Acute kidney injury is a frequent complication in critically ill neonates receiving extracorporeal membrane oxygenation: a 14-year cohort study

Introduction

Newborns in need of extracorporeal membrane oxygenation (ECMO) support are at high risk of developing acute kidney injury (AKI). AKI may occur as part of multiple organ failure and can be aggravated by exposure to components of the extracorporeal circuit. AKI necessitates adjustment of dosage of renally eliminated drugs and avoidance of nephrotoxic drugs. We aimed to define systematically the incidence and clinical course of AKI in critically ill neonates receiving ECMO support.

Methods

This study reviewed prospectively collected clinical data (including age, diagnosis, ECMO course, and serum creatinine (SCr)) of all ECMO-treated neonates within our institution spanning a 14-year period. AKI was defined by using the Risk, Injury, Failure, Loss of renal function, and End-stage renal disease (RIFLE) classification. SCr data were reviewed per ECMO day and compared with age-specific SCr reference values. Accordingly, patients were assigned to RIFLE categories (Risk, Injury, or Failure as 150%, 200%, or 300% of median SCr reference values). Data are presented as median and interquartile range (IQR) or number and percentage.

Results

Of 242 patients included, 179 (74%) survived. Median age at the start of ECMO was 39 hours (IQR, 26 to 63); median ECMO duration was 5.8 days (IQR, 3.9 to 9.4). In total, 153 (64%) patients had evidence of AKI, with 72 (30%) qualifying as Risk, 55 (23%) as Injury, and 26 (11%) as Failure. At the end of the study period, only 71 (46%) patients of all 153 AKI patients improved by at least one RIFLE category. With regression analysis, it was found that nitric oxide ventilation (P = 0.04) and younger age at the start of ECMO (P = 0.004) were significant predictors of AKI. Survival until intensive care unit discharge was significantly lower for patients in the Failure category (35%) as compared with the Non-AKI (78%), Risk (82%), and Injury category (76%), with all P < 0.001, whereas no significant differences were found between the three latter RIFLE categories.

Conclusions

Two thirds of neonates receiving ECMO had AKI, with a significantly increased mortality risk for patients in the Failure category. As AKI during childhood may predispose to chronic kidney disease in adulthood, long-term monitoring of kidney function after ECMO is warranted.     

Investigation of acute lower gastrointestinal bleeding with 16‐ and 64‐slice multidetector CT†

We evaluated the usefulness of 16‐ and 64‐slice multidetector CT (MDCT) in the detection of a bleeding site in acute lower gastrointestinal tract (GIT) haemorrhage by conducting a retrospective study of cases of presumed acute lower GIT haemorrhage imaged with CT in two teaching hospitals in an 11‐month period. The patients underwent contrast enhanced CT using either a 16 or 64 MDCT. No oral contrast was used. One hundred milliliters of non‐ionic intravenous contrast agent was injected at 4.5 mL/s, followed by a 60 mL saline flush at 4 mL/s through a dual head injector. Images were acquired in arterial phase with or without non‐contrast and portal phase imaging with 16 × 1.5 mm or 64 × 0.625 mm collimation. Active bleeding was diagnosed by the presence of iodinated contrast extravasation into the bowel lumen on arterial phase images with attenuation greater than and distinct from the normal mucosal enhancement or focal pooling of increased attenuation contrast material within a bowel segment on portal‐venous images. Further management and final diagnosis was recorded. Fourteen patients and 15 studies were reviewed. CT detected and localized a presumed bleeding site or potential causative pathology in 12 (80%) of the patients. Seven of these were supported by other investigations or surgery, while five were not demonstrated by other modalities. Eight patients had mesenteric angiography, of which only four corroborated the site of bleeding. CT did not detect the bleeding site in three patients, of which two required further investigation and definitive treatment. We propose that MDCT serves a useful role as the initial rapid investigation to triage patients presenting with lower GIT bleeding for further investigation and management.     

Reassessment of cochlear dead regions in hearing-impaired teenagers with severe-to-profound hearing loss

The aim of this study was to reassess cochlear dead regions after an interval of twelve months, using the Threshold Equalising Noise (TEN) test. Thirty-four ears of 24 teenagers (mean age of 14 years) with longstanding severe-to-profound sensorineural hearing impairment were tested. Testing was repeated after an interval of 12 months using the same experimental set-up. A total of eight (23.5%) out of 34 ears changed category on retest: this decreased to two (7.1%) out of 27 ears when the inconclusive category was removed from the analysis. In both of these ears (of the same participant) the criteria were met at a single frequency, and the masked threshold was only 10 dB above the TEN level per ERB_N. When all of the data were examined on a frequency-by-frequency basis, the instances that changed category ranged from 15 to 51%. The range decreased to between 4 and 34% when the inconclusive category was removed from the analysis.     

