Researchers working on economic evaluations alongside trials have to balance minimising data collection with maximising the ability to measure differences in costs. Using existing data sources may keep the costs of research down, but these data may not be entirely appropriate to the evaluation question. When evaluating technologies in intensive care it is particularly important to be able to classify patients correctly by their resource requirements especially when those requirements vary considerably from day to day. This paper describes and justifies methods for costing the care provided for babies in (one arm of) an on-going multi-centre trial, the Collaborative ECMO trial. This trial is evaluating alternative policies of life support for mature (full term) newborn babies with severe respiratory failure. The most reliable cost information on neonatal intensive care is available from a study, conducted independently from the trial, which has used simple cost apportionment on a large sample of units. By drawing on clinical opinion and carrying out a case note exercise we assessed whether this available information was appropriate to estimate 'baseline' costs for the control group during their initial 'acute' phase of illness. We concluded that the available cost estimates would need to be weighted to reflect the additional costs of drugs and investigations for this group of babies during the acute phase. Multidisciplinary collaboration on trials can help economists and other researchers to balance the requirement for simple cost measurements with more detailed primary research.

Cost-Benefit Analysis↗

PubMedDate not supplied

Inhibition of microembolization-induced pulmonary edema by early heparin treatment in dogs.

Explore the source record for details and available documents.

Animals↗

PubMedDate not supplied

Influence of electrical stimulation of the substantia nigra on spontaneous activity of raphe neurons in the anesthetized rat.

Recent studies of afferent connections of the anterior raphe using the horseradish peroxidase technique have demonstrated a major projection originating in the substantia nigra (SN). The present acute electrophysiological study examined the influence of stimulation of the afferent on the activity of individual neurons in the raphe of the posterior midbrain and anterior pons (n = 51), and of a control group of cells (n = 15) located 2 mm lateral to the raphe. The predominant effect of SN stimulation at 0.1-1.0 mA, 1 Hz or 10 Hz, was suppression of raphe activity, with 63% of the cells showing cessation of firing following SN pulses and only 8% showing excitation. The average duration of suppression was 200 msec at 1 Hz and 38 msec at 10 Hz. In contrast, 40% of the lateral cells were excited, with 27% of the cells showing suppression. The mean duration of total suppression of lateral cell firing was 61 and 17 msec at 1 and 10 Hz, respectively. The results from the raphe cells are consistent with recent reports of stimulation of other forebrain and brainstem afferents to the raphe in which suppression of raphe activity was the main effect.

Action Potentials↗

PubMedDate not supplied

Immediate versus deferred antiepileptic drug treatment for early epilepsy and single seizures: a randomised controlled trial.

BACKGROUND: The relative risks and benefits of starting or withholding antiepileptic drug treatment in patients with few or infrequent seizures are unclear. We sought to compare policies of immediate versus deferred treatment in such patients and to assess the effects of these policies on short-term recurrence and long-term outcomes. METHODS: We undertook an unmasked, multicentre, randomised study of immediate and deferred antiepileptic drug treatment in 1847 patients with single seizures and early epilepsy. Outcomes comprised time to first, second, and fifth seizures; time to 2-year remission; no seizures between years 1 and 3 and between years 3 and 5 after randomisation; and quality of life. Analysis was by intention to treat. FINDINGS: 404 patients invited to join the trial did not consent to randomisation; 722 were subsequently assigned immediate treatment with antiepileptic drugs and 721 were assigned deferred treatment. Immediate treatment increased time to first seizure (hazard ratio 1.4 [95% CI 1.2 to 1.7]), second seizure (1.3 [1.1 to 1.6]), and first tonic-clonic seizure (1.5 [1.2 to 1.8]). It also reduced the time to achieve 2-year remission of seizures (p=0.023). At 5-years follow-up, 76% of patients in the immediate treatment group and 77% of those in the deferred treatment group were seizure free between 3 and 5 years after randomisation (difference -0.2% [95% CI -5.8% to 5.5%]). The two policies did not differ with respect to quality of life outcomes or serious complications. INTERPRETATION: Immediate antiepileptic drug treatment reduces the occurrence of seizures in the next 1-2 years, but does not affect long-term remission in individuals with single or infrequent seizures.

Adolescent↗

PubMedDate not supplied

Early and late phase bronchoconstrictions in conscious sensitized guinea-pigs after macro- and microshock inhalation of allergen and associated airway accumulation of leukocytes.

