Perfusion

Extracorporeal membrane oxygenation (ECMO) patients have increased risk for limb acute compartment syndrome (ACS), but diagnosis remains difficult given the lack of subjective and pulsatility assessments in this patient population. This exploratory study characterized ECMO patients who developed ACS and investigated laboratory measures that can aid diagnosis.

We reviewed records of adult patients placed on ECMO between 2016 and 2022 at our single center, collecting clinical, laboratory, and survival data upon cannulation. We performed comparisons of baseline and laboratory data between ACS and No ACS patients. Threshold regression was then used to develop laboratory cutoffs for ACS diagnosis and logistic regression to characterize predictors of ACS. Survival analysis relied on Cox proportional hazards modeling.

278 ECMO patients were included, of which 14 (5%) developed ACS. ACS patients had a higher amputation rate (21.4% vs 1.9%, p < 0.001) and mortality risk (HR 2.35, p = 0.03); only 1 (7%) ACS patient had amputation-free survival. The most sensitive threshold cutoffs included maximum INR >1.95 (sensitivity 0.91), baseline lactate >7.85 (0.88), and 24-h lactate >3.75 (0.88). The most specific were baseline CpK >3765.5 (specificity 0.91), maximum K >5.95 (0.88), and maximum CpK >6362.0 (0.85). Laboratory values, namely CpK and lactate, predicted ACS with promising diagnostic sensitivity and specificity.

ACS remains associated with increased mortality and morbidity, most often occurring within 24 h after cannulation. Laboratory values, namely CpK and lactate values, independently predicted ACS development with promising sensitivity and specificity. These exploratory findings may help guide decision-making surrounding ACS in the ECMO setting.

Cardiopulmonary bypass (CPB) is essential to cardiac surgery but is associated with organ injury from non-physiological perfusion. Goal-directed perfusion (GDP) has emerged as a physiology-based strategy to optimize intraoperative perfusion by targeting specific hemodynamic and metabolic parameters, particularly oxygen delivery (DO₂). This review critically appraises the evidence supporting GDP during CPB, emphasizing comparative strategies, clinical outcomes, and limitations.

A narrative review of the literature was conducted, incorporating evidence from randomized controlled trials, observational studies, meta-analyses, and international guidelines addressing perfusion strategies during CPB. This review included studies evaluating DO₂-guided, pressure-guided, and oxygen-metabolic-indicator-guided approaches, focusing on target definitions, outcome measures, and patient populations.

Randomized and observational studies have consistently demonstrated that maintaining adequate DO₂ levels during CPB is associated with a reduced incidence of cardiac surgery–associated acute kidney injury (CSA-AKI), leading to the guideline endorsement of DO₂-guided perfusion. In contrast, evidence on neurological outcomes, length of stay, and mortality remains limited and inconsistent. Pressure-guided and venous-oxygen-saturation– or oxygen-metabolic-indicator–guided strategies provide complementary physiologic information but have not independently demonstrated superiority in randomized trials. Substantial heterogeneity has been reported in perfusion targets, outcome definitions, patient risk profiles, and potential trade-offs, including increased transfusion exposure and implementation complexity.

Current evidence supports DO₂-guided perfusion as an effective strategy to reduce CSA-AKI during CPB, although its impact on broader clinical outcomes remains uncertain. Future studies should focus on individualized perfusion targets that account for patient-specific risk, metabolic demand, temperature, and autoregulatory capacity, rather than universal thresholds.

Postcardiotomy cardiogenic shock (PCS) is a life-threatening complication after adult cardiac surgery that frequently necessitates venoarterial extracorporeal membrane oxygenation (VA-ECMO). Central and peripheral VA-ECMO cannulation strategies generate distinct hemodynamic and perfusion profiles; however, whether these differences translate into varying risks of acute brain injury (ABI) remains uncertain. We therefore compared ABI risk according to cannulation strategy in adults with PCS requiring VA-ECMO, with secondary objectives to determine the overall prevalence of ABI and characterize its major subtypes.

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Scopus through April 15, 2025, for studies reporting ABI in adult PCS patients receiving VA-ECMO. ABI outcome was defined as ischemic stroke, intracranial hemorrhage, hypoxic-ischemic brain injury, seizures, unspecified stroke, and brain death. Random-effects meta-analysis was performed, incorporating a contemporary single-center cohort from Johns Hopkins Hospital (2020–2025).

