Physiological effects of ventilation and diffusion disorders Flashcards
Define hypoxemia.
decreased oxygen saturation in the BLOOD
Define hypoxia.
decreased oxygen saturation in the TISSUE
What causes hypoxemia?
decreased oxygen in the air, hypoventilation, diffusion abnormalities (fibrosis), abnormal ventilation-perfusion ratios, shunting (alveolar collapse), CO poisoning
What does hypoxemia lead to?
leads to hypoxia while tissues adapt to lower levels of oxygen (severe cases metabolic acidosis, due to anaerobic metabolism)
What is mild hypoxemia?
- hemoglobin saturation is still 90%
- increase HR, peripheral vasoconstriction, diaphoresis
- slight impairment of mental function and visual acuity
What are the main concerns of hypoxemia?
leads to acidosis and enzymes lose their efficiency (neurons are also sensitive to acidosis)
What is moderate hypoxemia?
restless agitation, altered cognition, uncoordinated movement, euphoria, impaired judgement, delirium loss of consciousness leading to coma
What is chronic hypoxemia?
- pulmonary vasoconstriction in response to alveolar hypoxia
- polycythemia (increased RBCs
- cyanosis often a late sign
What is hypercapnia?
increased CO2
What are the causes o hypercapnia?
- hypoventilation pulmonary disease (edema) - restriction of thoracic movement - airway obstruction
What does hypercapnia lead to?
- respiratory acidosis (low pH affects all tissues including heart and nervous system)
- kidneys try to buffer by excreting hydrogen and producing bicarbonate
Define pneumothorax.
accumulation of air in the pleural layers
Define hemothorax.
accumulation of BLOOD in the pleural layers
Define transudate.
watery pleural effusion
Define exudate.
contains WBC, pleural effusion
Define empyema.
pus accumulation in pleura
What is the significance of accumulations in pleura?
can cause atelectasis
Define atelectasis.
collapse of the lung or incomplete expansion of alveoli
What can cause pneumothorax?
DIRECT INJURY (atmospheric air enters through disruption of chest wall (parietal))
What are the usual causes of hemothorax?
trauma or bleeding from pneumonia, TB or tumors
Define pleural effusion.
accumulation of fluid in the pleural space
What are the causes of pleura effusion
pulmonary infarction trauma tumor infection MI
What causes empyema?
bacterial infection/absess
What are the manifestations of empyema ?
cyanosis fever tachycardia cough pleural pain
What is the treatment of empyema?
antibiotics and thoracenteses
Define thoracentesis.
draining of the pleural space
What are the 2 main causes of atelectasis?
COMPRESSION (external pressure by tumour, fluid or air)
ABSORPTION (remove air within lung; usually obstruction from mucus plug or tumour)
Slide 17
slide 17
