Systematic review and meta-analysis of the effect of North American working hours restrictions on mortality and morbidity in surgical patients

Background

Short duty hours, imposed by the Accreditation Council of Graduate Medical Education (ACGME) regulations, have been claimed to be associated with loss of continuity of care among surgical patients, leading to a potentially increased risk of adverse surgical outcomes. This systematic review and meta-analysis assessed the strength of associations between duty hour restrictions and morbidity and mortality of various surgical procedures.

Methods

MEDLINE, Embase, BIOSIS Previews®, the Education Resources Information Center and the Cochrane Central Register of Controlled Trials (January 2000 to September 2009) were searched, and reports screened to identify comparative studies of mortality and morbidity before and after the introduction of ACGME regulation periods. Random-effects (RE) and quality-effects (QE) meta-analyses were performed to determine the risk of morbidity or death associated with long duty hours compared with shorter duty hours. Results are presented as odds ratio (OR) with 95 per cent confidence interval.

Results

A total of 19 data sets (10 articles), including 730 648 subjects in the mortality studies and 64 346 in the morbidity studies, were analysed. Long duty hours were associated with a non-significantly increased risk of death compared with shorter duty hours (OR 1·28, 0·94 to 1·73). There was no difference in morbidity between the two groups (OR 1·03, 0·67 to 1·57). Mortality associations were generally stronger for general surgery, more recent studies and higher-quality studies. Heterogeneity was evident among the studies included.

Conclusion

The reduction in working hours has not affected patient care negatively in terms of demonstrable differences in morbidity and mortality. However, it cannot be distinguished whether this effect is actually due to a non-detrimental effect of the reduction in working hours or whether any such detriment is offset by continually improving patient care and increased surgical supervision.

Circulating melanoma cells and survival in metastatic melanoma

A validated assay for the enumeration of circulating melanoma cells (CMCs) may facilitate the development of more effective therapies for metastatic melanoma patients. In this study CD146+ cells were immunomagnetically enriched from 7.5 ml of blood. Isolated cells were fluorescently stained with DAPI, anti-molecular weight melanoma-associated antigen (HMW-MAA), anti-CD45 and CD34 and Ki67. CMCs were identified as CD146+, HMW-MAA+, CD45-, CD34-, Ki67-/+ cells. Eighty-eight percent of spiked SK-MEL28 cells in 7.5 ml blood were recovered. In all 55 healthy donors ≤1 CMCs were detected in 7.5 ml of blood. A retrospective analysis was conducted comparing CMC counts and overall survival in 79 blood samples from 44 melanoma patients. CMCs ranged from 0 to 8,042 per 7.5 ml. Two or more CMCs were detected in 18 (23%) of the patients and 30-100% (mean 84%) of the CMCs expressed the proliferation marker Ki67. Patients with ≥2 CMCs per 7.5 ml of whole blood, as compared with the group with <2 CMCs, had a shorter overall survival (2.0 months vs. 12.1 months, P=0.001).

Circulating endothelial cells, circulating tumour cells, tissue factor, endothelin-1 and overall survival in prostate cancer patients treated with docetaxel

PURPOSE

We investigated whether serum markers of angiogenesis endothelin-1 (ET-1) and tissue factor (TF), and/or markers of vascular damage such as circulating endothelial cells (CECs), or their relative changes during treatment, were prognostic for overall survival (OS) in castration resistant prostate cancer (CRPC) patients. Additionally, we combined these markers with circulating tumour cells (CTCs) to construct a predictive nomogram for treatment outcome.

PATIENTS AND METHODS

One hundred and sixty two CRPC patients treated with a docetaxel containing regimen had blood drawn before and at 2-5 weeks and 6-8 weeks after treatment start. Prospectively determined CTC and CEC levels, and retrospectively measured serum concentrations of ET-1 (pg/mL) and TF (pg/mL) were evaluated to determine their prognostic value for OS.

