Application of Digital Artery Transposition in the Replantation of Severed Fingers with Vessel Defects and its Influence on Nerve Function and Joint Function Recovery.

OBJECTIVE: To investigate the application of digital artery transposition in replanting severed fingers with vascular defects and its impact on nerve and joint function recovery. METHODS: 200 patients who received replantation of severed fingers were randomly divided into artery transposition group (n = 100) and vein transplantation group (n = 100). The digital artery transposition technique was used in the artery transposition group, and the autologous vein bridging technique was used in the vein transplantation group. The clinical efficacy and survival rate of severed fingers were compared between the two groups. RESULTS: The clinical excellent and good rate in artery transposition group was significantly higher than that in vein transplantation group (P < 0.05). CONCLUSION: The transposition of digital artery is effective and safe in replantation of severed fingers with vascular defects.

Mortality risk factors in patients receiving ECPR after cardiac arrest: Development and validation of a clinical prognostic prediction model.

BACKGROUND: Previous studies have shown an increasing trend of extracorporeal cardiopulmonary resuscitation (ECPR) use in patients with cardiac arrest (CA). Although ECPR have been found to reduce mortality in patients with CA compared with conventional cardiopulmonary resuscitation (CCPR), the mortality remains high. This study was designed to identify the potential mortality risk factors for ECPR patients for further optimization of patient management and treatment selection. METHODS: We conducted a prospective, multicentre study collecting 990 CA patients undergoing ECPR in 61 hospitals in China from January 2017 to May 2022 in CSECLS registry database. A clinical prediction model was developed using cox regression and validated with external data. RESULTS: The data of 351 patients meeting the inclusion criteria before October 2021 was used to develop a prediction model and that of 68 patients after October 2021 for validation. Of the 351 patients with CA treated with ECPR, 227 (64.8%) patients died before hospital discharge. Multivariate analysis suggested that a medical history of cerebrovascular diseases, pulseless electrical activity (PEA)/asystole and higher Lactate (Lac) were risk factors for mortality while aged 45-60, higher pH and intra-aortic balloon pump (IABP) during ECPR have protective effects. Internal validation by bootstrap resampling was subsequently used to evaluate the stability of the model, showing moderate discrimination, especially in the early stage following ECPR, with a C statistic of 0.70 and adequate calibration with GOF chi-square = 10.4 (p = 0.50) for the entire cohort. Fair discrimination with c statistic of 0.65 and good calibration (GOF chi-square = 6.1, p = 0.809) in the external validation cohort demonstrating the model's ability to predict in-hospital death across a wide range of probabilities. CONCLUSION: Risk factors have been identified among ECPR patients including a history of cerebrovascular diseases, higher Lac and presence of PEA or asystole. While factor such as age 45-60, higher pH and use of IABP have been found protective against in-hospital mortality. These factors can be used for risk prediction, thereby improving the management and treatment selection of patients for this resource-intensive therapy.

Perioperative oxygenation impairment related to type a aortic dissection.

Type A aortic dissection (TAAD) is a life-threatening disease with high mortality and poor prognosis, usually treated by surgery. There are many complications in its perioperative period, one of which is oxygenation impairment (OI). As a common complication of TAAD, OI usually occurs throughout the perioperative period of TAAD and requires prolonged mechanical ventilation (MV) and other supportive measures. The purpose of this article is to review the risk factors, mechanisms, and treatments of type A aortic dissection-related oxygenation impairment (TAAD-OI) so as to improve clinicians' knowledge about it. Among risk factors, elevated body mass index (BMI), prolonged extracorporeal circulation (ECC) duration, higher inflammatory cells and stored blood transfusion stand out. A reduced occurrence of TAAD-OI can be achieved by controlling these risk factors such as suppressing inflammatory response by drugs. As for its mechanism, it is currently believed that inflammatory signaling pathways play a major role in this process, including the HMGB1/RAGE signaling pathway, gut-lung axis and macrophage, which have been gradually explored and are expected to provide evidences revealing the specific mechanism of TAAD-OI. Numerous treatments have been investigated for TAAD-OI, such as nitric oxide (NO), continuous pulmonary perfusion/inflation, ulinastatin and sivelestat sodium, immunomodulation intervention and mechanical support. However, these measures are all aimed at postoperative TAAD-OI, and not all of the therapies have shown satisfactory effects. Treatments for preoperative TAAD-OI are not currently available because it is difficult to correct OI without correcting the dissection. Therefore, the best solution for preoperative TAAD-OI is to operate as soon as possible. At present, there is no specific method for clinical application, and it relies more on the experience of clinicians or learns from treatments of other diseases related to oxygenation disorders. More efforts should be made to understand its pathogenesis to better improve its treatments in the future.

