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Neuroanesthesia Practice During COVID-19 Pandemic: Experiences from China

Minyu Jian, MD; Fa Liang, MD; Haiyang Liu, MD; Hengyu Zeng, MD; Yuming Peng, MD, PhD; Ruquan Han, MD, PhD (Correspondence Author - ruquan.han@ccmu.edu.cn)
Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China

Ruquan Han, MD, PhD

Since December 2019, the outbreak of Coronavirus disease (COVID-19) has spread in most of the countries all over the world. By April 30, more than 3.0 million cases have been confirmed and the numbers are still accelerating rapidly. The disease is transmitted mainly through respiratory droplets and close contact but for some healthcare workers, airborne transmission may occur1.

The secondary impact brought by the pandemic on the medical system includes the influence of normal medical demand. Many time-sensitive surgeries like oncology are affected. The majority of patients with brain tumor and cerebrovascular aneurysm have abnormal intracranial compliance and neurological symptoms and need surgery within a limited time. Moreover, it is estimated that the pandemic may become a new normal for healthcare workers2. Therefore, our major concern is how to prevent the transmission of COVID-19 while conducting non-COVID-19 surgeries at the same time. We need to rearrange the hospital functional area and the workflow, do more profound evaluation for the patients, and perform appropriate protection for the healthcare workers.

As neuroanesthesiologists, we are at high-risk of infection and need to take care of all the neurosurgical patients amid the pandemic. We want to share some our experiences from China in managing this specific patient population.

1. Operating Room and Environmental Safety

1.1 Classification and Zoning

We established separate, well-ventilated triage areas for screening of COVID-19 following the local in-hospital infection control protocol, and applied correct isolation and protective measures in order to safely provide care to patients.

Transitional units are set up for patients who have not been ruled out for COVID-19. Given the current pandemic, the majority of patients presenting for emergency surgeries are considered to be either “unknown” or “suspected” COVID-19. According to a cohort study published recently, it is very likely that the surgical stress occurred during the incubation period of COVID-19 could exacerbate disease progression and severity3. With the advance of PCR test kits, it takes shorter time to do the COVID-19 test. Thus, we require all patients to have a PCR test twice before they are admitted to the hospital. For patients who cannot take PCR tests twice apart for at least 24 hours or be in isolation for two weeks, they should be admitted to these transitional units for continuous evaluation. Patients can only be discharged from transitional units when PCR tests are negative twice or they have been isolated for two weeks without any symptoms (Figure 1).

Figure 1: Flow chart for anesthetic management of neurosurgical patients amid the pandemic of COVID-19 in Beijing Tiantan Hospital
*Low-risk surgery: patients that are ruled out for COVID-19 performing elective, limited and emergency surgery.
*Moderate-risk surgery: patients do not have epidemiologic history, have or have not symptoms of COVID-19, chest CT does not show ground glass opacities, first PCR tests are negative, waiting for the second PCR tests results, performing life-saving emergency surgery.
*High-risk surgery: patients confirmed or suspected with COVID-19 performing life-saving emergency surgery.

1.2 Dedicated OR Area for Surgery in Patients with COVID-19
For patients confirmed or suspected having COVID-19, high-risk surgery must be performed in the dedicated operating room with a negative pressure system and a separate access. An appropriate level of negative pressure must be ensured. If the negative pressure system is not available, the positive pressure system and air conditioning should be turned off4.

In the dedicated operating room, there should be three zones and two channels which have separate entrances for patients and healthcare workers: green zone (clean area), yellow zone (semi-contaminated area) and red zone (contaminated area); healthcare worker channel and patient channel.

1.3 Environmental and Equipment Disinfection
The same operating room and the same anesthesia machine should only be used for COVID-19 patients during the epidemic5. Disposable anesthesia supplies that have direct contact with patient’s skin or mucosa should be used as much as possible. These include but are not limited to the video laryngoscope blade, reinforced tubes, anesthesia masks, filters, etc. All supplies should be discarded immediately after the surgery.  All surfaces, screens, keyboard, cables and monitors should be cleaned and disinfected promptly after the procedure using chlorine wipes4.

