Informed consent for epidural analgesia in labour: a survey of UK practice.

Anaesthetists are legally obliged to obtain informed consent before performing regional analgesia in labour. A postal survey of consultant-led UK anaesthetic units was performed in September 2007 to assess practice regarding obtaining informed consent before inserting an epidural, and documentation of the risks discussed. The response rate was 72% (161/223). There was great variation between units regarding which risks women were informed about and the likely incidence of that risk. One hundred and twenty-three respondents out of 157 providing an epidural service (78%) supported a national standardised information card endorsed by the Obstetric Anaesthetists' Association, with all the benefits and risks stated, to be shown to all women before consenting to an epidural in labour.

Characterisation and evaluation of external quality assessment scheme serum. Discussion paper from the European External Quality Assessment (EQA) Organisers Working Group C.

This work reviews the procurement, specification and manufacture of serum for external quality assessment (EQA) and provides a checklist for scheme organisers. Guidance on the assessment of commutability and notes on the use of EQA materials to assess assay problems are provided. The importance of the appropriateness of materials in respect of scheme design and objectives, and the essential nature of a detailed specification prior to manufacture are emphasised.

Current stage of standardization of measurements of specific polypeptides and proteins discussed in light of steps needed towards a comprehensive measurement system.

We present a standardization model for the measurement of specific polypeptides and proteins, which is based on an integrated development of all important elements of a reference measurement system. Generally, the model is in line with other current recommendations. However, it puts special emphasis on the definition of the analyte and on the role of reference methods for verification of the standardization process by measurement of patient specimens. Further, we discuss the needs for its implementation in the routine laboratory. In the light of this model, we investigate the current stage of standardization of routine methods for enzymes, peptide hormones, proteins, apolipoproteins, glycohaemoglobin, and tumour markers.

Analytical specifications of reference methods compilation and critical discussion (from the members of the European EQA-Organizers Working Group B).

We present a compilation of published data for accuracy, precision, and measurement design for analytes that, currently, are of major interest for European reference laboratories. These data are compared with recent recommendations for performance of reference methods to be used within networks of European reference laboratories. In addition, we review the literature on reference methods and related topics.

Analytical quality specifications for reference methods and operating specifications for networks of reference laboratories. discussion paper from the members of the external quality assessment (EQA) Working Group B1) on target values in EQAS.

The aim of the Working Group was to describe guidelines for the establishment of networks of reference laboratories. The need for such networks to achieve an accuracy-based uniform measurement system with traceability of results of analytical systems/test-kits to the true value is outlined. Criteria for analytical quality specifications, which are related to the ultimate purpose of the reference method and thereby to the objectives of the networks, are emphasized. The group recommends the use of two models: one based on specifications for routine methods, which are dictated by the biological variations of the respective analytes, the second respecting the analytical state-of-the-art of reference methodology. Further, the group presents operating specifications for networks that guarantee the continuous performance of reference method measurements whilst maintaining a uniform and stable level of quality.

Standardization of hapten immunoprocedures: total cortisol.

The broad objectives of this report are to enhance the clinical utility of the results of hapten measurement immunoprocedures by encouraging standardization of the procedures. It was decided to restrict the subject of the report to one analyte, and cortisol was chosen because of its diagnostic importance, the need for improved comparability with routine procedures, and its relevance to many other analytes. Therefore, the immediate objectives are to improve the clinical utility of total serum cortisol concentrations measured on different occasions and in different laboratories, to make diagnostic reference intervals more reliable and widely applicable, and to improve diagnostic accuracy by: Improving the agreement between results from reference measurement procedures and the results obtained with normal routine immunoprocedures for the measurement of total serum cortisol, and hence the comparability of routine results; and Reducing the susceptibility of the immunoprocedures to crossreactivity and interference. It is recognized that good comparability of results depends on procedures which are specific, properly calibrated and validated, and that the most important factors are resistance to crossreactants and interferants. Analytical goals for cortisol immunoprocedures are zero bias for 'all' samples with respect to a reference procedures, with the total analytical standard deviation equal to, or less than, half the within-individual standard deviation for cortisol, or 7.6% according to a recent estimate. To these ends the group proposes the following measures: 1. An international network of reference laboratories for cortisol measurement should be established, and progressively developed to include other hapten analytes. The service of the participating laboratories would be necessary to make feasible other recommendations listed below. 2. Procedures should be comprehensively validated, including a thorough crossreactivity study with the results presented to indicate the possible significance of each crossreactivity, a direct comparison of results with those obtained by a reference procedure for an adequate number of varied fresh/frozen patient samples, and suitable clinical validation studies. 3. External quality assessment schemes should assess participating laboratory performance against reference procedure values, and not consensus values related to values determined by any group of participating procedures. They should also assess the ability to determine added standard and to resist common interferants. 4. Master calibrators for use in the production of calibrators included in commercial kits, and formulated identically to these, should be certified with at least one reference measurement procedure, so that the concentrations of analyte in calibrators can be traced back to concentrations determined by a reference procedure.(ABSTRACT TRUNCATED AT 400 WORDS)

External quality assessment of steroid hormone assays in the United Kingdom.

A brief history of the UK quality assessment schemes and their mode of operation is given, with summaries of overall and method-related performance for each analyte. Cortisol and 17 alpha-hydroxyprogesterone assay performance is very good, but clear differences between methods exist for the former. Both the progesterone and oestradiol schemes demonstrate marked differences between methods. The testosterone scheme is affected by differences in behaviour of direct and extraction methods for specimens from males and females. Results of recovery experiments indicate considerable under-recovery by some direct methods. Future developments and plans for the schemes are described.

