Temporal Structures in Positron Spectra and Charge-Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic positron fluxes in the rigidity range from 1.00 to 41.9 GV based on 3.4×10^{6} positrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The positron fluxes show distinctly different time variations from the electron fluxes at short and long timescales. A hysteresis between the electron fluxes and the positron fluxes is observed with a significance greater than 5σ at rigidities below 8.5 GV. On the contrary, the positron fluxes and the proton fluxes show similar time variation. Remarkably, we found that positron fluxes are modulated more than proton fluxes with a significance greater than 5σ for rigidities below 7 GV. These continuous daily positron fluxes, together with AMS daily electron, proton, and helium fluxes over an 11-year solar cycle, provide unique input to the understanding of both the charge-sign and mass dependencies of cosmic rays in the heliosphere.

Variations of accessory thoracic muscles identified in the ethnically diverse whole-body donation population in Northern California

Accessory thoracic muscles in humans are relatively common and it is important to draw awareness to their variable presentations and potential clinical implications owing to their close association with the axilla. Here we report four cases of accessory thoracic muscle variations identified in the ethnically diverse whole- -body donation population in Northern California (4 out of 48 donors, 8.3%). Of these, combined presentations of thoracic accessory muscles were observed in two of the donors, one involving bilateral axillary arches and a pectoralis quartus on the left and the other a unilateral axillary arch on the left and bilateral pairs of pectoral fascicles. In the former, the proximal ends of the left axillary arch and pectoralis quartus joined to form a common aponeurosis which inserted onto the deep tendon of the pectoralis major; in the latter, the pectoral fascicles originated from the surface of the ribs and inserted into the deep surface of the pectoralis major muscle. In the other two donors, unilateral axillary arches were observed. Our observations illustrate that accessory thoracic muscles, in isolated as well as combined forms, are commonplace in the general population. We also describe the proposed embryonic origins of these accessory muscles, which may reflect their frequent occurrence, and potential clinical implications of these muscles, as discussed in literature.

JS07.5.A 18F-fluciclovine PET and multi-parametric MRI to distinguish pseudoprogression from tumor progression in post-treatment glioblastoma

Background

Differentiation of tumor progression (TP) from pseudoprogression (PsP) is a major unmet need in glioblastoma (GBM). 18F-Fluciclovine is a synthetic amino acid PET radiotracer with higher uptake in tumor tissue vs. areas of treatment-related change. We aimed to assess the combined value of 18F-Fluciclovine PET and multi-parametric MRI for differentiating PsP from TP.

Material and Methods

We enrolled 30 patients with GBM with a new or enlarging contrast-enhancing lesion on MRI after chemoradiotherapy who were planned for surgical resection of the lesion. Patients underwent pre-operative 18F-Fluciclovine PET and multi-parametric MRI. Following surgery, the relative percentages of viable tumor and therapy-related changes observed on histopathology were quantified. Patients were categorized as TP if viable tumor represented ≥ 50% of the specimen, mixed TP if < 50% and > 10%, and PsP if ≤ 10%. SUVmax, SUVpeak, and 50% threshold SUVmean were calculated and normalized to contralateral brain, pituitary gland, and superior sagittal sinus (SSS). The least absolute shrinkage and selection operator (LASSO) was used to determine the variables most predictive of tumor percentage. The strength of association between the primary outcome and selected variables was assessed by Pearson’s or Point-biserial correlation.

Results

18 patients with TP, 4 with mixed TP-PsP, and 8 with PsP were included. There was a positive correlation between 50% threshold SUV mean measured from PET images acquired 50-60 minutes post-injection and rCBVmax by MRI and tumor percentage by histology (r= 0.56; p= 0.004 and r=0.50; p=0.012 respectively). 40-50 minutes SUVmax (OR=1.78 rpb=0.51) and rCBVmax (OR=1.64, rpb=0.48) were positively correlated with tumor TP/mixed TP group. Patients who demonstrated TP/mixed TP-PsP had significantly higher 40-50 minutes SUVmax compared to patients with histological PsP (6.71±2.03 vs 3.93±1.63; p=0.012). 40-50 minutes SUVmax cut-off of 4.46 provided 90% sensitivity and 80% specificity for differentiation of TP/mixed TP-PsP from PsP (AUC=0.88). Combining a 40-50 minutes SUVmax cut-off of 4.46 and an rCBVmax cut-off of 3.67 provided 100% sensitivity and 100% specificity for differentiating TP/mixed TP-PsP from PsP (AUC=1). Patients who demonstrated TP had a significantly higher 40-50 minutes SUVmax compared to patients with histological PsP (6.99±2.06 vs 3.93±1.63; p=0.008). A 40-50 minutes SUVmax cut-off of 4.66 provided 94% sensitivity and 80% specificity for differentiation of TP from PsP (AUC=0.89).

