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.

A randomized, double-blind, placebo-controlled trial of intravenous alpha-1 antitrypsin for acute respiratory distress syndrome secondary to COVID-19

Background

Patients with severe coronavirus disease 2019 (COVID-19) develop a febrile pro-inflammatory cytokinemia with accelerated progression to acute respiratory distress syndrome (ARDS). Here we report the results of a phase 2, multicenter, randomized, double-blind, placebo-controlled trial of intravenous (IV) plasma-purified alpha-1 antitrypsin (AAT) for moderate to severe ARDS secondary to COVID-19 (EudraCT 2020-001391-15).

Methods

Patients (n = 36) were randomized to receive weekly placebo, weekly AAT (Prolastin, Grifols, S.A.; 120 mg/kg), or AAT once followed by weekly placebo. The primary endpoint was the change in plasma interleukin (IL)-6 concentration at 1 week. In addition to assessing safety and tolerability, changes in plasma levels of IL-1β, IL-8, IL-10, and soluble tumor necrosis factor receptor 1 (sTNFR1) and clinical outcomes were assessed as secondary endpoints.

Findings

Treatment with IV AAT resulted in decreased inflammation and was safe and well tolerated. The study met its primary endpoint, with decreased circulating IL-6 concentrations at 1 week in the treatment group. This was in contrast to the placebo group, where IL-6 was increased. Similarly, plasma sTNFR1 was substantially decreased in the treatment group while remaining unchanged in patients receiving placebo. IV AAT did not definitively reduce levels of IL-1β, IL-8, and IL-10. No difference in mortality or ventilator-free days was observed between groups, although a trend toward decreased time on ventilator was observed in AAT-treated patients.

Conclusions

In patients with COVID-19 and moderate to severe ARDS, treatment with IV AAT was safe, feasible, and biochemically efficacious. The data support progression to a phase 3 trial and prompt further investigation of AAT as an anti-inflammatory therapeutic.

Funding

ECSA-2020-009; Elaine Galwey Research Bursary.

Effluent quality from 200 on-site sewage systems: design values for guidelines

The quality of effluent from an on-site sewage treatment system is a critical factor in designing the disposal area and, hence, ensuring the sustained performance of the system. Contaminant concentrations in effluent are typically specified in regulatory guidelines or standards; however, the accuracy of these guideline values are brought into question due to the poor performance of septic tanks and the high failure rates of disposal systems reported here and elsewhere. Results from studies of septic tank effluent quality indicated that the effluent is of poorer quality than currently suggested by guidelines. Aerated wastewater treatment systems were found to perform to accreditation guidelines; however, insufficient nutrient data is presently available to assess nutrient loads. It is proposed that the 80th percentile of system performance be adopted as the design value for sizing effluent disposal areas to minimise failure associated with overloading. For septic tanks this equates to 660 mg L(-1) SS, 330 mg L(-1) BOD, 250 mg L(-1) TN and 36 mg L(-1) TP.

Buffer distances for on-site sewage systems in Sydney's drinking water catchments

Pathogens and nutrients released from on-site sewage systems represent a risk to surface and ground water quality, particularly where there are sensitive receiving waters such as in drinking water catchments. Buffer zones between on-site systems and waterways are one barrier used to protect water quality. The increased time and distance they provide increases the opportunities for the effluent purification functions of the soil to occur. A risk management model is proposed to assess the efficacy of the buffer zones in Sydney's drinking water catchments. The model is the basis for the development of performance based setback distances for on-site systems from waterways, and incorporates stochastic analysis of pathogen and nutrient transport in the environment and consideration of the effluent quality variability from on-site systems. Catchment-scale integration of contaminant transport is employed to facilitate a risk assessment of on-site systems. The risk management model also allows for the impact of on-site system management and maintenance on catchment water quality to be assessed through scenario building and feedback mechanisms.

Centralised versus decentralised sewage systems: a comparison of pathogen and nutrient loads released into Sydney's drinking water catchments

Data collected from centralised and decentralised sewage treatment plants throughout Sydney's drinking water catchments was used to calculate the relative catchment loads of Cryptosporidium, enteric viruses, nitrogen and phosphorus for an initial screening assessment. Loads were assessed at median and 90 percentile values for expected and worst-cases scenarios. The expected scenario in the Sydney drinking water catchments is that decentralised systems (servicing 32,800 people) provide similar total loads to centralised systems (serving 70% of the catchment population) for total phosphorus (37,090 kg x y(-1)), Cryptosporidium (10(11) oocysts x y(-1)) and enteric viruses (9.1 x 10(13) y(-1)), but higher loads of total nitrogen (237,610 vs. 136,740 kg x y(-1)). Decentralised systems, however, were predicted to have higher loads in the worst-case scenario with 620,620 kg x y(-1) TN, 82,040 kg x y(-1) TP, 7.3 x 10(13) Cryptosporidium oocysts x y(-1) and 9 x 10(15) enteric viruses per year. Greater load variability was experienced with decentralised systems, which presumably reflects less reliability in their current operation and maintenance. Overall, catchment water quality is therefore not only affected by sewage disposal methods, but also failure issues. Decentralised system disposal to land may afford a degree of mitigation that can be enhanced, if the degree of failure is reduced.

