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COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control

COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control
Martin J London, MD, FASE
Section Editors:
Roberta Hines, MD
Michael F O'Connor, MD, FCCM
Deputy Editors:
Marianna Crowley, MD
Nancy A Nussmeier, MD, FAHA
Literature review current through: Nov 2022. | This topic last updated: Nov 15, 2022.

INTRODUCTION — Patients infected with the novel coronavirus disease 2019 (COVID-19 or nCoV) may be at increased risk of perioperative complications, and may transmit the virus to clinicians and other patients. This topic will discuss preoperative evaluation and risk assessment, management of anesthesia, and perioperative infection control for patients with known or suspected COVID-19.

UpToDate has added information on many aspects of COVID-19 including general infection control measures, medical and intensive care, and specialty care, in various topic reviews. Two are linked here:

(See "COVID-19: General approach to infection prevention in the health care setting".)

(See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection".)

Anesthetic concerns for regional anesthesia, obstetric anesthesia, and gastrointestinal endoscopy in patients with COVID-19, and considerations when performing transesophageal echocardiography are discussed separately.

(See "Overview of neuraxial anesthesia", section on 'Patients with suspected or confirmed COVID-19'.)

(See "Overview of peripheral nerve blocks", section on 'Patients with suspected or confirmed COVID-19'.)

(See "Neuraxial analgesia for labor and delivery (including instrumented delivery)", section on 'Patients with suspected or confirmed COVID-19'.)

(See "Anesthesia for gastrointestinal endoscopy in adults", section on 'Endoscopy in patients with suspected or confirmed COVID-19'.)

(See "Transesophageal echocardiography: Indications, complications, and normal views", section on 'COVID-19 precautions'.)

A separate topic discusses use of anesthesia machines for intensive care ventilation. (See "COVID-19: Intensive care ventilation with anesthesia machines".)

Many United States and international organizations and professional societies have issued guidelines or recommendations for perioperative care during the COVID-19 pandemic. This topic relies heavily on such recommendations, which are based on expert opinion and what is known about transmission of this and other viruses [1-16]. (See 'Society guideline links' below.)

PREOPERATIVE EVALUATION DURING THE PANDEMIC — During the COVID-19 pandemic, preoperative evaluation should include COVID-19 screening or testing for patients who are not known to have COVID-19. For all patients, risk assessment related to COVID-19 includes not only the likelihood of perioperative morbidity and mortality, but also the risk of spread of the virus to care providers and other patients.

Patients who require surgery soon after a diagnosis of COVID-19 may be taking nirmatrelvir-ritonavir (Paxlovid). Ritonavir is a strong CYP P450 3A inhibitor, and therefore may impair metabolism of a number of drugs used in anesthetic care, including midazolam, ketamine, rocuronium, lidocaine, and bupivacaine [17]. For this reason, dose adjustments or titration to effect should be considered for any patient taking nirmatrelvir-ritonavir, particularly if repeated doses or an infusion are administered. Drug interactions can be determined using the COVID-19 drug interactions program.

Other aspects of the preanesthesia evaluation are discussed separately. (See "Preoperative evaluation for anesthesia for noncardiac surgery".)

Preoperative screening and testing — All patients scheduled for surgery should be screened for exposure to COVID-19, and for symptoms (ie, fever, cough, shortness of breath, muscle pain, sore throat, and/or new loss of taste or smell) within the prior two weeks. Patients with symptoms should be referred for further evaluation. (See "COVID-19: Clinical features", section on 'Clinical manifestations'.)

Institutional protocols should be followed for preoperative testing for COVID-19 and the use of transmission precautions. Some institutions are routinely performing COVID-19 testing before scheduling elective surgery, and some states have specific mandates or advisories for testing. Especially with the rise of the highly contagious Omicron variant of SARS-CoV-2, continued vigilance is warranted even for patients who are vaccinated (see "COVID-19: Epidemiology, virology, and prevention", section on 'Omicron (B.1.1.529) and its sublineages').

The American Society of Anesthesiologists (ASA) and the Anesthesia Patient Safety Foundation (APSF) have published joint statements that include preoperative COVID-19 testing [18].  

Patients who have not had COVID-19 – ASA/APSF recommendations for preoperative COVID-19 testing have evolved as the pandemic has changed. They now recommend the following:

In areas of high COVID-19 prevalence (based on Centers for Disease Control and Prevention [CDC] data), all patients with symptoms of COVID-19 should be referred to primary care for evaluation, and all others should be tested for COVID-19 ≤3 days prior to non-emergency surgery, using a nucleic acid amplification test (eg, PCR test), regardless of their vaccination status [19].

In areas of low to moderate community transmission, institutions may decide to not require preoperative testing for asymptomatic vaccinated patients having low risk procedures.  

