|Year : 2020 | Volume
| Issue : 3 | Page : 190-193
Safe neuroanesthesia practice during COVID-19 pandemic – How different from routine?
Nidhi Gupta, KJ Choudhury
Department of Neuroanaesthesia, Indraprastha Apollo Hospitals, New Delhi, India
|Date of Submission||01-Jul-2020|
|Date of Acceptance||16-Jul-2020|
|Date of Web Publication||19-Aug-2020|
Department of Neuroanaesthesia, Indraprastha Apollo Hospitals, New Delhi
Source of Support: None, Conflict of Interest: None
Currently, we are in the midst of a global pandemic caused by SARS-CoV-2 viral infection, termed Coronovirus disease or COVID-19. Despite the enormous working constraints imposed by this highly contagious virus and limited healthcare infrastructure, the neurosurgeons and neuroanaesthetists worldwide continue to provide their emergency services to neurocritically ill patients who need immediate intervention. Appropriate treatment modifications are mandatory to minimize nosocomial spread of SARS-CoV-2 while providing emergency care to the suspected or confirmed cases with COVID-19. In this review, we shall discuss the salient points about the various COVID-19 specific modifications involved in neuroanaesthesia practice, pertinent to the ongoing pandemic.
Keywords: COVID-19, neuroanesthesia, pandemic
|How to cite this article:|
Gupta N, Choudhury K J. Safe neuroanesthesia practice during COVID-19 pandemic – How different from routine?. Apollo Med 2020;17:190-3
| Introduction|| |
Currently, we are in the middle of a global pandemic caused by SARS-CoV-2 viral infection and termed novel coronavirus disease (COVID-19). During these testing times, the neurosurgeons and neuroanaesthetists worldwide continue to provide their emergency services to neurocritically ill patients who need immediate intervention, irrespective of their COVID-19 status. In addition, certain neurosurgical pathologies are fast deteriorating in nature and need a definitive intervention within a limited time frame. Such situations often need appropriate modifications in techniques and coordinated decision-making to make the entire procedure smooth, safe, and efficient. In this review, we shall discuss the salient points about the various COVID-19-specific modifications involved in neuroanesthesia practice pertinent to the ongoing pandemic.
| Neuroanesthetic Measures to Mitigate Perioperative Nosocomial Spread of Covid-19|| |
As COVID-19 is here to stay with us for a while, preventing infection of patients, as well as the health-care professionals, should now be the new normal and thus, guide all the necessary modifications in the perioperative management techniques. These include:
Staff training and management
To ensure the safety of entire team (including neurosurgeons, neuroanaesthetists, operating room technicians, nurses, housekeeping staff, radiographers, and security personnel), it is imperative to conduct proper safety training through dummy practice sessions. Available audio-visual tools can be used to educate about the use of personal protective equipment (PPE), hand and respiratory hygiene, airway management, resuscitation, patient-transportation, infective waste disposal, and disinfection methods. The minimum required PPE in operating room (OR) includes hood caps, shoe covers, double face masks (respirator N95 or FFP2 standard covered with a surgical three-ply mask), sterile standard gown, double gloves, long-sleeved water-resistant gown and eye protection (goggles or face shield). An N95 mask fit testing is essential before its use to avoid inadvertent exposure secondary to improper fitting. When available, use of a powered air-purifying respirators (PAPRs), fitted with a high-efficiency particulate air (HEPA) filters with a filtration efficiency of 99.97% against 0.3 μ particles, is highly recommended during the intubation of COVID-19 patients.
Dedicated COVID-19 operating room
COVID-19 positive or suspected cases should be operated in the dedicated OR with separate donning and doffing areas. A negative pressure OR with a separate air duct flow is recommended to reduce the transmission of airborne infection. The “high touch” surfaces such as anesthesia machine and patient monitor should be covered with plastic covers to reduce their contamination. Postoperatively, the soda lime canister should be discarded, and all surfaces should be cleaned with ammonium chloride wipes. The OR should then be cleaned with sodium hypochlorite 1000 ppm and finally treated with hydrogen peroxide vaporization or ultraviolet-C irradiation.
