Normal Pleural Pressure Range

Your ability to breathe depends on something you may never have heard of, let alone pondered, namely intrapleural pressure.

Pleural Membrane

• A serous membrane enfolds the lungs consisting of an inner (visceral) layer enveloping each lung and an outer (parietal) layer that attaches to the chest wall, according to Professor Gerard J. Tortora.

Normal Intrapleural Pressure

• Arthur Vander and his team observed that, in between breaths, the pressure in the fluid-filled space between these two layers (intrapleural pressure) is approximately 756 mmHg (torrs)--four less than atmospheric pressure at sea level.

Normal Range

• As noted by Teleflex Medical, a manufacturer of chest-drainage devices, intrapleural pressure drops during inhalation to about 5.9 torrs below atmospheric pressure while rising during exhalation to about 2.9 torrs below atmospheric pressure, thus ranging from 754 to 757 torrs.

Normal Conditions

• The reason intrapleural pressure is normally subatmospheric is because while the elastic recoil of the lungs pulls the pleural membrane’s visceral layer inward, the chest is pulling the parietal layer outward, thus slightly increasing the space between the layers and thereby lowering pressure, according to Vander and his co-writers.

Trauma

• Anything that separates the two layers, such as air or blood due to a gunshot, will disrupt normal intrapleural pressure, possibly causing the affected lung to collapse, according to Tortora.