Conclusion

18F-Fluciclovine PET uptake is positively correlated with viable tumor quantification on histology and can accurately differentiate PsP from TP in patients with GBM. Further independent studies are required to cross-validate these promising early results.

457 The Effect of Biochemical Adversity of Primary Hyperparathyroidism on Preoperative Imaging (SPECT-CT and US Parathyroids)

Aim

Primary hyperparathyroidism (PHPT) is a common endocrine disorder, with an estimated incidence of 1/500 women and 1/2000 men older than 40 years. Several factors influence the positivity of preoperative scans including serum calcium, PTH and vitamin D levels, and gland size. The aim of our study is to examine the effect of biochemical adversity of primary hyperparathyroidism on preoperative imaging (SPECT-CT and US parathyroids).

Method

Retrospective study of 176 parathyroidectomies (2017-2020) in a tertiary referral centre with biochemistry, SPECT-CT, US parathyroids and histology outcomes being recorded. Failed parathyroidectomies were excluded.

Results

Patients were divided into 4 groups based on the preoperative calcium levels (normocalcemia <2.6, 3.4%; mild 2.60-2.79, 51.1%; moderate 2.80-2.99, 31.2%; severe >3.0 mmol/l, 14.2% of patients). Age (p-0.0297), preoperative vitamin D (p-0.03) and PTH levels (p-0.0001) were different while SPECT-CT positivity (p-0.29) weight of gland (p-0.015) and US positivity (p-0.09) were similar within the subgroups. Looking at the whole group, patients with positive SPECT-CT have a larger weight (p < 0.0001) while preoperative PTH levels was higher for the positive SPECT-CT patients (p-0.0289). No relation was identified between calcium levels and SPECT-CT positivity (p-0.18). No significance between preoperative vitamin D and positivity of US and SPECT-CT within the study group were noted.

Conclusions

Serum PTH levels and weight of the gland are directly correlated with positivity of preoperative imaging. Preoperative calcium and vitamin D levels correlates indirectly with the severity of the disease but did not influence the preoperative imaging positivity.

Standardization of a SNP panel for parentage verification and identification in the domestic cat (Felis silvestris catus)

The domestic cat (Felis silvestris catus) is a valued companion animal throughout the world. Over 60 different cat breeds are accepted for competition by the cat fancy registries in different countries. Genetic markers, including short tandem repeats and SNPs, are available to evaluate and manage levels of inbreeding and genetic diversity, population and breed structure relationships, and individual identification for forensic and registration purposes. The International Society of Animal Genetics (ISAG) hosts the Applied Genetics in Companion Animals Workshop, which supports the standardization of genetic marker panels and genotyping for the identification of cats via comparison testing. SNP panels have been in development for many species, including the domestic cat. An ISAG approved core panel of SNPs for use in cat identification and parentage analyses is presented. SNPs (n = 121) were evaluated by different university-based and commercial laboratories using 20 DNA samples as part of the ISAG comparison testing procedures. Different SNP genotyping technologies were examined, including DNA arrays, genotyping-by-sequencing and mass spectroscopy, to select a robust and efficient panel of 101 SNPs as the ISAG core panel for cats. The SNPs are distributed across all chromosomes including two on the X chromosome and an XY pseudo-autosomal sexing marker (zinc-finger XY; ZFXY). A population study demonstrated that the markers have an average polymorphic information content of 0.354 and a power of exclusion greater than 0.9999. The SNP panel should keep testing affordable while also allowing for the development of additional panels to monitor health, phenotypic traits, hybrid cats and highly inbred cats.

Correlation between biochemical features and outcomes of preoperative imaging (SPECT-CT and Ultrasound) in primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism is the third most common endocrine disorder, diagnosed by elevated parathyroid hormone (PTH) in hypercalcaemia. Several biochemical factors have been described to suggest severity of disease and may be correlated with preoperative imaging.

METHODS

This was a retrospective study of patients who underwent parathyroidectomy over a 3-year period. Preoperative calcium, PTH, vitamin D levels, ALP (alkaline phosphatase), vitamin D, serum phosphate and US and SPECT-CT positivity was noted.