The primary meta-analysis included seven cohorts (six published studies plus Johns Hopkins cohort; n = 2536), while secondary analyses included 17 cohorts (16 published studies plus Johns Hopkins cohort). Included patients (mean age = 65 years, BMI = 28 kg/m², 61% male) underwent central VA-ECMO cannulation in 32% and peripheral cannulation in 68%. The pooled risk of ABI did not differ by cannulation strategy (risk ratio [RR], 1.01; 95% CI, 0.85–1.21; I² = 0%), with similar ABI prevalence across groups (p = 0.99). Ischemic stroke and unspecified stroke were the most reported subtypes.

In adults with PCS supported by VA-ECMO, the risk of ABI was not significantly associated with cannulation strategy. These findings suggest that cannulation approach alone is unlikely to be the primary determinant of neurological risk in this population, underscoring the need for systematic neuroprotective strategies regardless of cannulation configuration.

Ex vivo perfusion (EVP) in heart transplantation (HTX) enables transportation of explanted organs over longer distances as well as monitoring of cardiac metabolism under unloaded coronary perfusion, thereby expanding the possible pool of suitable donors for HTX. We aimed at identifying possibly modifiable risk factors predicting impaired outcome after HTX through analysis of perfusion parameters, donor and recipient characteristics.

We included 64 patients after HTX using EVP (TransMedics Organ Care System) between February 2010 and October 2022 in this retrospective, single-center analysis. Blood gas analyses were taken during EVP in a standardized manner.

HTX recipients were 44.8 ± 16.2 years old, six patients being younger than 18 years at the time of transplantation. High urgency listing status was present in 79.7%, and 67.2% had previous cardiac surgery. Lower base excess during EVP predicted severe primary graft dysfunction (PGD) (−5.55 ± 1.95 vs −3.94 ± 2.38 mmol/L, p = 0.043). With every additional minute of warm ischemia, the risk of PGD was 3.7% higher (OR 1.037, 95% CI [1.004; 1.072], p = 0.028). Low donor serum potassium (3.4 ± 0.76 mmol/L vs 4.2 ± 0.60, p = 0.008), high glucose after EVP priming (207.63 ± 99.05 mg/dL vs 146.45 ± 51.99, p = 0.045), and resuscitation of the donor (55.6% vs 18.2%, p = 0.027) were associated with impaired survival after HTX.

EVP provides a unique method to assess graft function during the retrieval of hearts for cardiac transplantation. Low base excess, priming glucose, warm ischemia and donor hypokalaemia influence the frequency of adverse outcomes after HTX. Future studies may address possible strategies to safely modify these risk factors.

Cardiopulmonary bypass (CPB), which induces pulmonary injury, significantly impacts the quality of life in patients undergoing cardiac surgery. Preventing and treating pulmonary complications has become a critical clinical issue. Optimizing ventilation strategies during the preoperative, intraoperative, and postoperative stages is essential for adequate lung protection and preventing CPB-related pulmonary injury.

A comprehensive search of multiple databases including PubMed, Embase, and the Cochrane Library was conducted. After removing the duplicate studies, full-text review was performed, and all studies that reported mechanical ventilation strategies and lung protection during CPB were included.

This review systematically examines ventilation strategies during CPB, outlining optimized parameters and pharmacologic approaches across pre-, intra-, and post-CPB phases to reduce lung injury. Various modes — including volume control ventilation (VCV), pressure control ventilation (PCV), and pressure-controlled ventilation–volume guaranteed (PCV-VG) — demonstrate unique benefits and limitations. When combined with protective measures (low tidal volume [LTV], moderate positive end-expiratory pressure [PEEP], and recruitment maneuvers), they show clinical efficacy in lung protection. Pharmacologic agents like ambroxol, neutrophil elastase inhibitors, and sivelestat further enhance protection, underscoring the promise of combined mechanical-pharmacological strategies against CPB-induced lung injury.

A comprehensive approach integrating individualized ventilation management and pharmacological intervention is key to reducing CPB-induced lung injury, enhancing postoperative respiratory function, and improving patient outcomes.