There is a lack of a consensus for now on how to perform disinfection for the anesthesia machine. Recommended disinfection procedure of the ventilator on the anesthesia machine consists of either disassembly and sterilization with high temperature4，or following the manufacture’s advice. A plastic cover for the anesthesia machine and the monitors can be considered6.

2. Patient Safety

2.1 Screening for COVID-19
Preoperative visits and evaluations are extremely important, as it is necessary to verify the possibility of COVID-19 in patients. According to strict control policies of the highest level of emergency response to contain the outbreak of the epidemic, all the patients and their close contact family members should have epidemiologic history inquiry, body temperature check, complete blood count, chest CT, and PCR test. For the patients requiring emergency surgeries, the tests mentioned above should be done as soon as possible. Anesthesiologists are responsible for the second triage including reviewing the medical history, a brief physical examination, and checking the chest CT. The body temperature should be retaken in the operating room.

2.2 Differential Diagnosis
The occurrence of pulmonary dysfunction after brain injury, such as traumatic brain injury, cerebrovascular diseases or other neurosurgical conditions have long been described. The brain-lung crosstalk injuries caused by elevated intracranial pressure include ventilator-associated pneumonia (VAP), acute respiratory distress syndrome (ARDS) and neurogenic pulmonary edema (NPE)7,8. This needs to be carefully differentiated from Novel Coronavirus Pneumonia (NCP). NCP shows multiple ground glass opacities and infiltration in both lungs as the disease progresses9. Many neurosurgical diseases can cause elevated body temperature, which must be differentially diagnosed with fever caused by COVID-19. PCR tests would be the most accurate way to diagnose. It is recommended setting up a consulting team including experts from respiratory medicine, infectious diseases, neurosurgery, and anesthesiology.

2.3 Establishment of Surgery Risk System
Three levels of surgery risk according to the patients’ medical conditions and their triage are established.

• Low-risk surgery: patients that are ruled out for COVID-19 performing elective, limited and emergency surgery.
• Moderate-risk surgery: patients who do not have epidemiologic history, have or have no symptoms of COVID-19, chest CT does not show ground glass opacities, first PCR tests are negative, waiting for the second PCR tests results, and performing life-saving emergency surgery.
• High-risk surgery: patients confirmed or suspected with COVID-19 performing life-saving emergency surgery.

3. Healthcare Workers Protection

3.1 Personal Protective Equipment (PPE)
All the neuroanesthesiologists working in the operating room should be trained and better drilled to handle this specific situation. We have established three levels of PPE standards.

• Level-1 protection: scrubs, disposable cap, surgical mask, glove, and isolation gown.
• Level-2 protection: scrubs, disposable cap, N95 mask, protective coverall, glove, goggles or face shield, and boot covers.
• Level-3 protection: scrubs, disposable cap, N95 mask, protective coverall, double-layer gloves, goggles or face shield, boot covers, and isolation gown (Figure 2). For those personnel at high-risk of exposure (intubation, extubation and other procedures that may generate aerosolized small particles), powered air purifying respirators (PAPRs) are suggested.

Figure 2: Level-3 protection in Beijing Tiantan Hospital, China

3.2 Different Levels of PPEs According to the Triage
Distinct levels of PPEs according to the risks of the surgery are performed. Level-1 protection is used for low-risk surgery. Level-2 protection is used for moderate-risk surgery. Level-3 protection is used for high-risk surgery and transitional units.

3.3 Cross-contamination Prevention
Society for Healthcare Epidemiology of America (Arlington, Virginia) published an expert guidance on preventing cross-contamination in the anesthesia workplace6. There are some easy methods we can follow:

• Close injection ports with sterile isopropyl alcohol containing caps.
• Frequent hand hygiene with alcohol-containing gel or soap.
• Double gloves for airway management and discarding the outer glove immediately afterward.
• Environmental disinfection should be performed between cases and at the end of the day.

