Pathology

• What should students be able to explain regarding airway resistance and pulmonary compliance?


  How changes in airway resistance and pulmonary compliance lead to obstructive and restrictive ventilatory pathologies.
• What characteristic lung function parameters should students recognize?

  Parameters in obstructive and restrictive ventilatory pathology.
• What do students need to describe regarding medications for airway diameter?

  The pharmacodynamics of main classes of medications used to increase airway diameter.
• What physiological aspects should be included when discussing medications for airway diameter?


  Reference to their underlying physiology including various drug classes.
• How does turbulent airflow affect breath sounds?

  Turbulent airflow leads to breath sounds, with stridor and wheeze affected by inspiration/expiration.
• What are the four classic respiratory mechanisms of hypoxaemia?

  Shunt, V/Q mismatch, diffusion impairment, hypoventilation.
• What are the four main mechanisms by which an airway lumen is narrowed?


  External compression, intrinsic narrowing, mucosal inflammation, airway collapse.
• What is the pathophysiology of type 1 and type 2 respiratory failure?


  Type 1 is primarily a failure of gas exchange, while type 2 is primarily a failure of ventilation.
• What is the definition of ventilation?

  Ventilation is the movement of gases between the external environment and the alveolus.
• What is gas exchange?


  Gas exchange is the movement of gases between the alveolus and the pulmonary capillaries.
• What characterizes the work of breathing?

  The work of breathing is characterized by overcoming compliance and resistance.
• How does decreasing compliance affect ventilatory defects?


  Decreasing compliance leads to restrictive defects.
• How does increasing resistance affect ventilatory defects?


  Increasing resistance leads to obstructive defects.
• What are the characteristics of obstructive and restrictive ventilatory disorders?


  • Obstructive disorders: characterized by airway obstruction.
  • Restrictive disorders: characterized by a functional reduction in lung volume.
• What is indicated by a lower FEV1 in obstructive spirometry?


  Obstructed airways can't blow out as much in one second.
• What happens to the FEV1/FVC ratio in obstructive disorders?


  The FEV1/FVC ratio is lower.
• What is the FVC in obstructive disorders?


  The FVC is unchanged or changes very little.
• What does a flow volume loop indicate in obstructive defects?


  The expiratory flow rate is blunted, and the volume expired remains constant or only mildly reduced.
• What happens to the PEFR as the severity of obstructive defects increases?


  The PEFR drops as severity increases.
• What is indicated by a lower FVC in restrictive spirometry?


  The FVC is now lower compared to obstructive spirometry.
• How does the FEV1 behave in restrictive disorders?


  The FEV1 is normally a little lower but may only be mildly reduced.
• What happens to the FEV1/FVC ratio in restrictive disorders?


  The FEV1/FVC ratio tends to stay the same or can even be higher.
• What is the shape of the expiratory flow rate in restrictive disorders?


  The expiratory flow rate is not blunted in its shape.
• What causes stridor and wheeze?


  Stridor is caused by narrowing outside of the thorax, while wheeze is caused by narrowing inside the thorax.
• How does greater expiratory effort affect intrapleural pressure?


  It increases positive intrapleural pressure, compressing small intrathoracic airways further and limiting expiratory flow.
• What effect does greater inspiratory effort have on bronchiolar diameter?


  It helps increase bronchiolar diameter, improving airflow.
• What is the typical treatment for type 1 respiratory failure?


  Typically treated with CPAP to keep alveoli open and improve gas exchange.
• What is the typical treatment for type 2 respiratory failure?


  Typically treated with BiPAP to improve ventilation.
• What defines respiratory failure?


  It is defined by having a low partial pressure of oxygen in the blood (<8 kPa).
• What is the PaO2 and PaCO2 in type 1 respiratory failure?


  PaO2 is decreased (below 8 kPa) and PaCO2 is normal or low (below 6.7 kPa).
• What is the PaO2 and PaCO2 in type 2 respiratory failure?


  PaO2 is decreased (below 8 kPa) and PaCO2 is increased (above 8 kPa).
• What are the classic causes of hypoxaemia?

  V/Q mismatch, hypoventilation, failure of diffusion, and shunt.
• What is the role of the sympathetic nervous system in airway management?


  It dilates airways via muscle relaxation.
• What is the role of the parasympathetic nervous system in airway management?


  It narrows airways via muscle constriction.
• What are beta 2 agonists used for?


  They stimulate β2 receptors to dilate airways.
• What are the two types of beta 2 agonists?


  Short-acting (SABA) and long-acting (LABA).
• What is the role of corticosteroids in airway management?


  They dampen inflammation and can be inhaled or given orally.
• What is the role of methylxanthines in airway management?


  They can relax smooth muscle and reduce inflammation in severe obstructive disease.
• What is the role of magnesium in airway management?


  It can relax smooth muscle and is limited to intravenous administration in acute attacks of asthma.
• What are leukotriene receptor antagonists used for?


  They can reduce inflammation and are especially used in asthma, particularly in children.