Delirium is a common, distressing, and dangerous complication after cardiac surgery with cardiopulmonary bypass (CPB) with few modifiable risk factors. This study aims to determine the association between post-operative oxygen delivery (DO2i) and the risk of delirium and assess the critical threshold for DO2i associated with delirium risk after surgery.

This study is a multi-site retrospective cohort study with 1690 patients undergoing elective cardiac surgery with CPB who had multiple cardiac output measurements with a pulmonary artery catheter and arterial blood gas analyses.

The cohort of 1690 patients analyzed included 185 patients diagnosed with delirium within 7 days of surgery (11%). Patients with delirium had a lower post-operative DO2i (mean difference of 26 ml/min/m², 95% CI 14 to 36, p < 0.0001) compared to the 1505 patients without delirium. In a multivariable analysis controlling for age, sex, race, heart failure, diabetes, obstructive sleep apnea, body mass index, CPB time, circulatory arrest time, aortic cross clamp time, carotid stenosis, and cognitive impairment the post-operative mean DO2i was not independently associated with delirium. Post-operative DO2i was inversely correlated with CPB time with a decrease of 0.27 ml/min/m² per minute of CPB exposure (p < 0.0001). The critical threshold of DO2i after cardiac surgery is lower with increased age and female sex.

Post-operative DO2i over 7 days is not independently associated with the risk of delirium but significantly correlated with CPB time. Older patients may have a lower DO2i critical threshold for risk of delirium.

Anticoagulation management during extracorporeal membrane oxygenation (ECMO) remains an important challenge, with bleeding rates reaching 30%. Activated partial thromboplastin time (aPTT) is the most used biomarker for heparin titration, however static values may not reflect real-time bleeding risk. We hypothesized that cumulative aPTT exposure offers superior predictive value for bleeding and mortality compared to traditional threshold-based approaches.

In this retrospective cohort study, we analyzed 109 adult ECMO patients at a single Canadian center (2006–2021). Serial aPTT values were recorded approximately every 6 h. The primary outcome was time to first major bleeding event (BARC ≥3), with death treated as a competing risk. We applied a joint longitudinal-survival modeling framework to evaluate associations between dynamic aPTT trajectories, including slope, variability, and cumulative exposure,and adverse outcomes. Models were adjusted for baseline covariates and compared using deviance information criterion (DIC) and time-dependent AUC.

Fifty-one patients (46.8%) experienced major bleeding. The best-performing model incorporated the cumulative exposure to elevated log-transformed aPTT, which significantly predicted both bleeding (HR 2.39, 95% CI: 1.17–4.88, p = 0.0084) and death (HR 7.88, 95% CI: 2.59–23.94, p < 0.0001). This model outperformed static or trend-based approaches (AUC 0.77 at 48 h). There results were robust to sensitivity analysis. Hematocrit and ECMO configuration were also significant covariates.

Cumulative aPTT burden is a strong and independent predictor of bleeding and mortality in ECMO patients. These findings support a shift toward trajectory-based anticoagulation monitoring to enable safer, personalized management in this high-risk population.

Extracorporeal membrane oxygenation (ECMO) is an essential life-support modality for children with severe cardiac and respiratory failure. Although its global use has expanded, ECMO remains resource-intensive, requiring specialized training, multidisciplinary support, and institutional infrastructure.

To assess pediatric intensivists’ knowledge, practice patterns, and perceptions regarding ECMO in Saudi Arabia and the Gulf region, and to identify barriers to ECMO implementation and training.

A cross-sectional survey using a validated, self-administered electronic questionnaire was distributed to pediatric intensivists in Saudi Arabia and Gulf countries. The survey assessed demographics, ECMO knowledge, clinical practice patterns, and perceived barriers.

A total of 151 intensivists responded; 74.2% were male, and 61.6% had ≥11 years of clinical experience. ECMO services were available in 42.4% of institutions, predominantly in pediatric cardiac ICUs (82.8%). Perfusionist support was reported in 53.6% of centers. ECMO circuits were primarily managed by perfusionists (98.5%), and cannulation was mainly performed by cardiac surgeons (87.5%). Knowledge scores were generally low, with only 9.9% scoring 60–80%. Major barriers included inadequate training of medical (68%) and nursing staff (72%), lack of ECMO availability (60%), and limited cardiothoracic surgical support (56%). Higher knowledge scores were observed among respondents from ECMO-capable centers or those with prior ECMO training (p < 0.01). Only 25.3% reported having an ECMO transfer protocol.

