Effects of Two Different Stepwise Lung Recruitment Maneuvers on Patient Hemodynamics During Laproscopic Surgery

"The ventilation protocol consisted of volume controlled mechanical ventilation, FiO2 0.4, inspiratory-to-expiratory (I:E) ratio at 1:2, and respiratory rate (RR) set to normocapnia (end-tidal CO2 partial pressure between 35 and 40mmHg, TV 6 mL/kg PBW and 5 cmH2O PEEP.~RMs were conducted under volume controlled ventilation with initial settings of a limit of peak inspiratory pressure at 40cmH2O, TV at 6 mL/kg PBW (PBW = 50.0+0.905\*((height in cm)-152.4) for men, and = 45.5+0.905\*((height in cm)-152.4) for women) Brower, et al. 1999, RR at 7 breaths/min, PEEP at5 cmH2O, and I:E ratio at1:1. The TV was then increased by steps of 4 mL/kg PBW until plateau airway pressure (Pplt) was 40 cmH2O, after which 3 breaths were allowed. Finally, the limit of peak inspiratory pressure, TV, RR, and I:E ratio were reset at values equal to those preceding the RM."

The ventilation protocol consisted of volume controlled mechanical ventilation, FiO2 0.4, in RMs was conducted under pressure controlled ventilation so ventilation technique will be changed, pressure-control mode will be started and inspiratory time is increased to 50% (inspiratory: expiratory ratio will be set to 1:1). Peak airway inspiratory pressure (Ppeak) will be initially set to 20 cmH2O for three breaths, and then PEEP will be increased in steps from 5 to10 cmH2O for five breaths, from 10 to 15 cmH2O for seven breaths, from 15 to 20 cmH2O for ten breaths while Ppeak increased to 40 cmH2O and will be maintained for three more breaths. Following ARM, volume control will be re-established using Vt 6 mL/kg and step-wise reductions in PEEP from 20 to 15 cmH2O for three breaths,and then to 5 cmH2O until the end of recruitment maneuver