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Introduction
China reported the first outbreak of the novel severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) in Wuhan on 7 January 2020 [1]. As of 25 June 2020, coronavirus disease 2019 (COVID-19) had become a pandemic with more than 9 million cases with 2% critically ill and 9% deceased [2]. Importantly, healthcare workers accounted for 3.8% of the cases in China and 11% in Italy [3]. Virus transmission is through respiratory droplets and fomites, which places anesthetic staff at a high risk of nosocomial infection. Although the virus has been reported to be air-borne [4], this has not yet been confirmed in clinical studies.
Following the rapid and global spread of the virus, numerous guidelines have been published by national anesthesia societies to provide anesthetists with insights into the management of COVID-19 patients and the risk of infection during aerosol-generating procedures (intubation, extubation, airway suctioning) associated with anesthesia [5]. Ideally, guidelines should have scientific rigor, and they should be presented with clarity. They should also apply to practitioners internationally, irrespective of the minor variations in practice. An objective framework for developing and appraising clinical guidelines is provided by the Appraisal of Guidelines for Research and Evaluation (AGREE) II tool [6]. As various countries move from the containment phase to the gradual relaxation of community restrictions, the second surge of infections is anticipated.
The primary aim of our review was to appraise national guidelines on the anesthetic considerations for COVID-19 patients presenting for surgery and evaluate their quality with the AGREE II tool. Through updates, guidelines can be refined to ensure that they are more robust, and they can equip anesthetists for the potential viral resurgence.
Materials and Methods
Search strategy and selection of sources of evidence
We conducted a systematic search of the PubMed and EMBASE databases using the combination of Medical Subject Heading (MeSH) and keywords ([“anesthesia” or “anesthesiology”] OR [“airway management”] OR [“intubation”]) AND ([“SARS” OR “SARS-CoV” OR “SARS-CoV-2” OR “COVID-19” OR “Coronavirus”]) for guidelines/studies published between 1 Jan 2002 and 16 May 2020. To capture new guidelines that had not been indexed in these databases, national anesthesia organizations, with links to their official websites listed on the World Federation of Society of Anesthesiologists (WFSA) [7] COVID-19 resource webpage (up to 28 May 2020), were interrogated because it represents anesthesia societies from over 150 countries. We also expanded our search for guidelines from countries (China, Hong Kong, Singapore, and Taiwan) that were affected by the SARS-CoV epidemic in 2003 [8]. Guidelines from Hong Kong and Singapore, which reported SARS previously, were not endorsed by their official national societies, and they were excluded. The bibliographies of the retrieved articles were manually screened for additional relevant material.
Eligibility criteria
Only articles written in English and Chinese were included because the two co-authors who conducted the search were proficient in both languages. Articles that reported relevant aspects of perioperative anesthetic management of patients with COVID-19 were included. Two reviewers (SO and WYL) conducted the search independently and screened all article types for eligibility using their titles and abstracts. Duplicate and irrelevant articles were excluded. Articles that did not address the primary objective and those that were correspondences and editorials were also excluded. Discrepancies were discussed and resolved by PK.
Critical appraisal of sources of evidence
SO and PK independently appraised each eligible national guideline using the AGREE II instrument [6] (Supplementary Table 1). The AGREE II instrument has six domains (with 23 items) and two global rating items. The six domains were scope and purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability, and editorial independence. Each item in the domain is scored on a seven-point scale (1 = minimum to 7 = maximum). Total scores were scaled to a percentage of the maximum score in each domain; for example, 0% if each reviewer scored 1 and 100% if each reviewer scored 7. The AGREE II instrument has been validated and tested for inter-rater reliability.
In addition, full manuscripts of extracted articles from the literature search were analyzed independently by SO and WYL and graded according to the level of evidence as defined by the Centre for Evidence-Based Medicine, Oxford [9].
Results
Nineteen national guidelines from Australia, Canada, China, India, Italy, South Africa, South Korea, Taiwan, the UK, and the USA described the anesthetic management of COVID-19 patients [10–28]. China had the highest score for Scope and Purpose of guidelines followed by South Korea and the UK. The UK and South Africa scored the highest for the Clarity of guidelines. Among the domains, editorial independence had the lowest score, followed by rigor of development and applicability. Spearman correlation analysis of reviewer scores of all domain items demonstrated good inter-rater reliability (ρ = 0.714, P < 0.001, 95% CI: 0.436–0.868). A summary of the results is provided in Table 1.
