Clinical characteristics and outcomes of patients undergoing surgeries during the incubation period of COVID-19 infection

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Salient features

This article focuses on:

  • Aim
  • Methods
  • Study design and participants
  • Surgical difficulty category
  • Data collection
  • Statistical analysis
  • Results
  • Discussion
  • Limitations
  • conclusion

Detailed summary:


To present the epidemiological, clinical, and laboratory characteristics, treatment, and outcomes of patients undergoing elective surgeries during the incubation period of COVID-19 infection and to compare severe patients who received ICU care during disease progression and those who did not receive ICU care.


Study design and participants

  • It is a multicenter, retrospective study, which was done at Renmin Hospital, Zhongnan Hospital, Tongji Hospital and Central Hospital in Wuhan.
  • Patients who had undergone elective surgeries admitted from January 1 to February 5, 2020, the early stage of COVID-19 epidemic in Wuhan, China.
  • 37 asymptomatic patients developed symptoms after operation and were diagnosed with COVID-19 according to WHO interim guidance.
  • Laboratory confirmation of SAR-CoV-2 was done by quantitative RT-PCR on samples from the respiratory tract.
  • Of these patients, 3 patients were visited shortly after surgery by persons who were thereafter confirmed for COVID-19 infection.
  • Thus, these 3 patients were excluded, and finally 34 patients were included in this study.Oral consent was obtained from the patients.
  • The clinical outcomes of these operative patients were monitored up to March 10, 2020, the final date of follow-up, when all the patients were discharged.

Surgical difficulty category

  • The patients included in the study underwent various surgical procedures and were categorized into four levels based on the degree of technical difficulty, complexity and risk according to the measures for the hierarchical management of surgical procedures
  • Level-1: various operations with low risks, simple procedures and low technical difficulty
  • Level-2: various operations with mild risks, general complexity of procedures and general technical difficulty
  • Level-3: various operations with moderate risks, complex procedures, and moderate technical difficulty
  • Level-4: various operations with high risks, highly complex procedures and high technical difficulty.

Data collection

  • Clinical records, nursing records, laboratory findings, and chest computed tomographic (CT) scans were reviewed for all 34 operative patients.
  • Epidemiological, clinical, laboratory, and radiological characteristics and treatment and outcomes data were obtained with data collection forms from electronic medical records.
  • Information included demographic, exposure history, underlying comorbidities, chest CT image, surgical type, surgical time, signs and symptoms, time of surgery to first symptoms, time of first symptom to dyspnea, vita signs and laboratory values on hospital admission, COVID-19 onset and ICU admission, treatments, complications, and prognosis.
  • The durations from hospital admission to surgery, first symptom, dyspnea, ARDS, and ICU admission were also recorded.

Statistical analysis

  • Continuous variables were presented as median with interquartile range (IQR) and compared by using independent group t tests
  • Categorical variables were expressed as frequencies and percentages and compared by Pearson’s chi-square or Fisher’s exact test between ICU and non-ICU groups or survival and death groups.
  • Less than 0.05 was considered statistically significant. All statistical analyses were performed with the SPSS (version 25¢0) software.


