BackgroundOperating a cardiopulmonary bypass (CPB) system requires high-level multitasking while simultaneously maintaining continuous situation awareness. Among these, venous reservoir level is particularly critical. This level is monitored using sensors fixed to arbitrary positions on the reservoir. When a sudden drop in level, the rate of decline accelerates. Conventional sensor threshold settings do not allow sufficient time for the operator to recognize the danger and intervene, so a means of detecting dangerous drops in level earlier is necessary.ObjectiveThe purpose of this study was to develop a system that can detect a sudden drop in liquid level early, regardless of the shape of the reservoir, based on image analysis using a webcam and mathematical models, and to verify its effectiveness.MethodsWe used a webcam to quantify the level fluctuation rate in two types of venous reservoirs (Manufacturer T and Manufacturer M) with different shapes, and predicted level fluctuations from the resulting mathematical model. We further developed a system that uses the reservoir level fluctuation rate as a threshold. This system predicts dangerous situations based on the rate of level decline caused by poor drainage or massive bleeding of unknown cause, and issues alerts and alarms.ResultsThe rate of reservoir drawdown accelerated below the intermediate reservoir level. Our proposed method triggered a danger alarm an average of 7 s earlier (Manufacturer T) and 2 seconds earlier (Manufacturer M) than the conventional method (300 mL threshold).ConclusionsThe efficacy of an early warning system that issues alerts in advance of the conventional volume-based threshold was demonstrated by utilizing the slope (rate of change) of the level decline as the detection threshold. Implementation of this system may improve the safety of extracorporeal circulation and reduce the burden on the operator during cardiopulmonary bypass procedures.

BackgroundVeno-venous extracorporeal membrane oxygenation (VV ECMO) is a key therapy for refractory respiratory failure, but can trigger systemic inflammation and prothrombotic activation that impair the membrane lung (ML). ML dysfunction can lead to mechanical failure of extracorporeal support, severe hypoxemia, and the need for urgent or elective circuit replacement. Conventional single parameters (pressure drop, post-ML blood gases, hemoglobin saturation), and laboratory tests have limited ability to predict ML deterioration.MethodsWe conducted a single-center pilot retrospective study including 27 ECMO circuits from 20 adult patients with COVID-19-related acute respiratory failure. Membrane lung dead space (DSML) was calculated from ML exhaust carbon dioxide (CO2) and blood gas measurements and used to assess ML effectiveness. For each circuit we evaluated the association between DSML and subsequent circuit exchange.Results20 patients (27 ECMO circuits) were analyzed; 10 circuits required replacement. Circuits that were replaced showed higher DSML values and lower CO2 concentration in membrane lung exhaust gas and membrane lung CO2 removal compared with circuits that completed the run. CO2-derived variables were the only parameters that differed significantly between groups, while oxygenation-related measures and baseline characteristics were similar.ConclusionsIn this exploratory study conducted on COVID-19 patients, we found an association between DSML increase and membrane lung impairment. However, the analysis does not provide enough information to assess the predictive performance of DSML. The identification of a significant threshold for circuit exchange requires further validation in larger prospective and multicenter studies.

BackgroundIn aortic arch surgery, bilateral selective antegrade cerebral perfusion (bSACP) maintains cerebral blood flow during circulatory arrest. bSACP is often delivered using a single pump with a Y-connector, dividing the flow. Current practice has veered towards perfusion of the left common carotid artery by cannula and the right subclavian artery by a vascular graft. Flow distribution may therefore depend on left-sided cannula resistance, particularly in patients with limited collateral circulation. We investigated how cannula design influences perfusion pressure and flow distribution during bSACP.MethodsFour clinically available carotid perfusion cannulas were characterized using bench measurements (40-200 mL/min) and computational fluid dynamics (CFD). The resulting resistance models were integrated into patient-specific CFD models of the cerebral circulation in three patients with varying collateral capacity. Both flow- and pressure-targeted perfusion strategies were simulated.ResultsBench testing demonstrated a 3-4-fold difference in flow resistance between the lowest- and highest-resistance cannulas, which was accurately reproduced in CFD simulations. Importantly, resistance did not correlate with nominal French size. In the patient-specific CFD models, increasing left side cannula resistance roughly doubled the pressure laterality (7-9 to 14-23 mmHg) and halved the left side inflow (135-160 to 70-100 mL/min) for the cannulas tested. Effects were most pronounced in patients with limited collateral circulation. Sensitivity analyses confirmed robustness across physiological and geometric perturbations.ConclusionsCannula resistance does not correlate with nominal French size. Cannula design may influence cerebral perfusion pressure and flow distribution during bSACP and may warrant increased attention.