Electrical storm after correction of an uncomplicated congenital atrial septal defect in an adult: a case report.

BACKGROUND: There is a paucity of published literature describing electrical storm after the correction of uncomplicated atrial septal defect (ASD) in an adult. CASE PRESENTATION: We present a 49-year-old woman with a congenital ASD combined with mild tricuspid regurgitation who denied any history of arrhythmia or other medical history. She suffered from electrical storm (≥ 3 episodes of ventricular tachycardias or ventricular fibrillations) in the early stage after ASD repair with combined tricuspid valvuloplasty. During electrical storm, her electrolytes were within normal ranges and no ischemic electrocardiographic changes were detected, which suggested that retained air embolism or acute coronary thrombosis were unlikely. Additionally, echocardiographic findings and her central venous pressure (5-8 mmHg during the interval between attacks) failed to support the diagnosis of pericardial tamponade. After a thorough discussion, the surgeons conducted an emergent re-exploration and repeated closure of the ASD with combined DeVega's annuloplasty. Eventually, the patient recovered uneventfully, without reoccurring arrhythmias during follow-up. Although we fail to determine the definite cause, we speculate that the causes probably are iatrogenic injury of the conduction system due to a rare anatomic variation, poor intraoperative protection, latent coronary distortion during tricuspid valvuloplasty, or idiopathic or secondary abnormalities of the conduction system. CONCLUSIONS: For most surgeons, performing re-exploration without a known etiology is a difficult decision to make. This case illustrates that re-exploration could be an option when electrical storm occurs in the early stage postoperatively. Nevertheless, surgeons should assess the benefit-risk ratio when taking this unconventional measure.

General Anesthesia Increased the Risk of Atrial Fibrillation and Acute Kidney Injury in Transcatheter Aortic Valve Replacement.

PURPOSE: To examine key impacts of anesthesia on new-onset atrial fibrillation (AF) and acute kidney injury (AKI) in transcatheter aortic valve replacement (TAVR). METHODS: All consecutive patients who underwent transfemoral, transapical, and transaortic TAVR in Fuwai Hospital from 2012 to 2018 were retrospectively analyzed and dichotomized into 2 groups: TAVR under conscious sedation (CS) and under general anesthesia (GA). The primary endpoint was a composite of all-cause mortality, stroke, AF, permanent pacemaker implantation, myocardial infarction, heart failure, high-grade atrioventricular block, and AKI at 1 year. Binary logistic regression and adjusted multilevel logistic regression were performed to analyze the predictors of AF and AKI. RESULTS: A total of 107 patients were under CS and 66 patients under GA. No significant difference was observed in the composite endpoint (51.5% vs. 41.2%, GA vs. CS, P = .182) and ≥ mild paravalvular leakage (36.4% vs. 31.4%, GA vs. CS, P = .589) at 1 year. However, the GA group had a significantly higher rate of intensive care unit (ICU) admission (84.8% vs. 6.5%, P < .001), AKI (28.8% vs. 14.0%, P = .018), new-onset AF (15.2% vs. 5.5% at 1 year, P = .036). Multivariable analysis revealed GA to be the significant predictor of new-onset AF (odds ratio 3.237, 95% confidence interval 1.059 to 9.894, P = .039) and AKI (odds ratio 2.517, 95% confidence interval 1.013 to 6.250, P = .047). CONCLUSION: GA was associated with higher rates of ICU admission, postoperative AKI, and new-onset AF. The results may provide new evidence that CS challenges universal GA.

Association of IFN-γ polymorphisms with ankylosing spondylitis risk.

