Regional antibiotic delivery for sternal wound infection prophylaxis a systematic review and meta-analysis of randomized controlled trials.

Despite evidence suggesting the benefit of prophylactic regional antibiotic delivery (RAD) to sternal edges during cardiac surgery, it is seldom performed in clinical practice. The value of topical vancomycin and gentamicin for sternal wound infections (SWI) prophylaxis was further questioned by recent studies including randomized controlled trials (RCTs). The aim of this systematic review and meta-analysis was to comprehensively assess the safety and effectiveness of RAD to reduce the risk of SWI.We screened multiple databases for RCTs assessing the effectiveness of RAD (vancomycin, gentamicin) in SWI prophylaxis. Random effects meta-analysis was performed. The primary endpoint was any SWI; other wound complications were also analysed. Odds Ratios served as the primary statistical analyses. Trial sequential analysis (TSA) was performed.Thirteen RCTs (N = 7,719 patients) were included. The odds of any SWI were significantly reduced by over 50% with any RAD: OR (95%CIs): 0.49 (0.35-0.68); p < 0.001 and consistently reduced in vancomycin (0.34 [0.18-0.64]; p < 0.001) and gentamicin (0.58 [0.39-0.86]; p = 0.007) groups (psubgroup = 0.15). Similarly, RAD reduced the odds of SWI in diabetic and non-diabetic patients (0.46 [0.32-0.65]; p < 0.001 and 0.60 [0.44-0.83]; p = 0.002 respectively). Cumulative Z-curve passed the TSA-adjusted boundary for SWIs suggesting adequate power has been met and no further trials are needed. RAD significantly reduced deep (0.60 [0.43-0.83]; p = 0.003) and superficial SWIs (0.54 [0.32-0.91]; p = 0.02). No differences were seen in mediastinitis and mortality, however, limited number of studies assessed these endpoints. There was no evidence of systemic toxicity, sternal dehiscence and resistant strains emergence. Both vancomycin and gentamicin reduced the odds of cultures outside their respective serum concentrations' activity: vancomycin against gram-negative strains: 0.20 (0.01-4.18) and gentamicin against gram-positive strains: 0.42 (0.28-0.62); P < 0.001. Regional antibiotic delivery is safe and effectively reduces the risk of SWI in cardiac surgery patients.

Fascial plane blocks for cardiothoracic surgery: a narrative review.

In recent years, there has been a growing awareness of the limitations and risks associated with the overreliance on opioids in various surgical procedures, including cardiothoracic surgery.This shift on pain management toward reducing reliance on opioids, together with need to improve patient outcomes, alleviate suffering, gain early mobilization after surgery, reduce hospital stay, and improve patient satisfaction and functional recovery, has led to the development and widespread implementation of enhanced recovery after surgery (ERAS) protocols.In this context, fascial plane blocks are emerging as part of a multimodal analgesic in cardiac surgery and as alternatives to conventional neuraxial blocks for thoracic surgery, and there is a growing body of evidence suggesting their effectiveness and safety in providing pain relief for these procedures. In this review, we discuss the most common fascial plane block techniques used in the field of cardiothoracic surgery, offering a comprehensive overview of regional anesthesia techniques and presenting the latest evidence on the use of chest wall plane blocks specifically in this surgical setting.

Continuous Erector Spinae Plane Block for Pain Management in a Pediatric Kidney Transplant Recipient: A Case Report and Review of the Current Literature.

Pain management in patients undergoing kidney transplantation requires careful consideration due to their altered physiology, and potential risks associated with certain analgesic options. In recent years, personalized and multimodal approaches have proven to be pivotal in perioperative pain management, as well as in children. Implementing regional analgesia methods offers a valuable solution in many pediatric surgical settings and the erector spinae plane block (ESPB) could represent a possible analgesic strategy in pediatric patients undergoing renal transplantation. Here, we report the case of a 13-year-old child who underwent living-donor kidney transplantation (LDKx) and received continuous erector spinae plane block (ESPB) for perioperative pain management. This multimodal approach with continuous ESPB resulted in optimal pain control without the need for opioids, allowing for early mobilization and for an optimal postoperative course.

Anticoagulation and Bleeding during Veno-Venous Extracorporeal Membrane Oxygenation: Insights from the PROTECMO Study.

