DIALYSIS AND THE ENVIRONMENT: COMPARING HOME AND UNIT BASED HAEMODIALYSIS

Dialysis, with its high dependence upon technology, disposable products and transport requirements, presents an unusual perspective for environmental management. This study considers and compares the environmental aspects arising from the provision of haemodialysis (HD) in the hospital and home setting. Resource items were measured at two levels of aggregation — unit and individual patient. Unit level items applied to common resources used for HD and require apportioning appropriately with patient level items that could be attributable to individuals. The data was measured in standard units such as hours and number of treatments or apportioned appropriately. With equivalent emissions calculated as CO₂ annually per patient for standard HD. The findings indicate that HD in the home offers a net reduction in CO₂ emissions per patient annually compared to hospital based HD, and provides an overview of how healthcare provision and the use of resources can be measured, enabling refinement in environmental management plans.     

DPOAE对系统性低血压患者的耳蜗功能监测及其临床意义

目的用畸变产物耳声发射(distortion-product otoacoustic emission,DPOAE)来观察系统性低血压和慢性进行性听力损伤的关系。方法实验组为34例体检中发现的系统性低血压患者(诊断标准:舒张压<60mmHg,收缩压<90mmHg),对照组由年龄、性别相匹配的30例正常人组成,两组在同一实验室中进行了生化、心血管、耳鼻咽喉专科和纯音测听、声阻抗、DPOAE等听力学检查。将两组的各项结果进行比较。结果实验组DPOAE听力图结果显示16例患者有一个以上频率轻到中度的听力损伤,主要在低频范围。与对照组相比,实验组的DPOAE幅值在一个以上的频率低下甚至缺失。结论系统性低血压有可能是导致耳蜗功能损伤的因子之一,而DPOAE可作为早期监测此类患者耳蜗功能损伤情况的有效工具。     

The effects of anesthesia on otoacoustic emissions

We have measured transient-evoked and distortion-product otoacoustic emissions (OAEs) in the chinchilla and compared them in the awake and anesthetized animal (using either ketamine or barbiturate agents). We report a significant increase in OAE amplitudes during anesthesia, particularly using ketamine. These effects are most evident for transient-evoked otoacoustic emissions (TEOAEs) as measured in the non-linear mode. Our data support the hypothesis that tonic activity levels in cochlear efferents may be reduced by anesthetic effects, either directly or indirectly (e.g., by general reductions in descending pathway activity), and that reduced cochlear efferent activity will result in the observed increase of OAE amplitudes.     

一种用ICA去除瞬态诱发耳声发射伪迹的新方法

如何去除伪迹是瞬态诱发耳声发射检测中一个关键的问题。本研究提出了一种用ICA去除伪迹的新方法。首先用四组线性增长的刺激声在耳道内录音 ,得到的波形是瞬态诱发耳声发射和伪迹的混叠。因为伪迹和瞬态诱发耳声发射是统计独立的 ,而且伪迹随刺激声的变化线性增长 ,而瞬态诱发耳声发射随刺激声的变化非线性增长 ,逐渐趋于饱和 ,所以它们在混叠信号中具有不同的混叠系数。用ICA算法可以将各独立分量及混叠矩阵估计出来 ,伪迹是其中的一个独立分量。然后将伪迹的波形置零后再进行一次混叠 ,便达到了去除伪迹的目的。最后通过与传统的DNLR方法比较 ,证明这种方法是有效的     

Adaptive Wiener Filtering for Improved Acquisition of Distortion Product Otoacoustic Emissions

An innovative acoustic noise canceling method using adaptive Wiener filtering (AWF) was developed for improved acquisition of distortion product otoacoustic emissions (DPOAEs). The system used one microphone placed in the test ear for the primary signal. Noise reference signals were obtained from three different sources: (a) pre-stimulus response from the test ear microphone, (b) post-stimulus response from a microphone placed near the head of the subject and (c) post-stimulus response obtained from a microphone placed in the subjects nontest ear. In order to improve spectral estimation, block averaging of a different number of single sweep responses was used. DPOAE data were obtained from 11 ears of healthy newborns in a well-baby nursery of a hospital under typical noise conditions. Simultaneously obtained recordings from all three microphones were digitized, stored and processed off-line to evaluate the effects of AWF with respect to DPOAE detection and signal-to-noise ratio (SNR) improvement. Results show that compared to standard DPOAE processing, AWF improved signal detection and improved SNR. © 1998 Biomedical Engineering Society. PAC98: 4364Jb, 4360-c, 8790+y     

