Which pressures must remain negative to prevent lung collapse?

Intrapleural pressures must remain negative to prevent lung collapse.

Explanation:

The intrapleural pressure is the taking place within the cavity of pleural, whose pressure is marginally lower than the atmospheric pressure in what is understood as a negative pressure. The intrapleural pressure is equivalent to or exceeding the atmospheric pressure if the plural cavity is impacted, thus pneumothorax increasing occur.

This negative pressure is at resting mode and brings us a lung-expanding transpulmonary sensation. Put an easier way, if even when exhaling we didn't sustain a mildly negative pressure, our lungs would collapse on themselves as all the air would stream into the lower pressure area. The pressure intrapleural is subatmospheric, which is related to the lungs and chest recoil apart from each of the other.