Significant gaps in ECMO knowledge and training exist among pediatric intensivists in the Gulf region. Structured education programs, standardized practices, and enhanced multidisciplinary support are urgently needed to improve ECMO readiness and outcomes.

In mitral valve surgery, cardioplegia is commonly dosed by body weight or body surface area (BSA), which may not reflect true cardiac mass. We evaluated whether indexing the initial dose to left ventricular (LV) mass improves dosing fidelity.

We retrospectively studied 323 patients undergoing mitral surgery with St. Thomas solution (2019–2022). The initial dose of cardioplegia was based on a flow of 150 mL · min^–1 · m^–2 of body surface area. To reduce heterogeneity related to differences in ventricular remodeling and cardioplegia delivery strategies, the study was restricted to patients undergoing mitral valve surgery. Echocardiography-derived LV mass yielded two indices: C1 = initial perfusion dose (mL)/LV mass (g) and C2 = initial perfusion dose (mL)/LV mass index (LVMI, calculated as LV mass divided by body surface area [BSA]). Patients were divided into 2 groups, Group A (C1 ≤ 6.6 mL·g^-1) and Group B (C1 > 6.6 mL·g^–1). Primary endpoint was CK-MB mass (a quantitative measure of the creatine kinase-MB) at 0, 7, 24, and 48 h. High-sensitivity cardiac troponin T (hs-cTnT), ICU and hospital stay were also evaluated. Restricted cubic splines and segmented regression assessed nonlinearity and thresholds; propensity score matching (PSM) generated 67 pairs. Model performance was evaluated using the Akaike and Bayesian information criteria (AIC/BIC).

In unmatched and matched analyses, C1 showed a nonlinear association with CK-MB mass, with a threshold near C1 = 12.2 mL·g^–1, above which CK-MB increased more steeply. C2 displayed higher thresholds (17.5). After PSM, Group B (higher C1) had higher CK-MB mass at 0, 24, and 48 h; hs-cTnT at 24 h was slightly higher in Group A. ICU and hospital stay were similar between groups. Model fit favored C1 over C2 at 24 and 48 h (lower AIC/BIC).

LV-mass–indexed dosing captures a nonlinear relevant dose–response and suggests that C1 values above approximately 12.2 mL·g^–1 may represent a potential upper range that warrants caution.

Optimal sedation strategies for patients with respiratory failure requiring venovenous extracorporeal membrane oxygenation (VV ECMO) are not well defined.

Physicians caring for patients on ECMO in an intensive care unit were invited to complete an international survey about sedation and analgesia practices for adult patients undergoing VV ECMO for severe Acute Respiratory Distress Syndrome (ARDS).

The survey was completed by 234 physicians, most commonly identifying as critical care (29.9%) and practicing in North America (38.9%). The Richmond Agitation Sedation Scale (88.5%) and Clinical Pain Observation Tool (40.2%) were commonly used for monitoring. Agents of choice were propofol (73.9% prior to ECMO and 56% within 48 h after initiation) and fentanyl (57.3% and 40.2%), with increasing preference for dexmedetomidine after ECMO initiation (14.5% prior to and 25.6% after initiation). Routine neuromuscular blockade use beyond 48 h after cannulation was rare (1.3%). Common strategies to reduce sedatives included sweep gas titration (74.4%) and minimizing nocturnal interventions (63.7%). Most respondents believe antipsychotics also work to this effect (57.3%).

Sedation strategies for adult ARDS patients receiving VV ECMO seem to be influenced by time from cannulation and patient factors. Future research should focus on identifying optimal sedation strategies and developing a consensus for best practice.

Extracorporeal membrane oxygenation (ECMO) is a high-risk, low-frequency intervention requiring specialized training and effective teamwork, for which simulation-based training is a valuable tool. Across medical disciplines escape room-style simulations have been developed to enhance teamwork and engagement among learners.