Catheter-related sepsis in dialysis patients

Sir, Dr Thomson and his colleagues are to be commended for theirrecent work¹ which examines catheter-related-sepsis (CRS) indialysis patients, but I have a few concerns about their analysisand a few comments about their conclusions. While     

异基因供体骨髓细胞胸腺内注射对肠移植大鼠的影响

目的:观察异基因骨髓注射在大鼠小肠移植中的免疫耐受作用。方法:实验于2006-09/2007-03在平凉市第二人民医院及兰州大学第二医院完成。①将大鼠分为空白对照组(Wistar)、同基因移植组(FK344/N)、异基因移植组(Wistar)、骨髓胸腺内注射组(Wistar),空白对照组18只,其余每组18只受体大鼠,供体为18只FK344/N大鼠。除空白对照组外,各组选用供受体大鼠进行全小肠异位移植,骨髓胸腺内注射组在行异基因小肠移植前7d取供体骨髓细胞行受体胸腺内注入,同基因移植组、异基因移植组大鼠不注射异基因骨髓细胞,只进行全小肠移植。②每组大鼠分别于术后3,5,7d观察排斥反应,于各时间点每次处死6只,检测血清可溶性白细胞介素2受体表达,并取出移植肠进行苏木精-伊红染色后观察组织学变化。结果:纳入受体大鼠54只及空白对照组大鼠18只均进入结果分析。①排斥反应:异基因移植组大鼠异位全小肠移植术后3,5,7d可出现典型的轻、中、重度排斥反应,而同基因组和骨髓胸腺内注射组中未出现排斥反应。②可溶性白细胞介素2受体水平:术后3d,同基因移植组、骨髓胸腺内注射组可溶性白细胞介素2受体表达水平高于空白对照组(P<0.01),而第5,7天与空白对照组差异不显著(P>0.05),异基因移植组受体大鼠各时间点血清可溶性白细胞介素2受体表达均高于同基因移植组(P<0.01)。结论:移植术前7d异基因供体骨髓在受体胸腺内注射能显著减少小肠移植后急性排斥反应的发生。血清可溶性白细胞介素2受体的检测可能作为小肠移植急性排斥反应的早期诊断敏感的免疫指标。     

干细胞因子基因cDNA克隆及其在造血干细胞中的表达

目的:克隆人干细胞因子基因cDNA,构建真核表达载体并转导脐带血造血干细胞,观察干细胞因子在造血干细胞中的表达,从而为脐血造血干细胞扩增及移植奠定实验基础。方法:实验于2005-09/12在承德医学院基础医学研究所和湖南师范大学医学院寄生虫病研究室完成。①实验材料:健康胎儿脐带由承德医学院附属医院提供,产妇均签署知情同意书;pcDNA3.1.大肠杆菌E.coliDH5α由本室保存;pUCm-T vector (promega公司);BamHⅠ,XbaⅠ(New England BioLabs公司):②实验方法:无菌收集胎儿脐带,胶原酶 胰蛋白酶 乙二胺四乙酸联合消化,分离培养人脐带内皮细胞。从上述含脐带内皮细胞的培养液中分离提取干细胞因子mRNA,用反转录-聚合酶链反应扩增干细胞因子cDNA.纯化的PCR产物与载体pUCm-T加入连接反应体系,构建及克隆pUCm-T/SCF质粒,其与pcDNA3.1分别进行BamHⅠ、XbaⅠ双酶切反应,产物经琼脂糖凝胶电泳后回收干细胞因子cDNA和pcDNA3.1片段,构建真核表达型载体pcDNA3.1/SCF。以密度梯度法 免疫磁珠法分离收集人脐血CD34~ 造血干细胞.导入pcDNA3.1/SCF,设立未转导对照组。③实验评估:转导后1～7 d检测两组细胞上清液中干细胞因子水平的表达。结果:①人于细胞因子基因cDNA克隆:扩增的人干细胞因子基因cDNA理论上应为690 bp,实际PCR产物经琼脂糖凝胶电泳后,紫外线下可见-预期大小的条带,证明干细胞因子mRNA提取成功,反转录合成的cDNA完整。②分泌型真核表达质粒pcDNA3.1/SCF的构建:BamHⅠ和XbaⅠ双酶切后电泳可见690 bp的插入片段,与干细胞因子基因序列相同,表明分泌型真核表达质粒pcDNA3.1/SCF构建成功。③脐血造血干细胞培养上清中的干细胞因子水平:培养第1～7天.转导pcDNA3.1/SCF的脐血造血干细胞上清中的干细胞因子表达水平均明显高于未转导对照组(P<0.01)。结论:成功克隆人干细胞因子基因cDNA,并构建了重组质粒pcDNA3.1/SCF,该质粒转导脐血造血干细胞后.能在短期内有效表达。     