Patients who have had COVID-19 – For patients who have previously tested positive for COVID-19, ASA/APSF recommendations for preoperative testing follow CDC guidelines for discontinuation of precautions, which depend on the severity of illness and the patient’s immunocompetence. CDC guidelines on this issue are discussed in detail separately and are shown in a table (table 1). (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Discontinuation of precautions'.)

Risk of surgery with COVID-19 — The risks of perioperative morbidity and mortality may be increased in patients with COVID-19, and for some time after recovery [20-27]. Thus, the decision to perform surgery must balance this risk against the risks of delaying or avoiding the planned procedure. Most retrospective studies have found increased risks of pulmonary complications and mortality after surgery performed up to seven or eight weeks after a diagnosis of COVID-19.

Overall risk

High rates of postoperative pulmonary complications and mortality were reported in an observational international study of 1128 patients with perioperative COVID-19 (ie, diagnosed within 7 days before or up to 30 days after surgery) who underwent a variety of surgical procedures [20]. Pulmonary complications occurred in 51 percent of patients; among those patients 30 day mortality was 38 percent. Overall mortality was higher after emergency surgery compared with elective surgery (26 versus 19 percent), and was higher in men, patients >70 years of age, and those with ASA Physical Status grade ≥3. Of the 280 patients who had elective surgery, 22 were diagnosed with COVID-19 preoperatively and two of them died.

In a similar prospective multicenter study of 1581 adults with perioperative COVID-19 in the United States, postoperative pulmonary complications occurred in 39.5 percent, and mortality occurred in 11 percent of patients [26]. Independent predictors of mortality were age ≥70 years (odds ratio [OR] 2.46, 95% CI 1.65-3.69), male sex (OR 2.26, 95% CI 1.53-3.35), ASA Physical Status grade ≥3 (OR 3.08, 95% CI 1.60-5.95), emergency surgery (OR 2.44, 95% CI 1.31-4.54), malignancy (OR 2.97, 95% CI 1.58-5.57), respiratory comorbidities (OR 2.08, 95% CI 1.30-3.32), and higher Revised Cardiac Risk Index (OR 1.20, 95% CI 1.02-1.41).

Risk related to timing after infection — Several large observational studies suggest that perioperative risks of pulmonary complications and mortality are highest within seven to eight weeks following COVID-19 infection [24,27,28]. Whether risks are different in patients who are vaccinated is unclear, with limited available data. Two large retrospective studies with significant limitations have suggested that vaccination may reduce perioperative risk in patients who have been infected with COVID-19 [29,30]. It is unclear whether risks of surgery are different in patients who have been infected with the Delta or Omicron variants of SARS-CoV-2, since most studies that determined risk were performed before emergence of those variants.

Examples of relevant studies include the following:

In an international prospective cohort study of over 140,000 patients who underwent surgery during October of 2020, of whom approximately 3100 had a preoperative COVID-19 diagnosis, surgery within seven weeks of the diagnosis of COVID-19 was associated with increased odds of 30 day postoperative mortality [27]. Mortality data from this study are shown in a table (table 2).

Risk of 30 day mortality was higher after surgery performed within 7 weeks for patients who had been symptomatic with COVID-19, compared with patients who had been asymptomatic.

Patients with ongoing symptoms at the time of surgery had higher 30 day mortality than those whose symptoms had resolved, at all time periods.

Patients with a COVID-19 diagnosis had higher rates of pulmonary complications after surgery performed within the seven week window, but not after.

Conclusions from this study are limited by the lack of surgery specific data, and lack of any data on anesthesia management.

In a multicenter database study of >5400 patients with COVID-19 who underwent major non-emergency surgery, patients who had surgery in the first four weeks after the diagnosis of COVID-19 had higher risks of postoperative pneumonia (adjusted odds ratio [aOR] 6.6, 95% CI 4.1-10.3), respiratory failure (aOR 3.4, 95% CI 2.2-5.1), sepsis (aOR, 3.7, 95% CI 2.2-6.2), and pulmonary embolism (aOR 2.7, 95 1.4-5.5) compared with patients who had surgery more than 30 days prior to the COVID diagnosis [24]. Surgery within four to eight weeks was associated with increased risk of pneumonia (aOR, 2.4, 95% CI 1.2-5.0). Surgery ≥8 weeks after diagnosis was not associated with increased risk of complications. Most patients had mild to moderate COVID-19. There were no data on COVID-19-related symptoms at the time of surgery, or on postoperative mortality.

One retrospective study in 8100 patients noted a higher mortality if surgery was performed within 8 weeks of COVID infection, but this data was collected in an unvaccinated cohort early in the COVID pandemic [28].

