Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

1625 Genome-Wide Association Analysis and Replication In 810,625 Individuals Identifies Novel Therapeutic Targets for Varicose Veins

Aim

To elucidate the genetic architecture of varicose veins (VVs) and identify genes and biological pathways central to their pathobiology.

Method

We performed hitherto the largest two-stage genome-wide association study of VVs in 401,656 subjects from UK Biobank, and replication in 408,969 subjects from 23andMe, Inc (total 135,514 VVs cases and 675,111 controls). Genes and biological pathways were prioritised using several bioinformatic approaches, and potential therapeutic targets were identified in the Open Targets Platform. A weighted genetic risk score (wGRS) for VVs was constructed to compare genetic susceptibility in surgical vs non-surgical VVs patients.

Results

109 genome-wide significant (P ≤ 5 × 10-8) loci were identified in UK Biobank, 46 of which successfully replicated in the 23andMe cohort. Twenty-eight loci have not been previously reported. We mapped 237 genes to these loci, many of which are biologically relevant and tractable to therapeutic targeting or repurposing (notably VEGFA, COL27A1, EFEMP1, PPP3R1 and NFATC2). Tissue enrichment analyses implicated vascular tissue, and several genes were enriched in biological pathways relating to extracellular matrix biology, inflammation, angiogenesis, lymphangiogenesis, vascular smooth muscle cell migration, and apoptosis. The wGRS analysis demonstrated that VVs patients requiring surgery have a higher inherent genetic susceptibility than those managed non-surgically (P = 2.46 × 10−13).

Conclusions

This study has advanced our understanding of VVs pathobiology with the identification of several biologically plausible genes and pathways, many of which demonstrate strong therapeutic potential. The wGRS correlated with disease severity, representing a first step in personalised medicine approaches to VVs.

13 Medical Students’ Mood Adversely Affected By COVID-19 Pandemic: An Interim Analysis from the SPICE-19 Prospective Cohort Study Of 2075 Medical Students and Interim Foundation Doctors

Introduction

In order to appropriately support medical students and foundation year doctors, it is imperative that we understand the impact the COVID-19 pandemic has had upon them. This study assessed the effects of the COVID-19 pandemic on medical students and interim foundation year doctors across the United Kingdom (UK), and the support that they received and sought.

Method

A prospective, observational, multicentre study was conducted. All medical students and interim foundation year doctors were eligible to participate.

Results

A total of 2075 individuals participated. There was a decrease in participants’ mood when comparing their mood before the pandemic to during the pandemic (p < 0.0001). Social distancing negatively impacted the mood of the greatest number of participants. All areas of life included in the study were found to have been significantly more negatively impacted than positively impacted (p < 0.0001). 931 participants wanted more support from their university.

Conclusions

When medical students return to their universities, there is likely to be a need for enhanced wellbeing support, adaptations in the short-term and long-term strategies for medical education, and provision of financial guidance. If no action is taken, there may be a knock-on effect on workforce planning and the health of our future workforce.

A deep learning approach to generate contrast-enhanced computerised tomography angiograms without the use of intravenous contrast agents

Introduction

Contrast-enhanced computerised tomographic (CT) angiograms are widely used in cardiovascular imaging to obtain a non-invasive view of arterial structures. In aortic aneurysmal disease (AAA), CT angiograms are required prior to surgical intervention to differentiate between blood and the intra-luminal thrombus, which is present in 95% of cases. However, contrast agents are associated with complications at the injection site as well as renal toxicity leading to contrast-induced nephropathy (CIN) and renal failure.

Purpose

We hypothesised that the raw data acquired from a non-contrast CT contains sufficient information to differentiate blood and other soft tissue components. Therefore, we utilised deep learning methods to define the subtleties between the various components of soft tissue in order to simulate contrast enhanced CT images without the need of contrast agents.

Methods

Twenty-six AAA patients with paired non-contrast and contrast-enhanced CT images were randomly selected from an ethically approved ongoing study (Ethics Ref 13/SC/0250) and used for model training and evaluation (13/13). Non-contrast axial slices within the aneurysmal region from 10 patients (n=100) were sampled for the underlying Hounsfield unit (HU) distribution at the lumen, intra-luminal thrombus and interface locations, identified from their paired contrast axial slices. Subsequently, paired axial slices within the training cohort were augmented in a ratio of 10:1 to produce a total of 23,551 2-D images. We trained a 2-D Cycle Generative Adversarial Network (cycleGAN) for this non-contrast to contrast transformation task. Model output was assessed by comparison to the contrast image, which serves as a gold standard, using image similarity metrics (ex. SSIM Index).

Results

Sampling HUs within the non-contrast CT scan across multiple axial slices (Figure 1A) revealed significant differences between the blood flow lumen (yellow), blood/thrombus interface (red), and thrombus (blue) regions (p&lt;0.001 for all comparisons). This highlighted the intrinsic differences between the regions and established the foundation for subsequent deep learning methods. The Non-Contrast-to-Contrast (NC2C)-cycleGAN was trained with a learning rate of 0.0002 for 200 epochs on 256 x 256 images centred around the aorta. Figure 1B depicts “contrast-enhanced” images generated from non-contrast CT images across the aortic length from the testing cohort. This preliminary model is able to differentiate between the lumen and intra-luminal thrombus of aneurysmal sections with reasonable resemblance to the ground truth.

