Abstract
Introduction: Energy load (EL) describes the interaction between ventilator and respiratory system [1].
Aims and objectives: We investigated EL behavior in obese, ARDS and control (without lung injury) patients at two PEEP levels.
Methods: Flow and airway pressure (Paw) were recorded during mechanical ventilation in 19 obese, 50 ARDS and 30 control adults at tidal volume 6 mL/kg and respiratory rate (RR) 18±2 breaths/min at PEEP 5 and 15 cmH2O. EL was computed as the area between the inspiratory limb of Paw-TV curve and the TV axis, while EL’s components were derived from Gattinoni’s equation [1]. EL-functional residual capacity (EL/FRC) ratio was used to compare different groups.
Results: EL/FRC is significantly higher at PEEP 15 than 5 cmH2O in obese (1[0.9-1.6] vs 0.8[0.6-1], p=0.012), ARDS (0.8[0.7-1.1] vs 0.5[0.3-0.7], p<0.001) and controls (0.5[0.4-0.8] vs 0.3[0.2-0.4], p<0.001) (Fig. 1). Moreover, as expected, EL’s PEEP-related component (blue areas in Fig. 1) is significantly higher at PEEP 15 (p<0.001).
Conclusions: Higher PEEP levels are associated with higher EL, despite possible recruitment benefits, especially in obese and ARDS patients. Moreover, at PEEP 15, EL is spent primarily in baseline lug tension (PEEP-related component).
References
[1] Gattinoni L. Intensive Care Med 2016; 42:1567
- Copyright ©the authors 2017