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.

1045 Summarising the Reporting of Regulatory Procedures in Robotic Cholecystectomy: A Systematic Review and Narrative Synthesis

Introduction

Robotic cholecystectomy (RC) represents the most recent innovation in the management of gallstones. Whilst RC is becoming increasingly widespread, the evidence base surrounding its introduction has not been characterised. When evaluating innovative surgical techniques, adherence to regulatory and governance procedures is essential in maintaining patient safety. This study aims to appraise the reporting of studies of RC, focussing on regulatory procedures.

Method

Systematic searches identified all published studies reporting RC. Data collection was based on the IDEAL (Idea, Development, Exploration, Assessment, Long-term follow-up) framework, and included general study characteristics, governance approvals, trial registration, study funding, conflicts of interests, and information communicated to patients.

Results

Systematic searches identified 1425 abstracts. Of the 90 full-text papers included, only three were randomised controlled trials. The majority (71%) were single-centre studies. Conflicts of interest were common, with 11 (12%) studies funded by the robot manufacturer, and 23 (26%) reporting conflicts related to authors. Ethical approval was confirmed in 51 (57%) studies; four reported prior registration with a register. Only forty-two studies (47%) documented obtaining patient consent for study participation. Only four documented discussions regarding the innovative nature of RC. In ten, modifications to the robot or technique were described, but it was not apparent if patients were informed of these.

Conclusions

This comprehensive review highlights multiple deficiencies in the reporting of regulatory procedures in the evaluation of RC. Improved reporting is required in studies of RC to ensure transparency, interpretability, and the safe, evidence-based adoption of new technologies into clinical practice.

1096 Robot-Assisted Minimally Invasive Oesophagectomy: Comparing the Geography of Research Publication with The Global Burden of Disease

Introduction

Robot-assisted minimally invasive oesophagectomy (RAMIE) is increasingly used in the management of oesophageal tumours. It is unclear if there is equitable access to this innovative technique worldwide, specifically in areas of greatest need. This study aimed to map the geographic distribution of publications on RAMIE and compare this to global disease burden.

Method

Systematic searches identified all studies of RAMIE from inception to 2020. The country of origin of each study was identified. The incidence and age standardised rate (ASR) of oesophageal cancer for each country was obtained from The Global Cancer Observatory (GLOBOCAN) database. World Bank classifications of countries by income level were obtained.

Results

A total of 103 studies were identified. The majority (81%) were published in high-income countries, 15% in upper-middle, and 5% in lower-middle income countries. Thirty-four were published in the USA, the country with the fifth-highest incidence of oesophageal cancer worldwide, but 90th by ASR. The greatest incidence was in China (54% of global incidence) but was the source of only 15% of studies. Of the ten countries with the highest incidence, five were represented in published studies, in comparison to one of the top 10 by ASR.

Conclusions

There is evident disparity in the geographical distribution of published studies of RAMIE. This disparity may represent unequal access to surgical technologies, or a lack of evaluation of the technology in different healthcare settings. This may impact the generalisability of research findings. Equitable access to novel surgical technologies is ethical and can help address global disease burden.

858 Transoral Robotic Surgery: Comparing the Geography of Research Publications with The Global Burden of Disease

Introduction

Transoral robotic surgery (TORS) is increasingly used for the resection of oropharyngeal tumours. It is unclear if there is equitable access to this innovative technique worldwide, specifically in areas of greatest need. This study aimed to map the geographic distribution of publications on TORS and compare this to global disease burden.

Method

Systematic searches identified all studies of TORS from inception to 2018. The country of origin of each study was identified. The incidence and age standardised rate (ASR) of oropharyngeal cancer for each country was obtained from The Global Cancer Observatory (GLOBOCAN) database. World Bank classifications of countries by income level were obtained.

Results

A total of 132 studies were identified. The majority (96%) were published in high-income countries, 2% in lower-middle, and 2% in upper-middle income countries. Eighty-nine were published in the USA, the country with the second-highest incidence of oropharyngeal cancer worldwide (13% of total), but 20th by ASR. The greatest incidence was in India (21%), however this was the source of only 2% of studies. Of the ten countries with the highest incidence, eight were represented in published studies, in comparison to four of the top 10 by ASR.

Conclusions

There is evident disparity in the geographical distribution of published studies of TORS. This disparity may represent unequal access to surgical technologies, or a lack of evaluation of the technology in different healthcare settings. This may impact the generalisability of research findings. Equitable access to novel surgical technologies is ethical and can help address global disease burden.

P11 A systematic review of the reporting of robotic cholecystectomy

Introduction

Robotic cholecystectomy (RC) is reported to be an innovative alternative to laparoscopic cholecystectomy for the surgical management of gallbladder disease. Perceived technical benefits of RC include enhanced ergonomic capabilities and visualisation. Whilst RC is becoming increasingly widespread, there is a paucity of high-quality data supporting its use, and conflicting evidence of outcomes in current literature. With accumulating reports citing complications associated with novel invasive procedures, experts have suggested that robust clinical evaluation is required. It is vital that techniques such as RC are evaluated consistently, in order for surgeons to fully educate patients about the treatment and obtain informed consent. This study aims to summarise and appraise the reporting of studies of RC.

Methods

Systematic searches identified all published studies reporting RC. Data collection was based on the IDEAL (Idea, Development, Exploration, Assessment, Long-term follow-up) framework. This will be used to identify key areas of reporting including; general study characteristics, patient selection, regulatory and governance arrangements, operator and centre expertise, technique description, and outcome reporting. Because the study will not aim to draw conclusions about the effectiveness of robotic surgery, meta-analyses will not be not performed.

Results

Systematic searches identified 1425 abstracts; 90 full-text papers were included. Results will be summarised in a narrative synthesis and further data will be analysed prior to presentation.

Conclusion

This in-depth analysis of the published literature on RC will provide evidence to understand how this innovative procedure has been introduced and evaluated in relation to the IDEAL recommendations.

Heat stress interactions with protein, supplemental fat, and fungal cultures

Cows that were subjected to hot environmental temperatures yielded less milk (3.1 kg/d) on a diet high in CP (18.4%) and of medium degradability (65%) than on diets high in CP of low degradability (59%) or medium in CP (16.1%). The high CP diets were associated with decreased DMI and higher water intake, ruminal NH4, and blood urea. Negative effects on yield from the high CP, medium degradability diet were not observed at moderate temperatures. Evaporative cooling of cows in hot weather resulted in a greater milk yield response to low versus medium rumen-undegradabale protein diets than for uncooled cows. Evaporative cooling of cows also affected response to protein quality. For cooled cows, high Lys diet (soybean, fish, and blood meals) increased milk yield 14% over that with low Lys diet (corn gluten meal), but, for uncooled cows, a high Lys diet only increased yield by 9%. Percentage of CP, degradability, and protein quality had no effect on body temperatures or respiration rates of lactating cows. Some, but not other, reports showed that supplementation of 2 to 2.5% fat to diets fed under hot summer conditions resulted in less yield response than when fat was added at moderate temperatures. In several studies, fungal cultures (3 to 5 g/d) in the diet decreased body temperatures and respiration rates in hot, but not cool, weather. Increased milk yields and cellulose digestibility also resulted from dietary fungal cultures in some, but not all, trials. The mechanism of action exerted by fungal cultures on body temperature and respiration rate is unclear.