Conclusion

This study describes, for the first time, the ability to differentiate between visually incoherent soft tissue regions in non-contrast CT images using deep learning methods. Ultimately, refinement of this methodology may negate the use of intravenous contrast and prevent related complications.

CTA Generation from Non-Contrast CTs

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Clarendon

Prevalence and Epidemiological Pattern of Abdominal Aortic Aneurysms in Africa: A Systematic Review

Introduction

The incidence of abdominal aortic aneurysms (AAAs) in high-income countries has been declining in the last three decades. However, in most low-income and middle-income countries especially in Africa, little is known about its burden. The absence of screening services for AAA in African countries makes it difficult to detect and promptly manage AAA before rupture, which has significant implications for mortality. This study sought to systematically assess the prevalence of AAA amongst patients visiting hospitals in Africa and evaluate its epidemiological pattern.

Materials and Methods

A systematic review was performed on the EMBASE, GLOBAL HEALTH, MEDLINE, and PUBMED databases. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement standards and protocol registered with PROSPERO (CRD42020162214). A data extraction tool was used to get relevant information from these studies. Quality assessment and risk of bias were performed using the Newcastle Ottawa Scale for cross-sectional studies. Results were summarised in tables, figures, and a forest plot. A narrative synthesis approach of the articles was taken.

Results

Two hundred and sixty-one studies were identified and after the exclusion of 246, a final 15 were deemed suitable for analysis. A total of 4012 participants were screened for AAA and of these, 129 cases were identified. The prevalence of AAA in these studies ranged from 0.7 to 6.4%. Male participants accounted for 115 (89.1%) of the cases. There was a wide age range (31-72 years) reflective of both its possible infective and degenerative aetiology. AAA was reported to be associated with hypertension, smoking, advanced age, coronary artery disease, and HIV infection. There was no association between AAA and diabetes. Over 50% of cases were identified incidentally. About one-third (23-54%) of the participants presented aortic rupture with a mortality rate ranging between 65 and 72%.

Conclusions

AAA prevalence in Africa is probably higher than the current thinking as there is no baseline data to compare with. Aetiologically, AAA was shown to be associated with hypertension, smoking, coronary artery disease, and possibly infectious pathologies like HIV. Large epidemiological studies would help better characterise AAA in this setting. Lastly, efforts targeting the reduction of the risk factors for AAA would go a long way in reducing the burden of AAA.

Energy Drinks and Myocardial Infarction

The popularity and use of energy drinks have accelerated over the past decade and are a health concern worldwide. The key ingredients of energy drinks include caffeine, guarana, taurine, ginseng, and sugar. Most of the well-known side effects due to consumption of energy drinks include tachycardia, headache, anxiety, and palpitations and are frequently attributed to caffeine. Recently, a few cases of life-threatening cardiovascular events in individuals who overdosed massive quantities of caffeinated energy drinks have been reported. In this case report, we are documenting a case of myocardial infarction in a 25-year-old man who presented to the emergency department with chest pain. The patient had been consuming massive quantities of caffeinated energy drinks daily for the past week. This case report and the few previously documented studies support a possible connection between caffeinated energy drinks and myocardial infarction. The purpose of this case report is to promote awareness in the general population and the medical staff about cardiac mortality due to overdosing of massive quantities of caffeinated energy drinks.

Applied Machine Learning for the Prediction of Growth of Abdominal Aortic Aneurysm in Humans

Objective

Accurate prediction of abdominal aortic aneurysm (AAA) growth in an individual can allow personalised stratification of surveillance intervals and better inform the timing for surgery. The authors recently described the novel significant association between flow mediated dilatation (FMD) and future AAA growth. The feasibility of predicting future AAA growth was explored in individual patients using a set of benchmark machine learning techniques.

Methods

The Oxford Abdominal Aortic Aneurysm Study (OxAAA) prospectively recruited AAA patients undergoing the routine NHS management pathway. In addition to the AAA diameter, FMD was systemically measured in these patients. A benchmark machine learning technique (non-linear Kernel support vector regression) was applied to predict future AAA growth in individual patients, using their baseline FMD and AAA diameter as input variables.

Results

Prospective growth data were recorded at 12 months (360 ± 49 days) in 94 patients. Of these, growth data were further recorded at 24 months (718 ± 81 days) in 79 patients. The average growth in AAA diameter was 3.4% at 12 months, and 2.8% per year at 24 months. The algorithm predicted the individual's AAA diameter to within 2 mm error in 85% and 71% of patients at 12 and 24 months.

Conclusions

The data highlight the utility of FMD as a biomarker for AAA and the value of machine learning techniques for AAA research in the new era of precision medicine.

•

Flow mediated dilatation of brachial artery is a biomarker of AAA progression.

•

It is feasible to predict future AAA growth in individuals using machine learning techniques.

•

Endothelial dysfunction is a key feature in human AAA disease.