The case-control study was designed to investigate the genetic effects of interferon-gamma (IFN-γ) rs2069727 and rs1861494 polymorphisms on ankylosing spondylitis (AS) susceptibility in a Chinese Han population. Blood samples were collected from 108 AS patients and 110 healthy controls. IFN-γ polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Hardy-Weinberg equilibrium (HWE) test was performed in control group. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using chi-square test to evaluate the association between AS susceptibility and IFN-γ polymorphisms, and the results were adjusted by logistic regressive analysis. The frequency of rs2069727 CC genotype was much higher in cases than that in controls, suggested its significant association with increased AS risk (adjusted OR = 5.899, 95% CI = 1.563-22.261; P = .009). In addition, C allele also showed close association with increased risk of AS (adjusted OR = 2.052, 95% CI = 1.286-1.704, P  = 0 .003). While the genotype and allele frequencies of IFN-γ rs1861494 polymorphism were not significantly different between patients and controls (P  > 0.05 for all), IFN-γ rs2069727 polymorphism is significantly associated with increased AS risk in a Chinese Han Population.

The dynamic observation of plasma concentration of antimicrobial agents during balanced ultrafiltration in vitro.

Routine perioperative intravenous antimicrobial agents are administered as surgical prophylaxis. However, whether balanced ultrafiltration during extracorporeal circulation has substantial effect on the concentration of antimicrobial agents remains unclear. The concentrations of antimicrobial agents in plasma and ultrafiltrate samples were measured in this pseudo-extracorporeal circulation model. Extracorporeal circulation consisted of cardiotomy reservoir, membrane oxygenator, and pediatric arterial line filter. A hemoconcentrator was placed between the arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. Two kinds of antimicrobial agents, cefotiam (320 mg) and cefmetazole (160 mg), were bolus added into the circuit. After 30 min of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mm Hg with a Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. An identical volume of Plasmalyte A was dripped into the circuit to maintain stable hematocrit during 45 min of experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of antimicrobial agents (including cefotiam and cefmetazole) were measured with high performance liquid chromatography. Both antimicrobial agents were detected in ultrafiltrate, demonstrating hemoconcentration may remove antimicrobial agents. The concentrations of plasma antimicrobial agents decreased linearly with the increase of ultrafiltrate volume. At end of balanced ultrafiltration, the concentration of plasma cefotiam was 104.96 ± 44.36 mg/L, which is about 44.38% ± 7.42% of the initial concentration (238.95 ± 101.12 mg/L) (P < 0.001); the concentration of plasma cefmetazole decreased linearly to 25.76 ± 14.78 mg/L, which is about 49.69% ± 10.49% of the initial concentration (51.49 ± 28.03 mg/L) (P < 0.001). The total amount of cefotiam in ultrafiltrate is 27.16% ± 12.17% of the total dose administered, whereas cefmetazole in ultrafiltrate is 7.74% ± 4.17%. Balanced ultrafiltration may remove antimicrobial agents from plasma and has a prominent influence on plasma concentration of antimicrobial agent. The strategy of surgical prophylaxis should consider this unique technique during extracorporeal circulation.

Continuous monitoring of inflammation biomarkers during simulated cardiopulmonary bypass using a microfluidic immunoassay device - a pilot study.

This work demonstrates the use of a continuous online monitoring system for tracking systemic inflammation biomarkers during cardiopulmonary bypass (CPB) procedures. The ability to monitor inflammation biomarkers during CPB will allow surgical teams to actively treat inflammation and reduce harmful effects on postoperative morbidity and mortality, enabling improved patient outcomes. A microfluidic device has been designed which allows automation of the individual processing steps of a microbead immunoassay to allow continuous tracking of antigen concentrations. Preliminary experiments have demonstrated that the results produced by the microimmunoassay are comparable to results produced from a standard enzyme-linked immunosorbent assay (r = 0.98). Additionally, integration of the assay with a simulated CPB circuit has been demonstrated with temporal tracking of C3a concentrations within blood continuously sampled from the circuit. The presented work describes the motivation, design challenges, and preliminary experimental results of this project.

EXTRACORPOREAL CARDIOPULMONARY RESUSCITATION WITH THERAPEUTIC HYPOTHERMIA MITIGATES KIDNEY INJURY AFTER CARDIAC ARREST IN RATS.

