Analysis of radon reduction and ventilation systems in uranium mines in China.

Mine ventilation is the most important way of reducing radon in uranium mines. At present, the radon and radon progeny levels in Chinese uranium mines where the cut and fill stoping method is used are 3-5 times higher than those in foreign uranium mines, as there is not much difference in the investments for ventilation protection between Chinese uranium mines and international advanced uranium mines with compaction methodology. In this paper, through the analysis of radon reduction and ventilation systems in Chinese uranium mines and the comparison of advantages and disadvantages between a variety of ventilation systems in terms of radon control, the authors try to illustrate the reasons for the higher radon and radon progeny levels in Chinese uranium mines and put forward some problems in three areas, namely the theory of radon control and ventilation systems, radon reduction ventilation measures and ventilation management. For these problems, this paper puts forward some proposals regarding some aspects, such as strengthening scrutiny, verifying and monitoring the practical situation, making clear ventilation plans, strictly following the mining sequence, promoting training of ventilation staff, enhancing ventilation system management, developing radon reduction ventilation technology, purchasing ventilation equipment as soon as possible in the future, and so on.

[The sensitivity and accuracy of RIFLE and AKIN criteria for acute kidney injury diagnosis in intensive care unit patients].

OBJECTIVE: To evaluate the sensitivity/accuracy of 2 different acute kidney injury (AKI) diagnosis/classification criteria, the RIFLE (risk, injury, failure, loss of kidney function, end-stage kidney disease) and the acute kidney injury network (AKIN), for patients in intensive care unit (ICU). METHODS: Clinical data were collected from all adult patients admitted to the Department of Intensive Medicine in Guangdong General Hospital between October 2009 and July 2010, and AKI cases were identified/classified using RIFLE and AKIN criteria separately, for statistical evaluation of their diagnostic sensitivity, and accuracy in hospital mortality prediction. RESULTS: In all 524 patients evaluated, AKI were identified by RIFLE criteria in 95 of them, while by AKIN, 135. The AKI incidence by RIFLE (18.1%), and AKIN (25.8%) were significantly different (P < 0.05). Meanwhile, AKI incidence was found independent from the mortality, either by RIFLE or AKIN (both P < 0.001). In all patients, the area under the receiver operator characteristic curve (ROC curve), the index for hospital mortality prediction, was 0.7293 for RIFLE [with 95% confidence interval (95%CI) ranging from 0.6005 to 0.8581, P < 0.001], and for AKIN, 0.7777 (95%CI: 0.6664 - 0.8890, P < 0.001). No significant difference was found between the total hospital mortality by the two criteria (37.9% vs. 34.1%, P > 0.05). CONCLUSION: Although AKIN criteria has higher sensitivity in AKI diagnosis, it is not different from the RIFLE criteria in predicting hospital mortality in critically ill patients.

[Effect of early postoperative use of ACEI/ARB or diuretics on the incidence of acute kidney injury after cardiac surgery in elderly patients].

OBJECTIVE: To explore the influence of early postoperative use of angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEI/ARB) or diuretics on acute kidney injury (AKI) after cardiac surgery in elderly patients. METHODS: Data from elderly patients (age≥60 years old) who underwent cardiac surgery with extracorporeal circulation in Guangdong General Hospital between January 2007 and December 2010 were analyzed in this retrospective research. The primary endpoint was AKI as diagnosed according to the serum creatinine criteria of RIFLE (risk, injury, failure, loss, end stage renal disease). The baseline serum creatinine was defined as the latest serum creatinine level before cardiac surgery. Multivariate analysis by logistic regression was used to obtain the independent risk factors for AKI. RESULTS: Among 618 elderly patients, 76 (12.3%) patients received ACEI/ARB during early postoperative period, 491 (79.4%) patients were given diuretics during early postoperative period, and postoperative AKI occurred in 394 (63.8%) patients. The incidence of AKI was 46.1% in patients who received early postoperative ACEI/ARB, and 66.2% in patients who did not (P<0.001). Patients who received diuretics postoperatively were less likely to suffer from AKI compared with patients who did not (57.0% vs. 89.8%, P<0.001). After adjustment of other potential factors of postoperative AKI, logistic regression analysis showed that early postoperative use of ACEI/ARB [odds ratio (OR)=0.131, 95% confidence interval (95%CI) 0.033-0.517, P=0.004], and early postoperative use of diuretics (OR=0.149, 95%CI 0.076-0.291, P<0.001) independently predicted the occurrence of AKI. CONCLUSIONS: Early postoperative use of ACEI/ARB or diuretics is associated with a lower incidence of AKI after cardiac surgery with extracorporeal circulation in elderly patients.