Mechanical ventilation is a key part of treatment in intensive care. Therefore, understanding how to provide quality mechanical ventilation that minimizes potential harms is an important endeavor in improving outcomes.
Recent literature has shown an association between driving pressure (DP) and mortality in patients with acute respiratory distress syndrome (ARDS). Fortunately, most patients ventilated in the ICU do not have ARDS. For a study published in CHEST, my colleagues and I questioned whether DP remains an important metric to follow in mechanically ventilated adult patients without ARDS.
Utilizing a publicly available database of patients admitted to an academic ICU, we selected patients who had been ventilated for over 48 hours for inclusion in the study. We determined the presence of ARDS using the lowest daily partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2), or PF, ratio and a natural language search algorithm of chest X-ray reports, adapted from previous literature.
To validate our strategy, we analyzed the association between DP and mortality in patients with ARDS, and found that these were associated in our cohort. Then, we examined the association between these variables in patients who did not meet ARDS criteria within the first full day of mechanical ventilation. We found that DP was not associated with hospital or ICU mortality in non-ARDS patients.
It is important to note that both survivors and non-survivors received a median of 13 cmH20 of DP, and that our analysis was constrained by the limits of ventilator practices during the study period (2001 to 2008). That said, our findings suggest that within the boundaries of contemporaneous ventilator practices, DP is not associated with mortality and is likely not a useful target to follow in non-ARDS patients.
Schmidt MF, Amaral ACKB, Fan E, Rubenfeld GD. Driving Pressure and Hospital Mortality in Patients Without ARDS: A Cohort Study. Chest. 2017;153(1):46-54. doi:10.1016/j.chest.2017.10.004. Available at http://journal.chestnet.org/article/S0012-3692(17)32895-7/fulltext.
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