ABSTRACT: Many patients with cardiac arrest (CA) experience severe kidney injury after the return of spontaneous circulation. This study aimed to compare the renal protective effect of conventional cardiopulmonary resuscitation (CCPR), extracorporeal cardiopulmonary resuscitation (ECPR), and ECPR with therapeutic hypothermia (ECPR+T) in a CA rat model. Twenty-four adult male Sprague-Dawley rats were randomly and equally allocated into the sham, CCPR, ECPR, and ECPR+T groups. The sham group underwent basic surgical procedures without asphyxia-induced CA. The other three groups were treated with asphyxiation to establish the CA model. Subsequently, they were rescued using three different therapeutic methods. The end points were 1 h after return of spontaneous circulation or death. Renal injury was evaluated by histopathology. Oxidative stress, endoplasmic reticulum stress, necroptosis, inflammatory, and apoptosis-related genes, and proteins were detected using western blotting, ELISA, and assay kit. Compared with CCPR, ECPR and ECPR+T alleviated oxidative stress by upregulating nuclear factor erythroid 2-related factor 2, superoxide dismutase, glutathione and downregulating heme oxygenase-1, and malondialdehyde. Expression of endoplasmic reticulum stress-related proteins, glucose-regulated protein 78, and CCAAT/enhancer-binding protein homologous protein was lower in ECPR and ECPR+T groups than that in the CCPR group, along with levels of TNF-α, IL-6, and IL-ß, and necroptosis proteins (receptor-interacting serine/threonine kinases 1 and 3). Furthermore, the ECPR and ECPR+T groups had significantly increased B-cell lymphoma 2 and decreased B-cell lymphoma 2-associated X levels compared with the CCPR group. Extracorporeal cardiopulmonary resuscitation and ECPR+T alleviate kidney damage after CA in rats compared with CCPR. Furthermore, ECPR+T had a better renal protective effect.

The monitoring and preventing of spinal cord ischemic injury during thoracic descending aortic operating.

BACKGROUND: A model of ischemic injury to the spinal cord was established in pigs by clamping the thoracic descending aorta. The feasibility of monitoring spinal-cord ischemia using the cortical somatosensory evoked potential (CSEP) was evaluated. Outcomes between the simple clamp (SC) group and left-heart bypass (LHB) group were compared. METHODS: Twelve mini-pigs were randomly divided into two groups SC group and LHB group randomly. The left intercostal incision was adopted. The thoracic descending aorta was clamped under the left innominate artery outlet. CSEP was recorded to monitor the function of the spinal cord. The behavior score was observed every day after surgery. Mini-pigs were killed on the seventh postoperative day. Ultrastructural changes were observed by transmission electron microscopy. RESULTS: The surgical procedures were successful. Two animals developed incomplete paralysis and the remainder developed paraplegia in the SC group. The animals in the LHB group recovered completely and paralysis/paraplegia was not observed. CSEP measurements showed that the amplitude decreased to <50% of baseline values and prolongation of latency was >10% of baseline values in the SC group but not in the LHB group. Changes in CSEP values were in accordance with changes in behavior score. The ultramicrostructure of spinal-cord tissue under clamping indicated severe damage to tissue layers as well as swelling and damage to mitochondria in the SC group, whereas the morphology was almost normal in the LHB group. CONCLUSIONS: These data suggest that during a 30-minute clamping time, left-heart bypass may provide superior spinal protection than simple clamping, and monitoring of spinal-cord ischemia using CSEP was rapid and feasible.

Balanced ultrafiltration: inflammatory mediator removal capacity.

