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.

High-throughput genotyping of high-homology mutant mouse strains by next-generation sequencing

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Next generation sequencing is a scalable solution to genotyping mutant mice.

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Ratios of wild type and mutant sequence counts are used to call the genotype.

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Hundreds of samples can be multiplexed into one sequencing experiment.

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Amplification of high-homology genes can be easily filtered out during analysis.

Genotyping of knockout alleles in mice is commonly performed by end-point PCR or gene-specific/universal cassette qPCR. Both have advantages and limitations in terms of assay design and interpretation of results. As an alternative method for high-throughput genotyping, we investigated next generation sequencing (NGS) of PCR amplicons, with a focus on CRISPR-mediated exon deletions where antibiotic selection markers are not present. By multiplexing the wild type and mutant-specific PCR reactions, the genotype can be called by the relative sequence counts of each product. The system is highly scalable and can be applied to a variety of different allele types, including those produced by the International Mouse Phenotyping Consortium and associated projects.

One potential challenge with any assay design is locating unique areas of the genome, especially when working with gene families or regions of high homology. These can result in misleading or ambiguous genotypes for either qPCR or end-point assays. Here, we show that genotyping by NGS can negate these issues by simple, automated filtering of undesired sequences. Analysis and genotype calls can also be fully automated, using FASTQ or FASTA input files and an in-house Perl script and SQL database.

Rapid conversion of EUCOMM/KOMP-CSD alleles in mouse embryos using a cell-permeable Cre recombinase

We describe here use of a cell-permeable Cre to efficiently convert the EUCOMM/KOMP-CSD tm1a allele to the tm1b form in preimplantation mouse embryos in a high-throughput manner, consistent with the requirements of the International Mouse Phenotyping Consortium-affiliated NIH KOMP2 project. This method results in rapid allele conversion and minimizes the use of experimental animals when compared to conventional Cre transgenic mouse breeding, resulting in a significant reduction in costs and time with increased welfare benefits.

Molecular characterization of mutant mouse strains generated from the EUCOMM/KOMP-CSD ES cell resource

The Sanger Mouse Genetics Project generates knockout mice strains using the EUCOMM/KOMP-CSD embryonic stem (ES) cell collection and characterizes the consequences of the mutations using a high-throughput primary phenotyping screen. Upon achieving germline transmission, new strains are subject to a panel of quality control (QC) PCR- and qPCR-based assays to confirm the correct targeting, cassette structure, and the presence of the 3' LoxP site (required for the potential conditionality of the allele). We report that over 86 % of the 731 strains studied showed the correct targeting and cassette structure, of which 97 % retained the 3' LoxP site. We discuss the characteristics of the lines that failed QC and postulate that the majority of these may be due to mixed ES cell populations which were not detectable with the original screening techniques employed when creating the ES cell resource.

Mouse large-scale phenotyping initiatives: overview of the European Mouse Disease Clinic (EUMODIC) and of the Wellcome Trust Sanger Institute Mouse Genetics Project

Two large-scale phenotyping efforts, the European Mouse Disease Clinic (EUMODIC) and the Wellcome Trust Sanger Institute Mouse Genetics Project (SANGER-MGP), started during the late 2000s with the aim to deliver a comprehensive assessment of phenotypes or to screen for robust indicators of diseases in mouse mutants. They both took advantage of available mouse mutant lines but predominantly of the embryonic stem (ES) cells resources derived from the European Conditional Mouse Mutagenesis programme (EUCOMM) and the Knockout Mouse Project (KOMP) to produce and study 799 mouse models that were systematically analysed with a comprehensive set of physiological and behavioural paradigms. They captured more than 400 variables and an additional panel of metadata describing the conditions of the tests. All the data are now available through EuroPhenome database (www.europhenome.org) and the WTSI mouse portal (http://www.sanger.ac.uk/mouseportal/), and the corresponding mouse lines are available through the European Mouse Mutant Archive (EMMA), the International Knockout Mouse Consortium (IKMC), or the Knockout Mouse Project (KOMP) Repository. Overall conclusions from both studies converged, with at least one phenotype scored in at least 80% of the mutant lines. In addition, 57% of the lines were viable, 13% subviable, 30% embryonic lethal, and 7% displayed fertility impairments. These efforts provide an important underpinning for a future global programme that will undertake the complete functional annotation of the mammalian genome in the mouse model.

The mammalian gene function resource: the International Knockout Mouse Consortium

In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research.

Large-scale mouse knockouts and phenotypes

Standardized phenotypic analysis of mutant forms of every gene in the mouse genome will provide fundamental insights into mammalian gene function and advance human and animal health. The availability of the human and mouse genome sequences, the development of embryonic stem cell mutagenesis technology, the standardization of phenotypic analysis pipelines, and the paradigm-shifting industrialization of these processes have made this a realistic and achievable goal. The size of this enterprise will require global coordination to ensure economies of scale in both the generation and primary phenotypic analysis of the mutant strains, and to minimize unnecessary duplication of effort. To provide more depth to the functional annotation of the genome, effective mechanisms will also need to be developed to disseminate the information and resources produced to the wider community. Better models of disease, potential new drug targets with novel mechanisms of action, and completely unsuspected genotype-phenotype relationships covering broad aspects of biology will become apparent. To reach these goals, solutions to challenges in mouse production and distribution, as well as development of novel, ever more powerful phenotypic analysis modalities will be necessary. It is a challenging and exciting time to work in mouse genetics.