Flow Mediated Dilatation and Progression of Abdominal Aortic Aneurysms

Objective/Background

Biomarker(s) for prediction of the future progression rate of abdominal aortic aneurysms (AAA) may be useful to stratify the management of individual patients. AAAs are associated with features of systemic inflammation and endothelial dysfunction. Flow mediated dilatation (FMD) of the brachial artery is a recognised non-invasive measurement for endothelial function. We hypothesised that FMD is a potential biomarker of AAA progression and reflects the temporal changes of endothelial function during AAA progression.

Methods

In a prospectively recruited cohort of patients with AAAs (Oxford Abdominal Aortic Aneurysm Study), AAA size was recorded by antero-posterior diameter (APD) (outer to outer) on ultrasound. Annual AAA progression was calculated by (ΔAPD/APD at baseline)/(number of days lapsed/365 days). FMD was assessed at the same time as AAA size measurement. Analyses of data were performed in the overall cohort, and further in subgroups of AAA by size (small: 30–39 mm; moderate: 40–55 mm; large: > 55 mm).

Results

FMD is inversely correlated with the diameter of AAAs in all patients (n = 162, Spearman’s r = −.28, p < .001). FMD is inversely correlated with AAA diameter progression in the future 12 months (Spearman’s r = −.35, p = .001), particularly in the moderate size group. Furthermore, FMD deteriorates during the course of AAA surveillance (from a median of 2.0% at baseline to 1.2% at follow-up; p = .004), while surgical repair of AAAs (n = 50 [open repair n = 22, endovascular repair n = 28)] leads to an improvement in FMD (from 1.1% pre-operatively to 3.8% post-operatively; p < .001), irrespective of the type of surgery.

Conclusion

FMD is inversely correlated with future AAA progression in humans. FMD deteriorates during the natural history of AAA, and is improved by surgery. The utility of FMD as a potential biomarker in the context of AAA warrants further investigation.

Delays in the presentation to stroke services of patients with transient ischaemic attack and minor stroke

BACKGROUND

The UK National Institute for Health and Care Excellence (NICE) guidelines state that carotid endarterectomy should be scheduled within 2 weeks of symptoms. The recent National Stroke Strategy has reduced the time interval to 48 h. This study aimed to review the possible delays.

METHODS

This study analysed patients with confirmed transient ischaemic attack (TIA) or minor stroke, referred to a single tertiary centre clinic and followed up 1 month after the event. A questionnaire was used to collect data on the rapid-access clinic pathway, and details of previous medication and treatment.

RESULTS

Some 150 patients presented with a confirmed TIA or minor stroke during a 5-month interval (June to October 2014). Fifty-one (34·0 per cent) had a history of TIA or stroke and 35 (23·3 per cent) had undergone an 'index' event in the 5 days before presentation. Forty-five patients (30·0 per cent) experienced a reduction or loss of vision. Of this group, 32 had a deficit in vision only, none of whom attributed these symptoms to a cerebrovascular event. Overall 92 (61·3 per cent) of the 150 patients had a delay in presentation to medical services. Forty-seven (31·3 per cent) had residual symptoms at the clinic appointment. Eighty-eight patients (58·7 per cent) did not think they were having a stroke and 54 (36·0 per cent) were unaware of the National Stroke Strategy (FAST campaign - Face, Arm, Speech, Time).

CONCLUSION

Two-thirds of patients were not aware they were having a stroke, one-third were unaware of the FAST campaign and nearly one-third presented with eye symptoms. Inclusion of eye symptoms and reaffirmation of the need to react might avoid unnecessary delays in the presentation of patients with TIA and minor stroke.

Inhibition of Infection of T-Cells with Human Immunodeficiency Virus Type 1 by Dideoxynucleosides Conjugated with Oligopeptides

We conjugated nucleoside derivatives that have anti-HIV-1 activities with oligopeptides that should bind to the gp120 of the HIV-1 virion, and examined their anti-HIV-1 activities. These derivates included 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-dideoxyuridine (ddU), 2′,3′-dideoxycytidine (ddC), 2′,3′-dideoxyinosine (ddI) and 2′,3′-dideoxyadenine (ddA). Dipeptides consisting of N-carbomethoxy-carbonyl-prolyl-phenylalanylbenzyl ester (CPF) and oligopeptides derived from the complementarity-determining region 2 (CDR2) of domain 1 of CD4 were synthesized. The N-terminals of these peptides were conjugated with the 5′OH of AZT, ddU, ddC, ddl or ddA through carbonyl moieties. CPF conjugated with AZT, ddC, ddl or ddA through two-carbonyl moieties exhibited powerful anti-HIV-1 activity, which was similar to that of the respective nucleosides when compared at the same molar concentration. No complex compound connected by a one-carbonyl moiety had anti-HIV-1 activity, whereas a tetrapeptide or octapeptide of the CDR2 region combined with AZT did have such activity. The toxicity of these CPF-containing compounds to human peripheral blood lymphocytes was slightly weaker than the toxicities of the corresponding nucleosides lacking CPF. Antiviral nucleosides containing oligopeptides may be used as lead compounds in an effort to isolate more effective and less cytotoxic anti-HIV-1 agents.

Age-specific incidence, risk factors and outcome of acute abdominal aortic aneurysms in a defined population

BACKGROUND

Contemporary population-based data on age-specific incidence and outcome from acute abdominal aortic aneurysm (AAA) events are needed to understand the impact of risk factor modification and demographic change, and to inform AAA screening policy.