Ultrafiltration with a hemoconcentrator may remove excess fluid load and alleviate tissue edema and has been universally adopted in extracorporeal circulation protocols during pediatric cardiac surgery. Balanced ultrafiltration is advocated to remove inflammatory mediators generated during surgery. However, whether balanced ultrafiltration can remove all or a portion of the inflammatory mediator load remains unclear. The inflammatory mediator removal capacity of zero-balanced ultrafiltration was measured during pediatric extracorporeal circulation in vitro. Extracorporeal circulation was composed of cardiotomy reservoir, D902 Lilliput 2 membrane oxygenator, and Capiox AF02 pediatric arterial line filter. The Hemoconcentrator BC 20 plus was placed between arterial purge line and oxygenator venous reservoir. Fresh donor human whole blood was added into the circuit and mixed with Ringer's solution to obtain a final hematocrit of 24-28%. After 2 h of extracorporeal circulation, zero-balanced ultrafiltration was initiated and arterial line pressure was maintained at approximately 100 mmHg with Hoffman clamp. The rate of ultrafiltration (12 mL/min) was controlled by ultrafiltrate outlet pressure. Identical volume of plasmaslyte A was dripped into the circuit to maintain stable hematocrit during the 45 min of the experiment. Plasma and ultrafiltrate samples were drawn every 5 min, and concentrations of inflammatory mediators including interleukin-1ß (IL-1ß), IL-6, IL-10, neutrophil elastase (NE), and tumor necrosis factor-α (TNF-α) were measured. All assayed inflammatory mediators were detected in the ultrafiltrate, demonstrating that the ultrafiltrator may remove inflammatory mediators. However, dynamic observations suggested that the concentration of NE was highest among the five inflammatory mediators in both plasma and ultrafiltrate (P < 0.001). IL-1ß had the lowest concentration in plasma, whereas the concentration of TNF-α was the lowest in ultrafiltrate (P < 0.001). Concentrations of all inflammatory mediators in the ultrafiltrate did not increase linearly compared with those in plasma. The respective ultrafiltrate to plasma concentration and amount ratios indicated that the total removal effect of hemoconcentrator on the inflammatory mediators was 4.17 ± 2.68% for IL-1ß, 0.64 ± 0.69% for IL-6, 0.24 ± 0.18% for IL-10, 2.84 ± 1.65% for NE, and 0.51 ± 0.81% for TNF-α, respectively. Balanced ultrafiltration may selectively remove inflammatory mediators from serum. Respective ratios of inflammatory mediators in ultrafiltrate compared with plasma, as well as total amount of inflammatory mediators in the ultrafiltrate suggest that balanced ultrafiltration removes a limited portion of the total inflammatory mediator load.

Extracorporeal membrane oxygenation for thyroid surgery in patients with severe tracheal stenosis.

Venovenous extracorporeal membrane oxygenation is effective for maintaining gas exchange in patients with respiratory failure or severe tracheal stenosis. Perioperative anesthetic management of severe airway obstruction can be associated with ventilation or intubation difficulties. Consequently, venovenous extracorporeal membrane oxygenation could be an option for treating such patients to avoid potential risks. However, only a limited number of similar cases have been reported. Therefore, we have summarized two cases to provide theoretical and practical references for treating patients with respiratory failure or severe tracheal stenosis using extracorporeal membrane oxygenation.

Improved cerebral oxygen saturation and blood flow pulsatility with pulsatile perfusion during pediatric cardiopulmonary bypass.

Brain monitoring techniques near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD) ultrasound were used in pediatric patients undergoing cardiopulmonary bypass for congenital heart defect (CHD) repair to analyze the effect of pulsatile or nonpulsatile flow on brain protection. Regional cerebral oxygen saturation (rSO2) and cerebrovascular pulsatility index (PI) were measured by NIRS and TCD, respectively, in 111 pediatric patients undergoing bypass for CHD repair randomized to pulsatile (n = 77) or nonpulsatile (n = 34) perfusion. No significant differences in demographic and intraoperative data, including surgical risk stratification, existed between groups. Patients undergoing pulsatile perfusion had numerically lower decreases in rSO2 from baseline for all time points analyzed compared with the nonpulsatile group, with significant ∼12% lower decreases at 40 and 60 min after crossclamp. Patients undergoing pulsatile perfusion had numerically lower decreases in PI from baseline for the majority of time points compared with the nonpulsatile group, with significant ∼30% lower decreases between 5 and 40 min after crossclamp. Pulsatile flow has advantages over nonpulsatile flow as measured by NIRS and TCD, especially at advanced time points, which may improve postoperative neurodevelopmental outcomes.

