Predicting the efficacy of convection warming in anaesthetized children.

BACKGROUND: We previously described a convection warming technique (Cassey J, Armstrong P, Smith GE, Farrell PT. Paediatr Anaesth 2006; 16: 654-62). This study further analyses the children in that original study with three aims: (i) to investigate factors purported to influence children's heating rates, (ii) to describe the most effective usage of this warming technique, and (iii) to understand better the physiology of convection warming. METHODS: Children having anaesthesia for elective surgery lasting longer than 90 min in ambient temperature 21 degrees C were warmed by a 'Bair Hugger' attached to a custom-built heat dissipation unit. Relationships between child and procedure characteristics and various thermal measures were analysed, and a thermodynamic model was evaluated. RESULTS: Thirty-nine children (aged 2 days to 12.5 yr) were studied. There were statistically significant correlations between a number of factors (e.g. height and weight) and heating efficacy. Our model demonstrated the impact of changing patient characteristics on temperature profiles. Neither the morphological characteristics nor our model could predict an individual's T(core) behaviour. CONCLUSIONS: (i) Although the effectiveness of this warming technique is influenced by patient/procedure characteristics, these do not predict normothermia (uncertainty +/-28 min). Effectiveness is independent of simple thermal measures. (ii) Previously described measures of vasoconstriction are not valid in children. (iii) Our model shows children's thermal properties change with their T(core). However, key factors are unknown for an individual and our model does not predict heating efficacy. (iv) To minimize the risk of hyperthermia, we recommend continuous measurement of T(core) during convection heating. The device air temperature should be turned to medium (38 degrees C) as T(core) approaches 37 degrees C.

Good practice in head and neck fine needle aspiration cytology as assessed by CUSUM.

Providing data as evidence of good practice is becoming imperative to meet the demands of professional revalidation and clinical governance. Sensitivity and specificity are common performance measures in fine needle aspiration (FNA) but are vulnerable to discordant analytical methods. We introduce a CUSUM technique and show how it may be used to show attainment and maintenance of proficiency in head and neck (H&N) FNA. In addition, we show how it can be used to compare practices and demonstrate different performance for FNAs from different tissues; a fact that must be recognized by anyone devising minimum performance values.

Is there a better way to assess performance in breast cytology?

Is there a better way to assess performance in breast cytology? Results generated from a series of breast fine needle aspirates (BrFNA) are semi-qualitative and therefore sensitivity, specificity and accuracy are not necessarily the best measures of effectiveness. This paper considers the likelihood ratio of cancer (LR+), which can provide the probabilities for cancer being present or absent for cancer across the range of diagnostic categories used in the National Health Service Breast Screening Programme (NHSBSP), i.e. C1 to C5. Using LR+, receiver operating characteristic (ROC) curves can be generated and used to compare performance between pathologists, laboratories or years. These are illustrated using test results from 1997 to 1999 for the Derbyshire Royal Infirmary. LR + and ROC are meaningful measures. They could replace the 12 calculations currently used for the evaluation of effectiveness of BrFNA in the National Health Service Breast Screening Programme (NHSBSP) and for validation of pathologists' performance.

Does a joint ultrasound guided cytology clinic optimize the cytological evaluation of head and neck masses?

AIM: To compare the results of fine-needle aspiration (FNA) of head and neck masses performed in an ultrasound-guided cytology clinic (USGCC) staffed by a radiologist and pathologist to those obtained with specimens sent from other sources. METHODS: Comparison of broad-category FNA diagnoses (malignant, uncertain, benign or inadequate) with the patient's ultimate clinical or pathological outcome. Because FNA outcomes are semi-quantitative, accuracy of the procedure (the proportion of all tests resulting in a true- positive or negative fine-needle aspirate) is a better measure than sensitivity or specificity. Specimens (n = 292) from the first 2 years of the USGCC are compared with 600 specimens received from other sources over the previous 4 years. RESULTS: Accuracy was 23.4% better for specimens from the USGCC compared with those obtained by clinician guided aspiration (83.9%, 95% CI 79.7-88.1%, vs 60.5%, 95% CI 56.6-64.4%). There was an 84% reduction in inadequate specimens (from 21.5% to 3.4%). The proportion resulting in an uncertain result did not alter; 12.0% for USGCC and 11.9% for clinician-derived specimens. Improvement in accurate identification of salivary gland, lymph node, soft tissue and thyroid pathology was 27.0%, 21.2%, 18.3% and 15.8% respectively. CONCLUSIONS: The common practice of FNA performed by clinicians produces sub-optimal results in head and neck masses. A combined approach of ultrasound-guided fine-needle aspiration of head and neck masses, with immediate assessment of the material by a pathologist, is more accurate than with specimens obtained in other ways. If the results of FNA are to be incorporated into clinical decision making, the samples are best obtained using the USGCC model.

Factors predicting cases with unexpected clinical findings at necropsy.

