Blue bloaters and Pink puffers

Blue Bloaters

• • In this type, chronic bronchitis plays the major role

  • Chronic bronchitis is defined by excessive mucus production with airway obstruction and notable hyperplasia of mucus-producing glands

  • Damage to the endothelium impairs the mucociliary response that clears bacteria and mucus

  • Inflammation and secretions provide the obstructive component of chronic bronchitis

  • In contrast to emphysema, chronic bronchitis is associated with a relatively undamaged pulmonary capillary bed

  • Emphysema is present to a variable degree but usually is centrilobular rather than panlobular

  • The body responds by decreasing ventilation and increasing cardiac output

    • This V/Q mismatch results in rapid circulation in a poorly ventilated lung, leading to hypoxemia and polycythemia.

  • Eventually, hypercapnia and respiratory acidosis develop, leading to pulmonary artery vasoconstriction and cor pulmonale

Pink Puffers

• • In this type, emphysema is the primary underlying process

    • Emphysema is defined by destruction of airways distal to the terminal bronchiole.

  • Physiology of emphysema involves gradual destruction of alveolar septae and of the pulmonary capillary bed, leading to decreased ability to oxygenate blood

  • The body compensates with lowered cardiac output and hyperventilation

  • This V/Q mismatch results in relatively limited blood flow through a fairly well oxygenated lung with normal blood gases and pressures in the lung

    • In contrast to the situation in blue bloaters

  • Because of low cardiac output, however, the rest of the body suffers from tissue hypoxia and pulmonary cachexia

  • Eventually, these patients develop muscle wasting and weight loss

Comparison

Verbose Descriptions

A "pink puffer" is a person where emphysema is the primary underlying pathology. As you recall, emphysema results from destruction of the airways distal to the terminal bronchiole--which also includes the gradual destruction of the pulmonary capillary bed and thus decreased inability to oxygenate the blood. So, not only is there less surface area for gas exchange, there is also less vascular bed for gas exchange--but less ventilation-perfusion mismatch than blue bloaters. The body then has to compensate by hyperventilation (the "puffer" part). Their arterial blood gases (ABGs) actually are relatively normal because of this compensatory hyperventilation. Eventually, because of the low cardiac output, people afflicted with this disease develop muscle wasting and weight loss. They actually have less hypoxemia (compared to blue bloaters) and appear to have a "pink" complexion and hence "pink puffer". Some of the pink appearance may also be due to the work (use of neck and chest muscles) these folks put into just drawing a breath.

A "blue bloater" is a person where the primary underlying lung pathology is chronic bronchitis. Just a reminder, chronic bronchitis is caused by excessive mucus production with airway obstruction resulting from hyperplasia of mucus-producing glands, goblet cell metaplasia, and chronic inflammation around bronchi. Unlike emphysema, the pulmonary capillary bed is undamaged. Instead, the body responds to the increased obstruction by decreasing ventilation and increasing cardiac output. There is a dreadful ventilation to perfusion mismatch leading to hypoxemia and polycythemia. In addition, they also have increased carbon dioxide retention (hypercapnia). Because of increasing obstruction, their residual lung volume gradually increases (the "bloating" part). They are hypoxemic/cyanotic because they actually have worse hypoxemia than pink puffers and this manifests as bluish lips and faces--the "blue" part.