Ventilators for Nonintensivists: Troubleshooting Elevations in Plateau Pressure.

Troubleshooting elevations in plateau pressure.

As coronavirus disease (COVID-19) has rapidly evolved into a pandemic, many physicians without prior critical care training are being called upon to help manage severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–infected patients who develop respiratory failure and require mechanical ventilation. This video is intended to provide a brief and simplified approach to mechanical ventilation for nonintensivists. It is essential to regularly monitor two alveolar pressures in mechanically ventilated patients: the plateau pressure (Ppl) and the total positive end-expiratory pressure (PEEPtotal). This video provides an overview of monitoring and troubleshooting elevations in Ppl. Ppl is the alveolar pressure at end inspiration and represents the highest pressure in the alveoli during the respiratory cycle. It is important to monitor Ppl because high Ppl is associated with increased mortality among patients with acute respiratory distress syndrome. One of the goals of ventilation for mechanically ventilated patients is to keep the Ppl <30 cm H2O. Mathematically, the components of Ppl may be derived from the equation for compliance. Compliance (C) is equal to the change in volume (V) divided by the change in pressure (P):In the context of mechanical ventilation, the change in volume is equal to the tidal volume (TV), whereas the change in pressure is equal to the Ppl minus PEEPtotal:This equation may be rearranged using simple arithmetic, allowing us to solve for Ppl.From this equation, we can see that elevations in Ppl can be explained by high TV, high PEEPtotal, or low compliance (C). Therefore, if the Ppl is elevated, options include reducing the TV, improving compliance, or minimizing PEEPtotal. In patients with acute respiratory distress syndrome, the recommended TV is 6 ml/kg of predicted body weight. If the Ppl is elevated despite this TV, it may be reduced to 5 or even 4 ml/kg, provided that the patient's acid–base status tolerates such a change. A conservative fluid management approach is also recommended to increase compliance and shorten the duration of mechanical ventilation. Finally, PEEPtotal should be minimized by avoiding autoPEEP.