We conducted a prospective observational study at a large academic medical center to evaluate the feasibility and educational impact of an escape room–style ECMO simulation. Thirty-seven nurses completed the escape room simulation. Teamwork was assessed with the Clinical Teamwork Scale (CTS), and effectiveness with the Simulation Effectiveness Tool (SET-M).

Observer-rated CTS scores for overall teamwork (r = −0.76), communication (r = −0.52), and decision-making (r = −0.55) correlated negatively with completion time, suggesting that stronger teamwork was associated with greater efficiency. Participant self-ratings were significantly higher than observer ratings across most domains (p < 0.01), and showed positive correlations with completion times. SET-M results indicated high satisfaction, with all participants reporting improved ECMO knowledge and skills, though prebriefing and debriefing received lower ratings.

These findings support escape room–style simulations as a feasible and engaging approach to ECMO education, with external observation playing a key role in assessing teamwork. Future studies should focus on structured briefing, randomized team assignments, and multidisciplinary cohorts to enhance generalizability and learning outcomes.

Thoracoabdominal aortic aneurysm (TAAA) repair is associated with significant risks of blood loss and organ ischemia. This study evaluates the efficacy of a novel, modified Extracorporeal Circulation (mECC) circuit system designed to enhance blood conservation and selective organ perfusion during open TAAA repair.

In this retrospective analysis, 7 patients underwent open thoracoabdominal aortic repair between January 2022 and October 2024 using a modified extracorporeal circulation system. The system incorporated integrated roller pumps for selective visceral and renal perfusion, a centrifugal pump, and an integrated autotransfusion system reservoir to optimize hemodynamic control and minimize allogeneic blood transfusion. Demographic data, intraoperative parameters, transfusion requirements, and postoperative outcomes were assessed.

The cohort consisted of 7 patients (57.1% male; mean age 54.4 ± 15.0 years). Crawford type I repair was performed in 71.4% of cases. The mean ECC duration was 104.4 ± 16.8 min, and mean aortic clamp time was 72.0 ± 18.5 min. The use of the integrated autotransfusion system resulted in reduced postoperative transfusion requirements and helped maintain hemoglobin levels. Postoperative complications included gastrointestinal events (42.9%), wound infections (42.9%), and spinal cord deficit (14.3%). Early in-hospital mortality was 14.3% (one patient, postoperative day 5). Kaplan-Meier analysis showed a 1-week survival rate of 85.7%, with all surviving patients remaining alive throughout the follow-up period.

The modified ECC system with integrated roller pumps and cell-saver technology demonstrated favorable short-term outcomes and effective blood conservation in open TAAA repair. This reservoirless, isothermic, centrifugal circuit with peripheral cannulation may offer a safe and efficient alternative for complex aortic surgery. Larger, prospective studies with extended follow-up are warranted to confirm these findings and evaluate long-term durability.

Comparing clinical outcomes after cardiopulmonary bypass with hemodsorption (HA) versus cardiopulmonary bypass without HA in patients undergoing cardiac surgery in terms of mortality and major complications.

PubMed, Scopus, and Web of Science databases were searched for relevant randomized control trials (RCTs) that compared postoperative clinical outcomes between patients receiving intraoperative HA with cardiopulmonary bypass versus patients receiving cardiopulmonary bypass without intraoperative HA in cardiac surgery.

Sixteen RCTs with 851 patients (433 in the HA group and 418 in the control group), were included in our meta-analysis. Our meta-analysis found no significant differences between the intraoperative HA group and the control group in patients undergoing cardiac surgery in terms of 30-days/in-hospital mortality, new-onset atrial fibrillation, stroke or cerebrovascular events, postoperative delirium, renal failure/acute kidney injury, need for renal replacement, postoperative liver dysfunction, thrombocytopenia, bleeding, volume of blood loss, pneumonia, sepsis, respiratory insufficiency, duration of postoperative ventilation, distributive/septic shock, pericardial tamponade, need for extracorporeal membrane oxygenation (ECMO) support, sequential organ failure assessment (SOFA) score at ICU admission, plasma-free hemoglobin levels, and fibrinogen levels. However, the pooled analysis showed a significant association between HA and decreased albumin at ICU admission (MD = − 0.28, 95% CI [0.55 to 0.01], p-value = 0.04), decreased length of ICU stay (MD = −0.66, 95% CI [−1.24 to 0.08], p-value = 0.03), and decreased length of hospital stay (MD = −0.99, 95% CI [−1.88 to −0.10], p-value = 0.03).

