We have a wide body of evidence showing a strong correlation between the value of driving pressure and the risk of VILI - in ICU, and the incicende of postoperative pulmonary complications - in OR, even during brief periods of mechanical ventilation during general anesthesia.

I think the substrate of your question is the limitation of airway driving pressure, the calculation takes in consideration the compliance of 2 elastic structures: the lung and the chest wall - and any one of these if abnormal will influnece the global compliance of the respiratory system leading to increase in pressures measured at the airway. Sometimes you can decrease the tidal volume or perform a recruitment maneuvers (to counteract the atelectasis associated with anesthesia, intra-abdominal pressures or particular positions assumed during surgeries and increase the size of the container distributing your 6mL/Kg IBW tidal volume) but sometimes you can't. A better way to individualize your protective ventilation strategy is the use of esophageal manometry with the calculation of transpulmonary driving pressure. Grieco demonstrated that transpulmonary DP has the same correlation with risk of VILI as airway driving pressure. Another way, in ICU setting, is the measurement of FRC - a direct measurement of the size of baby lung in ARDS and select a tidal volume to give a dynamic strain lower that 0.25; PEEP optimization (I use this word from lack of a better one as any level of PEEP associates with the degree of baby lung distension but the idea is to be minimal while the recruitment of new alveoli is the predominent mechanism) will further help in the reduction of DP and volumetris strain if your patient is a recruiter.

New studies about the cut off values of DP in special populations, yes, I think we will see them in the future, current guidelines tell us that higher than 15 cm H2O is associated with an injurious ventilation strategy.

How do you manage your patients - ICU or OR - in which the DP is higher than 15 at tidals considered protective?

Thank you for your detailed answer. Regarding your question; I think we should follow lung protective ventilation; tidal volume (4-8ml/kg), stepwise lung recruitment maneuver -in recruitable patients- and setting of suitable PEEP according to Individualized PEEP titration after RM. We should also search for the possible causes of elevated driving pressure and manage them.

During the late 1980's it was accidentally discovered that "permissive hypercarbia" improves outcome in nearly all forms of pulmonary disease, including asthma, pneumonia, and ARDS. This has actually been known for more than 100 years since Yandell Henderson discovered the therapeutic benefits of carbon dioxide. Try reading the attached review of CO2 pathophysiology. Mechanical ventilation is inherently dangerous because it depletes body reserves of CO2, which undermines oxygen transport and delivery to tissues, and it threatens mechanical damage to lung tissues. Ventilator management should focus on restricting tidal volumes and pressures to maintain hypercarbia in the range of 50-100 torr. This will minimize lung damage and promote tissue oxygenation and organ protection.