  • All 34 patients included in this study were in the age range was 21 to 84 years, and median age was 55 year.
  • 20 patients were woman, and 15 patients were admitted to ICU because of the progression of organ dysfunction or the need for mechanical ventilation.
  • 20 patients had 1 or more comorbidities like hypertension, malignancy, diabetes and cardiovascular disease.
  • In the present study, most patients underwent surgeries with the surgical difficulty category at level-2 and level-3, only 2 patients underwent surgeries with the surgical difficulty category at level-4, the highest surgical difficulty category.
  • 13 of 15 patients admitted to ICU underwent level-3 surgeries.
  • The surgical difficulty category was level-2 for the majority of non-ICU patients.
  • The overall median surgical time was 178 min.
  • The patients in ICU had longer surgical time vs 70 min and shorter time from surgery to first symptom than that of non-ICU patients.
  • The most common symptoms at COVID-19 onset were fever, fatigue, dry cough , dyspnea, myalgia or arthralgia and expectoration.
  • Less common symptoms were dizziness, headache, pharyngalgia, nausea, diarrhea, and abdominal pain.
  • The median time from surgery to first symptom was 2 days and 3 days to diagnosis of pneumonia.
  • The median time from first symptoms to dyspnea was 3.5 days.
  • The median duration from hospital admission to surgery was 2.5 days, to first sign or symptoms was 5 days, to dyspnea was 9.5 days, to ARDS was 10 days.
  • For the non-survival patients, the median time from hospital admission to death was 16 days.
  • Numerous differences in laboratory findings were found between ICU and non-ICU patients including higher white blood cell and neutrophil counts as well as higher levels of total bilirubin , blood urea nitrogen and creatinine.
  • The number of patients with increased concentration of procalcitonin in ICU was more than non-ICU patients.
  • All the 34 patients demonstrated bilateral distribution of patchy shadows or ground glass opacity on chest CT scan.
  • All patients had developed pneumonia after surgery. Common complications among the 34 patients included ARDS, shock, secondary infection, arrhythmia, acute cardiac injury and acute kidney injury.
  • ICU patients were more likely to have ARDS, shock, second infection and acute cardiac injury than non-ICU patients.
  • All patients received antiviral therapy (lopinavir/ritonavir) and antibiotic therapy.
  • Part of the patients received glucocorticoid therapy and immunoglobulin therapy and 1 patient received kidney replacement therapy.
  • In ICU, 7 patients received high-flow oxygen or noninvasive ventilation, and 5 required invasive mechanical ventilation, 1 of whom received extracorporeal membrane oxygenation as rescue therapy.
  • Seven patients died after admission to the ICU, they all underwent surgeries at the surgical difficulty category level-3. The age range was 34 to 83 years old, and 4 were women.
  • The surgery duration ranged from 110 to 379 min.
  • All these patients had 1 or more coexisting medical conditions.
  • 4 of these 7 patients presented with fever as first symptom. The median duration from first symptom to death was 9 days.
  • All these patients developed respiratory failure and had three or more complications. The most common complications among the 7 patients included ARDS, shock , arrhythmia and acute cardiac injury.

Discussion :

  • All the 34 patients involved in this study had a history of direct exposure to Wuhan City before hospital admission, and none of them had any sign or symptom of COVID-19 before surgery.
  • Symptoms of COVID-19 manifested quickly after the completion of surgery and SARS-CoV-2 infection was confirmed.
  • The length of time from hospital admission to surgery is shorter than the median incubation time of 5.2 days and also shorter than the overall incubation time.
  • The patients included in the current study were in their incubation period of COVID-19 infection before undergoing surgeries.
  • During the disease progression, 15 of 34 postoperative patients received ICU care.
  • Most patients in ICU were older, had more underlying comorbidities and longer surgical time, and undergone more difficult surgery than patients not admitted to ICU. This suggests that old age, comorbidities, surgical time, and difficulty of operation may be risk factors for poor outcome.
  • Compared with the symptoms in non-ICU patients, dyspnea occurred earlier in critically ill patients.
  • The time of first symptom to dyspnea in ICU patients was much shorter than non-ICU patients. This symptom characteristic helped physicians identify patients with potential poor prognosis.
  • Seven of the 34 operative patients died of COVID-19 associated complications.
  • Furthermore, the average duration from the time of first symptom to death of the 7 non-survivors was apparently shorter.
  • The average time from the onset of symptoms to death was longer than 10.5 days and thus longer than that of the non-survivors in the study.
  • Surgery causes immediate impairment immune function but also induce early systemic inflammatory response.
  • The most common laboratory abnormalities in this study were lymphopenia and increased hypersensitive C-reactive protein.
  • The patients admitted to ICU showed higher counts of white blood cell and neutrophil.
  • For the patients routine laboratory tests were performed but did not specifically test for SARS-CoV-2 before surgery by use of quantitative RT-PCR.
  • 34 patients included in this study got infected before their hospital admission.
  • It is necessary that every patient has to be isolated for a certain period (such as the WHO recommended 14-days quarantine period) or the possibility of the new coronavirus infection being excluded before being considered for an elective surgery during the COVID-19 epidemic.


  • The sample size was small
  • Patients were not performed the specific SARS-CoV-2 confirmation test before surgery.
  • Thus, assumption of the intubation periods of the patients was mainly based on clinical profiles and routine laboratory tests.


This retrospective cohort study showed 44.1% patients needed ICU care, and mortality was 20.5%. Risk factors for the poor prognosis of operative patients with COVID-19 need to be further study in larger sample size.

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