IntroductionIsolated surgical revascularisation of the left anterior descending (LAD) coronary artery using the left internal mammary artery (LIMA) can be performed either with or without the use of cardiopulmonary bypass and is often performed by surgeons who do not otherwise routinely perform off-pump (OPCAB) surgery, despite evidence suggesting outcomes after off-pump surgery correlate with surgeon experience. We aimed to review short and long-term outcomes after isolated LIMA to LAD.MethodsSingle-centre retrospective review of all consecutive patients undergoing first-time isolated in-situ LIMA to LAD between 1997 and 2024 via median sternotomy. Primary outcomes were in-hospital mortality and overall survival. Secondary outcomes were post-operative length of stay (PLOS) and post-operative complications. Propensity score matching (PSM) was performed to produce two matched groups.Results662 patients were included (median follow-up time 84 months [29-154]). Off-pump surgery was performed in 58.2% (n = 385). In-hospital mortality was 0.9% (n = 6). PSM produced 275 matched pairs. Rates of post-operative stroke and blood transfusion were significantly lower in the OPCAB group, but in-hospital mortality (off-pump 0.8% vs on-pump 1.1%, p = 0.684) and overall survival (log-rank analysis p = 0.127) were similar between groups. The hazard ratio for OPCAB was 1.309 (95% confidence intervals 0.925-1.854, p = 0.127). Surgeon experience was not significantly associated with outcomes.ConclusionsIn this cohort, both off-pump and on-pump surgery emerged as safe treatment options for isolated LIMA to LAD surgery. Whilst OPCAB was associated with fewer complications, all other outcomes were comparable. Additional long-term studies extending beyond ten years are required to ensure these findings remain valid.

IntroductionType A aortic dissection (AD) rarely coexists with acute respiratory distress syndrome (ARDS). Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is avoided owing to bleeding and dissection progression concerns.Case ReportA 49-year-old man presented with sudden onset of chest pain and dyspnea. Computed tomography findings did not indicate rupture or malperfusion in Type A AD. He developed severe ARDS refractory to lung-protective ventilation and recruitment maneuvers. VV-ECMO was initiated with nafamostat anticoagulation, with temporary continuous hemodiafiltration for fluid balance. Oxygenation improved, allowing ECMO removal on Day 14. After tracheostomy, he was discharged from the ICU on Day 49 and mechanically ventilated without AD progression.DiscussionVV-ECMO can stabilize gas exchange without exacerbating AD in select patients with ARDS when perioperative risk outweighs the immediate risk of rupture or organ malperfusion.ConclusionVV-ECMO may be considered for ARDS complicated AD when the bleeding risk is mitigated by regional anticoagulation.

IntroductionAortic arch repair following the Norwood operation remains challenging because of dense adhesions and the risk of phrenic or recurrent nerve injury. We present a novel approach employing descending aortic antegrade perfusion using a balloon catheter to minimize the extent of dissection.Case ReportA 2-year-old male with hypoplastic left heart syndrome and post-Norwood operation underwent aortic arch repair. A balloon catheter was inserted through the aortic arch for simultaneous descending aortic occlusion and distal antegrade perfusion. This eliminated the need for external clamping. The procedure was successful with no nerve paralysis.DiscussionThis technique reduces the dissection area, mitigating nerve injury risks. Furthermore, it ensures continuous lower body antegrade perfusion, protecting visceral organs independent of deep hypothermia.ConclusionSimultaneous descending aortic occlusion and antegrade perfusion using a balloon catheter represents a safe, feasible strategy for complex arch repair, potentially reducing morbidity in high-risk single-ventricle patients.