慢性肾功能衰竭患者畸变产物耳声发射分析

测定２１例（４２耳）慢性肾功能衰竭（ＣＲＦ）患者的畸变产物耳声发射（ＤＰＯＡＥ）。结果表明：ＣＲＦ患者的耳聋 为耳蜗性聋,表现为高频听力损失,ＤＰＯＡＥ检测可客观、快速地反映耳蜗的病变。且ＤＰＯＡＥ具有频率特异性,有助于对该病患者听力障碍的早期诊断。     

遗传性无综合征耳聋一家系畸变产物耳声发射测试

目的　探索遗传性进行性无综合征耳聋患者的听功能改变特点。方法　一个常染色体显性遗传进行性无综合征耳聋家系 5 2名成员及听力正常组 15名 ,进行了纯音测试及畸变产物耳声发射 (distortionproductotoacousticemissions,DPOAE)测试。结果　无综合征耳聋家系中 34名成员纯音测试为感音神经性聋 ,其中纯音听阈均值 (puretoneaverage ,PTA)≥ 40dB的 15例 (2 9耳 )DPOAE反应缺失 ,PTA≤ 35dB伴高频下降的 12例 (2 3耳 )DPOAE高频或高、中频振幅下降或缺失 ;2 1名 (42耳 )纯音听阈正常成员中 ,有 12例 (15耳 )DPOAE高频或高、中频振幅下降或缺失。结论　DPOAE能鉴别出耳蜗亚临床的病理改变 ,对该病的早期诊断 ,遗传咨询有指导意义。     

Transient decrease in sound tolerance levels following hearing deprivation in normal-hearing subjects

ObjectiveTo determine the circadian influence on sound sensitivity produced by temporal hearing deprivation in healthy normal human subjects.DesignParticipants underwent bilateral earplugging before completion of anthropometry, the author's developed questionnaire, the Hamilton Anxiety and Depression Inventory, pure tone audiometry (PTA), stapedial reflex thresholds (SRT), distortion products otoacoustic emissions input/output (DPOAE-I/O), and uncomfortable loudness levels (ULLs). Afterward, the participants were randomly divided into group A, starting at 8:00 a.m. and finishing at 8:00 p.m., and group B, starting at 4:00 p.m. and ending at 4:00 a.m. Serum cortisol levels and audiological test results were obtained at the beginning and end of the session and 24-h free urinary cortisol levels were measured.Study sampleThirty healthy volunteers.ResultsPTA was 2.68 and 3.33 dB HL in groups A and B, respectively, with no statistical difference between them. ULLs were significantly lower in group A compared to group B, with an average of 8.1 dB SPL in group A and 3.3 dB SPL in group B (p < 0.0001). A SRT shift was observed in group A, with no difference in group B, and a night shift in DPOAE-I/O in group B.ConclusionsReduced loudness tolerance is demonstrated during daytime hearing deprivation in contrast to nighttime; this may be due to increased central gain in the awake cortex.     

215例正常新生儿瞬态诱发耳声发射测试分析及随访研究

目的：进一步了解正常新生儿瞬态诱发耳声发射（TEOAE）的特征，为新生儿听力筛查提供帮助。方法：采用ILO96型耳声发射仪，对出生后0（出生当天）-8d的215例（425耳）正常新生儿进行TEOAE测试，并跟踪随访结果：TEOAE总检出率为89%，检出率与检测时的天龄有一定的关系。新生儿出生后0-3d检出率平均为72%，4-8d为97%，分娩方式，左右耳，孕龄36至41周间的差异对检出率无明显影响；女性的检出率显著高于男性，快速扫描较TEOAE测试敏感，经随访确诊有1耳听力损害。结论：新生儿听力筛查应在出生后≥4d出院前进行；分娩方式对耳蜗功能无明显影响；人耳蜗毛细胞的成熟是在怀孕36周以前；快速扫描不能代替TEOAE测试；对于1耳或双耳未检出TEOAE的受测者必须跟踪随访和复检，并结合ABR测试尽早确诊。