Lower tidal volume strategy (≈3 ml/kg) combined with extracorporeal CO2 removal versus ‘conventional’ protective ventilation (6 ml/kg) in severe ARDS

Abstract

BackgroundAcute respiratory distress syndrome is characterized by damage to the lung caused by various insults, including ventilation itself, and tidal hyperinflation can lead to ventilator induced lung injury (VILI). We investigated the effects of a low tidal volume (VT) strategy (VT ≈ 3 ml/kg/predicted body weight [PBW]) using pumpless extracorporeal lung assist in established ARDS.MethodsSeventy-nine patients were enrolled after a ‘stabilization period’ (24 h with optimized therapy and high PEEP). They were randomly assigned to receive a low VT ventilation (≈3 ml/kg) combined with extracorporeal CO2 elimination, or to a ARDSNet strategy (≈6 ml/kg) without the extracorporeal device. The primary outcome was the 28-days and 60-days ventilator-free days (VFD). Secondary outcome parameters were respiratory mechanics, gas exchange, analgesic/sedation use, complications and hospital mortality.ResultsVentilation with very low VT’s was easy to implement with extracorporeal CO2-removal. VFD’s within 60 days were not different between the study group (33.2 ± 20) and the control group (29.2 ± 21, p = 0.469), but in more hypoxemic patients (PaO2/FIO2 ≤150) a post hoc analysis demonstrated significant improved VFD-60 in study patients (40.9 ± 12.8) compared to control (28.2 ± 16.4, p = 0.033). The mortality rate was low (16.5 %) and did not differ between groups.ConclusionsThe use of very low VT combined with extracorporeal CO2 removal has the potential to further reduce VILI compared with a ‘normal’ lung protective management. Whether this strategy will improve survival in ARDS patients remains to be determined (Clinical trials NCT 00538928).Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-012-2787-6) contains supplementary material, which is available to authorized users.

Extracorporeal Life Support for Acute Respiratory Failure. A Systematic Review and Metaanalysis

“…The level of bias was analyzed using the Cochrane Collaboration risk of bias instrument (Table E1). The four RCTs (19)(20)(21)(22) and two quasi-RCTs (14, 23) had an overall low risk of bias, whereas the observational studies tended to have sicker patients in the ECLS group, thus limiting the ability to compare the two modalities among a similar group of patients.…”

“…Ten studies fulfilled the inclusion criteria, including four RCTs (19)(20)(21)(22) and six observational studies (14,(23)(24)(25)(26)(27). No SYSTEMATIC REVIEW SYSTEMATIC REVIEW pediatric trials met the inclusion criteria, and, therefore, only adult patients were included in all analyses.…”

“…In a post hoc analysis of a recent RCT comparing "ultra"-lungprotective ventilation (3 ml/kg predicted body weight) combined with ECCO 2 R, as compared with conventional lungprotective ventilation, was associated with increased ventilator-free days in the most severe cohort of patients with ARDS (22). The ability of ECCO 2 R to facilitate a further reduction in VTs is intriguing in light of recent data suggesting a dose-response of lower VTs with long-term mortality in patients with ARDS.…”

‘Lung-protective’ ventilation in acute respiratory distress syndrome: still a challenge?

“…One possible strategy is to aim for even lower tidal volumes. So-called 'ultra-protective ventilation' combining very low tidal volumes (~3 mL/kg PBW) with extracorporeal CO 2 removal has the potential to further reduce VILI compared with a standard protective ventilation (24). Another way to achieve a low driving pressure is to titrated PEEP according to the driving pressure.…”

Preventing ventilator-induced lung injury—what does the evidence say?

“…ECMO might also enable the use of minimal tidal volume, as proper gas exchange is achieved extracorporeally, avoiding further baro-and biotrauma by VILI. However, it is unclear whether such "ultra"-protective ventilation strategies with minimal (or no) tidal volume resulting in near complete atelectasis, are more lung protective than a ventilation pattern with a lung recruitment strategy (18).…”