2008 Niday Perinatal Database quality audit: report of a quality assurance project

INTRODUCTION

This quality assurance project was designed to determine the reliability, completeness and comprehensiveness of the data entered into Niday Perinatal Database.

METHODS

Quality of the data was measured by comparing data re-abstracted from the patient record to the original data entered into the Niday Perinatal Database. A representative sample of hospitals in Ontario was selected and a random sample of 100 linked mother and newborn charts were audited for each site. A subset of 33 variables (representing 96 data fields) from the Niday dataset was chosen for re-abstraction.

RESULTS

Of the data fields for which Cohen's kappa statistic or intraclass correlation coefficient (ICC) was calculated, 44% showed substantial or almost perfect agreement (beyond chance). However, about 17% showed less than 95% agreement and a kappa or ICC value of less than 60% indicating only slight, fair or moderate agreement (beyond chance).

DISCUSSION

Recommendations to improve the quality of these data fields are presented.

Endovascular embolization of visceral artery aneurysms with ethylene-vinyl alcohol (Onyx): a case series

We report the application of the liquid embolic agent ethylene-vinyl alcohol (Onyx; MicroTherapeutics, Irvine, CA, USA) in the management of visceral artery aneurysms. The technique and indications for using Onyx are discussed with emphasis on the management of wide-necked aneurysms and maintenance of patency of the parent vessel. None of the cases was considered suitable for stent-grafting or embolization with conventional agents. Two aneurysms of the renal artery bifurcation and one aneurysm of the inferior pancreaticoduodenal artery were treated. Following treatment there was complete exclusion of all aneurysms. There was no evidence of end-organ infarction. Follow-up with intervals up to 6 months has shown sustained aneurysm exclusion. Onyx is known to be effective in the management of intracranial aneurysms. Our experience demonstrates the efficacy and applicability of the use of Onyx in the treatment of complex visceral artery aneurysms.

The impact of clinical audit on antibiotic prescribing in general dental practice

OBJECTIVE

To reduce the number of antibiotics inappropriately prescribed by general dental practitioners, and to increase overall prescription accuracy.

DESIGN

A prospective clinical audit carried out between September and March of 2002-3 and 2003-4.

SETTING

General dental practices in Eastern England.

SUBJECTS AND METHODS

The pre-audit antibiotic prescribing practices of 212 general dental practitioners were recorded over an initial six week period. On each occasion this included which antibiotic had been chosen, together with its dose, frequency and duration, as well as the clinical condition and reason for which the prescription had been raised. When related to prophylaxis, the patient's medical history was also noted. Following education on contemporary prescribing guidelines, presentations which illustrated the practitioners' previous errors, and the agreement of standards to be achieved, the process was repeated for another six weeks, and the results compared.

RESULTS

In the pre-audit period, 2,951 antibiotic prescriptions were issued, and during the audit this was reduced by 43.6% to 1,665. The majority were for therapeutic reasons, with only 10.5% and 13.6% for medical prophylaxis during the pre-audit and audit periods respectively. Over both periods, amoxicillin and metronidazole were the two most commonly prescribed antimicrobials (63.4% and 21.2% respectively). In the pre-audit period, only 43% of all prescriptions were error free in dose, frequency, and/or duration of use, but this rose significantly to 78% during the audit. Equally, using contemporary published guidelines, out of all the prescriptions made in the pre-audit period, only 29.2% were deemed to be justified, as compared to 48.5% during the audit.

CONCLUSIONS

Clinical audit, in conjunction with education, and prescribing guidelines can favourably change antibiotic prescribing patterns among general dental practitioners.

Health-related quality of life in type 2 diabetes (TARDIS-2)

BACKGROUND

Type 2 diabetes is now recognized as a major public health concern but its burden on society is under-researched.

METHODS

T(2)ARDIS was a postal survey of 1578 people with type 2 diabetes across four UK centres, incorporating measures of resource use, treatment satisfaction and health-related quality of life (HrQoL). The findings included data on the EQ-5D that enabled the HrQoL burden of the disease to be established by comparison with equivalent data for the general population and the diabetic population as a whole from the 1996 Health Survey of England.

RESULTS

The results indicate a significant deficit experienced by people with type 2 diabetes vs. their age group peers in the general population. The proportion of T(2)ARDIS respondents reporting problems increases in relation to the presence of complications, and microvascular complications appear to have more impact than macrovascular complications.

CONCLUSIONS

This confirms the need for treatment policies to focus on reducing the risk of such complications and hence improve patients' HrQoL.