There was a paucity of high-quality evidence supporting the current recommendations. Of the 63 articles retrieved from the literature search, only one systematic review (level 2) in 2012 related aerosol-generating procedures to the infections of health care workers [29], and one prospective single-center study (level 3) in 2006 focused on simulation [30]. The remainder of the reports were predominantly retrospective studies, case reports/series (level 4), and expert opinions (level 5) that focused on infection control and intubation. The results of the literature search are shown in Supplementary Table 2.
Guidelines on preoperative management
Preoperative evaluation, screening, and prioritization for surgery
The details on preoperative guidance varied. China and India detailed preoperative screening of history, symptoms, and investigations while South Africa used a brief checklist [15,17,20]. Australia recommended using telemedicine for preoperative assessment, counseling, consent, and a thorough airway assessment [10]. The UK through the Difficult Airway Society focused specifically on the MACOCHA (Mallampati III or IV; Apnea syndrome [obstructive]; Cervical spine limitation; Opening mouth-3 cm; Coma; Hypoxia; Anesthesiologist-non trained) score to assess and predict a difficult airway [24,31]. Only the USA linked preoperative screening with viral testing and prioritization for surgery involving a multidisciplinary team [26]. Recommendations on scheduling elective surgery during the pandemic were provided by Canada, India, South Africa, the UK, and the USA [12,17,20,24,26].
Infection control and personal protective equipment
This was the focus of all the guidelines. All countries recommended airborne precautions and Personal protective equipment (PPE) training [10–28]. There was unanimous agreement on the use of full PPE (N95 mask or powered air-purifying respirator (PAPR), face shield or goggles, gown, hat, double gloves) for aerosol-generating procedures and hand hygiene when donning and after doffing PPE [10–28]. All countries (apart from India and South Korea), recommended a buddy system for PPE donning. High-risk healthcare personnel who were pregnant, immunocompromised, or older than 60 years with cardiorespiratory diseases were advised by the UK to refrain from airway management [23,24]. The number and position of staff present in the inner and the outer rooms, the types of PPE, including the position of equipment and monitors, were detailed by Italy and the UK [19,24]. Other recommendations included using a negative pressure operating theater with warning signs [10–21,23–28], placing a hydrophobic filter interposed between the face mask/endotracheal tube and the breathing circuit or the reservoir bag [10–28], and using disposable equipment [10–16,18–28] where possible. A clear plastic sheet to limit the aerosol spread and the use of forced-air warming blankets only in intubated patients were recommended by Australia [10].
Training and resource planning
Simulation training for the provision of anesthetic care was advocated by Australia, Canada, China, India, Italy, the UK, and the USA [10–19,23–28]. In addition, team briefing before surgery was recommended by Australia, Italy, South Africa, the UK, and the USA [10,11,18,23–28]. China, India, and South Korea addressed fatigue by deploying several airway and anesthetic teams to support hospitals and operating theaters [14–17,21]. All guidelines (except those from Canada and Taiwan) detailed the most direct route for patient transfer to the operating theatre: bypassing the holding area with the patient wearing a surgical mask [10,11,14–28].
Evidence
Apart from one level 2 and one level 3 evidence studies, the evidence relating to preoperative management was weak (level 4 and 5 evidence), and it focused on infection control [29,30]. Reports from the SARS outbreak in 2003 detailed risk factors for the infection of healthcare workers related to PPE use and aerosol generation [29,30,32-34]. Recent reviews on the preoperative management of COVID-19 patients also described operating room optimization and infection control and the rational use of PPE [35,36].