METHODS

In a prospective population-based study (Oxfordshire, UK, 2002-2014), event rates, incidence, early case fatality and long-term outcome from all acute AAA events were determined, both overall and in relation to the four main risk factors: smoking, hypertension, male sex and age.

RESULTS

Over the 12-year interval, 103 incident acute AAA events occurred in the study population of 92,728 (men 72·8 per cent; 59·2 per cent 30-day case fatality rate). The incidence per 100,000 population per year was 55 in men aged 65-74 years, but increased to 112 at age 75-84 years and to 298 at age 85 years or above. Some 66·0 per cent of all events occurred in those aged 75 years or more. The incidence at 65-74 years was highest in male smokers (274 per 100,000 population per year); 27 (96 per cent) of 28 events in men aged less than 75 years occurred in ever-smokers. Mean(s.d.) age at event was lowest in current smokers (72·2(7·2) years), compared with that in ex-smokers (81·2(7·0) years) and never-smokers (83·3(7·9) years) (P < 0·001). Hypertension was the predominant risk factor in women (diagnosed in 93 per cent), with 20 (71 per cent) of all 28 events in women occurring in those aged 75 years or above with hypertension. The 30-day case fatality rate increased from 40 per cent at age below 75 years to 69 per cent at age 75 years or more (P = 0·008).

CONCLUSION

Two-thirds of acute AAA events occurred at age 75 years or above, and more than 25 per cent of events were in women. Taken with the strong associations with smoking and hypertension, these findings could have implications for AAA screening.

First Report of Apple Top Working Disease Caused by Viruses (Apple stem grooving virus, Apple chlorotic leaf spot virus, and Apple stem pitting virus) in Apple in India

Top working of apple (Malus domestica Borkh.) trees of old, unproductive, and less preferred cultivars with the newly introduced spur type commercial cultivars has become a common practice with many growers in the northwestern Himalayan region of India. Typical viral symptoms of curling, puckering, and necrosis on leaves were observed with an incidence of 80% on Red Chief, Super Chief, Scarlet Spur, Schillet Spur, Washington Red Delicious, and many other newly introduced cultivars during surveys conducted in May and June 2009. Leaf samples from top worked trees were tested for the presence of Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV), and Apple stem pitting virus (ASPV) by employing biological detection (herbaceous and woody indicators), double antibody sandwich (DAS)-ELISA), and reverse transcriptase (RT)-PCR based detection. Mechanical transmission to herbaceous indicators produced chlorotic lesions on Chenopodium quinoa and C. amaranticolor, whereas marginal necrosis was induced on Phaseolous vulgaris within 9 to 21 days after sap inoculations. All three viruses, i.e., ASGV, ASPV, and ACLSV, were detected from these herbaceous indicators in DAS-ELISA (BIOREBA AG, Switzerland). Furthermore, symptoms similar to those observed in orchards were produced when the test budwood was inoculated onto the woody indicator (M. pumila 'Spy 227') plant by double grafting, grafting cum budding, and double budding methods within time periods ranging from 4 months in double grafting, 5 months in double budding, to 1 year 4 months in the grafting cum budding method. The presence of all three viruses was confirmed by DAS-ELISA again in Spy 227 woody indicator. PCR detection was carried out by using the coat protein gene specific primers (ASGV5641 [forward], ASGV6396 [reverse]; ACLSV6784 [forward], ACLSV7365 [reverse] [2]; ASP-C [sense], ASP-A [anti-sense] [1]) of all the viruses detected through ELISA. The amplified products were cloned, sequenced, and deposited in NCBI (GenBank Accessions KC110892 for ASGV, KC154859 for ASPV, and KC154862 for ACLSV). BLASTn analysis showed the ASGV isolate had 97 to 98% sequence identity with Indian (FM204881) and Brazilian (AF438409) ASGV isolates. The ASPV and ACLSV isolates had 98% and 99% sequence identity with Chinese (JF895517) and Japanese (AB326230) isolates, respectively. To the best of our knowledge, this is the first report of apple top working disease associated with ASGV, ASPV, and ACLSV infection in commercial cultivars of apple from India and seems to be a serious threat for growing virus-free healthy stocks in orchards. Top working disease in apple associated with ASGV, ASPV, and ACLSV viruses has been reported from Japan (3,4). References: (1) J. K. Kundu et al. Plant Prot. Sci. 39:88, 2003. (2) O. Nickel et al. Fitopatol. Brasil. 26:655, 2001. (3) H. Yanase. Bull. Fruit Tree Res. Stn., Japan Ser. C 1:47, 1974. (4) H. Yanase et al. Acta Hortic. 44:221, 1975.

A survey of instructions to authors in surgical journals on reporting by CONSORT and PRISMA

INTRODUCTION

Guidance has been published on how best to report randomised controlled trials (Consolidated Standards of Reporting Trials – CONSORT) and systematic reviews (Preferred Reporting Items for Systematic Reviews and Meta-Analyses – PRISMA). The aim of this study was to establish to what extent surgical journals formally endorse CONSORT and PRISMA in the respective reporting of randomised controlled trials and systematic reviews.