Oestradiol assays: applications and guidelines for the provision of a clinical biochemistry service.

This paper reports on the provision of a clinical biochemistry service for serum oestradiol. The pathophysiology and recognised applications of oestradiol assays are discussed and the current availability of assay reagents and methodologies reviewed. Data are presented on the analytical performance of assays for serum oestradiol in the UK External Quality Assessment Scheme (UKEQAS) and general guidance is offered to laboratories providing a diagnostic service for this analyte.

The effect of dopamine on renal function during aortic cross clamping.

Eighteen male patients undergoing elective surgical reconstruction of the abdominal aorta were divided into two groups. Patients in Group I (nine) were given dopamine intravenously, in a dose of 2 micrograms/kg/min, during the first half of the period of cross-clamping, whilst those in Group II received dopamine during the second half. Each patient acted as his own control and for each, three periods were examined, namely: pre-clamp, clamping with dopamine and clamping without dopamine. Dopamine infusion during aortic clamping caused a significant rise in sodium output (P less than 0.01), potassium output (P less than 0.05), creatinine clearance (P less than 0.05) and urine output (P less than 0.05). We conclude that dopamine infusion during aortic clamping helps to protect the kidney from any deleterious effect of clamping.

Naturally arising tumors of the inbred WAB/Not rat strain. I. Classification, age and sex distribution, and transplantation behavior.

During a 3-year period, 97 naturally arising tumors were collected from an inbred colony of WAB/Not rats. These tumors were largely confined to the breeding groups of approximately 5,300 female and 2,700 male rats retained up to 2 years of age. The tumors included 39 nephroblastomas and 41 mammary tumors (24 of which were histologically benign); the remaining tumors were mainly connective tissue sarcomas and skin tumors with 1 lymphoma and 2 gastrointestinal lesions. With the exception of the incidence of mammary tumors, males and females had similar tumor incidence, although nephroblastomas in female rats had a marked preference for growth in the left kidney. Most tumors occurred in the first year of life, especially the histologically malignant mammary tumors and the nephroblastomas. Of the tumors investigated, 31 were transplantable. Poor correlation between histologic malignancy and transplantation was seen with the mammary tumors. Only 50% of the nephroblastomas were transplantable. Although most transplanted tumors retained histologic characteristics of the primary tumor, 1 mammary tumor, 1 gastrointestinal tumor, and 1 nephroblastoma deviated from this general finding. In the case of this nephroblastoma, separate transplant lines from opposite poles of the primary tumor also showed differences in histology.

Naturally arising tumors of the inbred WAB/Not rat strain. II. Immunogenicity of transplanted tumors.

The immunogenicity of 28 transplanted naturally arising tumors of the inbred WAB/Not rat was investigated at early passages in strictly syngeneic, contemporary animals. Included were nephroblastomas, histologically benign and malignant mammary tumors, soft tissue and skin tumors, 1 lymphoid tumor, and 2 gastrointestinal lesions. In no case was evidence of immunogenicity observed when animals were treated with multiple grafts of irradiated (15,000 rad) tissue or by excision of a growing tumor. A few of these tumors were further investigated by other methods of immunization, including injection at various sites of irradiated cells followed by challenge at different sites and multiple injections of mitomycin C- or Formalin-treated cells. Again no evidence of immunogenicity was seen. Attempts to immunize with viable cells mixed with BCG or Corynebacterium parvum failed due to lack of tumor suppression by these agents. Limited concomitant immunity experiments yielded similarly negative results, except in one case of a fibrosarcoma for which a slight reduction in second tumor growth was observed when primary implants were very large. Some alterations in biologic properties during transplant passage and the incidence of postexcision recurrence and metastatic spread of some of the tumors are described.

Immune responses to naturally occurring rat sarcomas.

Attempts were made to induce immunity to 5 spontaneous rat sarcomas transplanted into syngeneic recipients. Rats were immunized by surgical removal of growing tumour transplants or by treatment with attenuated tumour, followed by challenge with tumour cells in suspension. Two tumours wee apparently not immunogenic, but a low level of immunity was induced against 2, and weak evidence of immunity was observed with another. Induced immunity was individually specific rather than cross-reactive. It is concluded that, contrary to some reports, some spontaneous animal tumours are immunogenic in the strain of origin.

Monoclonal antibody against a naturally occurring rat mammary carcinoma.

Inbred rats were hyper-immunised against a syngeneic transplanted mammary carcinoma, Sp4, which originally arose spontaneously in a breeding female. Spleen cells from Sp4-immune rats were fused with P3-NSI-Ag4 mouse myeloma cells, and supernatants from the hybrid progeny were screened for antibody reacting with Sp4 cells using an isotopic antiglobulin assay. One hybrid culture was reactive with Sp4 cells but not against other target cells, and this hybrid was cloned in soft agar. Many Sp4-positive clones were isolated and one (Sp4/A4) was chosen for detailed study. Clone Sp4/A4 was positive only with Sp4 cells and failed to react with cells of other tumours or normal tissues. It contained much higher titres of antibody than detected in immune sera, and it is suggested that this approach offers a practical method for producing highly active tumour-specific antibodies.