A retrospective cohort study found that postoperative complications were not increased in vaccinated patients who had surgery within four weeks of COVID-19 infection, but were modestly increased in patients who were not fully vaccinated, and in patients who had general anesthesia for the surgery [29].

Limited data suggest that postoperative risks may be lower in pediatric patients with the Omicron variant. In a single institution retrospective study, 285 children who tested positive for COVID-19 in early 2022 (likely Omicron) subsequently underwent surgery [31]. Very few intra or postoperative complications occurred, even when surgery was performed at two to four weeks after infection. Most children had mild or asymptomatic COVID-19. Approximately 42 percent underwent otolaryngologic surgery, but no further detail was provided on other types of surgery.

Timing of surgery after COVID-19 infection — Elective procedures should not be performed in patients who are symptomatic with COVID-19 or who are suspected of having COVID-19. For patients who have had COVID-19, elective procedures should ideally be delayed until the patient has recovered to baseline cardiopulmonary status and is no longer infectious.

Patients with severe COVID-19 may have significant cardiopulmonary compromise long after the acute illness [32,33]. The decision to proceed with elective surgery after COVID-19 infection must be individualized, taking into account both the risks of complications after surgery and the risks of delaying surgery [34]. (See 'Risk of surgery with COVID-19' above.)

The Anesthesia Patient Safety Foundation (APSF) and the American Society of Anesthesiologists (ASA) have issued a 2022 joint statement on elective surgery after COVID-19 infection, with general guidelines on timing of elective surgery based on the severity of symptoms at the time of infection, ongoing symptoms, comorbidities, and complexity of surgery [35]. The joint statement recommends delaying elective surgery for seven weeks after a diagnosis of COVID-19 in unvaccinated patients, and extending that delay in those with ongoing COVID-19-related symptoms at the planned time of surgery. The statement notes that there is insufficient evidence to make different recommendations in patients who have COVID-19 after having been vaccinated.

A group of anesthesia and surgical societies in the United Kingdom published a consensus statement (updated in 2022) on the timing of surgery after COVID-19 infection, which is generally similar to the ASA and APSF statement [36]. (See 'Society guideline links' below.)

Recovery from COVID-19 – The time to resolution of symptoms and complete recovery from COVID-19 varies widely. Young healthy patients with mild COVID-19 may recover completely within several weeks. However, patients with comorbidities or severe infection may have a prolonged recovery lasting eight weeks or longer. Some patients have protracted changes in pulmonary function, multiorgan system involvement, including stroke, myocarditis, and kidney dysfunction, fatigue, and psychologic or cognitive problems (see "COVID-19: Evaluation and management of adults with persistent symptoms following acute illness ("Long COVID")", section on 'COVID-19 recovery'). Similar to other viral illnesses, decisions about the timing of elective procedures should be based on the type of procedure to be performed, patient comorbidities, and residual symptoms, including exercise tolerance relative to baseline.

Infectivity – Both the CDC and the World Health Organization (WHO) have provided recommendations for determining when a patient diagnosed with COVID-19 is no longer infectious. They provide options based on either testing or time from both initial symptoms and resolution of symptoms, or for patients who were asymptomatic, time since a positive test. The specifics of symptom and time based strategies for discontinuation of precautions are shown in a table (table 1).

For patients who are asymptomatic or with mild symptoms, the decision to discontinue precautions should be based on time and symptom-based criteria.

For patients who are immunocompromised and patients who are severely ill with COVID-19, testing should be managed in consultation with an infectious disease specialist.

Testing for infectivity is discussed in detail separately. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Discontinuation of precautions'.)

MANAGEMENT OF ANESTHESIA — Principles and practice of anesthetic management are discussed in multiple other UpToDate topics. Issues specific to patients with COVID-19 are discussed here.

Most of the following discussion is applicable to anesthesia for children as well as adults. Issues specific to children are discussed separately. (See "Airway management for pediatric anesthesia", section on 'Airway management for patients with COVID-19'.)

Choice of anesthetic technique — The choice of anesthetic technique (ie, general anesthesia [GA], regional anesthesia, monitored anesthesia care) should be based on patient factors and the planned procedure. Important considerations are discussed here.

Regional anesthesia — Regional anesthesia (neuraxial anesthesia, peripheral nerve block) is not contraindicated in patients with COVID-19. The use of regional anesthesia may avoid the need for general anesthesia, airway management, and the associated risk of aerosolization of airway secretions. (See "Overview of neuraxial anesthesia", section on 'Patients with suspected or confirmed COVID-19' and "Overview of peripheral nerve blocks", section on 'Patients with suspected or confirmed COVID-19'.):

However, many COVID-19 patients are anticoagulated, which may affect the timing of or decision to use neuraxial anesthesia or deep peripheral nerve blocks. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication" and "COVID-19: Hypercoagulability".)

