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At least 811 records · Page 45Linked to original sources
PubMed1987

[Acoustically evoked brain stem potentials. Prerequisites for clinical use, data quality and sources of error].

Ninety patients were subjected to brain-stem auditory evoked potential (BAEP) measurements in the intensive care unit. The data are analyzed and discussed with respect to their quality, reliability, and reproducibility. BAEPs of a quality satisfactory for diagnosis were found in 90% of the patients. About 10% of the measurements were distorted by artifacts and could not be used for diagnostic purposes. Reasons for these artifacts and problems of interpretation are discussed. Examples of single BAEPs and on-line monitoring of BAEPs in the form of "compressed BAEPs" are shown.

Adolescent↗
PubMed1986

[Contact gel as a source of error in roentgen images of the skull].

This paper sounds a note of warning in respect of simulation of non-existent osseous densifications or calcifications on x-ray film due to the use of contact gels that are common in sonography and electro-encephalography for the fixation of leads. If lumps of these gels adhere to the scalp, especially to the hair of the head and thus remain unnoticed, their roentgenographic density will falsify the subsequent x-ray (for example, marginal calcifications are simulated that are not necessarily visualised on the second plane).

Bone Diseases, Developmental↗
PubMedDate not supplied

Peritoneal washings in ovarian tumors. Potential sources of error in cytologic diagnosis.

Peritoneal washings were performed on 48 patients with suspected or known ovarian carcinoma. The procedure was part of the initial surgical staging in 27 patients with presumed stage I and II ovarian cancer and was performed during second-look operations in 21 other cases with proven ovarian malignancy. This paper presents the microscopic features of the washings, with particular emphasis on the cytologic differentiation between benign and malignant findings outside of the ovary. Thirty-four cases showed benign or reactive mesothelial cells and no evidence of peritoneal disease. The washings of six patient showed malignant cells, which were confirmed histologically. Notable atypia that mimicked ovarian carcinoma was found in eight patients who had benign or borderline lesions. These findings included papillary and glandlike epithelial structures, with varying degrees of cellular atypia and psammoma bodies. The histologic counterparts of these atypicalities were Müllerian inclusions, mesothelial proliferations and borderline serous tumors. The differential diagnosis between these entities is essential because false-positive cytologic diagnoses may alter postoperative treatment in some patients.

Adenocarcinoma↗
PubMed1985

The scored tablet--a source of error in drug dosing?

To determine the weight deviation of scored tablets after breaking we took 100 tablets of each of 34 brands of commercially available antihypertensive drugs and broke them into two, using the scored line. We graded the weights of the tablet halves according to their deviation from the expected weight (1 = less than or equal to +/- 5%, 11 = +/- 6-10%, 111 = greater than or equal to +/- 10%). The brands were ranked by the proportion of tablet halves (n = 200) in each category. Only seven brands divided very accurately and 11 brands divided reasonably accurately. Despite the scored line the remainder were either moderately (n = 10) or absolutely (n = 6) unsuitable for breaking, by hand or otherwise. A high proportion of these tablet halves showed weight deviations of 6-10% or more than 10% when compared to the expected weight. These findings show that a great number of antihypertensive drugs do not break evenly despite a scored line. This leads to inaccuracy of dosage.

Antihypertensive Agents↗
PubMed1986

Evaluation of blood glucose measurement techniques: locating sources of error.

Researchers evaluating the accuracy of rapid blood glucose monitoring (RBGM) techniques have often concluded that RBGM was sufficiently accurate for clinical use. However, investigators of patients' use of RBGM have more often reported unacceptable levels of accuracy and have shown individual differences between patients in the level of accuracy attained. Responsibility for excessive errors has commonly been attributed to patients' inadequacy in using RBGM. The logic of such attributions is questioned. Data are presented which indicates that errors attributed to patient inaccuracy may actually be due to (a) inaccuracy of reference blood glucose determinations used to evaluate patients' accuracy and (b) variable accuracy of RBGM techniques dependent on the range of blood glucose levels: some patients may appear to be less accurate than others simply because their blood glucose levels fall into a range less accurately measured by the RBGM technique. Furthermore, data presented reveal batch to batch variation in accuracy of the particular reagent strips used. Such variation between batches may help to account for inconsistencies between RBGM evaluation studies in which apparently identical reagent strips were used.

Autoanalysis↗
PubMed1985

[Protein binding of thromboxane--one of the sources of error in thromboxane determination].

The determination of thromboxane A2 (TxA2), the main metabolite of arachidonic acid (AA) in platelets, is very difficult due to extreme instability of this compound. Only stable end products such as TxB2, the hydrolysis product of TxA2, and malondialdehyde (MDA) can be analysed by means of routine techniques. Since the presence of proteins interferes with the photometric determination of MDA, these have to be eliminated by acidification. The TxB2 concentration was measured in the supernatant in parallel with MDA determinations before and after protein precipitation. A significant difference was found between these two TxB2 concentrations. The TxB2 values after precipitation were significantly lower than before precipitation, indicating that a high percentage (about 70%) of TxB2 is bound to proteins. Protein precipitation in a biological sample might, thus, cause misinterpretation of the measured value.

Blood Platelets↗
PubMed1977

[Sources of error in the preparation and interpretation of echocardiograms (author's transl)].

Diagnostic ultrasound is able to provide important information on cardiac structure and motion. Diagnostic errors and misinterpretations however are not uncommon, due to the manner in which data are acquired and recorded during the echocardiographic examination. This paper discusses the characteristic echocardiographic patterns of a variety of important changes in the mitral valve, the left ventricle, and the interventricular and interatrial septum as well as the influence of respiration on the performance of echocardiography. Essential pitfalls in establishing a correct diagnosis in each of these conditions are emphasized and supported by illustrations.

Cardiomyopathy, Hypertrophic↗