A new-generation stable inducible packaging cell line for lentiviral vectors

We have successfully generated and characterized a stable packaging cell line for HIV-1-based vectors. To allow safe production of vector, a minimal packaging construct carrying only the coding sequences of the HIV-1 gag-pol, tat, and rev genes was stably introduced into 293G cells under the control of a Tet(o) minimal promoter. 293G cells express the chimeric Tet(R)/VP16 trans-activator and contain a tetracycline-regulated vesicular stomatitis virus protein G (VSV-G) envelope gene. When the cells were grown in the presence of tetracycline the expression of both HIV-1-derived and VSV-derived packaging functions was suppressed. On induction, approximately 50 ng/ml/24 hr of Gag p24 equivalent of vector was obtained. After introduction of the transfer vector by serial infection, vector could be collected for several days with a transduction efficiency similar or superior to that of vector produced by transient transfection both for dividing and growth-arrested cells. The vector could be effectively concentrated to titers reaching 10(9) transducing units/ml and allowed for efficient delivery and stable expression of a GFP transgene in the mouse brain. The packaging cell line and all vector producer clones described here were shown to be free from replication-competent recombinants, and from recombinants between packaging and vector constructs that transfer the viral gag-pol genes. The packaging cell line and the assays developed will advance lentiviral vectors toward the stringent requirements of clinical applications.

T-cell killing of heterogenous tumor or viral targets with bispecific chimeric immune receptors

We have previously described several novel chimeric immune receptors (CIRs) that redirect human T cells to kill malignant or HIV-infected cells. These CIRs comprise a cancer- or virus-specific ligand or single-chain antibody fused to the signaling domain of the T-cell receptor CD3-zeta subunit. Binding of the ligand- or antibody-based CIR to the target antigen (Ag) triggers T-cell-mediated cytolysis of the tumor- or virus-infected cell independent of target cell major histocompatibility complex class I expression. A new type of CIR was developed to mediate the lysis of cells that expressed one or more distinct viral or tumor Ags; three bispecific CIRs (BCIRs) were generated that recognized the carcinoembryonic Ag (CEA) and TAG-72 tumor Ags or, alternatively, distinct epitopes in the HIV envelope (HIVenv). T cells expressing the antitumoral Ag BCIR lysed both CEA- and TAG-72-expressing targets and did not kill Ag-negative targets or target cells expressing other members of the CEA family. Similarly, T cells expressing the anti-HIVenv BCIR lysed target cells expressing both the wild-type HIVenv and a mutant HIVenv that lacked the epitopes recognized by the monospecific CIRs. This approach permits the generation of T cells with a broader spectrum of activity capable of killing virus-infected cells and malignant cells and reduces the potential of progression of disease due to Ag loss variants.

Large-scale manufacturing of safe and efficient retrovirus packaging lines for use in immunotherapy protocols

BACKGROUND

The use of gene modified T lymphocytes for immunotherapy in a cancer or AIDS clinical trial requires an efficient, safe ex vivo method for modification of these cells at manufacturing scale. Since retroviruses have been shown to be a moderately effective means of stably integrating therapeutic genes into T lymphocytes, we wanted to create packaging and producer cell lines that would produce replication competent retrovirus (RCR)-free supernatants, at large scale (> 200 l), and transduce with high efficiency.

METHODS

cDNA expression plasmids containing only coding sequences for gagpol or env were built and sequentially transfected into human 293 cells. Packaging and producer clones were characterized for stability, titer and RCR. A producer clone delivering chimeric immune receptors was scaled-up and supernatants used to transduce patient T lymphocytes for clinical studies. PCR and RT-PCR assays were utilized to evaluate the transmission of HERV-H sequences. Relative infectivity of producer clones pseudotyped with different envelopes was determined by transduction and RT assays.

