiopathic Pulmonary Fibrosis S/S
Dyspnea: - Rapid, shallow breathing - Worsens w/ exercise Mild hypoxemia at rest Crackles bilaterally to auscultation Finger clubbing CXR: - Reticulonodular pattern - Patchy shadows at base Cor pulmonale in advanced stages ↓arterial PO2 & PCO2 Normal pH ↓PO2 drastically w/ exercise Oxygen diffusion limited d/t interstitium thickness V/Q mismatch ↓diffusion capacity carbon monoxide 5mL/min/mmHg (normal 25-30mL/min/mmHg) ↓FVC (forced vital capacity) Normal FEV1/FVC Flow-volume curve shift to the R Pressure-volume curve flattened & displaced downward
Drug-Induced Pulmonary Disease
Chronic INtrinsic RLD Direct - toxic effects Indirect - inflammation or immune process enhancement Cytotoxic (cancer) Non-cytotoxic
Non-Cytotoxic Injury
Chronic INtrinsic RLD Amiodarone → ventricular dysrhythmic Etiology - direct toxicity, immunologic mechanisms, RAAS activation → chronic interstitial pneumonitis, pneumonia, ARDS, or fibrosis Clinical diagnosis (2+) - New onset pulmonary S/S, CXR abnormalities, ↓DLCO, abnormal gallium-67 uptake, histologic changes noted in lung biopsy Treatment - discontinue Half-life 40-70 days Fibrosis = irreversible
Bleomycin
Chronic INtrinsic RLD - cytotoxic injury
Bleomycin → anti-tumor antibiotic
Etiology - direct toxicity & inflammatory response → chronic pneumonitis & fibrosis, acute hypersensitivity, non-cardiogenic pulmonary edema
Clinical diagnosis
- Dyspnea, dry cough, low-grade fever, fatigue, & malaise developing over weeks to months
- CXR w/ diffuse interstitial infiltrates
Treatment - discontinue & corticosteroid therapy
Bleomycin Anesthesia Implications
Monitor O2 saturation ABG analysis Pre-oxygenation 3-4min Determine target PaO2 & utilize minimum FiO2 to achieve \+PEEP IV fluid management
Methotrexate
Chronic INtrinsic RLD - cytotoxic injury
Used to treat rheumatoid arthritis
Acute pulmonary toxicity common → dry cough, dyspnea, hypoxemia, infiltrates
Treatment - discontinue
Oxygen Toxicity
Chronic INtrinsic RLD
*Anesthesia caused
Risk factors - advanced age, prolonged exposure, radiation therapy, chemotherapy agents
Patho - excessive O2 free radicals production → damage to cells
Oxygen Toxicity S/S
Begins w/in 6hr exposure
Chest pain on inspiration, tachypnea, non-productive cough
24hr paresthesia, anorexia, nausea, headache
Physiological changes ↓tracheal mucus, vital capacity, pulmonary compliance, & diffusion capacity, & ↑PAO2/PaO2
Oxygen Toxicity
Anesthesia Management
Minimal FiO2
PEEP to maintain “open lung” (alveoli open & prevent atelectasis)
Corticosteroid therapy
Autoimmune Disorders
Chronic INtrinsic RLD
→ Sarcoidosis
Characterized by multiple organ involvement & dysfunction
Sarcoidosis
Chronic INtrinsic RLD
Predisposing factors: 20-40yo African Americans
Cause unclear - genetic component (?)
