An 88-year-old male patient without any underlying disease, who had been taking drugs due to symptoms of cough, sputum and myalgia a week prior to the visit to the hospital, came to our emergency room because fell from his height. At the time of the visit, his mental status was drowsy, and a fever of 37.7℃ was observed. Based on brain magnetic resonance imaging, an acute cerebral infarction was suspected. A left femur intertrochanteric fracture was observed on the radiography of the lower limbs. There were no specific findings on the chest X-ray and blood tests, but SARS-CoV-2 quantitative real-time polymerase chain reaction (RT-PCR) and chest computed tomography (CT) were performed due to symptoms of respiratory infection such as cough, sputum and fever. Chest CT showed consolidation in both lower lungs which was suspected to be pneumonia (Fig. 1), and a positive result of the SARS-CoV-2 RT-PCR was confirmed. The patient was admitted to an isolation ward and treated for acute cerebral infarction.

The patient was confirmed to be infected with SARS-CoV-2, but a bacterial pneumonia was not excluded; therefore, antibiotics and hydroxychloroquine were administered. Two RT-PCR tests performed on the 6th and 10th days of admission showed negative results. After 2 weeks of admission, there was no evidence of active infection on chest CT; therefore, it was decided to perform a closed reduction with internal fixation of the left femur intertrochanteric fracture on the 19th days of admission. Since the patient was taking an antiplatelet agent (clopidogrel) due to the cerebral infarction, we decided to administer a general anesthesia to the patient. According to our hospital’s COVID-19 response guidelines (Fig. 2) based on previous results of SARS-CoV-2 positive patient reports, we decided to wear enhanced PPEs.

A separate negative pressure zone was set to prevent aerosol spread. We covered the anesthesia machine, an operating bed, and equipment in the operating room with vinyl. To prevent contamination of the anesthesia machine, high-efficiency particulate air (HEPA) filters (GVS Filter Technology UK Ltd., UK) were applied to the inspiratory and expiratory limbs of the breathing circuit and the patient’s side was connected to the endotracheal tube. Healthcare workers wore enhanced PPEs including N95 respirator, surgical cap, double gown, double glove, shoe covers, and powered air-purifying respirators (PAPR), which was separately set in the negative pressure zone. The patient was moved to the operating room with healthcare workers wearing the enhanced PPE. After entering the operating room, we continuously monitored the electrocardiogram (EKG), pulse oximetry, and blood pressure. After preoxygenation, propofol 1.5 mg/kg was administered for anesthesia induction. Rocuronium bromide 0.8 mg/kg was administered to induce a neuromuscular blockade sufficient to prevent the spread of airborne droplets. Tracheal intubation was performed using a McGrath MAC (McGRATH, Aircraft Medical Ltd., UK) videolaryngoscopy. After intubation, we closed the operating room for 30 min to prevent aerosol transmission. Anesthesia was maintained with 1.5–2.0 vol% sevoflurane and remifentanil infusions.

After 45 min, the surgery was completed and sugammadex 2 mg/kg was administered to reverse the neuromuscular blockade. Five minutes after Sugammadex administration, the neuromuscular blockade was sufficiently reversed such that tracheal tube extubation was performed. After extubation, the operating room was closed for another 30 min to prevent aerosol transmission. Then, to prevent the post-anesthesia care unit (PACU) from being contaminated, the patient had to recover in the operating room. After recovering for 30 min, healthcare workers wearing enhanced PPEs moved the patient back to the isolation ward through a separate elevator. After the surgery was completed, healthcare workers who participated in the surgery removed the enhanced PPE in the anteroom of the negative pressure zone, and the operating room’s surface was disinfected and the operating room was ventilated for 30 min.

A week after the surgery, the chest CT result of the patient did not show any specific findings and the SARS-CoV-2 RT-PCR was also confirmed to be negative. Therefore, eight days after the surgery, the patient was discharged with no other complications.

A 73-year-old female patient was admitted for further evaluation due to a suspected right lesser trochanter pathologic fracture on the hip X-ray and bone metastasis on the whole body bone scan. The patient was on medication for hypertension and hypothyroidism. She was also diagnosed with pulmonary tuberculosis 10 years ago and was cured after treatment. The patient had been taking antiplatelet agents for 9 years after intra-arterial stent insertion due to right internal carotid artery stenosis. SARS-CoV-2 RT-PCR was performed because the patient had a fever of 37.8°C one week before admission. A negative result was reported. On the second day of admission, a fever of 38°C or higher was observed; thus, SARS-CoV-2 RT-PCR was performed but negative results were confirmed. Chest radiography showed no specific findings other than the old pulmonary tuberculosis lesion in the right upper lung. Later, the fever subsided.

