Asthma Flashcards
A
Secretions
B
Low oxygen saturation Increased respiratory rate Increased work of breathing Accessory muscle use Intercostal recession Expiatory wheeze Hyperinflation Cyanosis
C
Tachycardia
D
Reduced consciousness (hypoxia and hypercapnia)
What causes secretions?
Airway modelling results in increased number of goblet cells. The mucosal glands expand in response to a trigger, causing increased mucosal production and secretions
What causes low oxygen saturations?
The exchange of oxygen from the alveoli into the capillaries is reduced, preventing the haemoglobin from becoming saturated with oxygen and leading to an inadequate supply of oxygen in the blood.
What causes increased respiratory rate?
The RR increases to compensate for increased resistance to airflow caused by obstruction. The body is trying to maintain a normal pH after the cells have started to go into anaerobic respiration, and get rid of a build up of carbon dioxide. The peripheral chemoreceptors detect a drop in oxygen and increase of carbon dioxide, and send impulses to the medulla to increase the respiratory rate.
What causes an increased work of breathing?
Increased airway resistance and decreased lung compliance results in increased work of breathing as the body works harder to push air through the bronchioles.
What causes accessory muscle use and intercostal recession?
As a result of reduction in elasticity. To assist with forced expiration and increase the thoracic volume, a greater pressure is needed to push air through the narrowed bronchioles.
What causes an expiatory wheeze?
Turbulent airflow through narrowed bronchioles.
What causes hyperinflation of the chest?
The inability to exhale completely can cause the lungs to become overinflated. The lungs become less elastic and the bronchioles collapse leading to excess air becoming trapped in the alveoli.
What causes cyanosis?
Increased levels of desaturated haemoglobin being transported in the blood.
What causes tachycardia?
Low levels of oxygen in the tissues, so the heart rate increases in an attempt to get more oxygen into the tissues.
What causes reduced consciousness?
Exhaustion from extra respiratory effort.
The exchange of oxygen from the alveoli into the capillaries is reduced, leading to an inadequate supply of oxygen in the blood as it is transported around the body to the organs, so the brain becomes hypoxic. The ability to inhale enough fresh oxygen and exhale carbon dioxide is also reduced, causing levels of carbon dioxide to increase, or hypercapnia.
