Effect of position and positive pressure ventilation on functional residual capacity in morbidly obese patients

link.springer.com April 5, 2019

In awake morbidly obese volunteers, an increase in the FRC is observed when spontaneous ventilation at zero inspiratory pressure is switched to positive pressure. Compared with S positioning, the BC position had no measurable impact on the FRC. The RT position resulted in an optimal functional residual capacity (FRC). Using a prospective crossover randomized trial design, obese subjects underwent, in a randomized order, a combination of one of three positions, supine (S), beach chair (BC), and reverse Trendelenburg (RT), and one of two ventilation strategies, spontaneous ventilation at zero inspiratory pressure (ZEEP-SV) or with positive pressure(PP-SV) set to an inspiratory pressure of 8 cmH2O,positive end-expiratory pressure of 10 cmH2O, and fraction of inspired oxygen of 0.21.