BackgroundAutotransfusion devices concentrate white blood cells (WBCs) within the washed product that may lead to undesirable clinical effects when reinfused to the patient. This quality improvement project evaluated the leukocyte removal efficacy of three types of salvaged blood filters in autologous cell salvage.MethodsUsing a prospective observational cohort approach, we evaluated microaggregate, lipid-reducing, and leukocyte-reducing salvaged blood filters in adult patients undergoing surgery with autologous cell salvage. Filters were evaluated one after another, with samples of processed autologous blood collected prior to filtration and again after 30 mL had passed through each type of filter to allow for direct comparison of each filter's effects on WBC concentrations.ResultsSalvaged blood samples were collected from 35 patients. Median pre-filtration WBC count was 9.8 [6.8-13.3] × 10[9]/L, being reduced to 9.3 [6.6-12.6] × 10[9]/L after microaggregate filtration (1.7 [-0.6-4.6]% removal), 0.8 [0.5-2.5] × 10[9]/L after lipid filtration (89.7 [83.3-93.9]% removal), and 0.0 [0.0-0.0] × 10[9]/L after leukocyte filtration (100 [100-100]% removal). The microaggregate filter achieved significantly less WBC reduction than both the leukocyte-reducing filter (p < 0.0001) and lipid-reducing filter (p < 0.0001). There was no significant difference observed between the leukocyte-reducing and lipid-reducing filters (p = 0.3124).ConclusionsLeukocyte- and lipid-reducing filters were effective at reducing WBCs from processed autologous blood by nearly 10-fold, while microaggregate filters were significantly less effective at removing leukocytes. Use of leukocyte- or lipid-reducing filters minimizes the number of activated WBCs reinfused to the patient during autologous cell salvage.

Introductiondel Nido cardioplegia had not been commercially available in the United Kingdom prior to the DESTINY trial, a multi-centre individually randomised controlled trial to evaluate whether del Nido or St Thomas' blood cardioplegia provides better myocardial protection in children of all ages. In this sub-study, we explored the experiences of surgeons and perfusionists using del Nido in the trial, to support implementation of del Nido in the United Kingdom and identify any practical or safety concerns.MethodsWe conducted qualitative, semi-structured interviews with surgeons and perfusionists who had completed at least three cases with del Nido cardioplegia in the trial. Interviews were conducted face-to-face or via Zoom, digitally audio-recorded, transcribed, and analysed using a hybrid thematic approach, according to the Consolidated Framework for Implementation Research domains. Trial registration: ISRCTN13638147, registered July 2021.ResultsTwelve participants were interviewed, six surgeons and six perfusionists from all four paediatric cardiac surgical centres participating in the trial. Four key themes emerged: (1) attitudes towards the use of del Nido cardioplegia; (2) practical aspects of delivering del Nido cardioplegia; (3) blood conservation techniques; and (4) adopting del Nido cardioplegia into routine clinical use beyond the trial.ConclusionsSurgeons and perfusionists reported that they found del Nido cardioplegia to have practical benefits over St Thomas' blood cardioplegia but felt that further research on the optimal cooling temperature, blood conservation, and dosing for paediatric use are required to support the development of a best practice guideline and guide national implementation beyond the trial.

ObjectiveWe aimed to compare early and late postoperative clinical outcomes between minimally invasive surgery (MIS) and full sternotomy (FS) in patients with mitral valve (MV) infective endocarditis (IE).MethodsThis meta-analysis was conducted in compliance with the PRISMA guidelines. PubMed, Scopus, and Web of Science databases were searched for any randomized control trials or cohort studies that compared MIS versus FS in surgery for mitral valve infective endocarditis.ResultsFour cohort studies with 466 patients (137 in MIS group and 329 in FS group), were included in our study. Pooled analysis showed no significant difference between MIS and FS in terms of in-hospital/30-day mortality (RR = 0.71, 95% CI [0.31-1.60], p-value = 0.40), stroke (RR = 0.63, 95% CI [0.16-2.46], p-value = 0.50), atrial fibrillation (RR = 0.89, 95% CI [0.57-1.40], p-value = 0.62), acute kidney injury/renal failure (RR = 0.51, 95% CI [0.22-1.16], p-value = 0.11), multi-organ failure (RR = 0.94, 95% CI [0.33-2.70], p-value = 0.90), and readmission rates (RR = 0.75, 95% CI [0.39-1.45], p-value = 0.39). However, our study showed a statistically significant association between MIS and lower risk of postoperative sepsis (RR = 0.17, 95% CI [0.03-0.84], p-value = 0.03), fewer blood transfusions (RR = 0.63, 95% CI [0.48-0.84], p-value = 0.001), and shorter length of ICU stay (RR = -1.57, 95% CI [-2.16, -0.97], p-value <0.00001) compared to FS. The pooled effect estimate showed no significant difference between both groups in terms of need for reoperation, permanent pacemaker implantation, survival up to 2.5 years, and IE recurrence up to 3.5 years.ConclusionsOur findings suggest that MIS may be a safe and cost-effective alternative for FS in patients undergoing surgery for mitral valve infective endocarditis. Surgical approach should be tailored to the patient's clinical risk profile, the extent of endocarditis, and the team's experience, to ensure optimal clinical outcomes.