General anesthesia

Airway management — Procedures for airway management for patients with COVID-19 are discussed here. Infection control during airway management is discussed below. (See 'Infection control for anesthesia' below.)

Airway management for children with COVID-19 is discussed separately. (See "Airway management for pediatric anesthesia", section on 'Airway management for patients with COVID-19'.)

Rapid sequence induction and intubation — Many guidelines developed during the COVID-19 pandemic recommended routinely performing rapid sequence induction and intubation (RSII) for patients with COVID-19, primarily to avoid the aerosol generation that may be associated with mask ventilation. However, such guidelines were based primarily on expert opinion with little direct data. Subsequent studies have suggested that uncomplicated mask ventilation may not be associated with high levels of aerosol generation, as discussed below. (See 'Risk to clinicians during airway management' below.)

The decision to perform a RSII should be based on patient factors. In patients without risk factors for difficulty with airway management, RSII may be a reasonable approach in order to quickly secure the airway and minimize clinician exposure to airway secretions. (See "Rapid sequence induction and intubation (RSII) for anesthesia".)

For critically ill patients, if necessary, administer intravenous fluid and/or vasopressors in anticipation of induction of anesthesia, and consider using ketamine, etomidate, or a combination of ketamine and propofol for induction of anesthesia, rather than propofol alone. Anticipate that critically ill patients with COVID-19 may become even more hypoxemic and hypotensive after induction and during intubation. In a review of 202 critically ill COVID-19 patients who were intubated emergently, hypoxemia occurred in 74 percent of patients, hypotension occurred in 18 percent, and four patients had cardiac arrest [37]. However, most patients had hypoxemia, hypotension, and tachycardia prior to induction of anesthesia. Almost all of these patients were induced with propofol using a modified rapid sequence induction, and were intubated with a video laryngoscope.

If a modified rapid sequence induction with mask ventilation is necessary, use low pressure and small volume breaths, maintaining a tight mask seal.

Endotracheal intubation — Endotracheal intubation should be used to manage the airway during general anesthesia for patients with COVID-19, rather than a supraglottic airway, to most effectively seal the airway and prevent viral spread. However, endotracheal intubation and extubation may increase the risk of transmission of infection because of proximity to or contact with airway secretions, particularly if the patient coughs. Thus, high-level personal protective equipment (PPE) is necessary during intubation. (See 'PPE during airway management or aerosol generating procedures' below.)

Goals for airway management are to secure the airway rapidly, on the first attempt, and to reduce or eliminate aerosolization of respiratory secretions. Important considerations during airway management, based on expert opinion and what is known about viral transmission, include the following [6,13,14,38-42]:

Create a plan for airway management, with backup contingencies. Many guidelines suggest creating a COVID-19 intubation checklist, and performing COVID-19 intubation simulations. (See "Safety in the operating room", section on 'General approaches to risk reduction'.)

Initial recommendations were to intubate patients when possible in an airborne isolation room, or a negative pressure anteroom outside the operating room (OR); most ORs use positive pressure air flow [43]. However, those recommendations were predominantly expert opinion based on very limited data. Newer simulation studies suggest that the institution’s ventilation parameters (eg, air exchange rate) and other factors may affect aerosol distribution both within and outside the room, whether or not the room uses negative or positive pressure ventilation [44].

Use double gloves during intubation; remove the outer gloves immediately after laryngoscopy.

Use disposable airway equipment whenever possible.

Initial recommendations were to limit personnel during intubation to the intubator and one assistant. Some institutions no longer do this, and instead rely on the protection provided by N95 masks worn by all persons present in the operating room.

Optimize patient positioning and preoxygenation for intubation. (See "Preoxygenation and apneic oxygenation for airway management for anesthesia" and "Direct laryngoscopy and endotracheal intubation in adults", section on 'Positioning the patient'.).

For patients without risk factors for difficult airway management, rapid sequence induction and intubation is a reasonable choice to rapidly secure the airway and minimize exposure to airway secretions (see 'Airway management' above and "Rapid sequence induction and intubation (RSII) for anesthesia"). If face mask ventilation is used, perform low volume, low pressure breaths. Use cricoid pressure only for aspiration concerns.

Use whatever type of laryngoscope the clinician finds most comfortable and is likely to achieve intubation most rapidly. Videolaryngoscopy is typically preferred since this may increase the likelihood of first pass success in patients with a difficult airway [45], and also allows the clinician to remain farther from the patient's oropharynx during intubation [46].

Once the endotracheal tube is placed in the trachea at the proper depth, inflate the cuff before connecting the breathing circuit. After giving a breath, make sure there is no leak around the cuff.

