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The research team said the study results go completely against the current guidance in common use which mandates isolation before surgery.

Patients isolating before surgery - mainly to avoid COVID-19 and its complications – are actually at a 20% increased risk of developing post-operative lung complications compared with patients who do not isolate, unexpected study findings show.

The National Institute for Health Research (NIHR) funded study was carried out by the University of Birmingham-led GlobalSurg-COVIDSurg Collaborative - a global collaboration of over 15,000 surgeons working together to collect a range of data on the COVID-19 pandemic – and published today in Anaesthesia, a journal of the Association of Anaesthetists.

A total of 96,454 patients from over 1,600 hospitals across 114 countries were included in this new analysis, and, overall, 26,948 (28%) patients isolated before surgery. Post-operative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection.

The research team said the study results go completely against the current guidance in common use which mandates isolation before surgery.

Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries.

Although the overall rates of post-operative pulmonary complications were similar in patients who isolated and those that did not (2.1% vs. 2.0%, respectively), pre-operative isolation was associated with a 20% increased risk of post-operative pulmonary complications after adjustment for age, comorbidities, and type of surgery performed.

The rate of post-operative pulmonary complications also increased with periods of isolation longer than 3 days, with isolation of 4 to 7 days associated with 25% increased risk of post-operative lung complications and isolation of 8 days or longer associated with a 31% increased risk.

These findings were consistent across various environments whether or not other protective strategies were in place (pre-operative testing and COVID-free pathways), showing that regardless of those other strategies, pre-operative isolation does not seem to protect surgical patients from post-operative pulmonary complications or death.

Looking at the possible reasons for these unexpected findings, one of the study’s lead authors, Senior Lecturer and Surgeon Dr Aneel Bhangu, from the University of Birmingham-led NIHR Global Health Research Unit on Global Surgery, says: “Isolation may mean that patients reduce their physical activity, have worse nutritional habits and suffer higher levels of anxiety and depression.

“These effects in already vulnerable patients may have contributed to an increased risk of pulmonary complications. Further, there is increasing evidence demonstrating that prehabilitation (preconditioning) before surgery improves patient recovery and outcomes.

“It is possible that isolation may have, therefore, conversely led to patient deconditioning and functional decline, adversely influencing their outcomes.”

Co-lead author, Dr Joana Simoes, a Research Fellow at the University of Birmingham’s NIHR Global Health Research Unit on Global Surgery, adds: “Our evidence suggests that removing pre-operative isolation strategies is unlikely to lead to worse post-operative outcomes for patients, but institutions should monitor their post-operative pulmonary complication rates as strategies evolve.”

The authors do however warn that the study does not take into account the risk of transmission of SARS-CoV-2 from patients to other patients and staff in hospital. They say: “The benefits of pre-operative isolation are not only for the individual patient but also to other patients and staff in hospitals who are at risk from asymptomatic carriers of SARS-CoV-2.”

The authors say: “Healthcare providers may wish to take these findings into consideration when reviewing local and national guidance. Relaxation of pre-operative isolation policies appears to be safe for individual patients, especially in the presence of pre-operative testing, which this and previous studies showed to be beneficial. Selected isolation practices may remain in place in certain conditions (such as high-risk patients and periods of high community prevalence).”

They add: “Further research is needed to explore the most effective method for maintaining patient fitness and conditioning in patients that are isolating, which may include home or remote prehabilitation using telephone or online methods.”

Notes to editors:

  • For more information please contact the University of Birmingham on +44 (0) 7789 921 165.
  • Simoes et al (Aug, 2021). ‘Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study.’ Anaesthesia. DOI: 10.1111/anae.15560

About the University of Birmingham

The University of Birmingham is ranked amongst the world’s top 100 institutions, and its work brings people from across the world to Birmingham, including researchers and teachers and more than 6,500 international students from nearly 150 countries.

About the COVIDSurg Collaborative

Before the COVID-19 pandemic, 5 billion people lacked access to surgical care and 143 million more operations per year were required globally. There was already a major global inequity in access to safe and affordable surgery across low and middle-income countries, with an urgent need to expand capacity. This pandemic has acutely worsened that situation and placed a spotlight on the need for change in how surgery is delivered. Launched in March 2020, the University of Birmingham-led COVIDSurg collaborative has provided data needed to support this change in the fastest time frame ever seen by a surgical research group, with data from 150,000 patients across 2000 hospitals collected over the past 9 months.

About the NIHR Global Health Research Unit on Global Surgery

The NIHR Global Health Research Unit on Global Surgery is based at the University of Birmingham and is co-directed by Professor Dion Morton, a leading colorectal surgeon from the University of Birmingham’s Institute of Cancer and Genomic Sciences, and Professor Peter Brocklehurst, Director of the University of Birmingham’s Birmingham Clinical Trials Unit. It has established international research hubs across a range of low and middle income countries (LMICs) in order to set up pathways to rapidly translate research findings in to evidence-based patient care.

About the National Institute for Health Research (NIHR)

The mission of the National Institute for Health Research (NIHR) is to improve the health and wealth of the nation through research. We do this by:

  • Funding high quality, timely research that benefits the NHS, public health and social care;
  • Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services;
  • Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research;
  • Attracting, training and supporting the best researchers to tackle complex health and social care challenges;
  • Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system;
  • Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries.
  • NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK Aid from the UK government.