Impact of COVID-19 pandemic on surgical volume and outcomes in a terciary care center in Brazil

ABSTRACT Backgrounds: COVID-19 pandemic led to a sharp decline in surgical volume worldwide due to the postponement of elective procedures. This study evaluated the impact of COVID-19 pandemic in surgical volumes and outcomes of abdominal surgery in high-risk patients requiring intensive care unit admission. Methods: patients admitted for postoperative care were retrospectively evaluated. Data concerning perioperative variables and outcomes were compared in two different periods: January 2017-December 2019 and January 2020-December 2022, respectively, before (period I) and after (period II) the onset of COVID-19 pandemic. Results: 1.402 patients (897 women, mean age 62+17 years) were investigated. Most of the patients underwent colorectal (n=393) and pancreato-biliary (n=240) surgery, 52% of elective procedures. Surgical volume was significantly lower in period II (n=514) when compared to period I (n= 888). No recovery was observed in the number of surgical procedures in 2022 (n=135) when compared to 2021(n=211) and 2020 (n=168). Subjects who underwent abdominal surgery in period II had higher Charlson comorbidity index (4,85+3,0 vs. 4,35+2,8, p=0,002), more emergent/urgent procedures (51% vs. 45%, p=0,03) and more clean-contaminated wounds (73,5% vs. 66,8%, p=0,02). A significant decrease in the volume of colorectal surgery was also observed (24% vs, 31%, p<0,0001) after the onset of COVID-19 pandemic, 125 (8,9%) died, no deaths due to COVID-19 infection. Mortality was higher in period II when compared to period I (11% vs. 8%, p=0,08). Conclusions: COVID-19 pandemic was associated with a decrease in surgical volume of high-risk patients without apparent recovery in recent years. No influence of COVID-19 was noted in postoperative mortality.


Impact of COVID-19 pandemic on surgical volume and outcomes in a terciary care center in Brazil
The purpose of the present study was to evaluate the impact of COVID-19 pandemic in surgical volume and outcomes of abdominal surgery in high-risk patients requiring ICU admission in a tertiary care center in Brazil.Immediate need for surgery due to life threatening illnesses was required to characterize emergent surgical intervention.Surgical wound grades, as well as APACHE II score and CCI were classified and calculated as previously described [26][27][28] .Surgical procedures were grouped as colorectal, pancreatic, gallbladder and biliary tract, gastric, liver, and other surgeries.Other surgeries included procedures with volumes lower than 100 interventions in the observation period including appendicectomy, splenectomy and bariatric, cytoreductive, esophageal, gynecologic or obstetrics, small bowel, retroperitonealand urologic surgeries and procedures when no organ resection was caried out in the presence for example of adhesions or hernia repair.Patients were followed until death or hospital discharge.The primary endpoint was in-hospital mortality.

All
The study was performed in accordance with principles of the Declaration of Helsinki andapproved by the Ethics Committee in Research of the Portuguese Hospital of Salvador, Bahia (reference number 26210819.5.0000.5029).

Statistical analysis
Dichotomous variables are presented in text and tables as numbers and percentage and continuous variables were expressed as mean ± standard deviation (SD) or as median and interquartile range, respectively, whether the distribution was normal or skewed.Data concerning surgical procedures were compared using the chi-square test or Fisher's test for categorical variables or Student's t-test or the Mann-Whitney U test for continuous variables when appropriate.A p value <0,05 was considered significant.The software used for analysis was the Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, EUA), version 14.0 for Windows.

DISCUSSION
The present study demonstrated a 42% decrease in the volume of abdominal surgery of highrisk patients requiring ICU admission after the onset of COVID-19 pandemic without a major impact in surgical mortality.Our findings are consistent with several other authors, who demonstrated a decrease in the volume of several elective and emergency surgical procedures during the COVID-19 pandemic 23-25,29- 34 ,without a significant increase in mortalityin most 31,34- 37 but not all reports 32,38,39 .Higher mortality rates in some reports were attributed to higher frequencies of emergent/urgent procedures in sicker patients 39 as well as lower availability of ICU beds during the initial waves of COVID-19 infection 40 .In contrast to some reports, showing gradual return of surgical volume to pre-pandemic levels in several countries and institutions 24,41 ,our data demonstrated no increase in the volume of abdominal surgery in the last two years of observation.This is in accordance with several other reports demonstrating a large heterogeneity in surgical volume recovery even after the defervescence of COVID-19 pandemic in several parts of the world [23][24][25] .
The reasons for this lack of surgical volume recovery, particularly due to colorectal surgery, observed in the present study as well as in several others [23][24][25] is intriguing but may reflect the huge decrease in consultations and guidelines cancerscreening programs seen in the initial