METHODS

Overall, 136 surgical journals indexed in Journal Citation Reports® were studied. Author guidelines were scrutinised for the following guidance: conflict of interests (COI), the Uniform Requirements for Manuscripts (URM), clinical trial registration, CONSORT and PRISMA.

RESULTS

The frequency of guidance endorsement was found to be as follows: COI 82%, URM 62%, trial registration 32%, CONSORT 29% and PRISMA 10%. Journals with a higher impact were more likely to adopt trial registration, CONSORT and PRISMA. Journals with editorial offices in the UK were more likely to insist on disclosure of COI and to endorse CONSORT.

CONCLUSIONS

Guidelines produced to improve publication practice have not been implemented widely by surgical journals. This may contribute to an overall poorer quality of published research. Editors of surgical journals should uniformly endorse reporting guidance and update their instructions to authors to reflect this.

Increased use of laparoscopy in acute right iliac fossa pain - is it good for patients?

AIM

The use of laparoscopy, with or without appendicectomy, is becoming more common in the management of acute right iliac fossa (RIF) pain, but little is known of the 'unintended' consequences of this change. This study aimed to evaluate the impact of increased use of laparoscopy on the number and type of patients treated surgically and on the rate of negative appendicectomy.

METHOD

A prospective audit was carried out of admissions to a teaching hospital over two, 3-month periods during 2007 and 2008. The management, investigations and outcome of patients presenting with RIF pain were studied.

RESULTS

Admissions were stable over the two time-periods. There was a significant increase in the number of laparoscopic operations performed, from 22.5% (14/62) in 2007 to 85.7% (72/84) in 2008 (P < 0.0001), and the percentage of patients undergoing surgery rose from 55.4% (n = 62) in 2007 to 71.2% (n = 84) in 2008 (P < 0.01). In 2008, female patients were more likely to have surgery, an increase from 37.1% to 66.2% (P < 0.001), and were more likely to have a laparoscopic procedure, an increase from 50% to 98% (P < 0.0001). The rate of histologically confirmed appendicitis did not increase significantly (50/122 vs 57/118; P = 0.25), but the number of patients with a normal appendix either left in situ because it was macroscopically normal or found to be histologically normal following excision, increased significantly, from 9.01% in 2007 to 21.2% in 2008 (P < 0.01). The diagnostic value of pelvic ultrasound decreased from 75.6% of examinations in 2007 to 54.5% in 2008 (P = 0.039).

CONCLUSION

An increase in laparoscopic procedures has resulted in more operations in women, an associated higher negative appendicectomy rate and decreased usefulness of pelvic ultrasound. Increased use of laparoscopy needs to be balanced against the diagnostic benefits of 'negative' laparoscopy.

The effects of aviation-style non-technical skills training on technical performance and outcome in the operating theatre

Unintended harm to patients in operating theatres is common. Correlations have been demonstrated between teamwork skills and error rates in theatres. This was a single-institution uncontrolled before-after study of the effects of "non-technical" skills training on attitudes, teamwork, technical performance and clinical outcome in laparoscopic cholecystectomy (LC) and carotid endarterectomy (CEA) operations. The setting was the theatre suite of a UK teaching hospital. Attitudes were measured using the Safety Attitudes Questionnaire (SAQ). Teamwork was scored using the Oxford Non-Technical Skills (NOTECHS) method. Operative technical errors (OTEs), non-operative procedural errors (NOPEs), complications, operating time and length of hospital stay (LOS) were recorded. A 9 h classroom non-technical skills course based on aviation "Crew Resource Management" (CRM) was offered to all staff, followed by 3 months of twice-weekly coaching from CRM experts. Forty-eight procedures (26 LC and 22 CEA) were studied before intervention, and 55 (32 and 23) afterwards. Non-technical skills and attitudes improved after training (NOTECHS increase 37.0 to 38.7, t = -2.35, p = 0.021, SAQ teamwork climate increase 64.1 to 69.2, t = -2.95, p = 0.007). OTEs declined from 1.73 to 0.98 (u = 1071, p = 0.009), and NOPEs from 8.48 to 5.16 per operation (t = 4.383, p<0.001). These effects were stronger in the LC group than in CEA procedures. The operating time was unchanged, and a non-significant reduction in LOS was observed. Non-technical skills training improved technical performance in theatre, but the effects varied between teams. Considerable cultural resistance to adoption was encountered, particularly among medical staff. Debriefing and challenging authority seemed more difficult to introduce than other parts of the training. Further studies are needed to define the optimal training package, explain variable responses and confirm clinical benefit.

Profile of Culture Positive Enteric Fever from Bangalore

BACKGROUND

Enteric fever is endemic in India. The aim of this study was to analyse the clinical, laboratory, antibiotic sensitivity profile and response to antibiotics of culture positive enteric fever patients from Bangalore.

METHODS

In this retrospective study only culture positive enteric fever patients were taken and their clinical, laboratory, antibiotic sensitivity profile and the clinical response to antibiotics studied.

