Titration of ideal positive end-expiratory pressure in acute respiratory distress syndrome: Comparison between lower inflection point and esophageal pressure method using volumetric capnography

Case Report IntroductIonAcute respiratory distress syndrome (ARDS) is a syndrome resulting from damage to the alveolocapillary meshwork, [1] characterized by hypoxemic acute respiratory failure and high mortality ranging between 27% and 45%.[2] The management principles in ARDS include treatment of the basic inciting condition along with mechanical ventilation and supportive care.Mechanical ventilation not only corrects hypoxemia but also "buys time" for the basic condition to be reversed with specific therapy.Several ventilation strategies have been tried in the management of ARDS, but only a few (low tidal volume strategy and prone-position ventilation) have successfully improved survival in ARDS.Unfortunately, mechanical ventilation, if incorrectly applied can damage the lung per se, the so-called ventilator-associated lung injury (VALI).One important strategy during mechanical ventilation to prevent VALI is avoidance of overdistention and atelectrauma.Ventilating with low tidal volumes easily prevents overdistension.However, one needs to determine the optimal positive end-expiratory pressure (PEEP) to prevent atelectrauma.In addition, optimal PEEP also leads to lowest dead space with resultant better lung compliance and oxygenation.[3] Several methods have been used to determine the optimal PEEP in ARDS.Herein, we describe two different strategies of titrating PEEP in a patient of ARDS employing estimation of the lower inflection point (LIP) and esophageal balloon-guided transpulmonary pressure monitoring.We also compare the physiological parameters using the two methods with volumetric capnography. case rePortA 33-year-old pregnant female patient presented with 5 days duration of fever, breathlessness, and productive cough.OneThe tenets of mechanical ventilation in acute respiratory distress syndrome (ARDS) include the utilization of low tidal volume and optimal application of positive end-expiratory pressure (PEEP).Optimal PEEP in ARDS is characterized by reduction in alveolar dead space along with improvement in the lung compliance and resultant betterment in oxygenation.There are various methods of setting PEEP in ARDS.Herein, we report a patient of ARDS, wherein we employed measurement of dead space using volumetric capnography to compare two different PEEP strategies, namely, the lower inflection point and transpulmonary pressure monitoring.