RESULTS

176 patients underwent parathyroidectomy and these were divided into 4 groups based on preoperative calcium. Overall, 61% of patients showed concordance between imaging and operative findings. Severe hypercalcaemia was associated with higher PTH levels, lower vitamin D levels, an increased rate of abnormal ALP levels, lower phosphate, male gender and highest rate of imaging concordance. Imaging positivity was associated with severe hypercalcaemia and elevated PTH levels. Level of PTH >125 pmol/L and hypercalcaemia >2.8 mmol/L are the most accurate cut-off levels for scan positivity.

CONCLUSION

Biochemical factors associated with severity of the disease are directly correlated with positivity of preoperative imaging while ALP and vitamin D did not influence the preoperative imaging positivity but are associated with disease adversity. Serum phosphate level independently predicted results of parathyroid US.

A cadaveric analysis of anatomical variations of the anterior belly of the digastric muscle

BACKGROUND

The anterior belly of the digastric muscle (ABDM) presents highly variable and frequent anatomical variations. Since the ABDM functions as a landmark for clinical procedures involving the submental region, it is important to have a comprehensive understanding of its variations. In this study, we sought to improve our knowledge of ABDM variations in the ethnically diverse whole-body donor population in Northern California. Specific aims were: (1) to determine the frequency of ABDM and anterior belly (AB) accessory muscle variations in cadavers donated to the UC Davis Body Donation Programme, (2) to classify these variations identified in this population using the previously proposed nomenclatures by Yamada (1935) and Zlabek (1933), and (3) to investigate the innervation and arterial supply to the representative ABDM and AB accessory muscle variations.

MATERIALS AND METHODS

During the 2018 and 2019 gross anatomy dissection laboratories at the UC Davis School of Medicine, the submental regions of 48 cadavers were examined and classified.

RESULTS

Fifteen (31.2%) cadavers presented ABDM and AB accessory muscle variations. These variations were clearly categorised using the morphology of the ABDMs and attachments of the AB accessory muscles. We also identified three previously unreported types of variations, two of which presented the fusion of right and left ABDMs and one presenting an ectopic tubercle beneath the mandibular symphysis to which a pair of AB accessory muscles were attached.

CONCLUSIONS

Anterior belly of the digastric muscle variations were found in 1 in 3 individuals in the local Northern California population. Knowledge of the prevalence and common patterns of ABDM variations in the general population would be valuable information when an operation or examination is performed in the submental region.

Aerial baiting for feral cats is unlikely to affect survivorship of northern quolls in the Pilbara region of Western Australia

Abstract ContextFeral cats (Felis catus) are known predators of northern quolls (Dasyurus hallucatus). Management to suppress feral cat densities often uses the poison sodium monofluoroacetate (compound 1080) in baits broadcast aerially. Eradicat® baits have demonstrated efficacy at reducing feral cat densities in some environments. However, these are not registered for use in northern Australia because their risk to non-target northern quolls remains unknown. AimsWe investigated the risks of aerially deployed feral cat Eradicat® baits containing 4.5mg of the poison 1080 on the survival of free-ranging northern quolls. MethodsThe study was conducted over a 20000-ha area in the Pilbara bioregion in Western Australia. Twenty-one wild northern quolls from a baited area and 20 quolls from a nearby reference area were fitted with radio-collars, and their survivorship was compared following the aerial deployment of over 9700 feral cat baits. Survivorship of quolls was assessed before and after the baiting campaign. Key resultsFive radio-collared quolls died at the baited area; four mortalities were due to feral cat predation, and the cause of one death was uncertain. At the reference area, seven radio-collared quolls were confirmed dead; three mortalities were due to feral cat predation, two from wild dog predation, and the cause of death of two could not be determined. Evidence for sublethal poison impacts on quolls, inferred by monitoring reproductive output, was lacking; average litter size was higher in quolls from the baited area than in those from the unbaited area, and within range of litters reported elsewhere, suggesting that acute effects of 1080 (if ingested) on reproductive success were unlikely. ConclusionsRadio-collared northern quolls survived the trial using Eradicat® baits, and females showed no acute effects of sublethal poisoning on the basis of reproductive output. A lack of quoll deaths attributed to 1080 poisoning suggests that the use of Eradicat® poses a low risk to northern quolls in the Pilbara. Importantly, the high level of mortalities associated with predation by feral cats, and to a lesser extent, canids, validates the threats of these introduced predators on quolls, suggesting that their control in areas where quolls are present is likely to be beneficial for the recovery of this species. ImplicationsLand managers aiming to conserve northern quolls in the Pilbara would see conservation benefits if they introduced an operational landscape-scale feral cat baiting program using Eradicat® baits, with appropriate monitoring.