For confirmation of proper endotracheal tube placement, use end-tidal carbon dioxide (EtCO2) and pay particular attention to proper tube depth during videolaryngoscopy. Avoid auscultation with a conventional stethoscope, since this requires bringing the clinician’s face closer than necessary to the patient's face. Auscultation provides little additional information if videolaryngoscopy was used, and for patients in the intensive care unit, a chest radiograph will be used to confirm proper depth.

For any circuit disconnects (eg, transport, expiratory limb filter change), leave the viral filter on the endotracheal tube at all times if possible. As an alternative if a viral filter is not in place at the airway, for patients who are not breathing spontaneously, pause the ventilator and clamp the endotracheal tube before a disconnect.

Use a closed suction system as necessary for tracheal suction, or for oral suction prior to extubation.

Handle used airway equipment per institution protocols for disposal or removal for decontamination.

After intubation, wipe down all equipment and surfaces with disinfectant wipes [47].

Extubation — Extubation is as high risk for contact with and aerosolization of respiratory secretions as intubation, particularly if the patient coughs; similar infection prevention precautions should be followed. (See 'PPE during airway management or aerosol generating procedures' below.)

Some institutional protocols require that non-anesthesia personnel should leave the room during extubation, and should allow a number of air exchanges before reentry into a positive pressure room.

Some experts suggest prophylaxis for coughing before extubation [5]. Options include IV, topical, or intracuff lidocaine, low dose opioids, and dexmedetomidine. (See "Extubation following anesthesia", section on 'Minimizing physiologic response to extubation'.)

After extubation, place a surgical mask in the usual position over the patient's face. Apply a plastic mask for supplemental oxygen over the surgical mask, or nasal prongs under the surgical mask.

Management of the difficult airway — The basic principles for management of the difficult airway apply to patients with COVID-19, including the decision to intubate awake. (See "Management of the difficult airway for general anesthesia in adults".)

Early in the pandemic guidelines recommended avoiding flexible scope intubation whenever possible due to high risk of cough. However, these recommendations predated what is now known about efficacy of PPE for reducing risks for clinicians. If awake intubation is used, efforts should be made to avoid cough, with optimal airway topicalization. (See "Flexible scope intubation for anesthesia", section on 'Airway anesthesia'.)

OFF-SITE ENDOTRACHEAL INTUBATION — Considerations for emergency endotracheal intubation in locations outside the operating room (OR) are similar to those noted above, as summarized in the table (table 3) (see 'Airway management' above). Additional considerations include prepackaging, advance preparation of necessary equipment, and use of a COVID-19 modified intubation checklist (figure 1).

Importantly, PPE should be donned using proper technique and supervision, even in the most urgent clinical circumstances. Even small lapses in proper use of PPE increase the risk of transmission of infection to clinicians, particularly during emergency intubation and advanced cardiac life support (ACLS) scenarios [6].

Considerations for performing cardiopulmonary resuscitation in patients with COVID-19 are discussed separately. (See "Advanced cardiac life support (ACLS) in adults", section on 'Resuscitation of patients with COVID-19'.)

INFECTION CONTROL FOR ANESTHESIA — Goals for infection control during anesthesia include prevention of transmission of infection to care providers, and prevention of contamination of the anesthesia machine and other anesthesia equipment. Infection control measures should be the same for patients with suspected or confirmed COVID-19.

The primary means of virus transmission is thought to be via aerosols generated when an infected person coughs, sneezes, or talks, and the secretions are inhaled by another person, or when those secretions make direct contact with mucosal membranes of another person. (See "COVID-19: Epidemiology, virology, and prevention", section on 'Route of person-to-person transmission'.)  

Multiple United States and international organizations have published recommendations for infection control and the use of personal protective equipment (PPE) during anesthesia for patients with COVID-19. Precautions have been recommended by the Anesthesia Patient Safety Foundation (APSF) [48,49] and the American Society of Anesthesiologists (ASA) [50], which are based on guidance from the Centers for Disease Control and Prevention (CDC) and previous experience with other infectious agents (eg, severe acute respiratory syndrome [SARS-CoV] or Middle Eastern respiratory syndrome [MERS-CoV] viruses) [1-7,9,10,13-15,38,39,51-55]. They include meticulous hand hygiene, and the use of PPE including a gown, gloves, respirator, and eye or face protection, depending partly on the risk of aerosolization of the virus (ie, during aerosol-generating procedures). A variety of institutional protocols for operating room management have been developed and reported in response to COVID-19 concerns [56]. (See 'PPE during airway management or aerosol generating procedures' below.)