On the 4th day of admission, chest CT showed no specific findings except for the multifocal post-infectious old lesions in the right lung, and there was no change compared to the previous chest CT (Fig. 3A). Therefore, on the 5th day of admission, an excisional biopsy of the right femur was performed. Considering that the possibility of COVID-19 infection was excluded, the patient was transferred to a room different from the previous one after the excisional biopsy was performed. After the biopsy, a fever of 37.5°C or higher was noted and the C-reactive protein was elevated. As a result of the biopsy, a lymphoma was suspected.

On the 9th day of admission, a right femoral shaft pathologic fracture occurred, and it was decided to perform a closed reduction of the fracture with internal fixation at the emergency on that same day. We considered that the patient had been confirmed to be negative for SARS-CoV-2 by RT-PCR 6 days before admission and on the 2nd day of admission, and there was no evidence of active infection on chest CT on the 4th day of admission. For the persistent fever, we consulted with the division of infectious disease and infection control department. The division of infectious disease and infection control department suggested that the patient's fever seemed to be a neoplastic fever caused by lymphoma. Therefore, we excluded the possibility of a SARS-CoV-2 infection in the patient and decided to perform the surgery with standard PPEs including surgical gloves, gown, eye shields, and N95 respirators. Since the patient was taking an antiplatelet agent (clopidogrel) due to internal carotid artery stenosis, we decided to administer a general anesthesia to the patient. After preoxygenation, propofol 2 mg/kg was administered for anesthesia induction, and rocuronium bromide 0.6mg/kg was administered. Tracheal intubation was performed using McGrath MAC (McGRATH, Aircraft Medical Ltd.) and anesthesia was maintained with 1.5–2.0 vol% sevoflurane and remifentanil infusion. Oxygen saturation was maintained at 100% during anesthesia, and blood pressure, heart rate, and mechanical ventilation were maintained stable.

The surgery lasted 85 min. Then, sugammadex 2 mg/kg was administered to reverse the neuromuscular blockade. Five minutes after administration of sugammadex, the neuromuscular blockade was completlely confirmed; therefore, tracheal tube extubation was performed. After that, the patient was transferred to the PACU for recovery. After an hour, the PAR score was checked at 9 points; therefore, the patient was moved to the hospital room.

One day after the surgery, the patient developed a fever of 38.4°C again, and another patient in the same hospital room was confirmed to be COVID-19 positive. Therefore, the chest CT and SARS-CoV-2 RT-PCR test were redone on the patient. On chest CT, bilateral pleural effusion was observed (Fig. 3B), and the SARS-CoV-2 RT-PCR results were positive. As a result, the patient was confirmed to be COVID-19 positive and moved to the isolated room. After that, Lopinavir, ritonavir, and hydroxychloroquine were administered for COVID-19 treatment and antibiotics were administered in consideration of possible bacterial pneumonia.

We investigated healthcare workers who participated in the surgery. In the PACU, all healthcare workers were wearing standard PPEs, so there were no exposed healthcare workers, but confirmed that the anesthesiologist and nurse who participated in the surgery were exposed because they did not wear eye shields when they performed the anesthesia. Therefore, we ran SARS-CoV-2 RT-PCR on these two healthcare workers, and made them stay at home for two weeks. For the two tests, both showed negative results on SARS-CoV-2 RT-PCR. Fever and cough symptoms were not observed for two weeks. After two weeks, on the SARS-CoV-2 RT-PCR, both healthcare workers’ results were reported as negative.

By the way, the operating room was also exposed to the possibility of infection. Therefore, we performed surface disinfection, emptied the operating room for 24 h, and performed room air ventilation. A carbon dioxide absorber of the anesthesia machine was also replaced as we performed disinfection. 5 days after the surgery, a multifocal patchy ground-glass appearance (GGA) lesion in both lungs which were suspected to be viral pneumonia was reported on the chest CT scan (Fig. 3C); therefore, antibiotics and hydroxychloroquine were administered. However, pneumonia had not improved, and the patient was given a ventilator care in the intensive care unit. Twenty-three days after surgery, pneumonia was aggravated and the patient was died.