Patho - epithelioid-cell granulomata present → enlarged lymph nodes, scarring & granulomas, cough, liver/spleen enlargement, joint pain/swelling
Management - corticosteroids
Chronic EXtrinsic RLD
Non-traumatic - Obesity - Pregnancy - Skeletal & neuromuscular disorders (1° kyphosis) Traumatic - Flail chest - Pneumothorax - Pleural effusion
Skeletal Disorders
NON-traumatic Chronic EXtrinsic RLD - Pectus excavatum - Pectus carinatum - Kyphosis - Scoliosis
Pectus Excavatum
NON-traumatic chronic EXtrinsic RLD
- Most common chest wall deformity
- Nuss procedure
- ↑incidence CHD & asthma
- Only effective treatment = surgery
Pectus Carinatum
NON-traumatic chronic EXtrinsic RLD
- Longitudinal sternum protrusion
- Associated w/ ↑incidence CHD
- Only effective treatment = surgery
Kyphosis
Most common skeletal disorder
NON-traumatic chronic EXtrinsic RLD
- Posterior spine curvature accentuated
- Patients able to maintain normal respiratory function unless severe deformity
Scoliosis
NON-traumatic chronic EXtrinsic RLD
- Spinal column deformity resulting in lateral curvature & rotation of the spin & rib cage
- Most common spine deformity
- 25% patients also have concomitant congenital abnormalities (mitral valve prolapse most common)
- VC & FEV1 <50% → postop pulmonary complications
- Severity determined by Cobb angle
Cobb Angle
> 60 degrees = diminished pulmonary function
70 degrees = pulmonary symptoms develop
110 degrees = significant gas exchange impairment
↑curvature ↑pulmonary function LOSS
Ankylosing Spondylitis
Marie-Strumpell disease (rheumatoid spondylitis)
Chronic spine/joint inflammatory disorder
Etiology unclear
Most common in white males <40yo
Clinical S/S
- Pain, stiffness, & fatigue
Most patients are asymptomatic
Ankylosing Spondylitis Complications
Cardiac - Aortic valve disease, conduction disturbance, ischemic heart disease, & cardiomyopathy Pulmonary up to 70% - Apical fibrosis - Interstitial lung disease - Chest wall restriction - Sleep apnea - Spontaneous pneumothorax
Limited cervical ROM & extension
Cricoarytenoid involvement → weak, hoarse voice
Ankylosing Spondylitis
Anesthesia Implications
1° upper airway management Limited cervical spine movement Consider regional anesthetic Avoid intubation when possible Patient self-position prior to induction CV complications
Chest Trauma
Traumatic chronic EXtrinsic RLD
- Flail chest
- Pneumothorax
- Tension pneumothorax
- Hemothorax
Flail Chest
Traumatic chronic EXtrinsic RLD
Multiple 2+ rib fractures → paradoxical chest wall movement at the fracture site
Insufficient breathing limits alveolar ventilation → hypoventilation, hypercapnia, & progression alveolar collapse
Anesthetic considerations:
- Pain control w/ intercostal nerve block, epidural catheter, or erector spinae block
- ↓pain w/ breathing d/t patient unable to feel rib cage → more effective ventilation
Pneumothorax
Traumatic chronic EXtrinsic RLD
SIMPLE
- No communication w/ atmosphere
- No mediastinum or diaphragm shift
- Observation (treatment not always required, may potentially self-resolve)
- Aspiration or thoracotomy tube
COMMUNICATING
- Air in pleural cavity exchanges w/ atmospheric
- Dressing, FiO2, thoracotomy tube, intubation & ventilation
TENSION
Tension Pneumo
Traumatic chronic EXtrinsic RLD
Air progressively accumulates under pressure w/in pleural cavity = medical emergency
↑intra-thoracic pressure → contralateral lung & great vessels compression ↓VR ↓CO/BP
Shunt blood to non-ventilated areas
S/S:
- Hypotension, tachycardia, ↑CVP, ↑airway pressure
NEEDLE DECOMPRESSION 16G
*Ideally place chest tube
Hemothorax
Traumatic chronic EXtrinsic RLD Rapid collection blood w/in intra-thoracic cavity d/t trauma Chronic disease process or condition → blood builds-up over time Anesthetic considerations: - Airway management - Restore circulating blood volume - Evacuate blood accumulated - Potential thoracotomy
Atelectasis
General anesthesia → supine → induction
Patho - airways blocked ↓gas exchange, loss diaphragmatic tone, PPV maldistribution
Pleural Effusion
Abnormal fluid collection w/in pleural space
- Hydrothorax
- Empyema
- Hemothorax
- Chylothorax
Hydrothorax
Abnormal fluid collection w/in pleural space
- Lymph system blocked & unable to drain fluid
- Cardiac failure
- ↓plasma colloid osmotic pressure
Empyema
Abnormal fluid collection w/in pleural space
Pyothorax or purulent pleuritis
- Infection (pus)
Chylothorax
Abnormal fluid collection w/in pleural space
- Lipids
Pleural Effusion Treatment
Thoracostomy (chest) tube
Thoracentesis
Pleurodesis
Other RLD
Obesity
Pregnancy
Neurogenic
Surgical
Obesity
Restrictive load (direct weight & indirect abdominal panniculus) ↑pressure ↓FRC
Shallow rapid breathing → hypercapnia
Treatment - weight management & CPAP
Anesthetic considerations:
- I:E ratio BMI <40 1:1.5 or >40 1:1
- Adjust minute ventilation to accommodate ↑RR
- Maintain PIP (patient individualized)
Pregnancy
↑subcostal angle & circumference Upward diaphragm displacement ↓FRC (ensure fully de-nitrogenated) ↑RV (unable to utilize) Airway Δ after laboring hours
Neurogenic
Guillain-Barre or Myasthenia Gravis
Characterized by expiratory muscle weakness - inability to cough forcefully = aspiration risk
Absence abdominal muscle tone → inefficient diaphragm (unable to fully expand)
Weak swallowing muscles/reflex → aspiration
Surgical
Anesthetic medications
↓reflexes ↓tone
Patient positioning - supine, reverse Trendelenburg, lithotomy, etc.
Pneumoperitoneum (laparoscopic procedure w/ insufflation)