ObjectiveWe aimed to compare postoperative clinical outcomes between minimally invasive extracorporeal circulation (MiECC) and conventional extracorporeal circulation (CECC) in patients undergoing cardiac surgery.MethodsWe performed a meta-analysis of randomized controlled trials comparing MiECC and CECC in adult cardiac surgery. A literature search was conducted in PubMed, Web of Science, Scopus, and Cochrane library databases from inception to July 2026 to identify relevant studies. Primary outcomes included mortality, myocardial infarction, atrial fibrillation, stroke, acute kidney injury, delirium, transfusion requirements, ICU length of stay, ventilation duration, and hospital length of stay.ResultsForty-one RCTs with a total of 5215 patients (2652 in MiECC group, and 2563 in CECC group) were included. MiECC was associated with decreased myocardial infarction (RR = 0.50, 95% CI [0.34, 0.73], p-value = 0.0004), atrial fibrillation (RR = 0.82, 95% CI [0.72, 0.93], p-value = 0.002), stroke (RR = 0.50, 95% CI [0.27, 0.93], p-value = 0.03), delirium (RR = 0.42, 95% CI [0.24, 0.73], p-value = 0.002), chest tube drainage (RR = -123.27, 95% CI [-165.41, -81.13], p-value <0.00001), units of transfused RBC (MD = -0.67, 95% CI [-0.84, 0.49], p-value <0.00001), ICU length of stay (MD = -0.99, 95% CI [-1.42, 0.56], p-value <0.00001), hospital length of stay (MD = -0.61, 95% CI [-1.09, -0.12], p-value = 0.01) and ventilation duration (MD = -2.71, 95% CI [-3.72, -1.69], p-value <0.00001) compared to CECC. However, no significant differences were observed between both groups in terms of mortality, transient ischemic attack, acute kidney injury, reoperation for bleeding, and platelet transfusions.ConclusionMiECC may provide myocardial and neurological protection, better hemostasis, and faster early postoperative recovery compared to CECC, supporting its adoption as a preferred perfusion strategy in cardiac surgery.

Profound, transient hypotension refractory to α1-agonists and increased bypass flow during cardioplegia administration (intermittent vasoplegia) is a well-recognized yet unexplained phenomenon in cardiac surgery. Retrograde cardioplegia has been shown to cause profound hypotension with greater frequency than antegrade administration despite identical formulations, ischemic intervals, and perfusion parameters. It seems plausible that the link between cardioplegia administration to the arrested heart and the intermittent vasoplegic systemic response may result from a vagally mediated cardiac depressor reflex.Electrophysiologic and histologic studies have identified multiple vagal receptors within the ventricular myocardium and coronary vasculature that, when stimulated, produce a centrally mediated and prolonged withdrawal of efferent sympathetic activity to the systemic vasculature. During antegrade cardioplegia, hypotension most likely arises from activation of left ventricular chemoreceptors terminating in the inferoposterior wall. These afferents respond to endogenous mediators of ischemia and reperfusion such as bradykinin and prostaglandins.In contrast, the depressor reflex observed during retrograde cardioplegia likely arises from vagal afferent ventricular mechanoreceptors. In the arrested, decompressed heart, only 20-33% of retrograde cardioplegia traverses the capillaries, while the remainder is shunted through the Thebesian system. The resulting surge in coronary venous pressure causes distension that is easily transmitted to the surrounding interstitial space, creating the mechanical effects of grossly elevated end-diastolic pressure and pathological myocardial stretch despite the absence of true ventricular filling and wall tension.If the intermittent vasoplegic response to cardioplegia is viewed within the mechanistic framework of a vagally mediated depressor reflex, the optimal intervention to mitigate prolonged hypotension may not be stronger vasopressors (e.g., norepinephrine or vasopressin), but rather the inclusion of lidocaine in the microplegia additive. Lidocaine is known to markedly attenuate reflex vasodepressor responses through the blockade of sodium channels in nerve fibers.

