Respiratory failure and COPD Flashcards
Define respiratory failure
A potentially life-threatening deterioration in the gas exchange function of the respiratory system
The final common pathway for a lot of problems
Causes of Ventilation failure
Drugs depress CNS, Metabolic alkalosis, Spinal cord (quadriplegia), Guillain-Barre Syndrome, Myasthenia gravis, Pulm. disorders, Rib cage/spine problems, phrenic n. problem, hereditary myopathy (DMD)
Define hypoxemia and hypercapnea
PaO2 < 60 mm Hg and/or SaO2 < 90%
PaCO2 > 40 mm Hg +/- acidosis
Types of Respiratory failure
Acute or chronic.
Type 1: air comes in fine, but something prevents O2 entering = impaired oxygenation. Abnormal A-aDO2.
Type 2: hypoventilation - higher CO2, lower O2
Type 3: Can be some of both!
Explain the various pathophysiologic causes of impaired oxygenation
decreased FiO2; reduced barometric pressure; ventilation-perfusion mismatch; hypoventilation; shunt; diffusion impairment; decreased PvO2
Describe the various causes of hypercapnia
increased CO2 production; increased dead space ventilation; decreased minute ventilation
Describe the pathophysiology of decreased minute ventilation
central nervous system; spinal cord and peripheral nerves; neuromuscular junction; muscles; chest wall; lungs and/or airways
Signs and symptoms of respiratory failure
Accessory Muscle Use Altered mental status Anxiety Bradypnea Confusion Cyanosis Dyspnea Fatigue Headache Indrawing Paradoxical abdominal breathing Tachypnea
Diagnosis of respiratory failure
Hx and PE, with ABG to confirm
CXR/CT
Tx for respiratory failure
Fast evaluation.
ABCs
Supportive: O2, ventilator
Then underlying cause:
Pneumonia – antibiotics
CHF/pulmonary edema – diuretics, ACE inhibitors, etc.
CNS depression due to O.D. – antidote if available
COPD exacerbation – bronchodilators, steroids, antibiotics. Etc.
Causes of COPD
Tobacco smoke, occupation (esp poor ventilation), indoor/outdoor pollution, Family History (A1AT deficiency - doesn’t control proteases)
2 branches of COPD
Can be:
1. Emphysema = Abnormal, permanent dilatation of
airspaces distal to terminal bronchioles
-Alveolar wall destruction without fibrosis
-pink puffers = working hard to maintain normal CO2/O2 via breathing until late in disease, eventually lead to RHF.
2. Chronic bronchitis = productive cough > 3 months per year for 2 years in a row, with airflow obstruction
-blue bloaters = can’t do the extra work to maintain ventilation, hypoxia and hypercapnia earlier, RHF earlier
Co-morbidities of COPD
Weight loss with decreased fat-free mass Muscle wasting and weakness Other systemic effects: – osteoporosis – anemia – Depression – Cardiac Disease
Symptoms of COPD
Cough, sputum, dyspnea
- cough
- phlegm
- simple chores make you short of breath
- wheeze when you exert yourself, or at night
- frequent colds that persist longer than those of other people
Acute exacerbations of COPD (AECOPD)
aka lung attack
Non-Invasive Positive Pressure Ventilation (NIPPV)
Steroids (prednisone) 5 days
Antimicrobial agents - cause 50%
