Twenty-four-hour venoarterial extracorporeal membrane oxygenation without systemic heparinization in dogs

Venoarterial extracorporeal membrane oxygenation (ECMO) was performed in five dogs without systemic heparinization to assess the feasibility of heparin-free ECMO. The surfaces of the inverted hollow-fiber-type oxygenator and circuit of the ECMO system were coated with heparin by the endpoint-attached (covalent-bonded) technique. No heparin was administered to the animal except for a small dose to maintain patency of the arterial line (1 IU/h). ECMO was run for 24 h at a pump flow of 50 ml/kg · min and was successful throughout the experiment in four of the five dogs. Scanning electron microscopy did not detect any blood clots in the oxygenator or circuit except for inside and outside the cannulas that were not coated with heparin in the carotid artery and jugular vein. Activated clotting time (ACT), fibrinogen, and anti-thrombin III (AT-III) activity remained within the normal physiological range. Serum heparin concentrations were low throughout the experiment, indicating minimal heparin release. Platelet levels decreased and fibrinopeptide B 15–42 (FPB 15–42) increased significantly after 6 h ECMO. D-dimer levels did not change throughout the experiment. ECMO was discontinued in one case after successful a 23-h run because of macroscopic clot formation at the oxygenator blood inlet. ACT had suddenly increased to 160 s approximately 1 h prior to this clot formation. These results suggest that the amount of systemic heparinization required can be substantially reduced by a heparin-coated ECMO system. Total abolishment of heparin administration in pediatric venoarterial ECMO may be possible by refinement of this technique. Monitoring of AT-III and FPB 15–42 in addition to ACT may be useful for early diagnosis of latent but ongoing coagulopathies during ECMO.     

How often is extracorporeal membrane oxygenation needed in cases of congenital diaphragmatic hernia?

Some newborns with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension cannot be saved by conventional treatment and may obtain some benefit from extracorporeal membrane oxygenation (ECMO) as a bridging measure until adequate hematosis is possible. Early prediction of the insufficiency of optimal assistance is still unclear; we reviewed our recent experience with CDH patients in an attempt to evaluate the real need for ECMO in our institution. Between 1987 and 1994, 47 newborns with CDH manifested in the first 24 h were treated with maximal ventilatory assistance (including high-frequency ventilation in 12 cases) and vasoactive drugs prior to surgical repair. In order to summarize the ventilatory and blood-gas parameters, we determined oxygenation index (OI) and ventilatory index (VI) and compared the results in survivors and nonsurvivors. Overall survival was 60% (2 cases of Fryns' syndrome were excluded from analysis). OI was 10.3±5.7 (mean ± SD) for survivors and 46.2 ± 37.8 for nonsurvivors (P < 0.01). VI was 460.9±303 and 1,532±500.6, respectively (P <0.01). Bayesian analysis and receiver operating characteristic curves enabled us to select a threshold value of OI of 20 as the best means of predicting survival in our current conditions (sensitivity: 0.7, specificity: 0.83). The generally accepted figure of 40 had a sensitivity of 1 but a specificity of only 0.44. For VI, the best threshold value was 1,100 (sensitivity: 0.93, specificity: 0.94), whereas the generally used figure of 1,000 had 0.89 and 1, respectively. According to our results, with our current management conditions, approximately 50% of our CDH patients might have obtained some benefit from ECMO.     

The effect of separate red blood cells on capillary tissue oxygenation calculated with a numerical model

Author to whom correspondence should be addressed In simplified models that describe large quantities of capillariesthe capillary content is considered to be homogeneous for oxygentransport; but, in reality, the capillaries contain discretered blood cells (RBCs), and this discreteness will affect oxygentransport from the capillary to the tissue. This was previouslyinvestigated with an analytical model, where RBCs were modelledas point-like sources. A numerical approach is used in thisinvestigation, and the results are compared with the analyticalmodel. In both models the effect of the particulate nature ofblood depends on the haematocrit and on the RBC velocity. Thereis only a minor difference between the two models. For rat hearts,the correction factor used in this study, the extraction pressure,can be up to 3 kPa (23 mmHg).     

Dopamine,dopexamine and dobutamine in liver transplant recipients: a comparison of their effects on hemodynamics,oxygen transport and hepatic venous oxygen saturation

The purpose of this study was to determine the effects of vasoactive treatment with dopamine (DO), dopexamine (DX), and dobutamine (DOB) on hemodynamics, oxygen transport and hepatic venous oxygen saturation (SvhO₂) after orthotopic liver transplantation (OLT). A pulmonary artery catheter was inserted into the right hepatic vein of 17 OLT patients. Timed infusion of DO, DX, and DOB was performed at the following rates: DO at 4 and 8 g/kg per minute, and DOB at 5 and 10 g/kg per minute. Hemodynamics, oxygen transport variables, and SvhO₂ were assessed. Each catecholamine induced a significant increase in cardiac index, oxygen delivery, and SvhO₂. Mean arterial pressure was increased during DO and DOB, but significantly reduced during DX. Each inotrope increased oxygen delivery in parallel with SvhO₂, suggesting a corresponding increase in hepatic oxygen supply. Therefore, it appears that each vasoactive drug may be utilized in OLT patients to provide oxgen delivery without impairment of splanchnic oxygenation.     