Guidelines on intraoperative management
Intubation
All guidelines focused on the reduction of aerosol generation during procedures and limiting the exposure of healthcare personnel [10–28]. Recommendations included a rapid sequence induction and intubation by the most experienced airway personnel and the use of a videolaryngoscope [10–28]. Canada and the UK recommended using intravenous ketamine for induction in patients with hemodynamic instability [12,23]. Manual ventilation was to be avoided and, if required, small tidal volumes were to be delivered via two-handed facemask ventilation, with the VE hand position preferred to the C hand position [24] for a better mask seal. The Difficult Airway Society in the UK also recommended meticulous attention to preoxygenation, including optimizing patient positioning at induction to maximize a safe apnea time [24]. Only Italy suggested apneic nasal oxygenation delivery at a flow rate of 3 L/min during airway manipulation [18]. Positive pressure ventilation was only to be commenced after intubation and inflation of the tracheal tube cuff [10–20,22–28] to at least 5 cmH2O above the peak inspiratory pressure [24]. Awake fiberoptic intubation, including the use of high-flow nasal oxygen and non-invasive ventilation was discouraged by all guidelines (except for Canada and South Africa). Only Australia, Italy, and the UK provided specific recommendations for the management of a difficult airway [10,11,18,19,23,24]. These included using the VORTEX approach [37], intubation via a supraglottic airway device (SAD), and employing the scalpel bougie over the needle cannula approach in front of neck access in “cannot intubate, cannot oxygenate” scenarios [10,19,24]. Other heterogeneous recommendations included a smaller sized endotracheal tube, avoidance of cricoid pressure (to minimize coughing) [19], and loading the endotracheal tube routinely with an introducer [10,11].
Regional anesthesia
Regional anesthesia, where possible, has been advocated by Australia, China, India, and the USA [10,14–17,25–28]. Thrombocytopenia and coagulopathy should be excluded before neuraxial techniques, especially in patients with severe COVID-19 disease [38]. Although SARS-CoV-2 has been demonstrated in cerebrospinal fluid and brain tissue on autopsy, spinal anesthesia in obstetric parturients with COVID-19 has been reported to be safe [39]. For peripheral nerve blocks near the head and neck area, airborne precautions may be considered [40]. In addition, confirming the success of the block reduces the need for emergent conversion to general anesthesia [40].
Evidence
Evidence supporting airway management and endotracheal intubation was initially derived from a systematic review on aerosol-generating procedures and infection in healthcare workers (level 2 evidence) and case reports (level 4 evidence) published on SARS [29,33,34,41–44]. Recent reports on COVID-19 patients (level 4 and 5 evidence) have been published [14–16,45–51]. A recent retrospective review (which included an expert panel) of the emergency intubation of 202 patients with COVID-19 reported that hypoxemia (oxygen saturation < 90%) was common and associated with hypotension, cardiac arrest, and pneumothorax [14]. The authors recommended head elevation for intubation with propofol dose reduction, fluid boluses, or inotropes (to avoid hypotension). A ventilation protective strategy utilizing small tidal volumes to minimize barotrauma was recommended [14].
Guidelines on postoperative management
Postoperative cleaning and disinfection
Australia, Canada, China, India, Taiwan, the UK, and USA detailed environmental disinfection [10–17,22–28]. Australia and the UK recommended waiting 20 to 30 minutes between cases to allow for operating theater cleaning and air changes [10,23]. All guidelines advocated the disposal of waste into labeled bins [10–28]. Additionally, Australia, China, India, South Africa, South Korea, Taiwan, and the USA recommended sealing all contaminated equipment for disinfection in double zip-locked bags [10,11,15,17,20–22,26]. China and South Korea proposed the replacements of the end-tidal carbon dioxide sample line and water trap [15,21].
Staff monitoring and welfare
Australia, Italy, the UK, and the USA [10,19,23,26] recommended a team debriefing event, while Canada encouraged incident reporting of adverse events [12]. With regards to staff surveillance, Australia and the USA required staff to maintain a logbook of clinical exposure, while China required daily surveillance of temperature and respiratory symptoms [10,15,16,26,28]. Additionally, Australia, Canada, South Africa, the UK, and the USA provided support services on mental well-being [10,12,20,23,26].
Evidence
There was little evidence on postoperative management apart from a retrospective study (level 4 evidence) from China that reported surveillance and a 14-day quarantine of a team of anesthesiologists who performed intubation on all COVID-19 patients in two hospitals [52].
