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.

P1945High levels of unawareness and suboptimal management of hypertension in India: data from a large community based study

Background

Hypertension is the most common cause of the rising cardiovascular disease (CVD) epidemic in India. However, despite availability of proven therapies management remains sub-optimal.

Purpose

To determine the hypertension control rates and associated factors among adults with known hypertension in urban and rural India.

Methods

We conducted a representative population based cross-sectional survey among 12243 participants aged ≥30 years residing in rural and urban North and South India. Participants were selected using a multistage cluster random sampling technique. Trained personnel collected the data using an interviewer administered questionnaire, measured blood pressure, conducted anthropometry and collected bio-samples. Hypertension was defined as known hypertension (self-report of physician diagnosis) or systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥90 mmHg. Control was defined as SBP <140 mmHg and DBP <90 mmHg among those with known hypertension. The associations were measured using logistic regression.

Results

The mean (±SD) age of participants was 47.7 (±12.5) years, women comprised 54%. The age-standardized prevalence of hypertension was 29.0% (95% CI: 28.2- 29.8) and known hypertension was 14.0% (13.4- 14.6). Among all hypertensives 38.6% (37.0–40.2) were on treatment and 26.2% (24.6–28.0) had their blood pressure controlled, while among known hypertensives 79.8% (77.8–81.7) were on treatment and 55.7% (53.3–58.1) had their blood pressure controlled. In multivariate analysis, participants from North Indian site [OR: 1.9 (1.6–2.3)], urban residents [1.3 (1.1–1.6)], younger participants [1.5 (1.2–1.8)], men [2.0 (1.5–2.6)], those with low socio-economic status [1.6 (1.1–2.3)], without comorbidities and those without a family history hypertension were more likely to be unaware about their hypertensive status and less likely to take treatment. Hypertension control was significantly higher in participants from South Indian site [1.5 (1.2–1.0)], the highly educated [1.6 (1.1–2.4)], those without heart diseases [1.8 (1.1–3.1)], those without central obesity [1.4 (1.1–1.9)], physically active individuals [1.5 (1.1–2.0)] and current non-alcohol users [1.9 (1.3–2.6)].

Conclusions

Many individuals with hypertension remain unaware and sub-optimally managed. This warrants the implementation of tailored public education to raise awareness, complemented by active screening for the early detection and effective management of hypertension, in order to stem the rising tide of preventable CVD in India.

Acknowledgement/Funding

Unrestricted educational grant from Eli Lilly under the Lilly NCD Partnership

Prevalence, molecular characterization, genetic heterogeneity and antimicrobial resistance of Listeria monocytogenes associated with fish and fishery environment in Kerala, India

The prevalence of Listeria monocytogenes in the retail fish markets of the Kerala, India was investigated by screening 227 samples comprising of marine finfish (n = 97) shellfish (n = 19), ready-to-cook fish products (n = 47), ready-to-eat fish products (n = 10), dried fish (n = 11) and retail ice (n = 43). The prevalence of L. monocytogenes and L. innocua was 2·7% and 17·2% respectively. Sample category wise, prevalence of L. monocytogenes was higher in marine finfish (1·8%) and retail ice (0·9%). All the L. monocytogenes isolates carried virulent genes namely inlA, inlC, inlJ, hlyA, iap, plcA, prfA genes and majority (82%) belonged to 1/2a, 3a serogroups. L. monocytogenes isolates were multidrug-resistant and showed resistance to ampicillin, penicillin, erythromycin, tetracycline and clindamycin. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) delineated 58% genetic heterogeneity among the L. monocytogenes strains. The study reports that genetic similarities of the isolates were interlinked to their serogroup and sample origin. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence of Listeria monocytogenes, in the retail fish markets of Kerala, India was low but their relatively higher presence in marine finfish and retail ice and virulent nature of the isolates signifies food safety concerns. Moreover, multidrug-resistant nature of these isolates may potentially lead to spread of antimicrobial resistance. This study identified retail ice as a vehicle for entry of L. monocytogenes in retail fish and hence, there is a need to ensure quality of retail ice used for maintaining the cold-chain.