Effects of synchronous pulsatile extracorporeal membrane oxygenation in an endotoxin-induced shock model: an experimental study

A synchronous pulsatile venoarterial device for extracorporeal membrane oxygenation (ECMO) was designed to accomplish more effective circulatory support for neonates. The effect of this device was studied using an endotoxin-induced shock model, compared with conventional nonpulsatile ECMO. Twenty puppies weighing 1.6 to 4.0 kg were given endotoxin (5 mg/kg) intravenously. Thirty minutes after the administration of endotoxin, 10 were placed on pulsatile ECMO, and the others were placed on nonpulsatile ECMO, and they were studied for an additional 180 min. Peak blood pressure, arterial pH, base excess, and renal blood flow were significantly higher in the pulsatile group than in the nonpulsatile group. Serum lactate and serum noradrenaline were significantly lower in the pulsatile group than in the nonpulsatile group. These results indicate that pulsatile ECMO may provide more effective cardiopulmonary support in the treatment of neonates with serious circulatory failure that has failed to be supported by nonpulsatile ECMO.     

高压氧治疗小儿病毒性脑炎肢体运动障碍42例疗效分析

目的观察高压氧综合治疗对小儿病毒性脑炎肢体运动障碍恢复的临床效果。方法将82例小儿病毒性脑炎肢体运动障碍患儿随机分为治疗组42例和对照组40例,进行比较观察。采用Fugl—Meye积分评价运动功能,Ashworth痉挛等级评价肌痉挛。结果治疗组有效率95．2％,对照组有效率67．5％,两组疗效差异有统计学意义,治疗组治疗后患儿肢体运动障碍恢复率明显提高。结论高压氧综合治疗对小儿病毒性脑炎肢体运动障碍恢复疗效优于单纯药物治疗。     

局部脑组织氧饱和度监测在新生儿生后早期的应用价值

局部脑组织氧饱和度(regional cerebral oxygenation,rSO2)监测的应用范围很广,不受温度和搏动血流影响,是一种监测脑组织氧合状态的新方式,但目前在新生儿方面的研究较少.本文针对不同病理状况对新生儿生后早期rSO2的影响进行综述,阐明新生儿rSO2监测的重要临床意义并对其未来应用范围进行展望.     

Predictors associated with mortality of extracorporeal life support therapy for acute heart failure: single-center experience with 679 patients

BackgroundExtracorporeal life support (ECLS) therapy is increasingly used for cardiac and respiratory support postcardiotomy, refractory cardiogenic shock and cardiopulmonary resuscitation. This study aims to describe in-hospital mortality of patients requiring ECLS, identify independent predictors associated with mortality and analyze changes of mortality over time.MethodsThis retrospective study includes all adult ECLS cases at the University Hospital Zurich, a designated ECLS center in Switzerland, in the period 2007 to 2019.ResultsECLS therapy was required in 679 patients (median age 60 years, 27.5% female). In-hospital mortality was 55.5%. Cubic spline interpolation did not detect evidence for a change in mortality over the whole period of 13 years. In-hospital mortality significantly varied between ECLS indications: 70.7% (152/215) for postcardiotomy, 67.9% (108/159) for cardiopulmonary resuscitation, 47.0% (110/234) for refractory cardiogenic shock, and 9.9% (7/71) for lung transplantation and expansive thoracic surgery (P<0.001). Logistic regression modelling showed excellent discrimination in the receiver operating characteristic (ROC) area under the curve (AUC) of 0.89 [95% confidence interval (CI): 0.87–0.92] and identified significant mortality predictors: age, simplified acute physiology score (SAPS) II, as well as new liver failure and each allogenic blood transfusion unit given per day. ECLS after cardiopulmonary resuscitation was associated with significantly higher mortality compared to ECLS for refractory cardiogenic shock.ConclusionsIn-hospital mortality of patients treated with ECLS therapy is high. Outcomes have not changed significantly in the observed period. We identified age, SAPS II, new liver failure and each allogenic blood transfusion unit given per day as independent mortality predictors. Knowledge of predictors strongly associated with in-hospital mortality may affect future decisions about ECLS indications and the respective management to use this elaborate therapy more effectively.     

Ablación de taquicardia ventricular asistida con ECMO. Primera experiencia en nuestra institución

Catheter ablation is useful for reducing drug refractory ventricular tachycardia (VT) episodes and can be life-saving when VT is incessant or arrhythmic storm. Left ventricular hemodynamic support may be required in patients with VT and hemodynamic instability. Extracorporeal membrane oxygenation (ECMO) support is an alternative to achieve ventricular tachycardia mapping and ablation over long periods of time. We present a case of successful catheter ablation of substrate in a patient with ischemic heart disease and ventricular tachycardia with hemodynamic instability performed using venous- arterial ECMO support. There were not episodes of ventricular tachycardia after 2 years of follow-up.