Guinea-pigs were sensitized by i.p. injection of 10 micrograms OA and 100 mg aluminium hydroxide in 1 ml normal saline. Fourteen to twenty-one days after sensitization, animals were exposed to macroshock (1% OA for 2 min) or microshock (0.01% for 60 min) inhalation challenges with OA. Animals were protected against fatal anaphylaxis in the case of macroshocks with mepyramine (30mg/kg i.p.) 30 min before exposure. Specific airway conductance (sGaw) was measured in conscious animals by whole body plethysmography at intervals up to 72 h after challenge. An early phase bronchoconstriction peaked significantly (P < 0.05) at 15 min after both macroshock and microshock OA exposures, with maximum falls in sGaw of 70.8 +/- 3.8 and -40.0 +/- 5.9%, respectively. These had resolved after 5 h. A late phase bronchoconstriction peaked variably between 17 and 24 h: the mean peak falls in sGaw after the macro- and microshock challenges were significantly different from baseline (P < 0.05), at -21.6 +/- 3.7 and -38.0 +/- 3.9%, respectively. Control exposures of OA-sensitized guinea-pigs to saline for either 2 or 60 min, in place of OA, produced no significant variation in sGaw values over the predicted early and late phases. Bronchoalveolar lavage (BAL) performed at 5 or 24 h after OA challenge revealed significant increases in total cell numbers (P < 0.05) at 5 and 24 h after the OA macroshock challenge and at 24 h after the microshock, compared with saline challenges. Differential cell counts showed a significant (P < 0.05) increase in the proportion of neutrophils at 5 h and of neutrophils and eosinophils at 24 h after the macroshock exposure to OA, compared with saline controls. A significant (P < 0.05) increase in the proportion of eosinophils also occurred in BAL fluid at 24 h after microshock OA challenge. Neutrophils, however, did not alter at 24 h, yet a late phase bronchoconstriction was recorded. Thus, macroshock (with mepyramine cover) and microshock (without mepyramine cover) OA challenges result in both early and late phase bronchoconstrictions. The late phase is associated with influx of eosinophils in both models but neutrophils only appear after the macroshock, indicating that late phase responses may not involve neutrophil infiltration to the airways.

Administration, Inhalation↗

PubMedDate not supplied

The height of occlusal registration blocks before and after jaw registration.

OBJECTIVES: To assess the height of occlusal registration blocks made in dental laboratories compared with recommended dimensions. To relate these dimensions to the height of the blocks after registration of the occlusion. METHODS: All occlusal registration blocks received in a complete denture clinic at the Charles Clifford Dental Hospital, Sheffield, over a 1-year period were measured in height before and after registration of the occlusion. RESULTS: The height of occlusal registration blocks as received corresponded to the recommendations in the literature. However, after registration, a significant reduction in height was seen for both maxillary and mandibular blocks. CONCLUSIONS: Occlusal registration blocks produced by laboratories are 34 mm too high, requiring removal of excess wax in the surgery.

Analysis of Variance↗

PubMedDate not supplied

Telephone support for Canadian nurses in HIV/AIDS care.

An assessment study was conducted with Canadian nurses (N = 177) in HIV/AIDS care to determine how social support influences the relationship between job stress and health (job satisfaction and burnout). The assessment study revealed that social support and coping both moderate the effects of these stressors on nurses' health and functioning outcomes (i.e., job satisfaction and burnout). Accordingly, the follow-up study tested the effectiveness of an intervention designed to enhance social support, promote the use of certain coping strategies for managing occupational stress, and prevent burnout in nurses. Telephone support groups, co-led by an expert facilitator and an expert AIDS nurse, were tested in a demonstration project for nurses in HIV/AIDS care (n = 30). The nurse participants reported that the intervention enhanced their coping, confidence, relationships, client care, and connections to the HIV/AIDS nursing community.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

The influence of the impression tray on the accuracy of impressions for crown and bridge work--an investigation and review.

OBJECTIVE: To evaluate the accuracy of working casts for crown and bridge restorations made from twin mix putty/wash silicone elastomeric impression materials using different types of stock tray. DESIGN: A master cast was made from ivorine teeth in a mandibular model. Three teeth were prepared for full crown restorations to simulate a single unit and a three unit bridge. Impressions were taken using four different types of impression tray and two different viscosities of silicone putty, together with a wash. Full metal crowns were constructed and seated on duplicate master casts and measurements made of the marginal discrepancies. SETTING: The work was carried out in a dental technology laboratory in a university department of restorative dentistry in 1995/1996. RESULTS: Metal and rigid plastic impression trays showed the least discrepancy (about 50 microns), the latter slightly greater with the normal putty than the soft one. Impressions taken with flexible plastic trays produced considerable discrepancy with both putties, approximately 210 microns and 180 microns respectively. CONCLUSIONS: Metal and rigid plastic stock trays give greater accuracy in the putty/wash silicone twin mix impression technique compared with flexible plastic ones for crown and bridge work. Those using the latter should be aware of their shortcoming in this respect.