Heterozygosity testing and multiplex DNA panel screening as a potential tool to monitor health and inbreeding in a small, closed dog population

Background

Selective breeding in populations with a limited effective population size may result in a loss of genetic diversity, which can cause an increased concentration of specific disease liability genes. The Dutch Shepherd Dog (DSD) in the Netherlands is an example of such a breed with a small effective population.

Objective

To evaluate the measurement of genetic diversity and multiplex DNA panel screening for implementation in a breeding strategy for the Dutch Shepherd Dog (DSD) and to investigate the clinical relevance of potentially identified mutations in the multiplex DNA panel screening.

Results

Genome-wide SNP testing showed genetic isolation and reduced genetic diversity within coat variety subgroups of the DSD. Panel screening identified a Von Willebrand's Disease type I mutation. Although decreased Von Willebrand's Factor proteins were significantly lower in DSDs carrying the VWD-I allele compared to the wildtype, clinical follow-up did not show a significant association between the clinical phenotype and VWD-I genotype.

Conclusions

Genetic relationship measurement within a breed population may be a useful tool to enable breeding strategies to conserve genetic diversity. Results from a disease panel screening need to be evaluated for clinical relevance before breed selection restrictions can be considered.

Randomized phase III trial of low-molecular-weight heparin enoxaparin in addition to standard treatment in small-cell lung cancer: the RASTEN trial

Background

Coagulation activation and venous thromboembolism (VTE) are hallmarks of malignant disease and represent a major cause of morbidity and mortality in cancer. Coagulation inhibition with low-molecular-weight heparin (LMWH) may improve survival specifically in small-cell lung cancer (SCLC) patients by preventing VTE and tumor progression; however, randomized trials with well-defined patient populations are needed to obtain conclusive data. The aim of RASTEN was to investigate the survival effect of LMWH enoxaparin in a homogenous population of SCLC patients.

Patients and methods

We carried out a randomized, multicenter, open-label trial to investigate the addition of enoxaparin at a supraprophylactic dose (1 mg/kg) to standard treatment in patients with newly diagnosed SCLC. The primary outcome was overall survival (OS), and secondary outcomes were progression-free survival (PFS), incidence of VTE and hemorrhagic events.

Results

In RASTEN, 390 patients were randomized over an 8-year period (2008-2016), of whom 186 and 191 were included in the final analysis in the LMWH and control arm, respectively. We found no evidence of a difference in OS or PFS by the addition of enoxaparin [hazard ratio (HR), 1.11; 95% confidence interval (CI) 0.89-1.38; P = 0.36 and HR, 1.18; 95% CI 0.95-1.46; P = 0.14, respectively]. Subgroup analysis of patients with limited and extensive disease did not show reduced mortality by enoxaparin. The incidence of VTE was significantly reduced in the LMWH arm (HR, 0.31; 95% CI 0.11-0.84; P = 0.02). Hemorrhagic events were more frequent in the LMWH-treated group but fatal bleedings occurred in both arms.

Conclusion

LMWH enoxaparin in addition to standard therapy did not improve OS in SCLC patients despite being administered at a supraprophylactic dose and despite resulting in a significant reduction in VTE incidence. Addition of LMWH cannot be generally recommended in the management of SCLC patients, and predictive biomarkers of VTE and LMWH-associated bleeding in cancer patients are warranted.

Cardiopulmonary exercise testing (CPET) in the United Kingdom-a national survey of the structure, conduct, interpretation and funding

Background

Cardiopulmonary exercise testing (CPET) is an exercise stress test with concomitant expired gas analysis that provides an objective, non-invasive measure of functional capacity under stress. CPET-derived variables predict postoperative morbidity and mortality after major abdominal and thoracic surgery. Two previous surveys have reported increasing utilisation of CPET preoperatively in England. We aimed to evaluate current CPET practice in the UK, to identify who performs CPET, how it is performed, how the data generated are used and the funding models.

Methods

All anaesthetic departments in trusts with adult elective surgery in the UK were contacted by telephone to obtain contacts for their pre-assessment and CPET service leads. An online survey was sent to all leads between November 2016 and March 2017.