Our findings suggest that there is not enough evidence to endorse the role of routine intraoperative HA during cardiopulmonary bypass in improving clinical outcomes after cardiac surgery. Factors such as patient risk profile, procedure complexity, and cost implications should be taken into account when considering this adjunct therapy.

Cardiopulmonary bypass (CPB) impairs endothelial function, causing oedema and disturbed microcirculatory perfusion, that contribute to organ dysfunction following cardiac surgery. We hypothesised that the composition of CPB prime fluids with either albumin or gelofusine preserves sublingual microcirculatory perfusion in patients undergoing coronary artery bypass graft surgery.

Thirty-four patients were subjected to CPB primed with 1500 ml of either albumin/ringers (n = 8, gelofusine/ringers (n = 11), or solely ringers plus retrograde autologous priming (RAP) (n = 15). All solutions included 100 ml of mannitol. The primary outcome was perfused vessel density (PVD) assessed after anaesthesia induction, aortic cross-clamping, weaning from CPB, upon intensive care unit (ICU) arrival and 24 h after ICU arrival.

CPB immediately impaired PVD across all groups, persisting until ICU arrival. The decrease in PVD was most profound with albumin/ringers (estimated mean difference between baseline and ICU arrival −7.56 [95% CI -11.53 to −3.59] mm^.mm^-2), compared to gelofusine/ringers (−4.10 [−7.53 to −0.67] mm^.mm^-2), and ringers/RAP (−3.77 [-6.64 to −0.90] mm^.mm^-2), without differences between groups (p = 0.41). In patients receiving gelofusine/ringers COP was preserved after aortic cross clamping. Concentration of inflammatory (interleukin-6) and endothelial damage markers (angiopoietin-2) were increased with albumin/ringers compared with gelofusine/ringers and ringers plus RAP.

In this exploratory physiological study, all of the three CPB priming strategies, albumin/ringers, gelofusine/ringers or ringers plus RAP, similarly induced perioperative microcirculatory dysfunction in patients undergoing CABG surgery.

Cardiac surgery-associated acute kidney injury (CSA-AKI) remains a serious complication. The ratio of the venous-arterial carbon dioxide partial pressure difference (Pv-aCO₂) to the arterial-venous oxygen content difference (Ca-vO₂) is an indicator of tissue perfusion and anaerobic metabolism. We aimed to assess whether peak Pv-aCO₂/Ca-vO₂ during cardiopulmonary bypass (CPB) predicts CSA-AKI in pediatric patients with cyanotic congenital heart disease (CHD).

We retrospectively reviewed patients aged < 10 years with cyanotic CHD who underwent cardiac surgery with CPB between January 2019 and August 2024. Peak Pv-aCO₂/Ca-vO₂ during CPB was analyzed for its association with CSA-AKI using multivariate logistic regression adjusted for age, weight, CPB duration, aortic cross-clamp (ACC) time, and red blood cell transfusion. Classification and regression tree (CART) analysis was conducted to develop a predictive model.

This study included 191 patients (96 (50.3 %) males; median age: 196 days [interquartile range (IQR), 55–474]). CSA-AKI occurred in 65 patients (34.0 %). Peak Pv-aCO₂/Ca-vO₂ was higher in the AKI group than in the non-AKI group (IQR, 4.8 [3.9–7.5] vs 3.9 [2.8–5.4] mmHg·dL/mL; p = 0.001) and was significantly associated with CSA-AKI (adjusted odds ratio: 1.14; 95% confidence interval: 1.04–1.27). A CART-derived predictive model included ACC time, peak Pv-aCO₂/Ca-vO₂, and weight. A Pv-aCO₂/Ca-vO₂ cut-off of 4.0 mmHg·dL/mL yielded 36.9 % sensitivity, 96.0 % specificity, 82.8 % positive predictive value, and 75.9 % negative predictive value.

In pediatric cardiac surgery for cyanotic CHD, high Pv-aCO₂/Ca-vO₂ predicts CSA-AKI. These findings highlight the potential role of Pv-aCO₂/Ca-vO₂ monitoring during CPB in developing novel pediatric goal-directed perfusion strategies.