RESULTS

RCR-free, human 293 split-genome packaging lines, pseudotyped with amphotropic, xenotropic, or 10A1 envelopes, were created. A CC49 zeta producer clone was scaled-up to 5 x 54 l lots and supernatants used to safely and efficiently transduce patient T lymphocytes with minimal ex vivo manipulation. While 293 cells express HERV-H mRNA, the transmission frequency in our packaging clones was less than 1 HERV-H sequence per 5 x 10(5) proviral integrations. Additionally, 10A1 and xenotropic packaging lines had higher infectivities than the amphotropic clone.

CONCLUSION

These packaging lines represent the safest configuration for the large-scale production of retroviral vectors, and are capable of producing high titer, RCR-free retroviral vector for large scale clinical use. While all three clones efficiently transduce human T lymphocytes, the 10A1 clone has the highest infectivity. These packaging cell lines will be valuable for use in human gene therapy protocols.

Implantation of sutured posterior chamber intraocular lenses

We describe a technique for implanting sutured posterior chamber intraocular lenses. Results of a small series using this technique in different clinical situations with at least 12 months follow-up are presented.

Alport's syndrome and the eye

Alport's syndrome comprises hereditary deafness, nephritis and ocular abnormalities. The features of Alport's syndrome are illustrated by a family with Alport's syndrome and hereditary oesophageal leiomyomatosis. The evidence that Alport's syndrome is due to a widespread basement membrane disorder is noted. Treatment of anterior lenticonus, the principal ocular abnormality, by lensectomy and intraocular lens insertion is recommended.

Canthaxanthine (orobronze) retinopathy

A 50-year-old white Australian male was found on routine examination to have small golden particles in the macular region of both eyes. A history of canthaxanthine (Orobronze) ingestion to produce skin bronzing was obtained.

Gold dust retinopathy after the ingestion of canthaxanthine to produce skin-bronzing

On routine examination a 50-year-old white male Australian was found to have small golden particles in the macular regions of both eyes. He was found to have a history of canthaxanthine ingestion to produce skin-bronzing.

A review of Leiske style semi-flexible intraocular lenses 1981-1984

A consecutive series of 205 patients had 237 intracapsular cataract extractions performed with the insertion of a semi-flexible intraocular lens in the period 1981-1983. The average follow-up period was 17.8 months; 87.0% of cases obtained a visual acuity of 6/12 or better after operation, compared with 80.6% of cases whose preoperative visual acuity was 6/36 or worse. Twenty-six eyes (11%) had clinical cystoid macular oedema at some stage after operation, and seven eyes (3%) had persistent cystoid macular oedema at final follow-up. Only one eye had a postoperative retinal detachment. Thirty eyes (14.1%) required treatment for elevated intraocular pressure at some time after operation.

Timolol and dipivalyl epinephrine combination therapy

Combination therapy with timolol 0.25% eye drops and dipivalyl epinephrine (DPE) 0.1% eye drops twice daily is an acceptable form of medication for both chronic simple glaucoma and ocular hypertension. A group of eighteen patients using this combination therapy have been followed up for a period of two years with satisfactory control of intraocular pressure in the majority of cases. An additive effect in lowering intraocular pressure when the two drugs were used in combination was confirmed. Two patients developed a sensitivity reaction to DPE and were able to continue on timolol alone. There was a slight rise in the intraocular pressure between the sixth and ninth months of therapy, but following this the mean intraocular pressure was remarkably stable. Patient acceptance of this twice daily regime was excellent and compliance with the drug therapy was also good.

Atrax robustus envenomation

Two patients who developed massive pulmonary oedema, profound vasoconstriction and hypertension followed by hypotension after Atrax Robustus envenomation are described. The pulmonary oedema is due to increased pulmonary capillary membrane permeability which may be due to neurogenic or toxic causes. Use of artificial ventilation with high level PEEP, isoprenaline and high dose steroids allowed support of the patients during volume replacement with albumin. When the circulation was stable and airway frothing ceased, conventional dehydration therapy further improved lung function. Both patients were discharged well.

The Prince of Wales Hospital prospective aphakic macular oedema study

A two year study of one hundred and forty five cataract extractions showed a 38% incidence of post operative macular oedema. The leak had resolved in most cases by six months and the only factor of significance in the production of the oedema was preoperative hypertension. The likelihood of obtaining 6/6 vision postoperatively was much lessened in the presence of macular oedema.

Epiretinal membrane formation associated with spontaneous massive periretinal proliferation

A 74-year-old man with cardiovascular disease and epiretinal membrane formation developed spontaneous massive periretinal proliferation over a period of 3 months. No surgery was performed at any stage. A 3-year follow-up is described and theories concerning the production of these 2 entities are discussed.