RESULT

Eighty one culture positive enteric fever patients were taken into the study. Presenting symptoms included fever, pain abdomen (18.5%), loose stools (25%), vomiting (33%) and headache (30%). Absolute bradycardia at admission was not found in any of our patients. Normal or low total leucocyte count was seen in 97.5%. Typhoid hepatitis was seen in 8.5%. Salmonella enterica subspecies enterica serovar typhi (S typhi) were isolated in 80% of cases; 83% of all cases showed nalidixic acid resistance. All isolates were sensitive to chloramphenicol and third generation cephalosporins. Ciprofloxacin resistance was found in 19% cases. The time to defervescence in patients treated with ceftriaxone was 4.3 days. There was no statistical difference in time to defervescence in nalidixic acid resistant and sensitive strains. Complications included gastro intestinal bleed and encephalopathy.

CONCLUSION

Prevalence of nalidixic acid resistance is high, while clinical resistance to quinolones may be higher than that found in the laboratory which requires detailed study. Chloramphenicol sensitivity has returned and nalidixic acid resistant and sensitive isolates are uniformly sensitive to third generation cephalosporins with no difference in time to defervescence.

Hugh Cairns and the origin of British neurosurgery

Sir Hugh Cairns, the first Nuffield Professor of Surgery in Oxford and consultant neurosurgeon to the Royal Army Medical Corps during World War II, was a leader in helping to establish neurosurgery as a speciality in Britain. After learning the craft from Dr Harvey Cushing in Boston, Cairns fought against the general surgical orthodoxy in London to establish the first specialised neurosurgical unit in a teaching hospital. We review his early life, training with Cushing, his inspiring character and administrative prowess which not only helped to win the battle for neurosurgery in London but also helped to establish the Oxford Clinical School and to save thousands of lives during the Second World War.

The acute blue finger: management and outcome

INTRODUCTION

The objective was to assess the management, and short- and longer-term outcome of patients presenting with an acute blue finger.

PATIENTS AND METHODS

This was a retrospective, case-note review and prospective follow-up by telephone and general practitioner enquiry. All patients who presented with sudden onset blue discolouration of a finger within the previous 72 h, with normal radial and ulnar pulses, were included.

RESULTS

From 2000 to 2006, 22 patients, 15 female, 7 male, were reviewed. Median age was 56 years (range, 19-88 years). Median time from onset of blue finger was 6 days (range 1 day to 3 months). In most cases (17), no underlying cause was identified. Five patients had an underlying cause; two had symptoms compatible with Raynaud's phenomenon, one patient had signs (later confirmed on MRA) of arterial thoracic outlet syndrome and two had polycythaemia (haemoglobin > 17 g/dl). Otherwise, all laboratory investigations were normal. Upper limb duplex, echocardiogram and 24-h cardiac tapes were normal in all cases. Median follow-up was 19 months. Three patients had recurrent symptoms in the finger. No patient suffered tissue loss or loss of digit(s), and none had stroke or arterial embolisation.

CONCLUSIONS

The acute blue finger is a benign condition not suggestive of arterial embolisation. Tissue or digit loss is not a threat and, in the longer term, there is no threat of embolisation to other vascular sites.

Efficacy and limitations of the neuroform stent system for intracranial aneurysms

SUMMARY

We performed aneurysm embolization in seven patients using a self-expandable Neuroform stent (Boston Scientific/Target, Fremont, CA) and coils to cover the aneurysm neck and fill the aneurysm sac. Seven patients with an average age of 45 were treated in the period from October 2002 to July 2003. The aneurysm lesions involved the basilar trunk in one case, the basilar-superior cerebellar artery in one case, the internal carotid artery in four cases, and the middle cerebral artery in one case. The ruptured lesions involved the internal carotid artery in one case and the middle cerebral artery in one case. We used a Neuroform stent measuring 4.5 x 20 mm in four cases, 4.5 x 15 mm in two cases, 3.5 x 20 mm in one case, and 3.5 x 15 mm in one case. We performed aneurysm coil embolization after Neuroform stenting in all cases without development of neurological deficits caused by the interventional procedure. In performing these procedures, we investigated the efficacy and limitations of the Neuroform stent system for intracranial aneurysms. The advantages of Neuroform self-expanding stents include better flexibility and adaptability to different vessel sizes, but this stent system presents various technical difficulties during delivery.

Teamwork and error in the operating room: analysis of skills and roles

OBJECTIVE

To analyze the effects of surgical, anesthetic, and nursing teamwork skills on technical outcomes.

SUMMARY BACKGROUND DATA

The value of team skills in reducing adverse events in the operating room is presently receiving considerable attention. Current work has not yet identified in detail how the teamwork and communication skills of surgeons, anesthetists, and nurses affect the course of an operation.

METHODS

Twenty-six laparoscopic cholecystectomies and 22 carotid endarterectomies were studied using direct observation methods. For each operation, teams' skills were scored for the whole team, and for nursing, surgical, and anesthetic subteams on 4 dimensions (leadership and management [LM]; teamwork and cooperation; problem solving and decision making; and situation awareness). Operating time, errors in surgical technique, and other procedural problems and errors were measured as outcome parameters for each operation. The relationships between teamwork scores and these outcome parameters within each operation were examined using analysis of variance and linear regression.

