Linking non‐invasive parametric MRI with invasive physiological measurements (MR‐PHYSIOL): towards a hybrid and integrated approach for investigation of acute kidney injury in rats

Acute kidney injury of various origins shares a common link in the pathophysiological chain of events: imbalance between renal medullary oxygen delivery and oxygen demand. For in vivo assessment of kidney haemodynamics and oxygenation in animals, quantitative but invasive physiological methods are established. A very limited number of studies attempted to link these invasive methods with parametric Magnetic Resonance Imaging (MRI) of the kidney. Moreover, the validity of parametric MRI (pMRI) as a surrogate marker for renal tissue perfusion and renal oxygenation has not been systematically examined yet. For this reason, we set out to combine invasive techniques and non‐invasive MRI in an integrated hybrid setup (MR‐PHYSIOL) with the ultimate goal to calibrate, monitor and interpret parametric MR and physiological parameters by means of standardized interventions. Here we present a first report on the current status of this multi‐modality approach. For this purpose, we first highlight key characteristics of renal perfusion and oxygenation. Second, concepts for in vivo characterization of renal perfusion and oxygenation are surveyed together with the capabilities of MRI for probing blood oxygenation‐dependent tissue stages. Practical concerns evoked by the use of strong magnetic fields in MRI and interferences between MRI and invasive physiological probes are discussed. Technical solutions that balance the needs of in vivo physiological measurements together with the constraints dictated by small bore MR scanners are presented. An early implementation of the integrated MR‐PHYSIOL approach is demonstrated including brief interventions of hypoxia and hyperoxia.     

First 24-h SNAP-II score and highest PaCO2 predict the need for ECMO in congenital diaphragmatic hernia

Background/Purpose

Early clinical predictors for the use of ECMO in patients with congenital diaphragmatic hernia (CDH) are lacking. We sought to evaluate the first 24-h SNAP-II score and highest PaCO₂ as predictors of ECMO support and in-hospital mortality in neonates with CDH.

Methods

Retrospective review of 47 consecutive neonates with CDH admitted to our institution from January 2007 to December 2010 was performed. Covariates of ECMO use including SNAP-II score and highest PaCO₂ within the first 24 h of NICU admission were evaluated.

Results

Of the 47 infants in this study, 24 patients were supported with ECMO. The ECMO group had a higher incidence of pulmonary hypertension, higher PaCO₂, and higher 24-h SNAP-II scores. Only the SNAP-II score and not highest PaCO₂ predicted mortality following multivariate adjustment.

Conclusions

The first 24-h SNAP-II score and highest PaCO₂ may provide some prognostic value in identifying neonates who undergo ECMO support; however neither measure was independently associated with the use of therapy. Only the SNAP-II score was associated with in-hospital mortality following multivariate adjustment. Additional study is needed to validate these results in a larger data set.     

Developmental outcomes of children with congenital diaphragmatic hernia: A multicenter prospective study

Purpose

To determine developmental outcomes and associated factors in patients with congenital diaphragmatic hernia (CDH) at 2 years of age.

Methods

This is a multicenter prospective study of a CDH birth cohort. Clinical and socioeconomic data were collected. Bayley Scales of Infant Development (BSID-III) and Vineland Adaptive Behavior Scales (VABS-II) were performed at 2 years of age.

Results

BSID-III and VABS-II assessments were completed on 48 and 49 children, respectively. The BSID-III mean cognitive, language, and motor scores were significantly below the norm mean with average scores of 93 ± 15, 95 ± 16, and 95 ± 11. Ten percent (5/47) scored more than 2 standard deviations below the norm on one or more domains. VABS-II scores were similar to BSID-III scores with mean communication, daily living skills, social, motor, adaptive behavior scores of 97 ± 14, 94 ± 16, 93 ± 13, 97 ± 10, and 94 ± 14. For the BSID-III, supplemental oxygen at 28 days, a prenatal diagnosis, need for extracorporeal membrane oxygenation (ECMO) and exclusive tube feeds at time of discharge were associated with lower scores. At 2 years of age, history of hospital readmission and need for tube feeds were associated with lower scores. Lower socioeconomic status correlated with lower developmental scores when adjusted for significant health factors.

