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 findings from a UK National Institute for Health Research-funded study show.
The research 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 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 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 three days, with isolation of four to seven 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.”
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 hospitals. 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.”
Study details
Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study
COVIDSurg Collaborative, GlobalSurg Collaborative
Published in Anaesthesia 9 August 2021
Introduction
Several strategies have been explored to mitigate against the risk of peri-operative SARS-CoV-2 infection, given the high associated rate of postoperative pulmonary complications and mortality. It has become clear that a range of measures are needed to ensure safe surgery, including: COVID-19-free surgical pathways; patient testing for SARS-CoV-2; and delaying surgery in patients with SARS-CoV-2 infection. These measures will still be needed despite the roll-out of vaccination programmes, which may take years to achieve globally, be less effective against SARS-CoV-2 variants and not achieve universal implementation.
Isolation before elective surgery has been recommended by several national surgical associations. This attempts to reduce the risk of asymptomatic carriers undergoing surgery, thereby protecting individual patients and reducing in-hospital transmission to other patients and staff. It presents potential problems for patients, including: logistical considerations; reducing patient mobility before major surgery; and social isolation. It also means that last-minute additions to operating theatre lists are less likely, thereby representing an additional potential burden to surgical recovery plans.
These limitations would be acceptable if there was clear evidence of benefit in regard to reduction of postoperative complications, both related to SARS-CoV-2 and otherwise. Demonstrating benefit and optimum duration will support wider rollout of global best practice in elective surgery. Demonstrating no benefit will allow units to tailor clinical guidance and consider reducing the burden of isolation.
Summary
We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household.
The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. 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 postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively.
Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care.
Results
A total of 96,454 patients were included from 1634 hospitals in 114 countries. There were 62,839 (65.1%) patients who underwent surgery in areas with high SARS-CoV-2 prevalence and 33,615 (34.9%) patients in areas of low prevalence. The study included 65,228 (67.6%) patients from high-income countries and 31,226 (32.4%) patients from low- and middle-income countries. There were 74,347 (77.1%) patients who underwent surgery for a benign condition and 57,079 (59.2%) who underwent major surgery.
Overall, 26,948 (27.9%) patients isolated before surgery, 80,200 (83.1%) underwent surgery in a COVID-19-free pathway and 67,612 (70.1%) had a pre-operative SARS-CoV-2 test.
Patients who isolated before surgery were older, had more respiratory comorbidities and higher ASA physical status. Pre-operative isolation was more common in areas of high SARS-CoV-2 prevalence and in high-income countries. Patients who isolated pre-operatively were also more frequently tested for SARS-CoV-2 before surgery and underwent surgery in a COVID-19-free surgical pathway more often.
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