Reducing ventilator-induced lung injury

A method for promoting equitable distribution of liquid amongst pulmonary alveoli in the presence of alveolar edema with a ventilation means including a conduit for fluidly connecting a source of ventilation gas to a lung, the conduit having a receiving inlet for receiving ventilation gas from a source of ventilation gas and a discharge outlet for discharging ventilation gas to the lung, a vacuum outlet for fluidly connecting the conduit to a source of vacuum pressure, a normally-open proportional valve between the receiving inlet and the vacuum outlet, a normally-closed proportional valve at the vacuum outlet, and a pressure transducer for indicating the pressure within the conduit, the pressure transducer being located between the normally-open proportional valve and the discharge outlet of the conduit, said method including the steps of:

• fluidly connecting the receiving inlet of the conduit to a source of ventilation gas at a positive pressure, the vacuum outlet to a source of vacuum pressure, and the discharge outlet of the conduit to a lung having alveolar edema;
• inflating the lung to full pressure with the ventilation gas;
• performing the steps of suddenly closing the normally-open proportional valve and suddenly opening the normally-closed proportional valve, the suddenly closing step and the suddenly opening step being performed simultaneously, thereby effecting an abrupt deflation of the lung;
• holding the normally-closed valve open until the pressure transducer indicates a pressure in the conduit that is equal to a target positive end-expiratory pressure, then closing the normally-closed valve, thereby maintaining a positive pressure in the conduit and the lung;
• and
• gradually opening the normally-open valve, thereby increasing the pressure in the conduit above the target positive end-expiratory pressure.