Rationale: Definitive guidelines for anticoagulation management during veno-venous extracorporeal membrane oxygenation (VV ECMO) are lacking, whereas bleeding complications continue to pose major challenges. Objectives: To describe anticoagulation modalities and bleeding events in adults receiving VV ECMO. Methods: This was an international prospective observational study in 41 centers, from December 2018 to February 2021. Anticoagulation was recorded daily in terms of type, dosage, and monitoring strategy. Bleeding events were reported according to site, severity, and impact on mortality. Measurements and Main Results: The study cohort included 652 patients, and 8,471 days on ECMO were analyzed. Unfractionated heparin was the initial anticoagulant in 77% of patients, and the most frequently used anticoagulant during the ECMO course (6,221 d; 73%). Activated partial thromboplastin time (aPTT) was the most common test for monitoring coagulation (86% of days): the median value was 52 seconds (interquartile range, 39 to 61 s) but dropped by 5.3 seconds after the first bleeding event (95% confidence interval, -7.4 to -3.2; P < 0.01). Bleeding occurred on 1,202 days (16.5%). Overall, 342 patients (52.5%) experienced at least one bleeding event (one episode every 215 h on ECMO), of which 10 (1.6%) were fatal. In a multiple penalized Cox proportional hazard model, higher aPTT was a potentially modifiable risk factor for the first episode of bleeding (for 20-s increase; hazard ratio, 1.07). Conclusions: Anticoagulation during VV ECMO was a dynamic process, with frequent stopping in cases of bleeding and restart according to the clinical picture. Future studies might explore lower aPTT targets to reduce the risk of bleeding.

Risk factors for surgical site infection following cardiac surgery in a region endemic for multidrug resistant organisms.

OBJECTIVES: To identify risk factors for surgical site infections following cardiosurgery in an area endemic for multidrug resistant organisms. DESIGN: Single-center, historical cohort study including patients who underwent cardiosurgery during a 6-year period (2014-2020). SETTING: Joint Commission International accredited, multiorgan transplant center in Palermo, Italy. MAIN OUTCOME MEASURES: Surgical site infection was the main outcome. RESULTS: On a total of 3609 cardiosurgery patients, 184 developed surgical site infection (5.1 %). Intestinal colonization with multidrug resistant organisms was more frequent in patients with surgical site infections (69.6 % vs. 33.3 %; p < 0.001). About half of surgical site infections were caused by Gram-negative bacteria (n = 97; 52.7 %). Fifty surgical site infections were caused by multidrug resistant organisms (27.1 %), with extended-spectrum Beta-lactamase-producing Enterobacterales (n = 16; 8.7 %) and carbapenem-resistant Enterobacterales (n = 26; 14.1 %) being the predominant resistance problem. However, in only 24 of surgical site infections caused by multidrug resistant organisms (48 %), mostly carbapenem-resistant Enterobacterales (n = 22), a pathogen match between the rectal surveillance culture and surgical site infections clinical culture was demonstrated. Nevertheless, multivariate logistic regression analysis identified a rectal swab culture positive for multidrug resistant organisms as an independent risk factor for SSI (odds ratio 3.95, 95 % confidence interval 2.79-5.60). Other independent risk factors were female sex, chronic dialysis, diabetes mellitus, previous cardiosurgery, previous myocardial infarction, being overweight/obese, and longer intubation time. CONCLUSION: In an area endemic for carbapenem-resistant Enterobacterales, intestinal colonization with multidrug resistant organisms was recognized as independent risk factor for surgical site infections. IMPLICATIONS FOR CLINICAL PRACTICE: No causal relationship between colonization with resistant pathogens and subsequent infection could be demonstrated. However, from a broader epidemiological perspective, having a positive multidrug resistant organisms colonization status appeared a risk factor for surgical site infections. Therefore, strict infection control measures to prevent cross-transmission remain pivotal (e.g., nasal decolonization, hand hygiene, and skin antisepsis).

Cognitive outcomes in patients treated with neuromuscular electrical stimulation after coronary artery bypass grafting.