RESULTS

Baseline CEC, TF and ET-1 were not prognostic for OS. A > or = 3.8-fold increase in CEC 2-5 weeks after treatment initiation was associated with decreased OS (median 10.9 versus 16.8 months; P=0.015), as was any decrease in TF levels compared to baseline levels (median 11.9 versus 21.5 months; P=0.0005). As previously published, baseline and CTC counts > or = 5 at 2-5 weeks were also predictive of decreased OS. Combining CTC with changes in TF and CEC 2-5 weeks after treatment initiation yielded four groups differing in OS (median OS 24.2 versus 16.0 versus 11.4 versus 6.1 months; P<0.0001).

CONCLUSION

CEC, CTC and TF levels alone and combined can predict early on OS in CRPC patients treated with docetaxel-based therapy. A prospective study to confirm the use of these markers for patient management is needed.

A rapid two-step method for elimination of bcl-2/IgH positive non-Hodgkin's lymphoma cells from human blood or marrow stem cells, employing immunomagnetic purging with streptavidin-coated ferrofluids

BACKGROUND

Follicular lymphoma cells may contaminate blood or BM stem cell collections used for autologous transplants and contribute to relapse. We report on the development of a B-cell lymphoma-purging technique, using streptavidin-coated ferrofluids (SAFF) and a high-gradient magnetic-separation device (HGMSD).

METHODS

Blood or BM samples were spiked with bcl-2 positive lymphoma cells, labeled with biotinylated B cell MAb (CD19, CD20, CD37) then purged by positive selection of CD34(+) cells, followed by negative selection with SAFF and a high HGMSD. Purging efficiency was judged by dual-labeled flow cytometry and by PCR analysis of bcl-2.

RESULTS

A 6 log purge of bcl-2 lymphoma cells could be achieved by first enriching for CD34(+) cells, followed by negative selection with SAFF and HGMSD. The use of SAFF with HGMSD alone could only accomplish a 2-3 log purge.

DISCUSSION

CD34 selection from blood or BM of follicular lymphoma patients, followed by negative selection of MAb-labeled cells with SAFF could achieve a 6 log purge. However, cell yields were low (10%) and purging efficacy was limited to low starting concentration of lymphoma cells (< or = 1.0%). This technique, however, may be useful for full-scale clinical purging of minimal residual disease following debulking with a cyclophosphamide or other agents.

Integration of traditional and innovative characterization techniques for flux-based assessment of dense non-aqueous phase liquid (DNAPL) sites

Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( approximately 10 kg), which is also reflected in small source mass discharge ( approximately 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of approximately 6 g/day at a plume control plane approximately 175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult. Our analysis, based on a synthesis of the archived data and new data, suggests that source treatment is unwarranted, and that containment of the large TCE plume (approximately 1.2 km long, approximately 0.3 km wide; 17 m deep; approximately 2000-2500 kg TCE mass) or institutional controls, along with a long-term flux monitoring program, might be necessary. The flux-based site management approach outlined in this paper provides a novel way of looking beyond the complexities of groundwater contamination in heterogeneous domains, to make intelligent and informed site decisions based on strategic measurement of the appropriate metrics.

Economic analysis of esophageal stenting for management of malignant dysphagia

Over half of patients diagnosed with esophageal cancer are unsuitable for curative resection. A significant proportion of these patients will subsequently require palliative stenting to alleviate dysphagia. There is growing consensus in the literature that the deployment of a Self-Expanding Metal Stent is the optimum stenting strategy; however, it remains unclear whether covered or uncovered metal stents are more cost-effective. In order to determine which type of prosthesis is more cost-effective, we compared the different stenting strategies in terms of 1-year stent-related mortality, health-related quality of life, and cost. A decision analytical model was constructed to compare the 1-year stent-related mortality, health-related quality of life, and cost between covered and uncovered stents. Probabilistic sensitivity analysis was performed to quantify the uncertainty associated with our results. Value of Information analysis was performed to assess the value of further research. In order to fully characterize the uncertainty associated with this decision, plastic stents were included in our analysis. Stent-related mortality was slightly lower following covered stent deployment compared with uncovered stent deployment (1.00% vs. 1.26%). Covered stents were more effective by 0.0013 Quality-Adjusted Life Years (Standard Deviation [SD] 0.0013 Quality-Adjusted Life Years). They were also less expensive by $729.58 (SD $390.63). Probabilistic sensitivity analysis suggested that these results were not sensitive to model parameter uncertainty. Plastic stents deployment was $2832.64 (SD $1182.72) more expensive than uncovered metal stent deployment. Value of Information analysis suggests that the maximum value of further research in the UK is $61,124.30. The results of this study represent strong evidence for the cost-effectiveness of covered compared with uncovered self-expanding metal stents for the palliation of patients with malignant dysphagia. The findings support previously published literature asserting the dominance of self-expanding metal stents over plastic stents. Value of Information analysis suggests that further research may not be cost-effective. These findings have significant implication for both current clinical practice and future clinical research.