BackgroundThe relationship between rewarming rate during cardiopulmonary bypass (CPB) and postoperative delirium (POD) in cardiac surgery remains unclear. This retrospective study aimed to evaluate whether rapid rewarming is associated with an increased risk of POD.MethodsA total of 548 adult cardiac surgery patients (January 2021-December 2023) were enrolled. POD was identified through medical record review based on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)criteria or documented delirium symptoms combined with olanzapine use (serving as a surrogate marker). Rewarming rate was defined as the average temperature increase per minute from the lowest nasopharyngeal temperature during CPB to 36.5°C, calculated as (36.5°C - lowest temperature)/rewarming time (min). Multivariable logistic regression and ROC analysis were performed.ResultsRewarming rate was significantly higher in the POD group (n = 300) than the non-POD group (n = 248) (0.095 ± 0.044 vs 0.072 ± 0.034°C/min, p < 0.001). Olanzapine dosage (18.5 ± 8.2 mg vs 0 mg) and duration (4.2 ± 2.1 days vs 0 days) in the POD group showed significant positive correlations with rewarming rate (r = 0.887 and r = 0.814, respectively, both p < 0.01). Rewarming rate (OR = 1.782), red blood cell transfusion (OR = 1.456), CPB duration (OR = 1.023), and mean CVP (OR = 1.156) were identified as independent risk factors for POD (all p < 0.05). The predictive model achieved an AUC of 0.775 (95% CI: 0.736-0.814).ConclusionsRapid rewarming during CPB is associated with increased POD risk and may be a modifiable perioperative factor. Prospective studies with standardized POD screening are warranted to validate these findings.

BackgroundFrailty is increasingly recognized as a key determinant of outcomes in critically ill patients, yet its utility among patients receiving venoarterial extracorporeal membrane oxygenation (VA ECMO) remains unclear. We evaluated the hospital frailty risk score (HFRS) as a risk factor of 90-day mortality in VA ECMO patients.MethodsWe conducted a retrospective analysis of VA ECMO patients at Johns Hopkins Hospital from 2016 to 2024. HFRS was derived from ICD-10 codes. An optimal frailty cut point was determined using maximally selected rank statistics, and patients were subsequently stratified into high (>10) and low (<=10) frailty groups. Cox proportional hazards models evaluated the association between frailty and mortality, adjusting for demographics, comorbidities, and clinical variables.Results180 patients receiving VA ECMO were included (median age:53 years, 46.2% female). Overall, 25 patients (13.9%) were classified as high frailty (HFRS >10) and 155 (86.1%) as low frailty (HFRS≤10). Of the 180 patients, 80 patients survived 90-days following initial ECMO cannulation. Median HFRS was higher among non-survivors (4.9 vs 3.4), with a greater proportion classified as high frailty (18.0% vs 8.8%). In multivariable Cox regression adjusting for demographics, comorbidities, and clinical covariates, low HFRS remained independently associated with reduced 90-day mortality (HR=0.47, 95% CI 0.26-0.87, p=0.017), while obesity (HR=10.44) and older age (HR 1.02) were independently associated with increased mortality.ConclusionHFRS is independently associated with 90-day mortality in patients undergoing VA ECMO. Incorporating frailty into pre-ECMO evaluation may enhance prognostication and inform patient selection and clinical decision-making.

IntroductionSevere congenital diaphragmatic hernia (CDH) is associated with significant morbidity and mortality. Pre/post-natal risk factors guide decisions on extracorporeal membrane oxygenation (ECMO) intervention. We aimed to describe variations in ECMO decision-making for neonatal CDH.MethodsWe distributed a practice-based survey (October 2023) to assess institutional ECMO guidelines for neonatal CDH. Respondents included neonatal/pediatric intensivists, surgeons, and ECMO coordinators. We used descriptive statistics for analysis.ResultsFormal CDH management guidelines were reported by 60 (77%) from 82 respondents across 12 countries. The most common exclusion criteria were prematurity (73%), low birthweight (72%), and aneuploidy (58%). Pre-existing neurological complications, single ventricle palliation heart disease, and genetics-related poor neurodevelopmental prognosis were the most cited exclusion criteria independent of CDH severity.ConclusionSignificant practice variation exists in the exclusion criteria for ECMO in neonatal CDH. There remains an opportunity for a more unified approach regarding ECMO use in infants with severe CDH.