Objective: Mechanisms of neurocognitive injury as post-operative sequelae of coronary artery bypass grafting (CABG) are not understood. The systemic inflammatory response to surgical stress causes skeletal muscle impairment, and this is also worsened by immobility. Since evidence supports a link between muscle vitality and neuroprotection, there is a need to understand the mechanisms by which promotion of muscle activity counteracts the deleterious effects of surgery on long-term cognition. Methods: We performed a clinical trial to test the hypothesis that adding neuromuscular electrical stimulation (NMES) to standard rehabilitation care in post-CABG patients promotes the maintenance of skeletal muscle strength and the expression of circulating neuroprotective myokines. Results: We did not find higher serum levels of neuroprotective myokines, except for interleukin-6, nor better long-term cognitive performance in our intervention group. However, a greater increase in functional connectivity at brain magnetic resonance was seen between seed regions within the default mode, frontoparietal, salience, and sensorimotor networks in the NMES group. Regardless of the treatment protocol, patients with a Klotho increase 3 months after hospital discharge compared to baseline Klotho values showed better scores in delayed memory tests. Significance: We confirm the potential neuroprotective effect of Klotho in a clinical setting and for the first time post-CABG.

Erector spinae plane block versus paravertebral block for postoperative pain management in thoracic surgery: a systematic review and meta-analysis.

INTRODUCTION: The 2018 guidelines for enhanced recovery in thoracic surgery recommend paravertebral block (PVB) for postoperative pain management. However, recent studies demonstrate that erector spinae plane block (ESPB) achieves similar postoperative pain control with reduced block-related complications. EVIDENCE ACQUISITION: We conducted a meta-analysis of randomized controlled trials to evaluate the analgesic efficacy and safety of ESPB versus PVB for pain management after thoracic surgery. PubMed, Embase, and Scopus were searched through December 2022 (PROSPERO registration - CRD42023395593). Primary outcomes were postoperative pain scores, resting at 6, 12, 24, and 48 hours, and at movement at 24 and 48 hours. Secondary outcomes included opioid consumption at 24 and 48 hours, and incidence of postoperative nausea and vomiting or block-related complications in the first 48 hours. EVIDENCE SYNTHESIS: Ten randomized control trials enrolling a total of 624 total patients were included. There were no significant differences in pain scores, resting or at movement, at any time points except reduced resting pain scores at 12 hours with PVB (mean difference [MD]) 0.60, 95% confidence interval [CI] 0.32 to 0.88). Opioid consumption demonstrated no significant differences at 24 hours; PVB reduced opioid consumption at 48 hours (MD 0.40, 95% CI -0.09 to 0.89). There were no significant differences in postoperative nausea or vomiting. ESPB exhibited a nonsignificant trend toward reduced cumulative block-related complications (risk difference [RD] 0.05, 95% CI -0.10 to 0.00). CONCLUSIONS: Compared with PVB, ESPB is safe and demonstrates no clinically significant differences in pain management after thoracic surgery.

3D Culture and Interferon-γ Priming Modulates Characteristics of Mesenchymal Stromal/Stem Cells by Modifying the Expression of Both Intracellular and Exosomal microRNAs.

Mesenchymal stromal/stem cells (MSCs) have emerged as a therapeutic tool in regenerative medicine. Recent studies have shown that exosome (EXO)-derived microRNAs (miRNAs) play a crucial role in mediating MSC functions. Additionally, intracellular miRNAs have been found to regulate MSC therapeutic capacities. However, the molecular mechanisms underlying miRNA-mediated MSC effects are not fully understood. We used 3D culture and IFN-γ to prime/enhance the MSC therapeutic effects in terms of functional miRNAs. After priming, our analysis revealed stable variations in intracellular miRNA among the MSC biological replicates. Conversely, a significant variability of miRNA was observed among EXOs released from biological replicates of the priming treatment. For each priming, we observed distinct miRNA expression profiles between the MSCs and their EXOs. Moreover, in both types of priming, gene ontology (GO) analysis of deregulated miRNAs highlighted their involvement in tissue repair/regeneration pathways. In particular, the 3D culture enhanced angiogenic properties in both MSCs and EXOs, while IFN-γ treatment enriched miRNAs associated with immunomodulatory pathways. These findings suggest that 3D culture and IFN-γ treatment are promising strategies for enhancing the therapeutic potential of MSCs by modulating miRNA expression. Additionally, the identified miRNAs may contribute to understanding the molecular mechanisms underlying the miRNA-mediated therapeutic effects of MSCs.

Anesthesiological management of Brugada syndrome patients: A systematic review.