Tantalum cones for major osteolysis in revision knee replacement

We report the results of revision total knee replacement (TKR) in 26 patients with major metaphyseal osteolytic defects using 29 trabecular metal cones in conjunction with a rotating hinged total knee prosthesis. The osteolytic defects were types II and III (A or B) according to the Anderson Orthopaedic Research Institute (AORI) classification. The mean age of the patients was 72 years (62 to 84) and there were 15 men and 11 women. In this series patients had undergone a mean of 2.34 previous total knee arthroplasties. The main objective was to restore anatomy along with stability and function of the knee joint to allow immediate full weight-bearing and active knee movement. Outcomes were measured using Knee Society scores, Oxford knee scores, range of movement of the knee and serial radiographs. Patients were followed for a mean of 36 months (24 to 49). The mean Oxford knee clinical scores improved from 12.83 (10 to 15) to 35.20 (32 to 38) (p < 0.001) and mean American Knee Society scores improved from 33.24 (13 to 36) to 81.12 (78 to 86) (p < 0.001). No radiolucent lines suggestive of loosening were seen around the trabecular metal cones, and by one year all the radiographs showed good osteo-integration. There was no evidence of any collapse or implant migration. Our early results confirm the findings of others that trabecular metal cones offer a useful way of managing severe bone loss in revision TKR.

Cite this article: Bone Joint J 2013;95-B:1069–74.

Identification, isolation and characterization of potential degradation products in pioglitazone hydrochloride drug substance

During stress degradation studies of pioglitazone hydrochloride, one major unknown oxidative degradation impurity and two major unknown base degradation impurities were identified by LC-MS. These impurities were isolated using preparative liquid chromatography. Based on the spectral data (1H NMR, 13C NMR, MS and IR), oxidative degradation impurity, base degradation impurity-1 and base degradation impurity-2 were characterized as pioglitazone N-oxide, 3-(4-(2-(5-ethylpyridine-2yl) ethoxy) phenyl)-2-mercaptopropanoic acid and 2-(1-carboxy-2-{4-[2-(5-ethylpyridine-2yl)-ethoxy] phenyl}-ethyl disulfanyl)-3-{4-[2-(5-ethylpyridine-2yl)-ethoxy] phenyl propanoicacid, respectively. The formation and mechanism of these impurities were discussed and presented.

Development and validation of a high performance liquid chromatographic method for the separation of exo and endo isomers of granatamine (9-methyl-9-azabicyclo[3.3.1]nonan-3-amine); a key intermediate of granisetron

A simple and accurate high-performance liquid chromatographic method was developed for the determination of exo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine in endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine, commercially known as grantamine and used as a key intermediate in the preparation of granisetron bulk drug. Chromatographic separation of the exo and endo isomers of 9-methyl-9-azabicyclo[3.3.1]nonan-3-amine was achieved on an Inertsil C8 column using a mobile phase containing 0.3% trifluoroacetic acid. The resolution between the two isomers was found to be more than 4. The limit of detection (LOD) and limit of quantification (LOQ) of exo isomer were 0.8 and 2.5 microg x mL(-1) respectively, for a 10 microL injection volume. The percentage recovery of exo-isomer ranged from 99 to 102% w/w in the endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine sample. The test solution and mobile phase were observed to be stable up to 48 h after preparation. The validated method yielded good results for precision, linearity, accuracy, robustness and ruggedness. The proposed method was found to be suitable and accurate for the quantitative determination of exo-isomer in bulk samples of endo-9-methyl-9-azabicyclo[3.3.1]nonan-3-amine.

Enantiomeric separation of S-zopiclone and its R-enantiomer in bulk drug samples by validated chiral RP-HPLC

A simple and selective isocratic chiral RP-HPLC method was developed for the enantiomeric purity determination of S-zopiclone and the quantitative determination of R-zopiclone in bulk drug samples. Enantiomeric separation was achieved using Chiralcel OD-RH 150 x 4.6 mm, 5 microm particle size column at 25 degrees C using a mobile phase of 10 mM ammonium acetate and acetonitrile in ratio of 60:40 (v/v) as mobile phase at a flow rate of 1.0 mL x min(-1) and UV detection at 306 nm. The method resolves the R-zopiclone and S-zopiclone with resolution (Rs) greater than 1.6. The limit of detection (LOD) and limit of quantitation (LOQ) of the R-enantiomer were 0.12 microg x mL(-1) and 0.40 microg x mL(-1) respectively, for 10 microL injection volume. The percentage RSD of the peak area of six replicate injections of R-zopiclone at LOQ concentration was 4.6. The percentage recoveries of R-enantiomer from S-zopiclone were ranged from 97.3 to 99.8. Developed method was found to be selective in presence potential impurities. The developed chiral RP-HPLC method was validated with respect to precision, linearity, accuracy, robustness and ruggedness. The test solution and mobile phase was found to be stable up to 24 h after preparation.

