In mechanical ventilation, what is indicated by a consistently low plateau pressure in a patient receiving adequate tidal volume?

A consistently low plateau pressure in a patient receiving adequate tidal volume indicates high compliance of the lungs. Plateau pressure measures the pressure in the airways during the pause in airflow, reflecting the pressure required to maintain inflation of the lungs. When the lungs are highly compliant, they can expand easily with relatively low pressure, which results in lower plateau pressures during mechanical ventilation.

High compliance can be seen in conditions such as pulmonary edema, emphysema, or normal lung function, where the lung's ability to stretch and accommodate air is maintained or enhanced. In contrast, low compliance, as seen in restrictive lung diseases like pneumonia or pulmonary fibrosis, would result in higher plateau pressures.

Normal lung compliance typically results in plateau pressures within expected ranges, but if compliance is high, it will lead to lower plateau pressures, making it clear that the lungs can take in more volume without a corresponding increase in pressure. This relationship highlights the efficiency of the lung mechanics in delivering adequate ventilation.