Use of dual targeting during volume control ventilation is associated with increased delivery of non-lung-protective tidal volumes

PURPOSE: Dual targeting (DT) is a patient-comfort ventilator feature that allows for increased flow in response to patient demand. Since flow is augmented above the set flow, larger tidal volumes (VT) than set may be delivered. This study assessed the impact of DT on the ability to maintain delivered VT ≤ 8 mL/kg of ideal body weight (IBW). MATERIALS AND METHODS: This was a single center retrospective cohort study of medical ICU patients receiving volume-targeted mechanical ventilation in the year before and after system-wide implementation of a ventilator featuring DT. The primary outcome was the proportion of patients receiving an average VT > 8 mL/kg IBW during the first 48 h of intubation. Secondary outcomes included differences in set versus delivered VT and patient outcomes such as ventilator-free days, incidence of acute respiratory distress syndrome, mortality, and length of stay. RESULTS: After applying exclusion criteria, 274 patients remained in the analysis, 136 in the control group and 138 in the DT group. Despite no difference in the set VT (median 6.1 mL/kg IBW), patients in the DT group were more likely to receive an average VT > 8 mL/kg IBW (26.1% vs 12.5%, odds ratio 2.5, 95%CI 1.3 - 4.7; P = .006). Median delivered VT was higher with DT (7.2 vs 6.6 mL/kg IBW; P < .001), as was median difference between set and delivered VT (+53.3 vs + 27.5 mL; P < .001). These differences remained significant after adjustment for baseline characteristics. However, no significant differences in patient outcomes were observed after adjustment. CONCLUSIONS: DT was associated with more frequent delivery of larger VT than recommended for lung protection. Further studies are needed to assess the downstream impacts on patient outcomes.