Risk to clinicians during airway management — Airway management procedures may be high risk for transmission of COVID-19 due to proximity to or contact with airway secretions, particularly if the patient coughs. Extubation may be at least as high risk as intubation and efforts to avoid or minimize coughing at the time of extubation are warranted [57]. (See 'Airway management' above.)

Most guidelines have categorized all aspects of airway management as aerosol-generating procedures, though this was based primarily on indirect and low quality evidence. Whether intubation, extubation, mask ventilation, and use of supraglottic airways generate high levels of aerosols has been questioned [57-60]. Notably, the National Health Service in the United Kingdom has removed mask ventilation, intubation, and extubation from its list of aerosol-generating procedures [61]. In addition, the magnitude of risk of infection with SARS-CoV-2 when clinicians use appropriate precautions during airway management may be similar to other clinical patient encounters. Appropriate PPE during anesthesia is discussed below. (See 'PPE during airway management or aerosol generating procedures' below.)

Whether the use of noninvasive ventilation (NIV), high flow nasal oxygen (HFNO), and continuous positive airway pressure (CPAP) generate high levels of aerosols has also been questioned. In a small volunteer study, high levels of aerosol generation were associated with high amplitude, frequent respiratory activity (eg, cough, shouting, breathing during exercise) [62]. In contrast with these higher amplitude events, NIV, HFNO, and CPAP during quiet breathing generated aerosols at levels similar to quiet breathing.

Examples of relevant studies include the following:

Risk of infection

In an international self-reported registry study (Intubate COVID) that included 1718 clinicians who performed one or more intubations in patients with COVID-19, approximately 3 percent reported laboratory confirmed COVID-19 and another 8.4 percent developed symptoms of COVID-19, in a median of 32 days after the first intubation [63]. Twelve percent of clinicians used PPE that was not compliant with World Health Organization recommendations for aerosol generating procedures, and the types of PPE used varied. Conclusions from this study are limited by the self-reported study design, lack of standardized PPE, and the lack of data on possible exposures to COVID-19 other than the intubation.

In another study of health care workers in Wuhan, China, there was no evidence of SARS-CoV-2 transmission in a group of 420 doctors and nurses who wore protective suits, masks, gloves, goggles, face shields, and gowns, all of whom had direct contact with COVID-19 patients and performed at least one aerosol-generating procedure [64].

In a review of studies of COVID-19 infection among health care workers and the general population in the United Kingdom, anesthesia clinicians and intensive care unit staff had lower rates of infection and hospitalization than health care workers in other settings [65].

Aerosol generation – Small clinical studies of patients undergoing general anesthesia have used different technologies to measure aerosol and droplet generation during airway management [57,66]. Studies performed using ultraclean laminar flow operating rooms to minimize contamination from non-airway related sources have found that mask ventilation (with and without an intentional mask leak) [59], intubation and extubation [57], and supraglottic airway insertion and removal [60] generate respiratory aerosols at a level similar to tidal breathing, and substantially less than aerosol generation from a volitional cough. In contrast, two small studies conducted in standard operating rooms found increases in small particles during mask ventilation and intubation [66,67]. Differing results could reflect differences in sampling and detection methodologies and operating room ventilation. Examples of these studies are as follows:

Three studies performed by the same group measured aerosolized particles during airway management in an ultraclean laminar flow operating room using a laser-based Optical Particle Sizer [57,59,60], as follows:

-In a study of 19 patients who were intubated for elective surgery, the concentration of aerosol during intubation (non-rapid sequence, including mask ventilation) was similar to the background particle concentration in the operating room, and several orders of magnitude lower than the concentration resulting from a volitional cough [57]. The total number of particles generated over five minutes during extubation was similar to the number resulting from a single volitional cough.

-In another study of 12 patients who had supraglottic airways placed for general anesthesia, insertion and removal of the supraglottic airway produced concentrations of aerosol particles similar to tidal breathing, and <4 percent of the particle concentration generated by a volitional cough [60].

-In a study of 11 anesthetized patients, the aerosol concentration during mask ventilation with or without an intentional mask leak was 64-fold and 17-fold less, respectively, than the concentration during tidal breathing without a face mask [59].

In a study of three patients who underwent intubation for surgery in a standard positive pressure operating room, aerosols were detected using laser-based particle image velocimetry to detect larger particles and spectrometry with continuous air sampling to detect smaller particles [66]. Mean particle counts during intubation and during extubation were each 12 times greater than baseline. Among the components of intubation and extubation, the highest peak increases in particle counts occurred with bag mask ventilation prior to intubation (200 to 300 times baseline) and during cough after extubation (15 to 125 times baseline).

In another study of 39 patients who underwent general anesthesia in a laminar flow standard operating room, preoxygenation, mask ventilation, uncomplicated tracheal intubation, and extubation all generated aerosols at a level similar to coughing [67].

