This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Introduction
Obese patients with COVID-19 are at greater risk of requiring mechanical ventilation and developing ARDS.1 Obesity is characterized by an increased pleural pressure due to higher thoraco-abdominal loading, which reduces end-expiratory lung volume, and causes atelectasis and airway compression.2 Consequently, it is usually recommended to use high PEEP to improve gas exchange and avoid atelectrauma.2 However, inadequately high PEEP may cause overdistention and lung injury together with increased dead space, reduced cardiac output, and ultimately decreased oxygen delivery.3 Whereas clinicians often target oxygenation for PEEP titration, identifying more relevant bedside tools to guide PEEP selection may help to decide whether high PEEP might be deleterious. We assessed whether selecting subjects based on response in airway driving pressure (ΔP) when setting high PEEP would indicate potential physiological benefits that would otherwise not be recognized by the oxygenation response. The study was performed in a relatively homogeneous population of obese subjects with COVID-19 ARDS.
Methods
We conducted a physiological study including consecutive, sedated, and curarized obese (body mass index [BMI] > 30 kg/m2) subjects with moderate-severe COVID-19 ARDS ventilated in volume control with tidal volume (VT) of 6 mL/kg of predicted body weight to keep plateau pressure (Pplat) < 30 cm H2O and ΔP < 15 cm H2O, with 0.3 s of end-inspiratory pause and breathing frequency to achieve pH 7.20–7.45. We evaluated the respiratory system mechanics using a specific device (FluxMed, MBMed, Buenos Aires, Argentina). We inserted an esophageal balloon catheter (VA-A-008, MBMed) filled with 0.5 mL of air that correct position was confirmed accordingly.4 Expired CO2 was measured with a monitor previously validated (FluxMed, MBMed) that combines a mainstream Capnostat (Capnostat 5, Philips, Amsterdam, the Netherlands) and a specific software. After a stepwise recruitment maneuver (maximum airway pressure …
Correspondence: Laurent Brochard MD, Keenan Research Centre and Li Ka Shing Institute, Department of Critical Care, St Michael’s Hospital, Toronto, Ontario, Canada. E-mail: Laurent.Brochard{at}unityhealth.to
Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$30.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.