Guidelines on subspecialty anesthesia
Obstetric anesthesia
National guidelines on the perioperative anesthetic management of obstetric patients with COVID-19 were scarce. Australia, China, Taiwan, the UK, and the USA recommended neuraxial anesthesia as the technique of choice for cesarean delivery [10,15,22,23,25–28]. The use of nitrous oxide/oxygen mixture for labor analgesia was controversial. The UK endorsed its use with a viral filter, but Australia and Taiwan did not [10,22,23]. Evidence from retrieved articles was mainly of level 4 and 5 quality. An expert panel review recommended screening patients for COVID-19 symptoms remotely and observing droplet and contact precautions in the labor ward [53]. Parturients were to wear surgical masks as increased ventilation during labor and symptoms could predispose to airborne transmission [54]. Two studies reported safe administration of epidural and spinal in COVID-19 patients who underwent cesarean section [39,55]. However, a higher incidence of maternal hypotension was reported [55]. Combined spinal and epidural was recommended for anticipated prolonged procedures to minimize conversion to general anesthesia [56]. Thrombocytopenia, which may be present in COVID-19 infections, was to be excluded. Epidural was recommended for labor analgesia to reduce the need for general anesthesia if urgent delivery is required. Category 1 cesarean section delivery should be avoided by close fetal monitoring [42,56]. Patients should be informed of potential delays due to PPE donning [42].
Pediatric anesthesia
Australia, Canada, and the UK provided guidelines for pediatric anesthesia [10,13,23]. Aerosol generation from crying was to be minimized by sedation, parental presence, and deep extubation [10,13]. Inhalation induction was to be best performed with a circle system, utilizing the lowest gas flows. Airway management was to be performed by trained pediatric staff, and a cuffed endotracheal was recommended [10,13,23]. Recommendations for difficult airway management included using video laryngoscopy primarily, followed by fiberoptic intubation through a SAD, combined video laryngoscopy with fiberoptic bronchoscopy, and fiberoptic bronchoscopy alone [13]. The UK also highlighted the need to exclude pediatric multisystem inflammatory syndrome associated with COVID-19 [23]. The literature review revealed only expert opinions and narrative reviews (level 5 evidence) that supported the guidelines from Australia, Canada, and the UK [13,57].
Cardiothoracic anesthesia
Advanced hemodynamic monitoring such as transesophageal echocardiography can be used to guide fluid therapy and vasoactive drugs, especially for COVID-19 patients with multi-organ dysfunction presenting for cardiac surgery. In addition, blood conservation and rigorous evaluation of coagulation are needed for coagulation abnormalities [58]. For thoracic anesthesia, viral filters and clamps should be placed on the double-lumen tube before opening it to the atmosphere so that the release of positive pressure within the lung occurs through a viral filter. In addition, ventilation should be withheld and a swivel connector with a self-sealing valve should be used if the breathing circuit is to be accessed for procedures. Bronchoscopes are significantly contaminated, and disposable flexible bronchoscopes should be used where possible. Suctioning of the airways should be performed before reversing neuromuscular blockades [59,60].
Neuroanesthesia
Full PPE for aerosol-generating procedures should be used for trans-sphenoidal surgeries, as there is a high incidence of viral shedding. Patients undergoing awake craniotomy should be lightly sedated to avoid an emergent airway, and low-dose lidocaine or remifentanil can be used to minimize coughing. For the endovascular treatment of acute ischemic stroke, a low threshold for general anesthesia with intubation by airway personnel in a negative pressure room is preferred over the urgent conversion from sedation [61]. In addition, a lead gown can be worn under the PPE gown [62].
Anesthesia for otolaryngology
For airway surgery such as airway dilatation and tracheostomy, closed-loop communication between the surgeon and anesthesiologist is important to ensure that ventilation is held-off every time the endotracheal cuff is deflated, the tube is removed, or the circuit is disconnected [63].
Trauma anesthesia
Regional anesthesia is recommended where possible. Cricoid pressure during induction of general anesthesia should be used with caution, as it can stimulate coughing. Blood conservation is recommended and thromboprophylaxis should be instituted where possible [38].