RESULTS

Surgical (F(2,42) = 3.32, P = 0.046) and anesthetic (F(2,42) = 3.26, P = 0.048) LM had significant but opposite relationships with operating time in each operation: operating time increased significantly with higher anesthetic but decreased with higher surgical LM scores. Errors in surgical technique had a strong association with surgical situation awareness (F(2,42) = 7.93, P < 0.001) in each operation. Other procedural problems and errors were related to the intraoperative LM skills of the nurses (F(5,1) = 3.96, P = 0.027).

CONCLUSIONS

Detailed analysis of team interactions and dimensions is feasible and valuable, yielding important insights into relationships between nontechnical skills, technical performance, and operative duration. These results support the concept that interventions designed to improve teamwork and communication may have beneficial effects on technical performance and patient outcome.

Administration of 75 mg of aspirin daily for 28 days is sufficient prophylaxis against renal transplant vein thrombosis

INTRODUCTION

Early postoperative renal transplant vein thrombosis results in graft loss. We evaluate the effect of administering aspirin 75 mg daily for 28 days following transplantation.

METHODS

Prospectively collected data on the outcome of all transplants undertaken in our unit in the five-year period from January 1997 to January 2002 were reviewed, and in cases of graft failure before three months the cause was defined.

RESULTS

In the study period, a total of 401 transplants were undertaken (311 cadaveric and 90 living related). There was one case of renal transplant vein thrombosis (0.25%). This represents a significant reduction on the unit's historical incidence of 5.8%, P < 0.001.

CONCLUSION

Aspirin 75 mg daily is adequate to virtually abolish renal transplant vein thrombosis and has a role in thromboprophylaxis in other situations where heparin is contraindicated.

Urinothorax: an unusual cause of pleural effusion

Urinothorax refers to the presence of urine in the pleural space secondary to obstructive uropathy, and is an unusual cause of pleural effusion. The importance of recognising this entity lies in the fact that the condition is completely reversible following relief of urinary tract obstruction. We describe a 35-year-old man who developed urinothorax following a percutaneous nephrolithotomy for renal calculi. We also reviewed the literature for reported cases between 1968 and 2006.

Thromboelastographic Changes Following Nonionic Contrast Medium Injection During Transfemoral Angiography in Patients with Peripheral Arterial Occlusive Disease

BACKGROUND/PURPOSE

Patients with peripheral arterial occlusive disease (PAOD) are known to be systemically hypercoagulable and there is concern that exposing them to contrast media during angiography may exacerbate that thrombotic tendency. Many in vitro studies in which blood is exposed to contrast media suggest that nonionic contrast medium (NICM) has a weaker anticoagulant effect than ionic contrast medium (ICM) and some studies suggest that NICM can lead to activation of coagulation thus increasing the risk of thrombotic events where it is employed. We have looked at the changes in coagulation adjacent to the site of contrast injection/potential angioplasty to determine the magnitude of change locally.

METHODS

We measured changes in the coagulability of aortic blood samples immediately before and within 2 min after injection of the last bolus of iohexol (NICM) prior to any intervention procedure in 30 patients with PAOD. Samples were analyzed using thromboelastography (TEG) to identify changes in the coagulability of the aortic blood samples.

RESULTS

TEG tracings of samples taken from the aorta after injection of NICM showed a significant increase in R time (time to fibrin formation) (p = 0.036) and in k time (dynamics of clot formation) (p = 0.028) and a reduction in Angle (decreased acceleration of fibrin build-up) (p = 0.013), Maximal amplitude (MA) (reduced ultimate clot strength) (p = 0.018) and Coagulation Index (CI) (p = 0.032).

CONCLUSION

These changes in TEG parameters show that the local effect of NICM is a reduction in coagulation activity rather than the activation suggested by some previous studies.

Preoperative Duplex on Admission Prevents Unnecessary Carotid Surgery

OBJECTIVES

Our unit policy is to duplex on admission all patients undergoing carotid endarterectomy to confirm patency. The aim of this study was to evaluate whether this had led to avoidance of unnecessary carotid surgery in a significant number of patients.

METHODS

Over a 7-year period from January 1997 to December 2003, a total of 475 patients were scheduled for carotid endarterectomy. Of these, 439 patients subsequently underwent carotid endarterectomy. These data were obtained from prospectively collected vascular departmental records and we also hand searched notes of the 36 cancelled patients.

RESULTS

There were a total of 36 cancellations for various reasons. Of these, 8 were clearly occluded on duplex. A further 16 were highly suspicious of occlusion on duplex and thus surgery was deferred and selective angiography was undertaken. Of these 9 were confirmed to be occluded on angiogram and a further 4 had severe stenoses or virtual occlusion, 3 patients had a distal internal carotid artery occlusion. Thus a total of 24 patients had an occlusion either diagnosed directly on duplex or because of suspicion on duplex. Unnecessary carotid surgery was avoided in 24 of 475 (5%) of patients.

CONCLUSION

This study shows that a preoperative duplex on admission for surgery results in 1 of 20 patients avoiding unnecessary carotid surgery.

Double-lumen balloon microcatheter-assisted occlusion of cerebral vessels with coils: a technical note

The purpose of this study was to describe a balloon-assisted double-lumen microcatheter technique to perform a controlled and tight coil packing of a vascular segment for vessel occlusion. This technique can be performed immediately after a test occlusion with the balloon kept in place and was, as illustrated in six cases, in our experience safe, straight forward to use and fast.

