The following is a summary of “Retrospective analysis of multi-drug resistant Gram-negative bacteria on veno-venous extracorporeal membrane oxygenation. The multicenter RANGER STUDY,” published in the August 2024 issue of Critical Care by Boscolo et al.

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) is gaining popularity as a life-support technique globally. The most common indications were severe hypoxemia and hypercapnia unresponsive to conventional treatments of acute respiratory distress syndrome; potential contraindications included concerns about multi-drug resistant (MDR) bacteria isolated before V-V ECMO placement.

Researchers conducted a retrospective study to investigate the prevalence and incidence of MDR Gram-negative (GN) bacteria in a cohort of patients with V-V ECMO, the risk of 1-year mortality, particularly in cases with pre-detected MDR GN bacteria, and the impact of annual hospital V-V ECMO volume on the likelihood of acquiring MDR GN bacteria.

They screened adults admitted to the Intensive Care Units of 5 Italian university-affiliated hospitals who required V-V ECMO. Exclusion criteria included age under 18, pregnancy, veno-arterial or mixed ECMO configurations, incomplete records, and survival of less than 24 hours after V-V ECMO. A standard microbiological surveillance protocol was used, with MDR profiles identified through in vitro susceptibility tests. The Cox proportional hazard model was employed to examine the mortality rate. 

The results indicated that 279 V-V ECMO patients (72% male) were enrolled; the overall prevalence of MDR GN bacteria was 50%, with 21% (n=59) detected before V-V ECMO placement and 29% (n=80) after placement. The 1-year mortality rate was 42%, with a higher risk observed in patients with pre-detected MDR bacteria (aHR 2.14 [1.33–3.47], P=0.002), but not in those with V-V ECMO-acquired MDR GN bacteria (aHR 1.51 [0.94–2.42],  P=0.090), compared to the non-MDR GN bacteria group. Similar findings were observed when considering only infections. Additionally, a more extensive annual hospital V-V ECMO volume was associated with a lower probability of acquiring MDR GN bacteria during the V-V ECMO course (aOR 0.91 [0.86–0.97], P=0.002).

They concluded that 21% of MDR GN bacteria were detected before V-V ECMO, while 29% were detected after V-V ECMO placement. A history of MDR GN bacteria isolated before V-V ECMO was an independent risk factor for mortality. The annual hospital V-V ECMO volume also influenced the probability of acquiring MDR GN bacteria.

Source: ccforum.biomedcentral.com/articles/10.1186/s13054-024-05068-x