Risk of Acquiring Perioperative COVID-19 During the Initial Pandemic Peak

A Retrospective Cohort Study

Lucas G. Axiotakis Jr., BS; Brett E. Youngerman, MD, MS; Randy K. Casals, MD; Tyler S. Cooke, MD; Graham M. Winston, MD; Cory L. Chang, AB; Deborah M. Boyett, MD, MS; Anil K. Lalwani, MD; Guy M. McKhann, MD


Annals of Surgery. 2021;273(1):41-48. 

In This Article


The specter of hospital acquired COVID-19 infection is of significant concern to both clinicians and patients. At a Spanish tertiary care center, between February-March 2020, 24.4% of operating room staff tested positive for COVID-19 despite 68% reduction in the number of emergency surgeries.[14] Similarly, in Wuhan, China, between January-February 2020, absence of quarantine and personal protection and a "super spreader" was suspected of transmitting COVID-19 to patients and staff in a thoracic surgery department.[15] In the community, patients have delayed seeking medical care due to worries regarding nosocomial COVID-19 infection. Studies from Spain and Hong Kong have reported a decline in patients undergoing cardiac diagnostic and therapeutic procedures, and an increase in median time from onset of myocardial infarction symptoms to obtaining medical care, respectively.[16,17] This delay or avoidance of necessary health care during the COVID-19 outbreak may be responsible for the observed excess in non-COVID-19 related mortality.

Our study, from a New York City hospital at surge capacity during its initial COVID-19 peak, should serve to allay the fear of nosocomial COVID-19 for surgical patients. We found that only 1.8% of surgical patients, who were preoperatively either asymptomatic and thus presumed COVID-19 negative or tested negative, developed symptomatic COVID-19 infection in the postoperative period. All cases of perioperative infection occurred before the implementation of routine preoperative testing. More than half of these patients developed symptoms within 2 days after surgery, suggesting that their infection may have occurred preoperatively. Consistent with this suggestion, none of the patients who were PCR negative on the day of surgery developed COVID-19 postoperatively. Importantly, the trend in daily confirmed case count in the borough of Manhattan paralleled inpatient COVID-19 census at our hospital, peaking on March 30th, suggesting that the low rate of perioperative infection occurred despite considerable community transmission.[18]

Risk factors for acquiring COVID-19 with surgery included diabetes, cardiovascular disease, ARB use, and undergoing transplant surgery. The role of ARB use in promoting COVID-19 infection is controversial,[19,20] while transplant surgery has been associated with postoperative infection in case reports.[21] Diabetes and cardiovascular disease have been more firmly linked to severe presentations in nonsurgical populations.[22] Of note, case length was not significantly associated with perioperative infection, suggesting that length of operating room exposure did not increase risk of transmission.

For patients acquiring perioperative COVID-19, postoperative LOS, and mortality rate both exceeded expected values. Surgery with acute COVID-19 infection is known to be associated with greater morbidity and mortality. A recent international multicenter cohort study of surgical patients with perioperative SARS-Co-V-2 infection reported a 30-day mortality rate of 26.4% and 55.5% had pulmonary complications; in general, mortality was higher in older males undergoing emergent major surgeries.[23] Similarly, in our series, the 2 deaths occurred in patients with multiple co-morbidities, high preoperative non-COVID-19 expected mortality, and risk factors for severe COVID-19. When deconstructed by individual clinical course, patients who acquired infection divided roughly into 2 groups: rapid decompensation and benign upper respiratory symptoms. This dichotomy of outcomes is consistent with SARS-CoV-2 virus symptom epidemiology, as most patients with symptomatic disease experience benign courses, while a subset of patients experience severe complications.[24]

A variety of factors likely contributed to the low rate of hospital acquired postoperative COVID-19 seen in our series. These include, but are not limited to, reduction in surgical volume, separation of COVID-19 "+" and "–" patients, use of personal protective equipment for patients and staff, use of viral filters in anesthesia machines, enhanced environmental disinfection, and a "no visitor" policy. Of note, all perioperative infections were restricted to surgeries occurring before the implementation of routine preoperative testing. Thus, routine preoperative testing may have contributed to the low incidence of new postoperative infection. This is plausible as routine preoperative testing identified infected patients for isolation and guided special precautions, which may have further reduced perioperative transmission. Alternatively, preoperative testing may have simply allowed more accurate classification of COVID-19 status. Therefore, it is likely that the observed 1.8% infection rate may ultimately be an overestimate, as early cases before preoperative testing became routine may have gone undetected until the postoperative period.

The relatively low rate of perioperative infection reported herein may serve to increase public confidence in seeking necessary medical care in controlled hospital environments, especially as the rate of community transmission declines over time. Public confidence in the safety of medical centers is instrumental in reducing preventable death and disability from non-COVID-19 medical emergencies during the pandemic. It is also critical in ensuring that preventative screenings and routine care can resume safely in the future, regardless of fluctuations in transmission before widespread vaccine availability. With nearly half of Americans polled recently indicating that someone in their household has delayed seeking care due to the pandemic and that 11% of those experienced a worsening of their condition,[25] it is clear that institutions must act quickly to prevent any further harm.

This study is limited by the absence of postoperative SARS-CoV-2 virus testing of all patients and reliance on retrospective chart review to identify symptomatic COVID-19 both before and after surgery for encounters documented within our electronic medical record system; these shortcomings could lead to an underestimate of the true incidence of nosocomial COVID-19 with surgery, though our study likely captured cases rising to the level of clinical significance. Conversely, the possibility of preoperative asymptomatic infection and false negative preoperative testing could artificially elevate our rate of newly acquired postoperative disease, particularly during the period before routine testing. Additionally, due to the small number of new perioperative infection, the study had limited power to identify associated risk factors and outcomes; similarly, multivariable regression was not feasible. The low volume of surgery during this period may limit generalizability as case volume increases. Prospective studies are needed to better determine the true rate of nosocomial COVID-19 and impact of preventative interventions.

In summary, there was minimal risk of acquiring symptomatic perioperative COVID-19 infection during the initial peak of the COVID-19 pandemic. Risk factors for acquiring COVID-19 with surgery included diabetes, cardiovascular disease, ARB use, and undergoing transplant surgery. Perioperative COVID-19 infection was associated with poor postoperative outcome.