AIMS/BACKGROUND: A major medical role for postmortem examinations is the detection of clinically unexpected disease processes contributing to death. The aim of the present study was to determine whether simple clinical parameters can predict the presence of important unanticipated findings at necropsy. METHODS: Prospective audit of adult necropsies carried out in a single year to assess the extent of unexpected findings at necropsy, to compare these cases with non-necropsied deaths to confirm they are a similar population and to seek features that predict which cases have unexpected necropsy findings. RESULTS: No correlation was found between age, sex, duration of in-hospital treatment, surgical intervention, clinical specialty, or necropsy request rates and incidence of unexpected findings in 187 adult necropsies. CONCLUSIONS: No parameters have been identified for patient selection to permit an increase in the yield of clinically unexpected findings. Until there is clear evidence that the current practice of patient selection is anything more than random, an increase in postmortem examination rates, as proposed by the Joint Working Party of the Royal College of Pathologists, the Royal College of Physicians of London and the Royal College of Surgeons of England in their report The Autospy and Audit, will increase the workload without necessarily producing a commensurate gain in knowledge.

Lobular carcinoma of the breast: cytological features supporting the diagnosis of lobular cancer.

Lobular carcinomas have a distinct natural history with a better response to endocrine therapy and a higher incidence of local recurrence and are more often bilateral. The cytological diagnosis of lobular carcinoma permits a discriminating therapeutic approach with pre-operative Tamoxifen, more generous resection margins, and assessment of the contralateral breast. The cytological features of lobular cancer however are not well defined and the low cell yield from such neoplasms can result in a high false negative rate. To determine whether we could improve the pre-operative diagnosis, we reviewed the cytological features of 112 lobular carcinomas. They had small uniform sized nuclei with irregular outlines and inconspicuous nucleoli. The degree of dissociation was similar to duct carcinomas and the incidence of inadequate aspirates was no higher. We found no features that confidently diagnosed lobular cancer or its sub-types. However, using a combination of features, typing of lobular cancer on aspirated material is possible and should be attempted.

Typing and grading breast carcinoma on fine-needle aspiration: is this clinically useful information?

The ability of fine-needle aspiration (FNA) to diagnose breast cancer is beyond question. The established role of cytopathology is to maintain a low benign to malignant biopsy ratio by reducing the number of benign lesions excised. Both typing and grading of breast cancers on FNA have received attention in the cytology literature but how this knowledge can influence management has not been fully explored. Recently we described a method for the cytological grading of breast cancer that compares well with the established Bloom and Richardson grades. In this paper we present our experience of 1,387 breast cancer FNAs reported by us with histological verification. We show that cytologically typing and grading breast cancers are valid exercises that can predict the true nature of the neoplasm. This information may assist in the clinical approach to the malignant breast.

Prognostic value of cytological grading of fine-needle aspirates from breast carcinomas.

Because neoadjuvant therapy, including preoperative chemotherapy and tamoxifen, is becoming increasingly common for early breast cancer, it is desirable to grade tumours before surgery so that the most appropriate medical regimen can be selected. We have used a cytological grading system for ductal carcinoma of type not otherwise specified (NOS). Wet-fixed Papanicolaou-stained breast aspirates are examined for the extent of cell dissociation, cell size and uniformity, and the appearance of nucleoli, the nuclear margin, and chromatin. 377 invasive breast carcinomas were removed after preoperative diagnostic fine-needle aspiration cytology (FNAC) during the 25 months of the study. 286 tumours were ductal carcinomas NOS on histology. We established three cytological grades and found that cytological grade corresponded well with the established histological grades (Elston's modified Bloom and Richardson method). All cytological features included in the score were equally important on regression analysis. This study shows that grading of breast cancer on FNAC is feasible and reproducible. Cytological grade may substitute for histological grade, so a combination of FNAC and mammography can provide information on tumour type, grade, and size before surgery. We recommend this grading system to centres that use FNAC for the diagnosis of breast cancers.

Colo-rectal carcinoma 1975 and 1990: no improvement in the stage of disease at resection.

There is no overall consensus as to what screening patterns should be adopted for individuals of average risk for colo-rectal carcinoma. The single most important prognostic factor in survival is the stage of the colo-rectal neoplasm at the time of resection. Consequently significant resources have been directed to early detection while the disease is at a curative stage. To assess the impact of widespread availability of faecal occult blood testing and large bowel endoscopy we prospectively examined all large intestine specimens resected for carcinoma in 1990 and compared them with specimens resected for colonic carcinoma in 1975. We excluded adenomatous polyps with malignant change which had been treated by snaring at colonoscopy, without subsequent colectomy, as their precise Duke's staging was so difficult. In any event, their numbers were small (> 5 in 1990). Our study shows that despite the resources targeted at early diagnosis of colo-rectal carcinoma resection of tumours at a prognostically favourable stage has not been improved in the 25 years since 1975.