Indoor air pollution and pulmonary performance: investigating errors in exposure assessment

We use pulmonary function measurements on pre-adolescent children and indoor air pollution measurements in the homes of these children to illustrate estimation techniques for linear regression models containing independent variables measured with error. In our data set, replicate measures of indoor air pollutant concentrations provide one method of estimating measurement error variances. Surrogate information in the form of cigarettes smoked is also available for the pollutant of interest. Several estimation procedures are presented, and we combine two estimators, one based on surrogate information and one based on replication information, using generalized least squares.     

垂体高度的断层解剖及MRI测量

目的：通过尸体断层标本和MRI对照测量垂体的高度，为垂体的影像学诊断提供诊断标准、材料和方法：利用35例成人尸体断层标本，在各个断面上测量垂体的高度；在103例成人冠状头颅MRI上测量垂体的高度，并按年龄和性别分为十二组。将断层标本和MRI的测量数据进行比较。结果：在断层标本上测量垂体的平均高度为5．3±0．6（4．0－7．6）mm；MRI上的平均高度为5．4±1．3（4.0－8．3）mm。两组数据比较，无显著性差异（P＞0．05）。男性垂体的平均高度为5．3±1.2（4．0－7．2）mm，女性垂体的平均高度为5．5±1．4（4．0－8.3）mm。女性垂体的平均高度大于男性。各年龄组比较显示，20岁以后，随年龄增长，垂体高度逐渐下降。结论：在MRI诊断中，垂体高度女性≥9mm，男性≥8mm可考虑垂体异常。垂体高度女性大于男性；20岁以后，随年龄增长，垂体高度有逐渐下降的趋势。     

红细胞沉降率IV──红细胞沉降速度测量的原理和方法

本文从理论上提出了红细胞沉降速度的准确概念，阐明了红细胞沉降过程所包含的物理和生理信息，提出了一种新型测量红细胞沉降速度及其它特征参数的方法，并给出了其主体、硬件和软件设计要点。     

蒲氏间隙的高分辨率CT测量

目的:在HRCT图像上测量正常成人蒲氏间隙(Prussak space)的宽度,为胆脂瘤早期诊断提供参考。材料和方法:60例正常成人耳部(男性和女性各30例)做冠状位HRCT扫描,测量锤骨颈外缘至鼓室盾板尖端的距离(相当于蒲氏间隙宽度),并作统计学分析。结果:测量值在1-1.5mm之间,平均1.22±0.098mm。平均值分别为:男性左耳1.193±0.021mm;男性右耳1.227±0.019mm;女性左耳1.213±0.016mm;女性右耳1.233±0.015mm,统计分析显示男女之间和左右耳之间均无明显差异(t=0.255,t=1.137和t=0.845,均P>0.05)。结论:正常成人蒲氏间隙宽度在HRCT图像上约为1-1.5mm,性别与双耳之间无明显差异,此间隙宽度>1.5mm可作为诊断上鼓室胆脂瘤的一个重要依据。     

中国妇女乳房乳晕乳头比例的测定及相关因素分析

目的为塑造自然、匀称而具有美感的乳房提供参考和依据。方法对45例22~45岁、对自己乳房满意且无乳房手术史的女性志愿者,分别测量体重、身高、乳头直径、乳晕直径、胸乳线(乳头至胸骨切迹连线距离)、乳房内侧半径(乳头至乳房下皱襞内侧止点连线距离)、乳房外侧半径(乳头至乳房下皱襞外侧止点连线距离)、乳房下半径(乳头至乳房下皱襞最低点连线距离)。以乳房外侧半径长度作为乳房大小参考指标,由此计算和确定乳房、乳晕、乳头之间的比例,并对可能影响其变化的年龄、体重、身高等因素进行研究分析。结果该组样本显示中国妇女乳房与乳晕之比约为3.7∶1.0,乳晕乳头之比约为3.4∶1.0。体重、体重指数与乳房大小、乳晕乳头比例之间呈正相关,具有显著的统计学意义;而年龄、身高的影响在该样本中并未显现。结论乳房与乳晕、乳头间具有一定的合适比例,体重和肥胖可能是影响该比例关系的因素。乳房、乳晕、乳头比例的确定对东方妇女的乳房整形和再造具有美学价值,可被用于手术中对乳房大小的理想化设计和预测。     

The accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation values in piglets

A piglet model was used to evaluate the accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation (SaO₂) values. In eight anaesthetized piglets, the inspired oxygen concentration was varied from 30% to 6% resulting in a SaO₂ range from 100% to 15%. Paired data of the Opticath® fiberoptic catheter, which was placed in the descending aorta, and blood sample SaO₂ values assessed by a multiwavelength oximeter, were analysed. After in vitro calibration according to the manufacturer's instruction, the fiberoptic catheter started to underestimate the SaO₂ below 78%, worsening towards lower SaO₂ values. The overall bias was -3. 4% and the precision 3. 8%. An off-line fit with a non-linear model resulted in a standard deviation of residuals of 2. 6%. After several in vivo calibration adjustments when the Fiberoptic oximeter deviated more than 4% from the blood sample value, the bias was eliminated over the total SaO₂ range and the precision was 3. 7%. The Opticath® fiberoptic oximeter could have an accuracy for the whole SaO₂ range between 15–100% close to the accuracy of the multiwavelength oximeter, when the fiberoptic oximeter is adapted for the underestimation below 78% SaO₂.     

Can people hear the pitch change on a variable-pitch pulse oximeter?

The introduction of the variable-pitch feature on pulse oximeters in 1983 by the Nellcor Corporation (Hayward, CA) allowed users to rapidly detect changes in oxygen saturation by listening for changes in the pitch of the tones emitted by the pulse oximeter. A few individuals have reported that they have been unable to detect a change in pitch when oxygen saturation changes. To these individuals, the variable-pitch feature of these pulse oximeters has not been beneficial. Using the pitches from one manufacturer of oximeters, we created a computer program to simulate the pitches that accompanied various oxygen saturations. The pitches were recorded onto a tape player and played for 75 volunteer subjects unfamiliar with the pitches of a variable-pitch pulse oximeter. Of our sample, 67% were able to detect a single change in pitch corresponding to a 1% fall in oxygen saturation, and 11% of the population could not detect a change in pitch until there was a change in pitch with every beat. We suggested four alternative designs that may prove beneficial to this group of individuals.     

Measurement of airway resistance in anesthetized and paralyzed subjects: Proposal for evaluation of K1 values

The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflatoins decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K₁ + K₂X. K₁, calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K₂ value of the endotracheal tube used in this study (Portex^® I.D. 8mm, length 26cm) was quite high (5.0cmH₂O·1^–2·sec²), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K₁ measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.(Sakai T, Yoshida H, Yano H et al.: Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K₁ values. J Anesth 2: 139–145, 1988)     

Computerized axial tomo-epidurographic and radiographic documentation of unilateral epidural analgesia

A 23-year-old primigravid patient who received epidural analgesia for pain of labour presented with persistent, apparently irremediable, unilateral analgesia. Computerized axial tomo-epidurography demonstrated absence of circumferential spread due to lateral placement of the catheter. Transforaminal escape of contrast medium into the paravertebral area had occurred and anterior and posterior midline partitioning of the epidural space was obvious. All the usual measures to promote contralateral analgesia, except re-insertion of the catheter, had been tried without success.     

脚压测量用传感器

本文讨论了用于脚压测量的四类压力传感器，电阻式传感器、压电式传感器，光电式传感器，电容式传感器介绍了其结构、原理和特点，并分析了几种典型的测量接口电路。