Conclusion

CDH patients on average have lower developmental scores at 2 years of age compared to the norm. A need for ECMO, oxygen at 28 days of life, ongoing health issues and lower socioeconomic status are factors associated with developmental delays.     

New Generation Extracorporeal Membrane Oxygenation With MedTech Mag‐Lev,a Single‐Use,Magnetically Levitated,Centrifugal Blood Pump: Preclinical Evaluation in Calves

We have evaluated the feasibility of a newly developed single‐use, magnetically levitated centrifugal blood pump, MedTech Mag‐Lev, in a 3‐week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio‐Pump BPX‐80. A heparin‐ and silicone‐coated polypropylene membrane oxygenator MERA NHP Excelung NSH‐R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio‐Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200–240 s. All the MedTech ECMO calves completed the study duration. However, the Bio‐Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO₂ of the oxygenator outlet was higher than 400 mm Hg with the PCO₂ below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma‐free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio‐Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three‐week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag‐Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.     

Single‐Center Experience With Extracorporeal Life Support in 103 Nonpostcardiotomy Patients

Extracorporeal membrane oxygenation (ECMO) has been successfully used to support patients with cardiac arrest failing to respond to conventional cardiopulmonary resuscitation (CPR). Preimplant factors being indicative for success are unknown up to now. The study describes single center experience with special focus on differences between survivors and nonsurvivors. Between 2002 and 2009, 103 patients were supported within the scope of CPR by means of ECMO. Besides primary diagnosis, duration, and outcome, pH, lactate, mean arterial pressure, aspartate aminotransferase, bilirubin, catecholamine dosage, and oxygenation ratio before ECMO, after 2 h, 1 day, and at explantation were analyzed. One hundred three patients (51.2 ± 16 years, 35 women, 68 men) were analyzed. Primary cardiac failure led to CPR in 54%. Duration of support was 4.8 ± 0.6 days. Twenty‐nine (28.1%) patients survived to hospital discharge. On ECMO support, pH, lactate, and mean arterial pressure improved significantly. Catecholamine dosage was significantly reduced after ECMO implantation. Demographic data and primary diagnosis revealed no significant influence on outcome. pH, lactate, creatinine, and bilirubin differed significantly between survivors and nonsurvivors in the course of ECMO support. ECMO support during CPR reliably improves the circulatory and respiratory situation. Considering observed survival critical patient selection is mandatory. Although there are several significant differences between surviving patients and patients with fatal outcome, patient selection turns out to be difficult as clinically relevant factors show only limited predictive value. Future research should focus on better defining a population that may be best of all suited for the use of ECMO support in CPR.     

不同压力高压氧治疗对大鼠神经病理性痛的影响

目的 探讨不同压力高压氧治疗(HBO)对大鼠神经病理性痛的影响.方法 成年雄性SD大鼠24只,采用随机数字表法,将其分为4组(n=6):假手术组(S组)、神经病理性痛组(NP组)、2.O标准大气压高压氧治疗组(HBO2.0组)、2.5标准大气压高压氧治疗组(HBO2.5组).将HBO2.0组和HBO2.5组大鼠置于高压氧舱,以10 kPa/min的速率向舱内匀速加压直至目标压力并保持60 min.然后以10 kPa/min的速率匀速减压至正常大气压.从术后1d开始高压氧治疗,连续5d,1次/d.S组和NP组单纯放入氧舱100 min而不接受治疗.于出高压氧舱后即刻(T0)、1 h(T1)和2 h(T2)时测定机械缩足反应阈(MWT)和热缩足反应潜伏期(TWL).结果 与S组比较,NP组MWT降低,TWL缩短(P＜0.05).与NP组比较,HBO2.0组和HBO2.5组高压氧治疗期间T1时MWT升高,TWL延长(P＜0.05),T2时MWT和TWL差异无统计学意义(P＞0.05).HBO2.0组和HBO2.5组间各时点MWT和TWL比较差异无统计学意义(P＜0.05).结论 不同压力高压氧治疗均可减轻大鼠神经病理性痛,但压力改变不影响镇痛效果.     