Crowns↗

PubMedDate not supplied

Respiratory health at a pulpmill in British Columbia.

The respiratory parameters of 392 white male pulpmill workers were measured by standardized procedures and compared with those of 310 white male rail yard workers. The pulpmill workers complained more frequently of wheezing and chest tightness and missed work more commonly because of chest illness as compared with the rail yard workers. Significant airflow obstruction was noted in nonsmokers who worked in the bleach plant, and it was most striking in the younger members of this group. The principal environmental contaminant in this area was chlorine at levels generally below current permissible concentrations. Members of the maintenance group--especially older members--demonstrated significantly lower forced vital capacity compared to the rail yard workers.

Absenteeism↗

PubMedDate not supplied

Brief report: relationship between HIV infection and WPPSI-R performance in preschool-age children.

OBJECTIVE: To determine the neurodevelopmental effects of perinatally acquired HIV infection on children of preschool age. METHODS: Participants included 40 children infected with HIV between the ages of three and five and an equal number of noninfected controls individually matched according to ethnicity, age, sex, and prenatal drug exposure. Participants were administered the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), upon which an analysis of subtest distribution was conducted. RESULTS: Whereas both groups evidenced mean IQ and subtest scores significantly below published norms, an effect for HIV group status was not found when a factor combining Performance IQ (PIQ) and Verbal IQ (VIQ) was analyzed. However, the group infected with HIV scored significantly lower than controls on the Block Design subtest. CONCLUSIONS: Gross cognitive deficits are not evident among preschool children infected with HIV relative to matched controls. However, this study does provides some evidence for more focal deficits. Further investigation with older children should be conducted.

Case-Control Studies↗

PubMedDate not supplied

Incidence and prognostic significance of blood lymphocyte clonal excess in localized non-Hodgkin's lymphoma.

Despite elaborate staging procedures, a substantial number of patients with localized NHL experience dissemination after local therapy, indicating that current routine methods are insufficient to detect tumour spread. We have used flow cytometric clonal excess (CE) analysis of peripheral blood in conjunction with routine staging procedures to study the occurrence of occult leukaemic spread in patients with localized NHL stages I, IE and IIE. CE in peripheral blood was a rare finding, identified in only 11% (14/130), and slightly more frequent in low-grade NHL, 20% compared to high-grade NHL, 7%. There was no correlation to any of the other major prognostic factors studied. Occult tumour spread would suggest an increased risk of relapse and possibly a decreased survival after local therapy. Among 93 patients given only local treatment there was an increased risk of relapse in those with low-grade malignant lymphomas and CE, which was not found in patients with high-grade malignant lymphomas and CE. CE in peripheral blood had no influence on survival in either of the histologic groups. A tentative explanation is that circulating lymphoma cells represent indolent populations irrespective of the histology of the primary tumour. The malignant nature of such a lymphoma spread might not be obvious during this rather limited follow-up of a median 34 months. The clinical interpretation is that the existence of CE in peripheral blood in patients with localized high-grade NHL should have no influence on the choice of therapy. In localized low-grade lymphoma the same therapeutic attitude which applies to widespread disease might be considered.

Adult↗

PubMedDate not supplied

Initial experience with the AbioCor implantable replacement heart at the University of Louisville.

Potential benefits of heart transplantation are limited by the severe donor organ shortage. The AbioCor implantable replacement heart has been developed as a potential alternative to heart transplantation. We report our initial experience with the AbioCor in a bovine model. A right thoracotomy was performed for access to the heart and great vessels. After initiation of cardiopulmonary bypass, excision of the native ventricles was followed by orthotopic placement of the IRH and complete implantation of the transcutaneous energy transfer coil, controller, and battery pack. Invasive monitoring of IVC, SVC, carotid artery, pulmonary artery, and left atrial (LA) pressures was performed in all animals. Twelve calves have undergone implantation of the AbioCor. There were three early deaths, one from bleeding, one from respiratory failure, and one from neurodysfunction from low flow during CPB. Nine animals have had a normal recovery and survived a mean of 24.5 days (range, 4-48 days). All the animals have demonstrated excellent hemodynamics with the maintenance of normal pressures in the LA, SVC, IVC, pulmonary artery, and aorta. Adjustment of the right-sided internal hydraulic fluid shunt has allowed for control of right-left balance and, thereby, manipulation of left and right side filling pressures. Late morbidity has consisted of neck wound infection and sepsis, pneumonia, and bleeding. Successful orthotopic implantation of all components of the AbioCor has been achieved in a bovine model. This device has demonstrated restoration of normal hemodynamics and excellent function of the atrial hydraulic shunt to achieve right-left balance.

Animals↗