Discussion
The strength of this review is that it provides a comprehensive appraisal of all the available guidelines; it also summarizes their strengths and limitations. Our review found that national guidelines for the anesthetic management of COVID-19 patients were moderately comprehensive, but they scored poorly for rigor of development, editorial independence, and applicability. Evidence underpinning guidelines was weak, leading to heterogeneity in recommendations. Gaps in preoperative screening, prioritization for surgery, and anesthesia for specific groups were identified and addressed, albeit with low-quality evidence consisting of retrospective studies, case reports, narrative reviews, and expert opinions.
The Institute of Medicine defines clinical guidelines as “statements that include recommendations, intended to optimize patient care, that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options” [64]. Clinical guidelines assist physicians in providing the best care, and they should adhere to a robust reporting framework. Given the rapid spread of the pandemic, initial guidelines were undoubtedly subjected to time-sensitive pressure in development and publication. As the virus is highly contagious, early guidelines focused on defining aerosol-generating procedures, mitigating aerosolization, and appropriate PPE and infection control practices. These were largely based on retrospective studies and case series during the SARS outbreak in 2003 [30,33,34,42–44]. These initial guidelines have served their purpose in successfully limiting disease spread to healthcare workers. Moving forward, national guidelines should be updated as new data emerge to include the entire perioperative process. Dagens et al. [65] suggested that pandemic guidelines should have transparent timelines for revision and amendment to ensure that they are more robust, especially for the potential viral resurgence. The recommendations should describe how they were derived and indicate their strengths and limitations and whether they were reviewed by experts, including infectious disease physicians and epidemiologists. Importantly, recommendations should be linked to an evaluation of supporting evidence and presented clearly with the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system [66]. GRADE is widely used by many organizations globally, and it is a transparent and reproducible framework that helps clinicians to understand the underlying logic and principles of the guidelines. The GRADE system comprises a two-level representation of the strength of recommendation (weak or strong) and a four-level representation of the certainty of the evidence (very low, low, moderate, and high) [67]. In addition, conflict of interest, which is essential for any scientific publication, should be disclosed, as many involved experts may have industry affiliations. Non-declaration implies bias, and it reduces the quality and reliability of the recommendations. Contributions from experts in subspecialty interest groups make national guidelines more inclusive and comprehensive. Although attempts to address difficult airway management were addressed by the Difficult Airway Society in the UK and Safe Airway Society in Australia and New Zealand, guidance for other patient groups was scarce.
With countries resuming elective surgeries, gaps in current guidelines would need to be addressed. Of relevance would be preoperative screening, which has important implications for resource utilization, especially PPE, processes, facilities, and manpower. Preoperative screening for COVID-19 and prioritization for surgery is also important, as morbidity and mortality have been reported in pre-symptomatic carriers who have undergone elective surgeries [68]. The USA has proposed two approaches to the perioperative testing of COVID-19 depending on the local prevalence of SARS-CoV-2. The American College of Surgeons recommends that a committee comprising surgeons, anesthesiologists, and nurses (guided by the Elective Surgery Acuity Scale) should assist with the prioritization of patients for surgery [69].
Categorizing COVID-19 to mild, moderate, severe, or critical may also help to refine anesthetic plans [70]. For COVID-19 patients with moderate to severe pneumonia, careful airway assessment is important, as hypoxemia during intubation is common and the options for oxygenation or awake intubation are limited. Critically ill patients with organ dysfunction would require preemptive inotropes, fluid resuscitation, careful titration of drugs, and a lung-protective ventilation strategy [14].
Areas of controversy relating to anesthetic technique, the use of airway devices, the extent of aerosol dispersion, and the management of specific groups require further research and guidance updates as new evidence emerges. Further research on temperature, blood, and fluid management, including the degree of staff surveillance for infection and burnout is also needed.
This review was limited by the language restriction of our search and the quality of evidence available. Evidence was mostly from retrospective studies involving small samples, case reports, narrative reviews, and expert opinions.
Conclusion
National anesthetic guidelines published in the early phase of the COVID-19 pandemic were largely guided by weak evidence, and they lacked robust reporting. As countries move into easing lockdown during the second phase of the pandemic, recommendations need to be updated as new data become available. Guidelines should be subjected to established grading and appraisal systems such as GRADE and AGREE II to provide clarity, especially during a pandemic.
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