48例小儿心脏术后体外膜肺氧合临床结果分析

目的:对阜外医院小儿心脏手术后,不同适应症下实施体外膜肺氧合(ECMO)治疗的效果及并发症情况进行分析,为更好的把握ECMO的临床适应症提出依据。方法:回顾性分析2004年12月至今48例小儿心脏术后ECMO的临床资料。结果:患儿年龄5 d～6岁;体质量3～17 kg。48例中脱离ECMO 30例(62.5%),最终治愈出院24例(50%)。心、肺功能持续不恢复及后期继发的急性肾衰竭是导致死亡的主要原因。结论:适应症的选择及治疗期间的并发症决定了ECMO总体的治疗效果。     

应用体外膜式人工肺氧合治疗体外循环脱机困难38例的临床经验

目的:总结心脏外科术后脱离体外循环机困难的患者接受体外膜式氧合(ECMO)治疗的临床经验。方法:2004年9月至2010年12月北京安贞医院共38例患者行ECMO治疗,男性29例,女性9例,年龄6个月～74岁,ECMO辅助时间6～280 h,平均65 h。结果:ECMO成功脱机20例(52.6%),其中14例(36.8%)痊愈,6例脱机后死亡;18例未能脱机均死亡。结论:ECMO对于体外循环脱机困难患者是一种有效的辅助措施,及早应用并积极防治ECMO并发症可提高院内生存率。     

磁共振成像评价常压高浓度氧对大鼠脑缺血的保护作用

目的利用磁共振弥散加权成像(DWI)评价常压高浓度氧(NBO)对大鼠脑缺血的保护作用。方法选择雄性SD大鼠16只,采用线栓法制作右侧大脑中动脉闭塞脑缺血模型,随机分为NBO组和对照组,每组8只。分别于2 h和24 h行头颅MRI扫描。冠状位DWI测量大鼠的脑梗死体积及增大率;在脑梗死最大层面的表观扩散系数(ADC)图上测量脑梗死中心区和边缘区的ADC值,并计算ADC值的降低率。取脑行HE染色,并与DWI结果进行比较。结果 NBO组与对照组大鼠右侧大脑中动脉供血区异常高信号,ADC图上为低信号。NBO组大鼠2h和24 h脑梗死体积增大率均低于对照组,但差异无统计学意义(P>0.05)。NBO组大鼠2 h和24 h梗死中心区ADC值降低率与对照组差异无统计学意义(P>0.05);而NBO组梗死边缘区ADC值降低率明显小于对照组(P<0.01)。NBO组与对照组大鼠HE染色脑梗死灶与相应DWI层面差异无统计学意义(P>0.05)。结论 DWI显示NBO对大鼠脑缺血有保护作用。     

APACHEⅢ评分及氧合指数对老年重症肺炎预后影响的分析

目的 探讨APACHEⅢ评分与氧合指数对老年重症肺炎预后的影响.方法 56例患者,根据出院是否存活,分为存活组与死亡组,测定动脉血气,计算氧合指数,进行APACHEⅢ评分,分析APACHEⅢ评分与氧合指数对预后的影响.结果 存活组APACHEⅢ评分及氧合指数与死亡组比较,均有显著差异(P＜0.05),死亡组APACHEⅢ评分随住院延长而增高,氧合指数随住院延长而降低,存活组与之相反.氧合指数与APACHEⅢ评分负相关(r=-0.7542,P＜0.01).结论 APACHEⅢ评分与氧合指数有助判断病情危重程度,观察两者变化,对判断预后有一定的作用.