The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts


Tom Piraino, Deborah J. Cook; St. Joseph’s Healthcare, Hamilton, ON, Canada

Introduction: In theory, esophageal pressure monitoring utilized early in the management of the acute respiratory distress syndrome (ARDS) may aid lung protection ventilation by providing optimal settings specific to each patient. However, current best practice for ARDS is lung protective ventilation targetting 4- 6mls/kg tidal volume and plateau pressures < 30 cm H2O. A key limitation to mechanical ventilators is that they report peak airway pressures without distinguishing compliance that reflects intrinsic lung mechanics or chest wall and abdominal pressures. We utilized esophageal pressure monitoring to help guide optimal positive end expiratory pressure (PEEP) and to estimate the transpulmonary pressure distending the lungs in a patient suspected of having decreased compliance due to elevated abdominal pressures. Case Summary: A 45 yr old female was admitted to the ICU with septic shock due to an obstructive ureteric stone. When she was turned during routine care, the SpO2 decreased to 78%. The patient had ascites and an elevated bladder pressure of >32 mmHg . Despite an increase in FiO2 to 1.0, high PEEP levels, and intermittent recruitment maneuvers, it was challenging to obtain and sustain a SpO2 > 85%. We inserted an esophageal balloon to determine whether the abdominal pressures were affecting lung compliance. PEEP was guided to a level of 32 cm H2O to achieve a transpulmonary pressure of 0 cm H2O. Within 6 hours, the FiO2 was weaned and the PaO2/FiO2 ratio increased from 80 to 244. We made subsequent PEEP changes according to transpulmonary pressures with reference to Talmor’s study (NEJM, November 2008), and the patient was weaned from mechanical ventilation in 8 days with no adverse sequelae associated with very high PEEP levels. Discussion: The care of this patient renewed our interest in measuring esophageal pressures to determine optimal PEEP during mechanical ventilation. These PEEP levels were much higher than expected, and helped us to liberate the patient from mechanical ventilation sooner than expected. Sponsored Research - None

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