Brugada syndrome (BrS) is a major risk factor for sudden cardiac death and ventricular tachyarrhythmias. Several drugs are contraindicated in patients with BrS, including some commonly administered drugs during anesthesia or in the perioperative period; however, there is still a paucity of evidence regarding BrS and common anesthetic pharmaceuticals. We conducted a systematic literature search (PubMed, updated October 10, 2022), including all studies reporting pharmacological management of BrS patients during anesthesia or intensive care, with a specific focus on proarrhythmic effects and possible pharmacological interactions in the context of BrS. The search revealed 44 relevant items, though only three original studies. Two randomized controlled studies were identified, one comparing propofol and etomidate for the induction of general anesthesia and one investigating lidocaine with or without epinephrine for local anesthesia; there was also one prospective study without a control group. The other studies were case series (n = 5, for a total of 19 patients) or case reports (n = 36). Data are reported on a total population of 199 patients who underwent general or local anesthesia. None of the studies evaluated BrS patients in the intensive care unit (ICU). We found the studies focusing on the pharmacological management of BrS patients undergoing general or local anesthesia to be of generally poor quality. However, it appears that propofol can be used safely, without an increase in arrhythmic events. Regional anesthesia is possible, and lidocaine might be preferred over longer-acting local anesthetics. Considering the quality of the included studies and their anecdotal evidence, it seems increasingly important to conduct large multicenter studies or promote international registries with high-quality data on the anesthesiological management of these patients.

Telemedicine in Patients Affected by Chronic Liver Disease: A Scoping Review of Clinical Outcomes and the Devices Evaluated.

For patients with chronic liver disease (CLD), telemedicine is emerging as a useful tool to prevent liver decompensation or hospitalization, allowing access to and the decentralization of care, even for patients with limited resources. However, research and attendant evidence are still lacking; thus, this review aims to systematically explore the topic of telemonitoring for CLD to describe the currently used tools and clinical outcomes. The review was conducted by using key terms on PubMed/EMBASE and searching for observational studies or clinical trials (according to PRISMA recommendations) that were published between 6 April 2013 and 6 April 2023 to keep the technological framework limited to the last 10 years. The studies were described and grouped according to the aim of telemonitoring, the underlying disease, and the tools adopted to achieve remote monitoring. A total of 32 articles met the inclusion criteria. Of these, 11 articles report the successful use of a telehealth program to support and improve access to care in the management of HCV-related cirrhosis, eight articles examine the efficacy of telemedicine for remote monitoring interventions to prevent or decrease the risk of decompensation in high-risk patients, and five articles examine improvements in the physical performance and quality of life of cirrhotic patients through telehealth rehabilitation programs. Four studies were completed during the recent COVID-19 pandemic. Telehealth has the potential to provide and expand treatment access and reduce barriers to care for the most disadvantaged patients and might be able to reduce the need for hospital readmission for CLD, though most practice to test feasibility is still in the pilot stage.

Topical vancomycin for sternal wound infection prophylaxis. A systematic review and updated meta-analysis of over 40,000 cardiac surgery patients.

BACKGROUND: Despite guideline recommendations, routine application of topical antibiotic agents to sternal edges after cardiac surgery is seldom done. Recent randomized controlled trials have also questioned the effectiveness of topical vancomycin in sternal wound infection prophylaxis. METHODS: We screened multiple databases for observational studies and randomized controlled trials assessing the effectiveness of topical vancomycin. Random effects meta-analysis and risk-profile regression were performed, and randomized controlled trials and observational studies were analyzed separately. The primary endpoint was sternal wound infection; other wound complications were also analyzed. Risk ratios served as primary statistics. RESULTS: Twenty studies (N = 40,871) were included, of which 7 were randomized controlled trials (N = 2,187). The risk of sternal wound infection was significantly reduced by almost 70% in the topical vancomycin group (risk ratios [95% confidence intervals]: 0.31 (0.23-0.43); P < .00001) and was comparable between randomized controlled trials (0.37 [0.21-0.64]; P < .0001) and observational studies (0.30 [0.20-0.45]; P < .00001; Psubgroup = .57). Topical vancomycin significantly reduced the risk of superficial sternal wound infections (0.29 [0.15-0.53]; P < .00001) and deep sternal wound infections (0.29 [0.19-0.44]; P < .00001). A reduction in the risk of mediastinitis and sternal dehiscence risks was also demonstrated. Risk profile meta-regression showed a significant relationship between a higher risk of sternal wound infection and a higher benefit accrued with topical vancomycin (ß-coeff. = -0.00837; P < .0001). The number needed to treat was 58.2. A significant benefit was observed in patients with diabetes mellitus (risk ratios 0.21 [0.11-0.39]; P < .00001). There was no evidence of vancomycin or methicillin resistance; on the contrary, the risk of gram-negative cultures was reduced by over 60% (risk ratios 0.38 [0.22-0.66]; P = .0006). CONCLUSION: Topical vancomycin effectively reduces the risk of sternal wound infection in cardiac surgery patients.