Other aerosol-generating procedures that may transmit COVID-19 and may involve anesthesia care include jet ventilation with an open airway, bronchoscopy and interventional pulmonology procedures, tracheostomy, open suctioning of airways, upper endoscopy, and transesophageal echocardiography (TEE) [68-70]. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Aerosol-generating procedures/treatments'.)

Considerations for the use of TEE in patients with COVID-19 are discussed separately. (See "Transesophageal echocardiography: Indications, complications, and normal views", section on 'COVID-19 precautions' and "Overview of perioperative uses of ultrasound", section on 'Ultrasound use during the COVID-19 pandemic'.)

The risks of aerosolization and preventive measures during laparoscopic surgery and electrocautery are discussed separately. (See "Complications of laparoscopic surgery", section on 'Related to pneumoperitoneum' and "Overview of electrosurgery", section on 'Smoke plume and filtering'.)

Hand hygiene — Clinicians should perform meticulous hand hygiene (washing with soap and water or using alcohol based gel) before donning (putting on) PPE, after removing gloves, after every contact with the patient, and before touching anesthesia equipment.

PPE during airway management or aerosol generating procedures — For patients with suspected or confirmed COVID-19 who undergo airway management or aerosol-generating procedures, appropriate PPE for health care workers includes a gown, gloves, respirator, and eye or face protection. Aerosol generation during airway management is discussed above. (See 'Risk to clinicians during airway management' above.)

Some experts have recommended the use of full PPE (ie, including N95 or higher respirator, or powered air purifying respirator [PAPR]) for all patients who require airway management, since patients may be asymptomatic or minimally symptomatic, and COVID-19 may not be suspected [71-73]. Others have recommended airborne precautions for all patients who undergo surgery, since electrocautery and both open and laparoscopic surgery can generate aerosols of body fluids [74]. However, the risk of transmission from procedures that do not directly involve the respiratory tract has not been documented.

Of note, unnecessary use of high level PPE should be avoided (ie, outside of airway management or other aerosol-generating procedures), as its use may affect the clinician's ability to provide clinical care by impeding communication and breathing, impairing vision, degrading manual dexterity, and/or overheating the clinician, particularly when using a PAPR [75,76].

Appropriate PPE for health care workers during airway management or aerosol generating procedures includes the following:

Respirator – N95 (picture 1) or other respirator (eg, a powered air-purifying respirator [PAPR]) that offers a higher level of protection if properly fit-tested. (See "COVID-19: General approach to infection prevention in the health care setting", section on 'High-risk procedures (eg, aerosol-generating procedures)'.)

PAPRs provide high-level respiratory protection, do not require fit testing and can be repeatedly disinfected and reused [77]. Elastomeric respirators are reusable devices that can be used with high efficiency filters to provide a level of protection similar to PAPRs [78]. Elastomeric respirators avoid the limitations of vision that occur with the use of full head PAPRs and are quieter. However, they require strict cleaning protocols, may make verbal communication more difficult, and make the use of stethoscope more difficult.

Options for extended use, reuse, and decontamination of N95 respirators when they are in short supply are discussed separately. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'When PPE is limited'.)

Eye protection – Goggles, face shield that covers the front and sides of the face, or full face PAPR.

Some experts prefer the use of a full face shield rather than goggles or a surgical mask with an attached eye shield, whenever possible. A full face shield provides eye protection and a double layer of protection for the nose and mouth. It also prevents contamination of the respirator or mask. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Type of PPE'.)

Some experts recommend the use of both goggles (for airborne protection) and face shields (for droplet protection of the eyes and face), or hooded PAPR [6,79,80], while others, including the CDC and WHO, recommend either goggles or a face shield.

Standard eye glasses do not provide sufficient protection against droplets, and should be worn with a face shield, goggles, or PAPR.

Other PPE - Gloves, fluid resistant gown, disposable caps and beard covers.  

Protective barriers – A wide variety of prototype protective barrier devices (boxes or drapes) were created early in the COVID-19 pandemic, before the truly low risks of clinician infection in the operating room setting with precautions in place were appreciated. Such devices were designed to protect the anesthesiologist from droplet or aerosol contamination during intubation and extubation [81-86]. Clinicians should always use full PPE during airway management, whether or not a protective barrier is used. Contributors to this topic do not use these devices.

In August of 2020 the US Food and Drug Administration issued an alert recommending against the use of passive protective barriers (ie, those that do not use fans, air filters, or other features and were not intended to generate negative pressure) for use when caring for patients with known or suspected COVID-19, citing concerns that they may actually increase exposure of health care providers and patients to aerosolized airborne particles and may make intubation more difficult [87-91].