4. Perioperative Management for Neurosurgical Patients

Many patients infected with COVID-19 are elderly. They are at high risk of becoming critically ill with a higher D-Dimer10,11. Some of the patients co-exist with cerebrovascular diseases and may present acute ischemic stroke in the ICU. Since 2019-nCov-virus uses angiotensin converting enzyme II (ACE2) as a cellular entry receptor12，some of the hypertensive patients with COVID-19 are vulnerable to hemorrhagic stroke. Therefore, COVID-19 patients can encounter acute cerebrovascular diseases that may need surgery, which brings more challenges for neuroanesthesiologists. For these kind of patients, we must recognize their need for some special care in addition to usual key points of perioperative management.

4.1 Challenge Brought by Screening
Neurosurgical or neurointerventional procedure effectiveness progressively decreases as the time between stroke onset and start of surgery increases. Thus, within the bounds of safety, the time between the decision to perform surgery and starting the procedure should be as brief as possible13. Under the current circumstances, we need to do our best to minimize the screening time for COVID-19 by establishing an experienced triage system, setting up a consult team with experts, taking the brain and chest CT at the same time, and reporting the suspected cases to the operation team earlier, etc.

4.2 Reducing Perioperative Exposure
Patient should wear a face mask before intubation and after extubation. It is recommended to cover the patients’ nose and mouth with two layers of wet gauze with pre-oxygenation. Bag-mask ventilation ideally should be avoided. Rapid sequence induction should be used and the order of administration should be intravenous general anesthetic, muscle relaxation drugs, and opioids to avoid cough. Adequate muscle relaxation should be confirmed to prevent coughing during intubation. Use of laryngeal mask except for difficult airway management should be avoided. Oral intubation with a video laryngoscope is preferred and it should be performed by an experienced anesthesiologist. A closed airway suction system must be available to reduce viral aerosol production. Breathing viral filters must be installed between the breathing circuit and the patient’s airway and between the expiratory limb and the machine.

Suction of the airway and extubation may be attempted under deep anesthesia. Bolus or infusion of lidocaine, opioids or continuous infusion of dexmedetomidine during the surgery may reduce the risk of coughing or bucking. If the patient does not meet the criteria for extubation and is kept intubated, a single-patient-use Ambu bag must be used during transfer to the dedicated ICU1,4.

Any PPE component that becomes heavily soiled by patients’ blood or body fluid during procedures should be replaced immediately14.

4.3 Sedation or General Anesthesia?
The consensus statement from SNACC has made some suggestions15. Sedation or general anesthesia are both available options for emergency endovascular thrombectomy of acute ischemic stroke; each has its own cons and pros. Sedation has an advantage in reducing the time for anesthesia preparation, decreased exposure risk for healthcare workers and the medical environment, minimizing the risk of pulmonary complications in COVID-19 patients, and reduction of the contamination of anesthesia machines and other equipment. However, at least 5%–10% of the patients require conversion to general anesthesia because of “agitation” or excessive patient movement16,17. Advantages of general anesthesia with intubation are full access to the airway, protection from aspiration and hypoxemia, motionless during the procedure, but it needs more attention for hypotension and lung injury18. Therefore, during the COVID-19 pandemic, the neuroanesthesiologists should take a full consideration of patients’ conditions, the neurointerventional procedure and other medical conditions to make a decision.

If general anesthesia is performed, we must realize it is more difficult for anesthesiologists to manage airway under level-3 protection precaution, and the risk of difficult airway is increased. Prepare a difficult airway kit and other necessary equipment in advance if necessary. The preparation is like that for the care of an ordinary patient.

A low tidal volume of lung protective ventilation strategy is recommended for these patients to reduce brain-lung crosstalk injury. Target tidal volume is 6 mL/kg predicted body weight, inspiratory plateau pressure is less than 30 cm H2O, PEEP level is less than 8 cm H2O, and recruitment maneuvers are performed every 30 min19. Ventilation parameters should be adjusted to maintain normocapnia.

The current outbreak of COVID-19 has rapidly expanded. It is a very new infectious disease; there are full well-designed studies to provide any evidence-based proof. Special concerns are needed for healthcare workers during the pandemic. This article is based upon relatively limited data on transmission of this novel virus combined with the experiences from neuroanesthesiologists in China. This recommendation will be updated as more becomes known about the disease.

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