Analysis of multiple casualty incidents - a prospective cohort study

Background:  Our aim was to report the rate and causes for multiple casualty incidents (MCI) to analyse the prehospital part of responding to MCIs, report mortality and find areas for improvement.
Methods:  A prospective cohort study conducted in an urban emergency medical service (EMS) between 1.3.1998 and 28.2.2004.
Results:  Fifty-nine MCIs involving 263 patients (167 walking, 96 non-walking) occurred. The incidence of MCIs was 1.8/100,000 inhabitants year⁻¹. Traffic accidents were the most common cause followed by residential fires, intoxications and stabbings or shootings. Early MCI alarm by the dispatching centre was performed in 18 MCIs. Deviations from standard emergency medical care occurred in 12% of patients. Lack of immobilization of the neck or back in trauma patients and lack of administration of 100% oxygen in suspected carbon monoxide intoxication were the most common deviations. Deviations were related to the lack of presence of on-scene medical command ( P =  0.0013) and inadequate resources ( P =  0.0342). One hundred and ninety-two patients were transported to emergency departments. Mortality during the prehospital phase was 4.9% (13/263) and during the next 28 days 2.3% (6/263). Adequate resources for safe and effective management of a MCI were related to an early MCI alarm by the dispatching centre ( P =  0,022) and to the presence of on-scene medical command ( P <  0,001).
Conclusions:  Traffic accidents, residential fires and intoxications were the leading causes for MCIs. Emergency medical service could respond to most MCIs efficiently and safely. Majority of deviations from standard medical care seemed potentially preventable. Several areas for improvement were identified. From prehospital links, the dispatching centre and on-scene medical command had a vital role in the successful management of MCIs.     

Dose-response relationship for radiation-induced mutations at micro- and minisatellite loci in human somatic cells in culture

Purpose : The study was designed to determine the dose-response relationship for radiation induction of mutations at mini- and microsatellite loci in human somatic cells. Mutations induced by graded doses of gamma-irradiation were quantified by screening clones derived from single irradiated cells for micro- and minisatellite alterations following irradiation with 1, 2 or 3 Gy. Materials and methods : After irradiation, the moderately radioresistant glioma cell line UVW was seeded at low density into Petri dishes to allow formation of discrete colonies, 100 of which were examined at each dose. All the cells within a colony were presumed to have arisen from a single irradiated cell. Radiation-induced microsatellite alterations were determined at 16 different loci, by PCR amplification and visualization on polyacrylamide gels. Minisatellite alterations were identified at four different minisatellite loci by restriction enzyme digestion and Southern blotting. Results : A dose-response curve for mutation frequency was obtained by analysis of 100 clones, yielding a minisatellite mutation rate of 5.5 X 10 -3 mutations/locus/Gy/cell and a microsatellite mutation rate of 8.75 X 10 -4 mutations/locus/Gy/cell. At microsatellite loci, alterations were predominantly simple loss or gain of repeat units and loss of heterozygosity (LOH). The mutations in minisatellite loci resulted predominantly in LOH and variation in repeat number. The background instability at each locus was determined by analysis of non-irradiated clones. Only 2% and 1% of the micro- and minisatellite loci respectively showed altered bands. Conclusions : This is the first report of a dose-response relationship for radiation-induced micro- and minisatellite mutations in human somatic cells. Described is a sensitive method for analysis of low-dose radiation mutagenesis in somatic cells that may prove to be a useful tool for radiation protection and dosimetry.     

Smaller Hip Circumference is Associated with Dyslipidemia and the Metabolic Syndrome in Obese Women