An investigational study of minimum rotational pump speed to avoid retrograde flow in three centrifugal blood pumps in a pediatric extracorporeal life support model.

During extracorporeal life support with centrifugal blood pumps, retrograde pump flow may occur when the pump revolutions decrease below a critical value determined by the circuit resistance and the characteristics of the pump. We created a laboratory model to evaluate the occurrence of retrograde flow in each of three centrifugal blood pumps: the Rotaflow, the CentriMag, and the Bio-Medicus BP-50. At simulated patient pressures of 60, 80, and 100 mmHg, each pump was evaluated at speeds from 1000 to 2200 rpm and flow rates were measured. Retrograde flow occurred at low revolution speeds in all three centrifugal pumps. The Bio-Medicus pump was the least likely to demonstrate retrograde flow at low speeds, followed by the Rotaflow pump. The CentriMag pump showed the earliest transition to retrograde flow, as well as the highest degree of retrograde flow. At every pump speed evaluated, the Bio-Medicus pump delivered the highest antegrade flow and the CentriMag pump delivered the least.

A single-center analysis of outcomes, risk factors, and new valves in Asian patients treated with early transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) continues to expand as an optimal treatment in Western countries; however, Asian countries have been slower to adopt this procedure. This research aimed to explore the outcomes and status of early TAVI performed at a single center in Asia, and provide comparative outcomes of the newly designed Chinese valves. METHODS: We enrolled 175 consecutive patients who successfully underwent TAVI from September 2012 to January 2018 at Fuwai Hospital (Beijing, China). After a preliminary assessment of age, we included 109 older patients (≥69 years) who underwent surgical aortic valve replacement (SAVR) during the same period. The primary endpoint was all-cause mortality. The inverse probability of treatment weighting (IPTW) was used to reduce potential bias. Cox regression was used to identify the risk factors of a poor prognosis. RESULTS: The TAVI cohort had higher rates of all-cause mortality [11.4% vs. 2.4%, hazard ratio (HR): 4.79, 95% confidence interval (CI): 1.47 to 15.57, IPTW-adjusted P=0.009] and permanent pacemaker implantation (PPI; 14.6% vs. 1.6%, HR: 9.98, 95% CI: 2.71 to 36.67, IPTW-adjusted P<0.001) at 3 years than the SAVR cohort. In the multivariable Cox regression analysis based on the entire sample, liver disease was associated with all-cause mortality (HR: 5.080, 95% CI: 1.067 to 24.174, P=0.041). A smoking history was associated with an increased risk of postoperative heart failure (HF) (HR: 4.902, 95% CI: 1.265 to 18.999, P=0.022). Additionally, age (HR: 1.141, 95% CI: 1.010 to 1.288, P=0.034) and diabetes (HR: 7.301, 95% CI: 2.414 to 22.079, P<0.001) were identified as predictors of postoperative stroke. In the new valve subgroups, the 1-year composite endpoints were 38.2% (Venus A), 35.3% (TaurusOne), 34% (J-Valve), and 28% (VitaFlow) (P=0.857). CONCLUSIONS: Not all TAVI procedures had satisfactory outcomes compared with SAVR when initiated. At first, our center faced some challenges in delivering TAVI, and this is probably one of the reasons why the use of TAVI has developed slowly in Asia. Further investigations are needed to explore the underlying factors precluding the rapid expansion of TAVI in Asia.

Evaluation of neonatal membrane oxygenators with respect to gaseous microemboli capture and transmembrane pressure gradients.