Culture development for human embryonic stem cell propagation: molecular aspects and challenges

Basic fibroblast growth factor and members of the transforming growth factor-beta superfamily are important regulators of human embryonic stem cell (hESC) self-renewal. Extensive cross-talk between the intracellular signaling pathways activated by these factors contributes to maintenance of the undifferentiated hESC state. Understanding the molecular regulation of hESC self-renewal will facilitate the design of improved systems for hESC propagation and provide a foundation for strategies to direct the differentiation of hESCs to clinically relevant cell types.

A validated chiral LC method for the enantioselective analysis of Levetiracetam and its enantiomer R-α-ethyl-2-oxo-pyrrolidine acetamide on amylose-based stationary phase

A new, simple chiral HPLC method was developed for the enantiomeric separation of Levetiracetam, [(S)-alpha-ethyl-2-oxo-pyrrolidine acetamide], an antiepileptic drug in pharmaceutical formulations and in bulk materials. Enantiomeric separation was achieved on a chiralpak AD-H column using a mobile phase consisting of hexane and isopropanol in the ratio (90:10, v/v) at a flow rate of 1.0 ml/min. The resolution between the enantiomers was found to be not less than 7 in the optimized method. Interestingly, unwanted enantiomer, namely R-alpha-ethyl-2-oxo-pyrrolidine acetamide ((R)-enantiomer), was eluted prior to its mirror image in the developed method. The developed method was found to be selective in the presence of related impurities of Levetiracetam, namely N-(1-carbamoyl-propyl)-4-chloro-butyramide (Imp-1) and 1-ethyl-2-oxo-1-pyrrolidine acetic acid (Imp-2), and also under exposed conditions of UV light and 60 degrees C. The limit of detection (LOD) and limit of quantification (LOQ) of (R)-enantiomer were found to be 900 and 2250 ng/ml, respectively, for 10 microl injection volume. The method precision for (R)-enantiomer at limit of quantification level was within 8% R.S.D. Calibration curve for (R)-enantiomer was linear over the studied ranges (2250-9000 ng) with correlation coefficient greater than 0998. The active pharmaceutical ingredient was extracted from its finished dosage form (tablet) using isopropanol. The percentage recoveries of (R)-enantiomer were ranged from 94.2 to 102.6 and from 93.5 to 104.1 in spiked bulk and formulation samples of Levetiracetam, respectively. Levetiracetam sample solution and mobile phase are found to be stable for at least 48 h. The developed method was found to be rugged and robust. The proposed method was found to be suitable and accurate for the quantitative determination of (R)-enantiomer in bulk drugs and commercial formulations. Chiralcel OD-H column can also be used as an alternative column for the above purpose.

Effective atomic numbers of biological materials in the energy region 1 to 50 MeV for photons, electrons, and He ions

A study of effective atomic numbers for biological materials such as bone, muscle, spleen, liver, mucin, and water has been carried out in the energy region 1 to 50 MeV for photons, electrons, and He ions. It is noticed that the effective atomic number for photons and electrons increases with energy, and remains, more or less the same, for He ions.

Investigation on the reduction of electron contamination with a 6-MV x-ray beam

Experimental investigations have been carried out on the reduction of electron contamination of a 6-MV x-ray beam of Clinac model 1800 for square field sizes 5 X 5 to 30 X 30 cm2 in steps of 5 cm and for rectangular field sizes 19 X 7 and 7 X 19 cm2. The electron contamination of both the open beam and the beam with the tray can be effectively reduced by placing a lead foil filter immediately below the blocking tray. Measurements at 100-cm source-skin distance with filter in place showed a reduction in dose in the buildup region and also a displacement of the location of Dmax to greater depths, even for small field sizes such as 10 X 10 cm2.