BACKGROUND: There is great need for simple anthropometric measures that predict risk. The authors explored the relationship between body composition measures and features of the metabolic syndrome (MtS) in women aged between 20 and 50 years with class I obesity. METHODS:This is a cross-sectional study of 49 obese (BMI 30-35) women recruited into a weight management randomized trial. An analysis was conducted of the baseline weight, anthropometric measures, skin-fold thickness, bioelectrical impedance, whole body dual-energy x-ray absorptiometry (DEXA), and their relationships with the features of the MtS. RESULTS: All women but one (n=48) had a population risk waist circumference of >88 cm. 16 of the 49 (33%) fulfilled the criteria of the metabolic syndrome. Simple anthropometric measures provided the strongest correlations with the presence of the MtS. Cut-off values were selected using receiver operator characteristics. Waist circumference of >100 cm and hip circumference <115cm was associated with odds ratios of 5.2 (95% CI, 1.4-20) and 12.3 (95% CI, 3.0-51) respectively for the MtS. Regional DEXA analysis showed that lower leg fat mass rather than fat-free mass was associated with the MtS. The dyslipidemia of the MtS was associated with a lower leg fat mass, while higher HbAlc levels and HOMA, an indirect measure of insulin resistance, were seen with increased trunk fat. Percentage fat as measured by skin-fold thickness and bioelectrical impedance were not related to any features. Women with the metabolic syndrome were found to have lower bone mineral content as measured by DEXA. CONCLUSION: Weight distribution is highly predictive of metabolic risk. Smaller hip and larger waist circumference provided independent effect. BMI adjusted anthropometric measures may be of value.     

Surgical site infections and supplemental perioperative oxygen in colorectal surgery patients: a systematic review

BACKGROUND: Four randomized trials have evaluated the impact of supplemental perioperative oxygen on the incidence of surgical site infections (SSIs), with mixed results. The objectives of this meta-analysis were: (1) To evaluate further the effect of supplemental perioperative oxygen on SSIs after colorectal surgery; and (2) to generate a strategy for future studies to determine definitively the value of this intervention. METHODS: We conducted a MEDLINE search to identify randomized trials of supplemental perioperative oxygen with a primary endpoint of SSI. Fixed-effects and random-effects models were employed, and the null association was tested for each. Tests also were performed for heterogeneity and publication bias. RESULTS: Four studies were identified that satisfied the search criteria. The total number of patients was 943, of whom 477 received supplemental oxygen and 466 served as controls. The pooled risk ratio (RR) for SSI favored the patients who received supplemental oxygen (RR = 0.68; 95% confidence interval [CI] 0.49, 0.94), but this difference was not maintained with a random-effects model (RR = 0.73; 95% CI 0.42, 1.28; p = 0.27). Heterogeneity was present among the studies. There was no evidence of publication bias. CONCLUSIONS: Supplemental perioperative oxygen is associated with a lower risk of SSI in patients undergoing colorectal surgery. The heterogeneity among the individual reports may be secondary to differences in study protocols.     

Effect of off-pump coronary artery bypass grafting on risk-adjusted and cumulative sum failure outcomes after coronary artery surgery

BACKGROUND AND AIM: We have shown that cumulative sum (CUSUM) failure analysis may be more sensitive than standard statistical methods in detecting a cluster of adverse patient outcomes after cardiac surgical procedures. We therefore applied CUSUM, as well as standard statistical techniques, to analyze a surgeon's experience with off-pump coronary artery bypass grafting (OPCAB) and on-pump procedures to determine whether the two techniques have similar or different outcomes. METHODS: In 320 patients undergoing nonemergent, first time coronary artery bypass grafting, preoperative patient characteristics, rates of mortality and major complications, and ICU and hospital lengths of stay were compared between the on-pump and OPCAB cohorts using Fisher's exact tests and Wilcoxon two sample tests. Predicted mortality and length of stay were determined using previously validated models of the Cardiac Care Network of Ontario. Observed versus expected ratios of both variables were calculated for the two types of procedures. Furthermore, CUSUM curves were constructed for the on-pump and OPCAB cohorts. A multivariable analysis of the predictors of hospital length of stay was also performed to determine whether the type of coronary artery bypass procedure had an independent impact on this variable. RESULTS: The predicted mortality risk and predicted hospital length of stay were almost identical in the 208 on-pump patients (2.2 +/- 3.9%; 8.2 +/- 2.5 days) and the 112 OPCAB patients (2.0 +/- 2.2%; 7.8 +/- 2.1 days). The incidence of hospital mortality and postoperative stroke were 2.9% and 2.4% in on-pump patients versus zero in OPCAB patients (p = 0.09 and 0.17, respectively). Mechanical ventilation for greater than 48 hours was significantly less common in OPCAB (1.8%) than in on-pump patients (7.7%, p = 0.04). The rate of 10 major complications was 14.9% in on-pump versus 8.0% in OPCAB patients (p = 0.08). OPCAB patients experienced a hospital length of stay that was a median of 1.0 day shorter than on-pump patients (p = 0.01). The observed versus expected ratio for length of stay was 0.78 in OPCAB patients versus 0.95 in on-pump patients. On CUSUM analysis, the failure curve in OPCAB patients was negative and was flatter than that of on-pump patients throughout the duration of the study. Furthermore, OPCAB was an independent predictor of a reduced hospital length of stay on multivariable analysis. CONCLUSIONS: OPCAB was associated with better outcomes than on-pump coronary artery bypass despite a similar predicted risk. This robust finding was documented on sensitive CUSUM analysis, using standard statistical techniques and on a multivariable analysis of the independent predictors of hospital length of stay.     

