Could someone explain to me why this occurs? I really am struggling to understand this concept, thanks so much for any input.
Negative Intrathoracic Pressure In Disease States
- Thread starter stop2stop
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Intrathoracic pressure is always negative under physiological conditions. The Lungs pull in (Elastic recoil) and the chest wall wants to expand out. The small amount of air in this space is pulled on by both sides until the forces even out, leaving you with roughly -5 mmHg (or H2O, I forget which/whether it matters).
Disease states can mean a variety of things:
____thorax - something is in the thorax, like fluid, blood, or air. This leads to the pressure increasing (since the negative pressure would simply pull fluid/air from whatever opening introduced it). Exception would be tension pneumothorax, where the flap of skin acts as a 1 way valve, leading to air coming in but not leaving with every breathe, eventually crushing the lung.
Restrictive Lung disease - Lungs have built up something which increases recoil (like fibrosis), which increases the elastic recoil, and potentially increases the negative ITP.
Obstructive Lung disease - Air is either blocked from leaving or the elastic elements which squeezed it out are now gone. Ant-Post diameter of the chest increases because the lung's recoil is diminished and the chest wall remains prone to expansion. I don't know whether ICP changes, but if it did, it would become less negative, closer to atmospheric pressure.
Not 100% sure of everything above, so if someone sees something wrong please comment.
Disease states can mean a variety of things:
____thorax - something is in the thorax, like fluid, blood, or air. This leads to the pressure increasing (since the negative pressure would simply pull fluid/air from whatever opening introduced it). Exception would be tension pneumothorax, where the flap of skin acts as a 1 way valve, leading to air coming in but not leaving with every breathe, eventually crushing the lung.
Restrictive Lung disease - Lungs have built up something which increases recoil (like fibrosis), which increases the elastic recoil, and potentially increases the negative ITP.
Obstructive Lung disease - Air is either blocked from leaving or the elastic elements which squeezed it out are now gone. Ant-Post diameter of the chest increases because the lung's recoil is diminished and the chest wall remains prone to expansion. I don't know whether ICP changes, but if it did, it would become less negative, closer to atmospheric pressure.
Not 100% sure of everything above, so if someone sees something wrong please comment.