Changes in blood coagulability as it traverses the ischemic limb

OBJECTIVE

We undertook this study to determine whether changes in blood coagulability associated with peripheral arterial occlusive disease are due to contact with the atherosclerotic arterial wall or passage through distal ischemic tissue.

METHODS

Thirty patients with peripheral arterial occlusive disease undergoing angiography participated in the study. Ankle-brachial pressure index was recorded before intervention. Blood samples taken from the aorta, common femoral artery, and common femoral vein were analyzed at thromboelastography. Angiograms were scored for stenotic disease by a radiologist blinded to the other results.

RESULTS

When femoral artery samples were compared with aortic samples there was a decrease in reaction time (R; P <.05), an increase in maximum amplitude (MA; P <.05), and an increase in coagulation index (CI; P <.002), indicating an increase in coagulability as blood flowed down the iliac segment. These changes also correlated (DeltaR, r = 0.442, P <.05; DeltaMA, r = 0.379, P <.05; DeltaCI, r = 0.429, P <.05) with the severity of disease in the ipsilateral iliac segment. Significant differences in R (P <.05), angle (P <.05), MA (P <.005), and CI (P <.001) between common femoral arterial and venous samples confirmed that venous samples were more coagulable in this group of patients. This difference in Thromboelastography parameters across the arteriovenous segment correlated inversely with the degree of ischemia (represented by ankle-brachial pressure index; DeltaCI, r = -0.427, P <.05; DeltaMA, r = -0.370, P <.05) in the puncture side limb.

CONCLUSION

Passage of blood down an atherosclerotic artery leads to an increase in coagulability proportional to the degree of stenosis in that vessel. Passage of blood through ischemic tissue may also contribute to increased coagulability in peripheral arterial occlusive disease.

Radiological intervention to the iliac segments for patients with claudication and coexistent significant infrainguinal disease

Background

The policy with regard to patients with lifestyle-limiting intermittent claudication is to investigate with duplex ultrasonography and then to treat suitable lesions in the aortoiliac system with balloon angioplasty with or without stenting. In those with coexistent infrainguinal disease, further management is conservative. The aim of this study was to assess the outcome of iliac intervention in this group of patients.

Methods

Over 30 months 600 patients with intermittent claudication were assessed; 110 subsequently underwent balloon angioplasty (87 aortoiliac and 23 infrainguinal). Of those undergoing aortoiliac angioplasty 47 also had significant infrainguinal disease. These 47 had a median claudication distance of 80 m and median maximum walking distance 180 m. They underwent angioplasty of 61 arterial segments (one aorta, 32 common iliac, 28 external iliac), with 11 stents deployed in eight patients. There were no immediate complications and a technically satisfactory result was obtained in all but one patient. All patients were reassessed at 6 weeks.

Results

The Table gives the findings at 6 weeks.

Fifteen patients (32 per cent) had a pain-free walking distance greater than 450 m and a further two were limited by angina rather than claudication. Overall the 47 patients had a median claudication distance of 270 m and median maximum walking distance of 420 m.

Conclusion

Even in the presence of significant infrainguinal disease, angioplasty in the aortoiliac segments at least doubles the claudication distance in 70 per cent of patients, and appears to be safe. Radiological intervention in these patients is worthwhile.

Carotid artery plaque morphology is related to time since last neurological event

Background

Conflicting conclusions have been drawn regarding the relationship of plaque morphology and symptomatology of carotid atherosclerosis. Previous papers have examined the nature of symptoms and the degree of stenosis. This study determined whether plaque morphology was related to symptomatology with regard to the nature, timing and amount of symptoms, and the degree of stenosis.

Methods

In 60 consecutive carotid endarterectomies the symptoms (transient ischaemic attack (TIA), cerebrovascular accident (CVA), amaurosis fugax (AF), other), time between last neurological event and surgery, number of episodes and the degree of stenosis were recorded prospectively. The plaques removed at surgery were examined immediately and by histology. The macroscopic appearance was recorded as stable (fibrous or fatty plaque with or without calcification) or unstable (plaques with ulceration, rupture or thrombosis). Microscopic grading as either stable or unstable was done using the criteria of a consensus document (Circulation 1995).

Results

There were more CVAs (11 of 34 versus four of 26), and fewer TIAs (17 of 34 versus 16 of 26) and instances of AF (six of 34 versus six of 26) when the plaque was deemed unstable, but this was not statistically significant. Twenty of 34 patients with an unstable plaque had an event in the 6 weeks preceding surgery compared with one of 26 with a stable plaque (P &lt; 0·001). Unstable plaques were associated with more events (12 of 34 patients had more than three events compared with one of 26 with a stable plaque; P = 0·012). Degree of stenosis was not related to plaque morphology. In a logistic regression model, the only predictive factor for finding an unstable plaque at surgery was the timing of the last neurological event (P &lt; 0·001).

Conclusion

The importance of time since the last neurological event in predicting plaque instability is shown. This factor may help to clarify future studies attempting to determine plaque morphology before operation by ultrasonography.