Dentofacial form in the five-year-old child with unilateral cleft lip and palate

It is generally believed that studies of outcome for children with clefts of the lip and palate should be based on patients who are in their teens. This means that health care workers who look after these children would have to wait many years until the quality of treatment could be evaluated. In this study, significant differences between two centers, Oslo and Manchester, in facial form at the age of 5 years were detected. Based on cephalometric analysis, children from Manchester were more likely to have a retrognathic maxilla with the upper lip significantly behind the esthetic plane. An important future step may be the setting up of "reference centers" with a large archive of database information for each racial group. This would assist smaller centers in comparing their outcomes.

Cimetidine-nicoumalone interaction in man: stereochemical considerations

1. The cimetidine-nicoumalone interaction was studied in five subjects who received a single 10 mg oral dose of racemic nicoumalone alone and 3 days into an oral regimen of cimetidine of 200 mg three times daily and 400 mg at night. 2. The concentrations of R(+)- and S(-)-nicoumalone in plasma were measured using a stereospecific h.p.l.c assay; augmentation of prothrombin time was used as a measure of response. 3. Cimetidine increased the rate (but not extent) of absorption of both R(+)- and S(-)-nicoumalone, and reduced the clearance of R(+)-nicoumalone but not that of the S(-)-enantiomer. 4. Cimetidine increased the anticoagulant response produced by nicoumalone in some but not all subjects, despite a consistent effect on the pharmacokinetics of the oral anti-coagulant. 5. Cimetidine appears to produce its effect by stereoselectively inhibiting the elimination of R(+)-nicoumalone.

A Reflex Plotter investigation into the dimensional stability of alginate impressions following disinfection by varying regimes employing 2.2 per cent glutaraldehyde

Alginate impressions of an acrylic study cast pair were disinfected to a variety of regimes using 2.2 per cent glutaraldehyde. A number of linear measurements on the resultant plaster study casts were made using a Reflex Plotter to assess the effect on the dimensional stability of the casts. Significant differences were found for a number of the variables measured. Quantitatively these differences were small and of limited clinical significance; they may, however, be of greater significance where serial records are being collected for research.

Fibrinogen Manchester. Detection of a heterozygous phenotype in the intraplatelet pool

Family members heterozygous for the congenitally abnormal fibrinogen designated fibrinogen Manchester, A alpha 16Arg----His, have previously been shown by h.p.l.c. and amino acid analysis to release a variant fibrinopeptide, [His16]fibrinopeptide A, from plasma fibrinogen after the addition of thrombin. The present study was designed to determine if the same abnormal phenotype was also present in the intraplatelet fibrinogen pool. Fresh platelets were washed in buffers containing EDTA until it could be shown that all washable plasma fibrinogen was removed. Normal platelets were then lysed by freezing and thawing to release their intracellular proteins, which were then treated with thrombin. The fibrinopeptides, cleaved from the intraplatelet fibrinogen, could be detected by an optimized h.p.l.c. technique. Quantification of the intraplatelet fibrinogen gave a result (means +/- S.D., n = 5) of 110 +/- 30 and 90 +/- 30 micrograms/10(9) platelets, when determined by h.p.l.c. quantification of fibrinopeptide B content and fibrinogen fragment E radioimmunoassay respectively. Examination of fibrinopeptides released from the platelet fibrinogen from the family with fibrinogen Manchester with the same techniques showed elution peaks in the same positions as both [His16]fibrinopeptide A and normal fibrinopeptide A. The identity of these peaks was further substantiated by analysis of the h.p.l.c. peaks by using specific radioimmunoassay to fibrinopeptide A. Our results therefore demonstrate that platelet fibrinogen expresses the heterozygous A alpha 16His phenotype. This supports the view that the A alpha chains of platelet and plasma fibrinogen are produced from a single genetic locus.

Comparison of liquid and dried sodium citrate as the anticoagulant for Thrombotest and prothrombin time estimations

Samples which are taken for the Quick one-stage prothrombin time estimation for the control of patients receiving oral anticoagulant treatment are by convention taken into liquid sodium citrate anticoagulant. Dried sodium citrate has been rejected on the grounds that excessive haemolysis causes activation of clotting factors and therefore falsely short clotting times. Tests were performed with both liquid and dried sodium citrate as an anticoagulant for prothrombin time and Thrombotest. No clinically significant difference between the values given by the two anticoagulants was observed.

Practolol therapy associated with a systemic lupus erythematosus-like syndrome and an inhibitor to factor XIII

A patient is described who had an inhibitor to coagulation factor XIII associated with serum autoantibodies to certain tissues. The relationship of these abnormal findings to practolol therapy suggests that this was practolol-induced lupus erythematosus. Further investigations delineating the site of action of the inhibitor to factor XIII are reported.

The dimensional stability of self-disinfecting alginate impressions compared to various immersion regimes

Alginate impressions of a master acrylic study model pair were made in order to assess the effect of various disinfection techniques on dimensional stability. Impressions were made using self-disinfecting alginate, traditional alginate which had been dipped or soaked in a disinfecting solution, and included was a control group which was not disinfected. Inter- and intra-arch linear measurements of the resultant study casts were made using a Reflex Metrograph. The small differences found for the variables measured were not statistically significant.