Preoperative patient evaluation
In addition to the standard preanesthetic check-up, the patients should be adequately screened for COVID-19 infection through a detailed history of fever, cough, dyspnea, chills/rigors, muscle pains, headache, sore throat, loss of taste/smell, and diarrhea. Nevertheless, despite a negative history, all patients should be currently treated as potential asymptomatic infected cases. Furthermore, COVID-19 may present with neurological symptoms, which may act as confounding factors during evaluation. The reported neurological spectrum of COVID-19 includes central (encephalopathy, encephalitis, meningitis, acute ischemic stroke (AIS) and hemorrhagic stroke, and venous sinus thrombosis) as well as peripheral manifestations (anosmia or hyposmia, dysgeusia, and Guillain–Barré syndrome and its variants). COVID-19 infection has been shown to have a significant independent association with AIS secondary to pathophysiologic mechanisms such as the proinflammatory prothrombotic state and cytokine storm. Hence, not only the patients with COVID-19 could present more frequently for emergency treatment of stroke but also at an increased risk of perioperative stroke if operated on during the incubation period.
Preoperative COVID-19 testing
At present, real-time RNA sequencing with RT-PCR of throat swab and nasal swab samples represents the gold standard test for COVID-19. However, the long-time taken for test results (minimum 2–5 h), limits its utility in emergency settings. Comparatively, COVID-19 Ag detection assay has a faster turnaround time of 90 min only and may be beneficial during emergency settings. Nonetheless, in view of its high specificity (99.3%–100%) while relatively low sensitivity (50.6%–84%), negative test in a patient with symptoms strongly suggestive of COVID-19 should always be tested sequentially by RT-PCR. However, in the event of an acute life-saving emergency, a direct surgical intervention should be performed considering the patient as COVID-positive and taking all necessary precautions.
Induction of general anesthesia
Administering general anesthesia (GA) to patients with a known respiratory infection is a challenge because anesthetic drugs suppress immunity and can thus contribute to intubation-related mechanical stress and inflammation. This may be compounded in patients with COVID-19 infection as a relative immune suppression, and a dysregulated inflammatory response acts as the main driver of this disease. Patients with severe COVID-19 may experience myocardial injury and multiple organ failure, which causes hemodynamic instability coinciding with low oxygen saturation, thus making endotracheal intubation a huge challenge. A rapid sequence anesthetic induction using propofol and muscle relaxants (either succinylcholine or rocuronium) is preferred to minimize the period of hypoxemia. Fentanyl may be given 30 s after the muscle relaxant to avoid any coughing stimulus.
Patients head should be covered by a protective barrier enclosure to prevent droplet and aerosol infection. These enclosure devices may include an acrylic “aerosol box” with two open ports for the anesthesiologist to insert his/her arm so that the whole intubation may be performed inside it [Figure 1]; a double clear plastic drape technique or by simply covering the patient's head and face area with a transparent sheet and hands inserted under the sheet to intubate the patients. Although effective in limiting the spread of aerosols, these devices may make the endotracheal intubation difficult to perform, especially in a difficult intubation scenario. Poor visibility because of fogging of goggles and communication difficulty, commonly encountered with the use of PPE, further adds to anesthesiologist's difficulty. Hence, endotracheal intubation should be performed by the most experienced provider, preferably by video laryngoscopy using single-use blade and disposable covers. To avoid virus scattering, assisted mask ventilation should be avoided. If positive mask ventilation is needed, on should cover the area around the patient's mouth and nose with wet gauze to help prevent the virus spreading. Confirming the depth of the endotracheal tube (ETT) is extremely difficult using auscultation while wearing PPE. Hence, it is recommended instead to observe bilateral chest expansion, end-tidal CO2, and ventilator breathing waveform.
|Figure 1: (a) “Aerosol box” (b) Aerosol box placed over patient's head during airway management|
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In the event of encountering a difficult airway, repeated tracheal intubation attempts should be avoided, and a laryngeal mask airway (LMA) should be used for interim ventilation. Alternative difficult tracheal intubation techniques include tracheal intubation through an intubating LMA (blind or flexible bronchoscope-assisted), or with video-guidance. If an emergency tracheostomy needs to be performed, the scalpel-bougie-tube technique is particularly preferred due to the risk of aerosolization with the oxygen insufflation associated with cannula techniques. One should avoid awake fiberoptic intubation if possible, as atomized local anesthetic can aerosolize the virus, and the procedure may induce coughing.