Arterial calcification in race horses

Calcification of large arteries has been sporadically reported in horses. The pathogenesis is still unknown, but recent studies in humans suggest that this is a regulated biomineralizing process. This study surveyed the prevalence, distribution, and severity of vascular calcification in Thoroughbred and Standardbred racehorses. Histopathologic, ultrastructural imaging, and energy dispersive X-ray elemental analyses were used to examine the lesions. Calcification of the tunica media, predominantly the pulmonary artery, was found in 82% of horses (83/101). Young adult horses (mean [SD] age in years, 4.44 +/- 2.17) of both breeds and sexes were similarly affected. Lesions appeared as white-to-yellowish, hard, and gritty plaques of variable size. On microscopic examination, elastic fibers within the tunica media were thinned, fragmented, and calcified, and surrounded by dense collagen matrix. Elemental analysis showed distinct peaks for calcium and phosphorus, consistent with hydroxyapatite mineral. The frequent occurrence of calcification in the tunica media of large pulmonary arteries of young racing horses indicates the need to investigate its pathogenesis and potential clinical implications.

Interstitial cells of Cajal and intestinal function in Trinidadian children

OBJECTIVE

This study was carried out to compare the density of the interstitial cells of Cajal (ICCs) in the bowel wall of children with Hirschsprung's disease (HD), anorectal malformations (ARM) and normal controls in Trinidad and Tobago.

SUBJECTS AND METHOD

Segments of bowel wall excised from eight children with HD, three controls and two children with ARM were immunostained with c-Kit primary antibody. Cells with features of ICCs were counted.

RESULTS

All three controls and the two children with ARM had dense distribution of ICCs. Most children (6/8; 75%) with HD had markedly reduced counts in aganglionic bowel. Two (25%) also had a decrease in ganglionic bowel. Possible influences were patient age and gender and the level of bowel sectioned.

CONCLUSION

Analysis of this sample suggests that immunostaining for c-Kit positive cells might be a useful screening test in the assessment of bowel motility disorders. The possible effects of age, gender and the level of bowel sampled await determination.

Revision of Oxford medial unicompartmental knee arthroplasty to total knee arthroplasty - results of a multicentre study

The advantages of Unicompartmental Knee Replacement (UKR) over Total Knee Replacement (TKR) includes the preservation of soft tissue as well as bone stock, and better function with improved range of motion and more natural gait. It is therefore believed that the revision of failed UKR to TKR is technically easier than revision of failed TKR. In our study we tested this hypothesis by assessing the reconstruction requirements and early clinical and radiological outcome following the revision of UKR to TKR. During a 15-year period 1060 primary Oxford medial UKR procedures were performed at three centres, 36 of which underwent revision to TKR due to aseptic failure. The mean operating time for revision surgery was 113 min. Among the revision prostheses used, 28 were standard TKRs, six were constrained, and two were semi-constrained. Thirty had no intramedullary stems whereas six had intramedullary stems. In 30 cases reconstruction for bone loss was not required whereas metal augmentation was used in two knees, contained peg defects in the femur were filled with cement in two knees and contained keel defects in the tibia were grafted using the bone from revision cuts in two knees. After a mean follow-up of 2 years, the mean 'total knee score' was 86.3 and the mean functional score was 78.5. These findings suggest that the complexity of operation and complications encountered during Oxford medial UKR revision and the clinical outcome compare favorably with those of TKR revision.