Respiratory

Question 1

Differential Diagnosis of Dyspnea

Answer 1

Pulmonary: Asthma, COPD, Interstitial, Chest Wall Dz
Cardiac: Left Heart Failure, Pericardial Disease
Other: Anemia, Deconditioning, Psychological

Question 2

Etiology of Asthma

Answer 2

Hyperirritability of the tracheobronchial tree.
Atopic: other allergies, + skin test, elevated IgE
Non-atopic: - skin test, normal IgE, later onset, ASA sensitive.

Question 3

Pathogenesis of Asthma

Answer 3

Stimulus triggers inflammatory cells and structural cells to release mediators that lead to bronchospasm, vascular congestion, increased capillary permeability, and thick secretions. Thus, reduction in airway diameter, increase in resistance, decreased FEV and flow rate, hyperinflation, increased WOB.

Question 4

Pathogenesis of COPD

Answer 4

Goblet cell hypertrophy, inflammatory cell activation, altered structural cells leads to increased mucus production, airway fibrosis, loss of alveolar attachments, pulmonary vascular remodeling. Can lead to pulmonary HTN and right heart failure.

Question 5

Triggers of Bronchospasm

Answer 5

Allergens, Infections, Pharmacologic agents (beta antagonists, NSAIDs), Environment and Air Pollution, Occupational Factors, Exercise, Emotional Stress.

Question 6

Universal finding in ABG during asthmatic attacks

Answer 6

Hypoxemia. Tend to see respiratory alkalosis due to hyperventilation. Elevated CO2 is a late finding and possible sign of chronic changes.

Question 7

Abnormalities in PFTs, Lung Volumes and Capacities during Asthma Attack

Answer 7

Reduction in FEV1 and decreased FEV1/FVC. Decreased ERV. Increased RV, FRC, TLC.

Question 8

Preoperative Evaluation of Asthma/COPD (History)

Answer 8

Assessment of Exercise Tolerance, Recent or Current Respiratory Infections, Sputum Quantity and Quality, Known Triggers, Most Recent Exacerbation, Current Medications and Last Use, Smoking History, Prior Surgical and Anesthetic History.

Question 9

Preoperative Evaluation of Asthma/COPD (Physical)

Answer 9

Signs of bronchospasm, infection, right heart failure. Note general appearance and breathing pattern. Use of accessory muscles, purse lip exhalation, cyanosis, wheezing. Split second heart sound - cor pulmonale, murmur of TV or PV regurgitation. JVD, peripheral edema, hepatic enlargement.

Question 10

Preoperative Evaluation of Asthma/COPD (labs, studies)

Answer 10

If major surgery: CBC, CMP, ECG, CXR, room air SpO2. Do not routinely perform PFTs.

Question 11

Differences between Restrictive and Obstructive Lung Disease (spirometry)

Answer 11

Restrictive: decreased VC, decreased TLC, decreased RV, normal FEV1/FVC
Obstructive: normal VC, TLC. Increased RV. Decreased FEV1/FVC

Question 12

Volumes and Capacities

Answer 12

Volumes: TV (6-8 ml/kg), IRV (2500-3500 ml), ERV (1200 ml), RV (1200 ml)
Capacities: VC (TV+ERV+IRV), IC (TV+IRV), FRC (RV+ERV), TLC (VC+RV = 5-6L)

Question 13

Closing Volume and Closing Capacity

Answer 13

CC = volume at which small airways in dependent lungs begin to close. CC = CV+RV
CV = volume above RV where small airways close during exhalation.
Normal CV = 10% of the VC (400-500 ml)

Question 14

FRC change with position

Answer 14

Going from upright to supine reduces FRC by 30%

Question 15

Closing Capacity changes with age

Answer 15

Closing Capacity increases with age.
CC>FRC when supine over the age of 44
CC>FRC when upright over the age of 70

Question 16

FRC changes with anesthesia

Answer 16

General Anesthesia reduces FRC by 20%