Minimizing aerosol spread in operating room
Other important considerations to minimize aerosol spread in OR include minimizing ventilator disconnections, closed airway suctioning, and optimal placement of high-efficiency viral filters in the anesthesia circuit. A heat and moisture exchange and filter (HMEF), with a viral filtration efficiency (VFE) of >99.99%, is typically positioned at the patient end of the breathing system between the circuit Y-piece and the patient's airway. In addition, a second HMEF (or HEPA filter with VFE of >99.9999) should be placed at the end of the expiratory limb at its connection to the anesthesia machine. If required, the circuit should be disconnected from the point after the attachment of the HMEF filter, using ETT clamps in a well-sedated and paralyzed patient after putting the ventilator on a standby mode and zeroing the oxygen flow.
Extubation following GA should, if possible, be performed in a negative pressure environment using airborne PPE. One should consider using medications such as dexmedetomidine or xylocard during extubation to minimize or avoid coughing. Extubated patients should receive oxygen through facemask (at a rate <6 L/min, given the risk of aerosolization) with an additional surgical mask placed underneath. To minimize risk to other members of the team, it is of utmost importance that only the anesthesia providers remain inside OR during anesthetic induction and extubation. At the end of the surgery, all staff should then shower and change into a clean set of scrubs.
All pre- and post-operative transfer of nonintubated patients should be done in dedicated COVID-19 lifts and corridors by the nurses in full PPE and patients face covered with a surgical mask. For transporting intubated COVID-19 patients, closed-circuit transport ventilators appear to be the safest way. However, in the event of nonavailability of transport ventilator, patients can be ventilated with a Bain's circuit (or an Ambu Bag, in the event of an emergency), wrapping its adjustable pressure limiting valve with a gauze piece soaked with normal saline or hypochlorite solution. An HMEF filter should always be placed between the patient's airway and the breathing circuit. An appropriately-sized transparent box or plastic hoods or C-arm covers can be used to cover the patient trolley, especially the head-end, to further minimize aerosol spread.
High-risk neurosurgical procedures
Among all neurosurgical procedures, endoscopic endonasal procedures have the highest risk of aerosol dispersion. Hence, for patients presenting with pituitary apoplexy, an alternative transcranial approach should be considered. However, if the transnasal route is unavoidable, all OR personnel should use the highest level of PPE with PAPR. For urgent cases, two COVID-19 tests separated by 24 h should be performed with the patient quarantined in the interval between tests before the surgery, with the surgery proceeding only if both test results are negative.
Emergency management of acute ischemic stroke
COVID-19 pandemic has unique implications for neuroanaesthetists during emergency endovascular management of AIS. Every effort should be undertaken to minimize the delay in treatment while also ensuring that the entire team has donned PPE. The choice of anesthetic technique should be individualized based on the patient's neurological status. In general, a lower threshold is recommended to induce GA electively to avoid the need for urgent conversion from Monitored Anaesthesia Care to GA within the radiology suite. Since a negative pressure environment may not be available near interventional radiology suites, airway management should ideally be done in a separate negative-pressure isolation room, and then the patient should be transported to the radiology suite.
| Conclusion|| |
The situation regarding COVID-19 is rapidly evolving and dynamic, and hence, the best neuroanesthetic techniques may still change with the emerging evidence. We, as an emergency care specialty, should be quick in embracing these necessary technical modifications while ensuring strict implementation of COVID-safe protocols for better safety of not only our patients but also ourselves and our colleagues.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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