Current UK practice in emergency laparotomy

Introduction

Emergency laparotomy is a common procedure, with 30,000–50,000 performed annually in the UK. This large scale study reports the current spectrum of emergency laparotomies, and the influence of the surgical procedure, underlying pathology and subspecialty of the operating surgeon on mortality.

Methods

Anonymised data on consecutive patients undergoing an emergency laparotomy were submitted for a three-month period. The primary outcome measure was unadjusted 30-day mortality. Appendicectomy and cholecystectomy were among the procedures excluded.

Results

Data from 1,708 patients from 35 National Health Service hospitals were analysed. The overall 30-day mortality rate was 14.8%. ‘True’ emergency laparotomies (ie those classified by the National Confidential Enquiry into Patient Outcome and Death as immediate or urgent) comprised 86.5% of cases. The mortality rate rose from 8.0% among expedited cases to 14.3% among urgent cases and to 25.7% among laparotomies termed immediate. Among the most common index procedures, small bowel resection exhibited the highest 30-day mortality rate of 21.1%. The presence of abdominal sepsis was associated with raised 30-day mortality (17.5% in the presence of sepsis vs 12.6%, p=0.027). Colorectal procedures comprised 44.3% and within this group, data suggest that mortality from laparotomy may be influenced by surgical subspecialisation.

Conclusions

This report of a large number of patients undergoing emergency laparotomy in the UK confirms a remarkably high mortality by modern standards across the range. Very few pathologies or procedures can be considered anything other than high risk. The need for routine consultant involvement and critical care is evident, and the case distribution helps define the surgical skill set needed for a modern emergency laparotomy service. Preliminary data relating outcomes from emergency colonic surgery to surgical subspecialty require urgent further study.     

Cardiopulmonary exercise testing as a predictor of complications in oesophagogastric cancer surgery

Introduction

An anaerobic threshold (AT) of <11ml/min/kg can identify patients at high risk of cardiopulmonary complications after major surgery. The aim of this study was to assess the value of cardiopulmonary exercise testing (CPET) in predicting cardiopulmonary complications in high risk patients undergoing oesophagogastric cancer resection.

Methods

Between March 2008 and October 2010, 108 patients (83 men, 25 women) with a median age of 66 years (range: 38–84 years) underwent CPET before potentially curative resections for oesophagogastric cancers. Measured CPET variables included AT and maximum oxygen uptake at peak exercise (VO₂ peak). Outcome measures were length of high dependency unit stay, length of hospital stay, unplanned intensive care unit (ICU) admission, and postoperative morbidity and mortality.

Results

The mean AT and VO₂ peak were 10.8ml/min/kg (standard deviation [SD]: 2.8ml/min/kg, range: 4.6–19.3ml/min/kg) and 15.2ml/min/kg (SD: 5.3ml/min/kg, range: 5.4–33.3ml/min/kg) respectively; 57 patients (55%) had an AT of <11ml/min/ kg and 26 (12%) had an AT of <9ml/min/kg. Postoperative complications occurred in 57 patients (29 cardiopulmonary [28%] and 28 non-cardiopulmonary [27%]). Four patients (4%) died in hospital and 21 (20%) required an unplanned ICU admission. Cardiopulmonary complications occurred in 42% of patients with an AT of <9ml/min/kg compared with 29% of patients with an AT of ≥9ml/min/kg but <11ml/min/kg and 20% of patients with an AT of ≥11ml/min/kg (p=0.04). There was a trend that those with an AT of <11ml/min/kg and a low VO₂ peak had a higher rate of unplanned ICU admission.

Conclusions

This study has shown a correlation between AT and the development of cardiopulmonary complications although the discriminatory ability was low.