Section 2: Asthma and COPD 2 Flashcards
Diagnosis: Decreased TLC, Decreased RV, Decreased VC, Normal FEV1, Normal FEV1/FVC ratio, Normal DLCO
Extra-parenchymal (extra-thoracic) restriction
- Kyphosis
- Obesity
Diagnosis: Increased TLC, Increased RV, Decreased FEV1, Decreased FVC, Decreased FEV1/FVC ratio, Decreased DLCO
COPD
Diagnosis: Normal or Increased TLC, Normal or Increased RV, Decreased FEV1, Decreased FVC, Normal or Decreased FEV1/FVC ratio, Normal or Increased DLCO
Asthma
Diagnosis: Decreased TLC, Decreased RV, Decreased FEV1, Decreased FVC, Normal or Increased FEV1/FVC ratio, Decreased DLCO
Fibrotic (or Interstitial Lung) Disease
List the minimum that should be done for all patients with shortness of breath (SOB)
Oxygen
Continuous oximeter
Chest X-ray
Arterial blood gas (ABG)
Causes of low DLCO
Emphesema
Pneumonectomy
Interstitial lung disease
pulmonary embolism
Pulmonary HTN
Arterial blood gases measurements
pH: 7.35 to 7.45
PCO2: 33-45mmHg
PO2: 75-105mmHg
What is A-a gradient?
A-a gradient is alveolar-arterial gradient (PAO2-PaO2 gradient). It is a useful calculation for the assessment of oxygenation. A-a gradient increases with age and is only valid in room air. It is calculated as follows:
PA02-Pa02 gradient = 150 - 1.25 X PaCO2 - PaO2
i.e.,
A-a gradient = [150 - (1.25 X PaCO2) - PaO2]
This gradient is between 5 and 15 mmHg in normal young adults. It increases with all causes of hypoxemia except hypoventilation and high altitude
List the typical physical findings in COPD
Barrel-shaped chest
Clubbing of fingers Increased anterior-posterior diameter of the chest Loud P2 heart sound (sign of pulmonary hypertension)
Edema as a sign of decreased right ventricular output (the blood is backing up due to the pulmonary hypertension)
Laboratory findings in COPD
EKG: Right axis deviation, right ventricular hypertrophy, right atrial hypertrophy
Chest x-ray: Flattening of the diaphragm (due to hyperinflation of the lungs), elongated heart, and substernal air trapping
CBC: Increased hematocrit is a sign of chronic hypoxia. Reactive erythrocytosis from chronic hypoxia is often microcytic. An erythropoietin level is not necessary.
Chemistry: Increased serum bicarbonate is metabolic compensation for respiratory acidosis.
ABG: Should be done even in office-based cases to assess CO2 retention and the need for chronic home oxygen based on pO2 (you expect the pCO2 to rise and the pO2 to fall).
Pulmonary function testing (PFT): You should expect to find the following:
– Decrease in FEV1
– Decrease in FVC from loss of elastic recoil of the lung
– Decrease in the FEV1/ FVC ratio
– Increase in total lung capacity from air trapping
– Increase in residual volume
– Decrease in diffusion capacity lung carbon monoxide (DLCO) caused by destruction of lung interstitium
Chronic medical therapy for COPD
Tiotropium or ipratropium inhaler
Albuterol inhaler
Pneumococcal vaccine: Heptavalent vaccine,
Pneumovax Influenza vaccine: Yearly
Smoking cessation
Long-term home oxygen if the pO2 < 55 or the oxygen saturation is < 88 percent
Name two interventions that lower mortality in COPD
Smoking cessation
Home oxygen therapy (continuous)
Spot Diagnosis: A case of COPD at an early age (< 40) in a nonsmoker who has bullae at the bases of the lungs.
Alpha-1 antitrypsin deficiency
Diagnosis: Decreased TLC, Decreased RV, Decreased VC, Normal FEV1, Normal FEV1/FVC ratio, Normal DLCO
Extra-parenchymal (extra-thoracic) restriction
- Kyphosis
- Obesity
Diagnosis: Increased TLC, Increased RV, Decreased FEV1, Decreased FVC, Decreased FEV1/FVC ratio, Decreased DLCO
COPD