R E S U M O R E S U M O
patients admitted to the Gastroenterology and Hepatology Unit of the Portuguese Hospital of Salvador, Bahia, Brazil after elective or emergency laparotomy from January 2017 to December 2022, were retrospectively evaluated except for those patients admitted after organ transplantation.This facility is an intensive gastrointestinal ICU dedicated to postoperative care of high-risk patients submitted to abdominal surgery.It remained a COVID free environment throughout the observation periodfor admission of high-risk surgical patients with a negative RT-PCR for SARS-CoV-2.The Portuguese Hospital of Salvador, Bahia is a non-profit private organization who remained active throughout the COVID-19 pandemic.Data concerning demographics; year at admission; type and duration ofsurgery; surgical procedure; surgical wound classification; surgical team; comorbidity, according to Charlson Comorbidity Index (CCI) and presence of concurrent malignancy, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, in the first 24 hours in the ICU; ICU and intrahospital length of stay (LOS) and mortality was retrospectively reviewed in two different periods of time between January 2017 and December 2019 and between January 2020 to December 2022, respectively, before (period I) and after (period II) the onset of COVID-19 pandemic.Patients in palliative care were excluded from the analysis.Surgery was considered elective when it was scheduled or planned and urgent in the present of an acute event leading to admission in the emergency department and requiring surgery in the first 24 hours.
APACHE II: acute physiology and chronic health evaluation II, CCI: Charlson Comorbidity Index (CCI), ICU: intensive care unit, LOS: length of stay.

Figure 1 .
Figure 1.Number of surgical procedures admitted to the ICU.

Bittencourt
Impact of COVID-19 pandemic on surgical volume and outcomes in a terciary care center in Brazil waves of COVID-19 pandemic.It is possible to speculate that many of those patients lost from healthcare due to social isolation measures may remainup to now undiagnosed or mayalternatively have progression to an unresectable stage of cancer afterwards.The purpose of this study was to evaluate the impact of COVID-19 pandemic in high-risk patients requiring abdominal,instead of general or cardiovascular surgery, who were referred to the ICU for postoperative care.When comparing the most frequent surgical procedures, a greater impact of COVID-19 pandemic was noted in the volume of colorectal procedures as highlighted by some other reports who additionally demonstrated a higher risk emergency presentation and more advanced stage of colorectal cancer at surgery after the onset of COVID-19 infection 39,42,43 .In the same line of thinking, probably the colorectal cancer was the most affected disease in terms of early diagnosis when the tumor is still resectable.Colonoscopy is frequently indicated as screening exam for patients over forty-five or fifty years old, and it can detect asymptomatic small tumors.The fear of getting infected by COVID made the people stop doing colonoscopies during the pandemic time.Other cancers, like pancreas, liver and gallbladder were less affected by this issue, as they don't have the same screening policy, what can explain the bigger impact in colorectal cancer with lower number even after the COVID period.This increase in the frequency of emergent surgical procedures usually with more cleancontaminated wounds in those sicker patients with higher comorbidity are in accordance with the literature and may reflect initial worldwide recommendation for postponement of all unessential surgical procedures.The different abilities of public and private healthcare systems to recover from the healthcare disruptioncausedby COVID-19 pandemic and most importantly the delay in the public perception that elective surgery is nowadays as safe as before the COVID-19 pandemiccan be another reason for the reduced numbers of surgical procedures.In summary COVID-19 pandemic was associated with a decrease in surgical volume of highrisk patients submitted to abdominal surgery without apparent recovery in following years.No influence of COVID-19 was noted in postoperative mortality.

Figure 2 .
Figure 2. Number of admissions of high-risk surgical patients in the ICU according to year and period of time.

Table 1 -
Demographics, clinical and postoperative features of surgical patients admitted to the ICU before and after the onset of COVID-19 pandemic.