Effects of adding the second drainage cannula in severely hypoxemic patients supported with VV ECMO due to COVID-19-associated ARDS.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a recognized method of support in patients with severe and refractory acute respiratory distress syndrome (ARDS) caused by SARS-CoV-2 infection. While veno-venous (VV) ECMO is the most common type, some patients with severe hypoxemia may require modifications to the ECMO circuit. In this study, we aimed to investigate the effects of adding a second drainage cannula to the circuit in patients with refractory hypoxemia, on their gas exchange, mechanical ventilation, ECMO settings, and clinical outcomes. METHODS: We conducted an observational retrospective study based on a single-center institutional registry including all consecutive cases of COVID-19 patients requiring ECMO admitted to the Centre of Extracorporeal Therapies in Warsaw between March 1, 2020 and March 1, 2022. We selected patients who had an additional drainage cannula inserted. Changes in ECMO and ventilator settings, blood oxygenation, and hemodynamic parameters, as well as clinical outcomes were assessed. RESULTS: Of 138 VV ECMO patients, 12 (9%) patients met the inclusion criteria. Ten patients (83%) were men, and mean age was 42.2 ± 6.8. An addition of drainage cannula resulted in a significant raise in ECMO blood flow (4.77 ± 0.44 to 5.94 ± 0.81 [L/min]; p = 0.001), and the ratio of ECMO blood flow to ECMO pump rotations per minute (RPM), whereas the raise in ECMO RPM alone was not statistically significant (3432 ± 258 to 3673 ± 340 [1/min]; p = 0.064). We observed a significant drop in ventilator FiO2 and a raise in PaO2 to FiO2 ratio, while blood lactates did not change significantly. Nine patients died in hospital, one was referred to lung transplantation center, two were discharged uneventfully. CONCLUSIONS: The use of an additional drainage cannula in severe ARDS associated with COVID-19 allows for an increased ECMO blood flow and improved oxygenation. However, we observed no further improvement in lung-protective ventilation and poor survival.

Outcomes of Transcatheter Aortic Valve Implantation Comparing Medtronic's Evolut PRO and Evolut R: A Systematic Review and Meta-Analysis of Observational Studies.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has become a broadly acceptable alternative to AV surgery in patients with aortic stenosis (AS). New valve designs are becoming available to address the shortcomings of their predecessors and improve clinical outcomes. METHODS: A systematic review and meta-analysis was carried out to compare Medtronic's Evolut PRO, a new valve, with the previous Evolut R design. Procedural, functional and clinical endpoints according to the VARC-2 criteria were assessed. RESULTS: Eleven observational studies involving N = 12,363 patients were included. Evolut PRO patients differed regarding age (p < 0.001), sex (p < 0.001) and STS-PROM estimated risk. There was no difference between the two devices in terms of TAVI-related early complications and clinical endpoints. A 35% reduction of the risk of moderate-to-severe paravalvular leak (PVL) favoring the Evolut PRO was observed (RR 0.66, 95%CI, [0.52, 0.86] p = 0.002; I2 = 0%). Similarly, Evolut PRO-treated patients demonstrated a reduction of over 35% in the risk of serious bleeding as compared with the Evolut R (RR 0.63, 95%CI, [0.41, 0.96]; p = 0.03; I2 = 39%), without differences in major vascular complications. CONCLUSIONS: The evidence shows good short-term outcomes of both the Evolut PRO and Evolut R prostheses, with no differences in clinical and procedural endpoints. The Evolut PRO was associated with a lower rate of moderate-to-severe PVL and major bleeding.

Raised FGF23 Correlates to Increased Mortality in Critical Illness, Independent of Vitamin D.