Results

The response rate to the online survey was 73.1% (144/197) with 68.1% (98/144) reporting an established clinical service and 3.5% (5/144) setting up a service. Approximately 30,000 tests are performed a year with 93.0% (80/86) using cycle ergometry. Colorectal surgical patients are the most frequently tested (89.5%, 77/86). The majority of tests are performed and interpreted by anaesthetists. There is variability in the methods of interpretation and reporting of CPET and limited external validation of results.

Conclusions

This survey has identified the continued expansion of perioperative CPET services in the UK which have doubled since 2011. The vast majority of CPET tests are performed and reported by anaesthetists. It has highlighted variation in practice and a lack of standardised reporting implying a need for practice guidelines and standardised training to ensure high-quality data to inform perioperative decision making.

Early unprotected return to contact sport after metacarpal fixation in professional athletes

AIMS

To determine whether an early return to sport in professional Australian Rules Football players after fixation of a non-thumb metacarpal fracture was safe and effective.

PATIENTS AND METHODS

A total of 16 patients with a mean age of 25 years (19 to 30) identified as having a non-thumb metacarpal fracture underwent open reduction and internal plate and screw fixation. We compared the players' professional performance statistics before and after the injury to determine whether there was any deterioration in their post-operative performance.

RESULTS

Of the 16, 12 sustained their fracture during the season: their mean time to return to unrestricted professional play was two weeks (1 to 5). All except two of the 48 player performance variables showed no reduction in performance post-operatively.

CONCLUSION

Our data suggest that professional athletes who sustained a non-thumb metacarpal fracture can safely return to professional play without restriction two weeks after internal fixation. Cite this article: Bone Joint J 2017;99-B:1343-7.

Cancer referral and treatment activity 2010-2015: a population-based study from Vancouver Island

INTRODUCTION

The years since 2005 have seen major changes in cancer treatment and significant increases in the number of anticancer drugs available. However, there are relatively few published data to reflect how those changes are affecting the activity and workload of oncology services. To explore the effects of those changes, we reviewed the population-based cancer treatment activity on Vancouver Island for the period 2010-2015.

METHODS

Information about new patient referrals, radiation courses, new chemotherapy cycles commenced, total intravenous (IV) chemotherapy treatment visits, and pharmacy activity for oral anticancer drug prescriptions was obtained from BC Cancer Agency databases.

RESULTS

During the 5-year study period, the Vancouver Island population increased by 2.8% and the number of new referrals to the BC Cancer Agency increased by 17.7%. The overall number of radiation courses increased by 6.1%. In contrast, IV chemotherapy activity increased by 52.1% for new courses commenced and by 62% for total IV chemotherapy attendances. Oral anticancer drug prescriptions rose by 22.9% during the 5-year period.

CONCLUSIONS

Our study documents substantial recent increases in cancer therapy activity in terms of patient referrals and particularly IV chemotherapy and oral anticancer therapy. The data reported here could be of value in planning for future care provision.

No breast cancer subgroup can be spared postoperative radiotherapy after breast-conserving surgery. Fifteen-year results from the Swedish Breast Cancer Group randomised trial, SweBCG 91 RT

BACKGROUND

Breast-conserving surgery (BCS) followed by radiotherapy (RT) is an established treatment for women with T1-2N0 breast cancers. Since subgroups of patients have low ipsilateral breast tumour recurrence (IBTR) rates, it is important to study whether RT is necessary for all patients.

PATIENTS AND METHODS

A total of 1187 women with primary T1-2N0M0 breast cancer were randomised, after standardised sector resection, to postoperative whole breast RT or no local treatment. Adjuvant systemic therapy was offered to patients with stage II cancers. Patients were followed with clinical examinations and annual mammography for 10 years and thereafter referred to the Swedish mammography screening program.

RESULTS

After 15 years of follow-up, a higher cumulative incidence of IBTR was observed in control patients, 23.9%, versus irradiated patients, 11.5%, P<0.001. Recurrence-free survival was inferior, 51.7% versus 60.4%, P=0.0013. The main effect of RT was seen during the first 5 years. However, overall survival was not significantly lower 68.4% versus 71.1%, P=0.68, nor was breast cancer-specific mortality significantly higher.

CONCLUSIONS

RT after BCS significantly reduced the incidence of IBTR at 15 years of follow-up. We were unable to identify subgroups which could be spared RT. Breast cancer mortality was not significantly reduced after RT. Good predictive markers for radiation sensitivity and improved adjuvant systemic therapy are needed to omit RT after BCS.