A series of studies performed at our center demonstrates that gaseous microemboli (GME) remain a challenge in cardiac surgical procedures. Evaluation of novel oxygenators must address hemodynamic parameters and microemboli capture capability. The objective of this study is to compare two neonatal membrane oxygenators, the Quadrox-i (MAQUET Cardiopulmonary AG, Hirrlingen, Germany) and the Capiox RX05 (Terumo Corporation, Tokyo, Japan), with respect to GME capture and hemodynamic energy delivery. The experimental circuit included a Maquet HL-20 heart-lung machine, a Heater-Cooler Unit HCU 30 (MAQUET Cardiopulmonary AG), a membrane oxygenator (Quadrox-i Neonatal or Capiox RX05), and »-inch tubing from the COBE Heart/Lung Perfusion Pack (COBE Cardiovascular, Inc., Arvada, CO, USA). A Capiox cardiotomy reservoir CX*CR10NX (Terumo Corporation) acted as a pseudopatient. The circuit was primed with human packed red blood cells and lactated Ringer's solution and de-aired according to clinical priming procedure. Heparin (5000IU) was added into the circuit. The total volume was 400mL and hematocrit was 30%. Pump flow rate was maintained at 500 or 1000mL/min under both pulsatile and nonpulsatile modes. All trials were conducted under 100mm Hg of circuit pressure at normothermia (35°C). In each trial, bolus air (0.5mL) was injected into the circuit at the prepump site over 5s. Total emboli counts and total emboli volume were significantly reduced by the Quadrox-i Neonatal membrane oxygenator compared to the Capiox RX05 membrane oxygenator. Classification and quantification of GME detected at the postoxygenator site at two different flow rates indicated that the Quadrox-i Neonatal captures the majority of microemboli larger than 40µm in diameter. The Quadrox-i Neonatal membrane oxygenator had a higher transmembrane pressure drop at 500mL/min, whereas it had a lower pressure drop at 1000mL/min compared to the Capiox Baby RX05 oxygenator. Additionally, the Quadrox-i Neonatal oxygenator preserved more pulsatile energy than the Baby RX05 oxygenator at both flow rates. Compared to the Capiox RX05 membrane oxygenator, the Quadrox-i Neonatal membrane oxygenator has significantly improved GME handling capacity and had better hemodynamic energy preservation. Further research encompassing in vivo and clinical studies is needed to investigate the magnitude and mechanisms of these benefits.

Air-handling capabilities of blood cardioplegia delivery systems in a simulated pediatric model.

Blood cardioplegia delivery systems are employed in most pediatric open heart cases to arrest the heart and keep it preserved during aortic cross-clamping. They are also used as part of a modified ultrafiltration system at the end of cardiopulmonary bypass. We evaluated and compared the air-handling capabilities of different types of blood cardioplegia delivery devices. A simple circuit incorporating a cardiotomy reservoir, a roller pump, a cardioplegia test system, and two emboli detection and classification sensors were used to investigate the air-handling capabilities of the following cardioplegia delivery systems: GISH Vision, Maquet Plegiox, Medtronic Trillium MYOtherm XP, Sorin Group BCD Vanguard, Sorin Group CSC14, and Terumo Sarns Conducer and Bubble Trap. The 0.25-in. circuit was primed with 400mL of Lactated Ringer's. Outdated packed red blood cells were added to obtain a hematocrit of 24-28%. System pressure was maintained at 50mmHg. Air (0.1, 0.3, 0.5mL) was injected at a speed of 0.1mL/s into the circuit just after the pump head. Gaseous microemboli (GME) were measured prior to the cardioplegia system and after the device to evaluate the air-handling characteristics. The tests were run at 100, 200, and 400mL/min blood flow for both 4 and 37°C. There were no significant differences among the groups when comparing precardioplegia delivery system GME, thus demonstrating that all devices received the same amount of injected air. When comparing the groups for postcardioplegia delivery system GME, significant differences were noted especially at the 400mL/min blood flow rate. These results suggest that for the devices compared in this study, the Maquet Plegiox and the Medtronic Trillium MYOtherm XP eliminated GME the best.

Differential immune activation during simulated cardiopulmonary bypass procedure using freshly drawn and week-old blood­a pilot study.

The goal of this study is to assess whether the use of different aged blood, used during the simulated PennState Hershey Pediatric cardiopulmonary bypass (CPB)model affects immune activation. In order to study and compare the cytokine release involved in the humoral immune response during simulated CPB, both freshly drawn whole blood used less than 1 h after donation (n = 2)and reconstituted whole blood (1 week old) (n = 3) were circulated in a simulated CPB circuit under identical perfusion conditions. Discrete samples were collected in both experiments and analyzed for the proinflammatory cytokines concentrations of tumor necrosis factor-alpha, interleukin(IL)-6, and IL-8 using immunofluorocytometry as an indicator of immune activation. The results indicated that the cytokine concentrations of freshly drawn blood increased significantly compared with the reconstituted blood over the CPB circulation time. The fresh blood activation was two to three orders of magnitude larger than the week-old blood for all cytokines analyzed. These results suggest that the use of freshly drawn blood is required to evaluate immune responses to the extracorporeal circulation.