Investigations on the near surface dose for three 10-MV x-ray beam accelerators with emphasis on the reduction of electron contamination

A study of three 10-MV x-ray clinical accelerators with emphasis on the reduction of electron contamination was conducted. This study, which was performed with different types of trays and filters, suggests that, at 100-cm source-surface distance (SSD), Pb can be used as an effective filter material up to 30 X 30 cm2; however, due to its transparency, a Clear-Pb tray is useful for field sizes up to a 20 X 20 cm2. Percent depth doses for a few selected depths and field sizes at this nominal SSD were examined. No significant differences, with the exception of the location of Dmax, amongst the three accelerators were noticed.

Interaction of low-energy photons with biological materials and the effective atomic number

The effective atomic numbers for total photon interaction in bone, muscle, liver, spleen, fat, and water are determined and found to decrease up to 50% as the energy increases from 10 to 200 keV. Muscle, spleen, liver, and water are found to behave in an approximately similar manner in this energy region, as far as photon interaction is concerned.

Depression in general practice: clinical features and comparison with out-patients

General practice (GP) depressives prescribed an antidepressant were compared with those given other treatment, and with antidepressant-treated psychiatric out-patient depressives. GP depressives were considerably less severely ill than out-patients, with fewer depressive symptoms and shorter illness, as well as less primary and less endogenous depression. The two groups of GP depressives differed less, but those receiving other treatment tended to have less severe depression than those receiving antidepressants and were less likely to satisfy diagnostic criteria for depression. Depressives in GP differ considerably in clinical characteristics from psychiatric out-patient depressives, and clinical features influence the GP's decision to treat with antidepressants.

Depression in general practice: case thresholds and diagnosis

Using multiple diagnostic and epidemiological criteria, three samples of general practice (GP) depressives were studied: those prescribed a new course of antidepressants, those given other treatment, and those missed by the GP. The majority of patients qualified as psychiatric cases on the PSE Index of Definition, the Bedford College Criteria, and the Research Diagnostic Criteria. Most satisfied diagnostic criteria for depression, or (fewer) anxiety. The disorders were relatively mild and often borderline on all three systems. Depressives given other treatment most often failed to meet diagnostic criteria. About half the antidepressant treated patients received RDC diagnoses of major depression. Among the other treatment sample, only one-fifth met these criteria, and half had non-depressive diagnoses. Most cases of depression treated by GPs satisfy criteria for psychiatric disorder, but tend to be relatively mild and borderline in quality.

Unrecognised depression in general practice

Patients attending their general practitioner were screened and a group with unrecognised major depressive disorder identified. This group was interviewed and the findings compared with those in a group of patients recognised correctly as depressed by their general practitioners. Half of the patients with severe depression screened in their doctors' waiting rooms went unrecognised, and they differed in few ways from those who were recognised. The differences found were that the patients with unrecognised depression were less obviously depressed and their illness had lasted longer. Physical illness was present in nearly 30% of patients in the unrecognised group, and the depression seemed related to it. Patients with unrecognised depression were more likely to have feelings other than those of normal sadness and more likely to respond with change of mood to intercurrent events. These data suggest that patients might benefit if general practitioners were better trained to recognise depression, although it is not known whether treatment would be effective.

Life stress and symptom pattern in out-patient depression

The relationship was examined between symptoms rated in a sample of out-patient depressives, and measures of life stress derived from a separate interview. There was an association between symptoms reflecting the endogenous-neurotic distinction and life stress. However, the association was relatively weak, and was mainly with total social problems at the time of presentation, rather than with life events at onset. These findings are consistent with other studies which indicate that the absence of prior life events and the presence of the endogenous symptom pattern are only weakly related.

Nosology of atypical depression

A review of the literature on atypical depression indicated three relatively separate usages for the term: anxiety or phobic symptoms additional to depression, reversed functional shift, and non-endogenous depression. A sample of 160 out-patient depressives was rated on a variety of diagnostic systems measuring these concepts. Inter-relationships between groups selected by the three definitions were found to be low. In addition, although there was moderate consistency within different definitions of endogenous depression and of additional anxiety, reversed functional shift symptoms did not correlate well with each other. These findings suggest that atypical depression may be of limited value as a specific diagnosis within non-psychotic depression.