Reproducibility of direct quantitative measures of cortical bone microarchitecture of the distal radius and tibia by HR-pQCT

Quantitative cortical microarchitectural end points are important for understanding structure–function relations in the context of fracture risk and therapeutic efficacy. This technique study details new image-processing methods to automatically segment and directly quantify cortical density, geometry, and microarchitecture from HR-pQCT images of the distal radius and tibia.An automated segmentation technique was developed to identify the periosteal and endosteal margins of the distal radius and tibia and detect intracortical pore space morphologically consistent with Haversian canals. The reproducibility of direct quantitative cortical bone indices based on this method was assessed in a pooled data set of 56 subjects with two repeat acquisitions for each site. The in vivo precision error was characterized using root mean square coefficient of variation (RMSCV%) from which the least significant change (LSC) was calculated. Bland–Altman plots were used to characterize bias in the precision estimates.The reproducibility of cortical density and cross-sectional area measures was high (RMSCV < 1% and < 1.5%, respectively) with good agreement between young and elder medians. The LSC for cortical porosity (Ct.Po) was somewhat smaller in the radius (0.58%) compared with the distal tibia (0.84%) and significantly different between young and elder medians in the distal tibia (LSC: 0.75% vs. 0.92%, p < 0.001). The LSC for pore diameter and distribution (Po.Dm and Po.Dm.SD) ranged between 15 and 23 µm. Bland–Altman analysis revealed moderate bias for integral measures of area and volume but not for density or microarchitecture.This study indicates that HR-pQCT measures of cortical bone density and architecture can be measured in vivo with high reproducibility and limited bias across a biologically relevant range of values. The results of this study provide informative data for the design of future clinical studies of bone quality.     

Determinants of Radiation Exposure during EVAR

ObjectivesEndovascular aneurysm repair (EVAR) is an established method of aortic aneurysm repair, in favourable anatomical configurations. It does however expose patients to radiation. The study aim was to determine if the aneurysm neck morphology influenced radiation exposure.Patients and methodsAll elective and emergency EVAR patients were identified. Elective patients had a bifurcated stent-graft deployed, while emergency patients were repaired with an aorto-uni-iliac stent-graft and fem–fem crossover bypass. Proximal and distal aortic neck diameters, neck length, neck angles and sac diameter were recorded, with the radiation dose, screening time and contrast volume. The two subgroups of elective and emergency patients were compared and correlation between anatomical and radiological parameters calculated by using Pearson’s correlation coefficient.Results320 (270 male) elective patients and 64 (55 male) emergency patients from October 1998 to October 2008 underwent EVAR. The mean proximal (p = 0.004) and distal (p = 0.01) neck diameters were smaller and mean sac diameter (p < 0.0001) was greater in emergencies. No difference between groups existed in the neck length (p = 0.36) and suprarenal diameter (p = 0.30), sagittal (p = 0.05) and coronal (p = 0.62) neck angles. The screening time (p = 0.053) and contrast volume (p = 0.04) were lower, with a slightly higher radiation dose (p = 0.12) in emergencies. There was no definite correlation between the seven anatomical and three radiological parameters.ConclusionWhile radiation exposure is different in emergency patients, this is thought due to surgical technique rather than the aneurysm neck morphology.