Comparison of perfusion quality in hollow-fiber membrane oxygenators for neonatal extracorporeal life support.

Perfusion quality is an important issue in extracorporeal life support (ECLS); without adequate perfusion of the brain and other vital organs, multiorgan dysfunction and other deficits can result. The authors tested three different pediatric oxygenators (Medos Hilite 800 LT, Medtronic Minimax Plus, and Capiox Baby RX) to determine which gives the highest quality of perfusion at flow rates of 400, 600, and 800 mL/min using human blood (36 degrees C, 40% hematocrit) under both nonpulsatile and pulsatile flow conditions. Clinically identical equipment and a pseudo-patient were used to mimic operating conditions during neonatal ECLS. Traditionally, the postoxygenator surplus hemodynamic energy value (SHE(post), extra energy obtained through pulsatile flow) is the one relied upon to give a qualitative determination of the amount of perfusion in the patient; the authors also examined SHE retention through the membrane, as well as the contribution of SHE(post) to the postoxygenator total hemodynamic energy (THE(post)). At each experimental condition, pulsatile flow outperformed nonpulsatile flow for all factors contributing to perfusion quality: the SHE(post) values for pulsatile flow were 4.6-7.6 times greater than for nonpulsatile flow, while the THE(post) remained nearly constant for pulsatile versus nonpulsatile flow. For both pulsatile and nonpulsatile flow, the Capiox Baby RX oxygenator was found to deliver the highest quality of perfusion, while the Minimax Plus oxygenator delivered the least perfusion. It is the authors' recommendation that the Baby RX oxygenator running under pulsatile flow conditions be used for pediatric ECLS, but further studies need to be done in order to establish its effectiveness beyond the FDA-approved time span.

Evaluation of HL-20 roller pump and Rotaflow centrifugal pump on perfusion quality and gaseous microemboli delivery.

The purpose of this study was to compare the HL-20 roller pump (Jostra USA, Austin, TX, USA) and Rotaflow centrifugal pump (Jostra USA) on hemodynamic energy production and gaseous microemboli (GME) delivery in a simulated neonatal cardiopulmonary bypass (CPB) circuit under nonpulsatile perfusion. This study employed a simulated model of the pediatric CPB including a Jostra HL-20 heart-lung machine (or a Rotaflow centrifugal pump), a Capiox BabyRX05 oxygenator (Terumo Corporation, Tokyo, Japan), a Capiox pediatric arterial filter (Terumo Corporation), and »-inch tubing. The total volume of the experimental system was 700mL (500mL for the circuit and 200mL for the pseudo neonatal patient). The hematocrit was maintained at 30% using human blood. At the beginning of each trial, a 5mL bolus of air was injected into the venous line. Both GME data and pressure values were recorded at postpump and postoxygenator sites. All the experiments were conducted under nonpulsatile perfusion at three flow rates (500, 750, and 1000mL/min) and three blood temperatures (35, 30, and 25°C). As n=6 for each setup, a total of 108 trials were done. The total number of GME increased as temperature decreased from 35°C to 25°C in the trials using the HL-20 roller pump while the opposite effect occurred when using the Rotaflow centrifugal pump. At a given temperature, total GME counts increased with increasing flow rates for both pumps. Results indicated the Rotaflow centrifugal pump delivered significantly fewer microemboli compared to the HL-20 roller pump, especially under high flow rates. Less than 10% of total microemboli were larger than 40µm in size and the majority of GME were in the 0-20µm class in all trials. Postpump total hemodynamic energy (THE) increased with increasing flow rates and decreasing temperatures in both circuits using these two pumps. The HL-20 roller pump delivered more THE than the Rotaflow centrifugal pump at all tested flow rates and temperature conditions. Results suggest the HL-20 roller pump delivers more GME than the Rotaflow centrifugal pump but produces more hemodynamic energy under nonpulsatile perfusion mode.