BACKGROUND: Fibroblast Growth Factor (FGF23) is an endocrine hormone classically associated with the homeostasis of vitamin D, phosphate, and calcium. Elevated serum FGF23 is a known independent risk factor for mortality in chronic kidney disease (CKD) patients. We aimed to determine if there was a similar relationship between FGF23 levels and mortality in critically ill patients. METHODS: Plasma FGF23 levels were measured by ELISA in two separate cohorts of patients receiving vitamin D supplementation: critical illness patients (VITdAL-ICU trial, n = 475) and elective oesophagectomy patients (VINDALOO trial, n = 76). Mortality data were recorded at 30 and 180 days or at two years, respectively. FGF23 levels in a healthy control cohort were also measured (n = 27). RESULTS: Elevated FGF23 (quartile 4 vs. quartiles 1-3) was associated with increased short-term (30 and 180 day) mortality in critical illness patients (p < 0.001) and long-term (two-year) mortality in oesophagectomy patients (p = 0.0149). Patients who died had significantly higher FGF23 levels than those who survived: In the critical illness cohort, those who died had 1194.6 pg/mL (range 0-14,000), while those who survived had 120.4 pg/mL (range = 15-14,000) (p = 0.0462). In the oesophagectomy cohort, those who died had 1304 pg/mL (range = 154-77,800), while those who survived had 644 pg/mL (range = 179-54,894) (p < 0.001). This was found to be independent of vitamin D or CKD status (critical illness p = 0.3507; oesophagectomy p = 0.3800). FGF23 levels in healthy controls were similar to those seen in oesophagectomy patients (p = 0.4802). CONCLUSIONS: Elevated baseline serum FGF23 is correlated with increased mortality in both the post-oesophagectomy cohort and the cohort of patients with critical illness requiring intensive care admission. This was independent of vitamin D status, supplementation, or CKD status, which suggests the presence of vitamin D-independent mechanisms of FGF23 action during the acute and convalescent stages of critical illness, warranting further investigation.

Transfusion practice in patients receiving VV ECMO (PROTECMO): a prospective, multicentre, observational study.

BACKGROUND: In patients receiving venovenous (VV) extracorporeal membrane oxygenation (ECMO) packed red blood cell (PRBC) transfusion thresholds are usually higher than in other patients who are critically ill. Available guidelines suggest a restrictive approach, but do not provide specific recommendations on the topic. The main aim of this study was, in a short timeframe, to describe the actual values of haemoglobin and the rate and the thresholds for transfusion of PRBC during VV ECMO. METHODS: PROTECMO was a multicentre, prospective, cohort study done in 41 ECMO centres in Europe, North America, Asia, and Australia. Consecutive adult patients with acute respiratory distress syndrome (ARDS) who were receiving VV ECMO were eligible for inclusion. Patients younger than 18 years, those who were not able to provide informed consent when required, and patients with an ECMO stay of less than 24 h were excluded. Our main aim was to monitor the daily haemoglobin concentration and the value at the point of PRBC transfusion, as well as the rate of transfusions. The practice in different centres was stratified by continent location and case volume per year. Adjusted estimates were calculated using marginal structural models with inverse probability weighting, accounting for baseline and time varying confounding. FINDINGS: Between Dec 1, 2018, and Feb 22, 2021, 604 patients were enrolled (431 [71%] men, 173 [29%] women; mean age 50 years [SD 13·6]; and mean haemoglobin concentration at cannulation 10·9 g/dL [2·4]). Over 7944 ECMO days, mean haemoglobin concentration was 9·1 g/dL (1·2), with lower concentrations in North America and high-volume centres. PRBC were transfused on 2432 (31%) of days on ECMO, and 504 (83%) patients received at least one PRBC unit. Overall, mean pretransfusion haemoglobin concentration was 8·1 g/dL (1·1), but varied according to the clinical rationale for transfusion. In a time-dependent Cox model, haemoglobin concentration of less than 7 g/dL was consistently associated with higher risk of death in the intensive care unit compared with other higher haemoglobin concentrations (hazard ratio [HR] 2·99 [95% CI 1·95-4·60]); PRBC transfusion was associated with lower risk of death only when transfused when haemoglobin concentration was less than 7 g/dL (HR 0·15 [0·03-0·74]), although no significant effect in reducing mortality was reported for transfusions for other haemoglobin classes (7·0-7·9 g/dL, 8·0-9·9 g/dL, or higher than 10 g/dL). INTERPRETATION: During VV ECMO, there was no universally accepted threshold for transfusion, but PRBC transfusion was invariably associated with lower mortality only when done with haemoglobin concentration of less than 7 g/dL. FUNDING: Extracorporeal Life Support Organization.