Incidence, clinical presentation and mortality of liver cirrhosis in Southern Sweden: a 10-year population-based study

BACKGROUND

In Sweden, the most common causes of liver cirrhosis are alcohol overconsumption and hepatitis C. However, recent data on the clinical characteristics of Swedish patients with cirrhosis are scarce.

AIMS

To determine the incidence, clinical presentation, aetiological spectrum and survival rates of liver cirrhosis in Southern Sweden from 2001 to 2011.

METHODS

We used population-based medical registries to conduct a cohort study of all patients with liver cirrhosis in the southernmost region of Sweden with a population of 1.17 million. Medical records and histopathology data were reviewed. Patients were classified according to aetiology, and clinical parameters were registered. Patients were followed until death or December 2014.

RESULTS

A total of 1317 patients with cirrhosis were identified. The crude annual incidence of cirrhosis was estimated at 14.1/100 000. The most common aetiology was alcohol overconsumption with or without additional causes of cirrhosis (58%) followed by HCV alone (13%) and cryptogenic cirrhosis (12%). At diagnosis, ascites occurred in 43%, variceal bleeding in 6% and overt encephalopathy in 4%. The median follow-up was 4.3 years. The total 1-, 5- and 10-year survival rates were 79%, 47% and 27% respectively. Survival rates were better for women than for men. A 10-year cumulative incidence of transplantation was 7.3%. Mortality was worst for alcoholic cirrhosis with concomitant HCV when adjusted for age and gender.

CONCLUSIONS

Sweden continues to have a low incidence of cirrhosis compared with other European countries. Mortality varies with gender, aetiology and severity at diagnosis. Patients with alcoholic cirrhosis with concomitant HCV infection fare worst.

Mammography casting-type calcification and risk of local recurrence in DCIS: analyses from a randomised study

BACKGROUND

We studied the association between mammographic calcifications and local recurrence in the ipsilateral breast.

METHODS

Case-cohort study within a randomised trial of radiotherapy in breast conservation for ductal cancer in situ of the breast (SweDCIS). We studied mammograms from cases with an ipsilateral breast event (IBE) and from a subcohort randomly sampled at baseline. Lesions were classified as a density without calcifications, architectural distortion, powdery, crushed stone-like or casting-type calcifications.

RESULTS

Calcifications representing necrosis were found predominantly in younger women. Women with crushed stone or casting-type microcalcifications had higher histopathological grade and more extensive disease. The relative risk (RR) of a new IBE comparing those with casting-type calcifications to those without calcifications was 2.10 (95% confidence interval (CI) 0.92-4.80). This risk was confined to in situ recurrences; the RR of an IBE associated with casting-type calcifications on the mammogram adjusted for age and disease extent was 16.4 (95% CI 2.20-140).

CONCLUSION

Mammographic appearance of ductal carcinoma in situ of the breast is prognostic for the risk of an in situ IBE and may also be an indicator of responsiveness to RT in younger women.

Clinical factors associated with the non-utilization of an anaesthesia incident reporting system

BACKGROUND

Incident reporting is a widely recommended method to measure undesirable events in anaesthesia. Under-utilization is a major weakness of voluntary incident reporting systems. Little is known about factors influencing reporting practices, particularly the clinical environment, anaesthesia team composition, severity of the incident, and perceived risk of litigation. The purpose of this study was to assess each of these, using an existing anaesthesia database.

METHODS

We performed a retrospective cohort study and analysed 46 207 surgical patients. We used multivariate analysis to identify factors associated with the non-utilization of the reporting system.

RESULTS

We found that in 7022 (15.1%) of the procedures performed, the incident reporting system was not used. Factors associated with the non-use of the system were regional anaesthesia/local anaesthesia, odds ratio (OR) 1.64 [95% confidence interval (CI) 1.03-2.62], emergency procedures OR 1.15 (95% CI: 1.05-1.27), and a consultant anaesthetist working without a trainee, OR 1.71 (95% CI: 1.03-2.82). In contrast, factors such as longer duration of surgery, OR 0.85 (95% CI: 0.76-0.94), the presence of a senior anaesthesia trainee, OR 0.86 (95% CI: 0.81-0.92), and the occurrence of severe complications with a high risk of litigation (i.e. death, nerve injuries) were less associated with a non-use of the reporting system, OR 0.65 (95% CI: 0.44-0.97). Team composition and time of day had no measurable impact on reporting practices.

CONCLUSIONS

Clinical factors play a significant role in the utilization of an anaesthesia incident reporting system and more particularly, severity of complications and higher liability risks which appear more as incentives than barriers to incident reporting.