PPE during low risk procedures — For care of patients with suspected or confirmed COVID-19 who do not undergo aerosol-generating procedures, the CDC and other organizations recommend that optimally, the same precautions (including N95 or higher respirator, or PAPR) that are described above should be used. In some circumstances a surgical mask may be an acceptable alternative. The details of these recommendations are discussed separately. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Type of PPE'.)

An N95 respirator or PAPR should be used by clinicians during low-risk procedures in any COVID-19 patient who is coughing (figure 2).

Donning and doffing PPE — Health care workers should follow institutional protocols and pay special attention to the appropriate sequence of putting on (donning) and taking off (doffing) PPE to avoid contamination (figure 3 and figure 4). (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Type of PPE'.)

PROTECTION OF ANESTHESIA EQUIPMENT — The internal components of the anesthesia machine must be protected from contamination by respiratory secretions from infected patients. Thus, the breathing circuit should contain two filters rated for high viral filtration efficiency (VFE) (figure 5). Heat and moisture exchange (HME) filters have been shown to effectively filter out the SARS-CoV-2 virus even with prolonged mechanical ventilation in the ICU [92]. Use of breathing circuit filters and other aspects of infection prevention related to anesthesia equipment are discussed separately. (See "Safety in the operating room", section on 'Contamination of the anesthesia machine' and "Safety in the operating room", section on 'Infection risks for patients'.)

Early in the pandemic it was thought that surface contamination was an important route of viral spread, since some data suggested that viral debris persisted on a variety of surfaces. Thus, there were recommendations to remove all unnecessary equipment from the operating room and to keep emergency equipment outside the door unless needed. However, contaminated surfaces are no longer thought to be a major route of transmission, and routine cleaning and disinfection is recommended by the Centers for Disease Control and Prevention (CDC). (See "COVID-19: General approach to infection prevention in the health care setting", section on 'Environmental cleaning and disinfection'.).

OPERATING ROOM DISINFECTION — After the patient has left the operating room (OR), the room should remain closed until there have been enough air exchanges to remove aerosolized pathogens, which may be determined on an institutional level. Disinfection procedures for rooms that have been used for patients with COVID-19 are discussed separately. (See "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Environmental disinfection'.)

INFECTION CONTROL DURING PATIENT TRANSPORT — Patients with COVID-19 should wear a surgical mask whenever they are transported within a medical facility. Patients should ideally be transported directly to a procedure or operating room (OR), bypassing the holding area or pre-induction area. Some institutions use a portable tent system with HEPA filtration during transport for patients with COVID-19 [93-95].

For transporting intubated patients, a high-quality heat and moisture exchanging filter (HMEF) should be inserted between the self-inflating (Ambu) bag and the patient at all times. During transport, clinicians who contact the patient should not touch environmental surfaces such as elevator buttons; this should be done by a security officer or another helper with clean hands.

Patients should recover from anesthesia in the OR or should be transported directly to an airborne infection isolation room for recovery, bypassing the post-anesthesia care unit (PACU).

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: COVID-19 – Index of guideline topics".)


Preoperative evaluation

Screening – Preoperative evaluation should include COVID-19 screening, risk based testing for patients who are not known to have COVID-19, and for all patients, risk assessment related to COVID-19. (See 'Preoperative screening and testing' above.)

Surgical risk and timing of surgery – The risks of perioperative morbidity and mortality may be increased in patients with COVID-19 and for seven to nine weeks after uncomplicated illness. Elective surgery should not be performed for patients who are symptomatic with COVID-19, who are suspected of having COVID-19, or who are likely to be still infective after having had COVID-19. Existing symptoms and the severity of the initial illness should be considered when assessing perioperative risk for patients who have had COVID-19. (See 'Risk of surgery with COVID-19' above and 'Risk related to timing after infection' above.)

Choice of anesthetic technique – The choice of anesthetic technique should be based on patient factors and the planned procedure. Regional anesthesia is not contraindicated by COVID-19, however, many COVID-19 patients are anticoagulated, which may affect the timing of or decision to use neuraxial anesthesia or deep peripheral nerve blocks. (See 'Choice of anesthetic technique' above.)

Airway management

Risk of viral transmission – Airway management and extubation may increase the risk of transmission of COVID-19 due to proximity to or contact with respiratory secretions, particularly if the patient coughs. Whether airway management procedures themselves generate levels of respiratory aerosols over and above tidal breathing and normal speech has been questioned. (See 'Risk to clinicians during airway management' above.)

Induction and intubation

-Rapid sequence induction and intubation (RSII) is a reasonable strategy for patients without predictors for difficulty with airway management. (See 'Rapid sequence induction and intubation' above.)

-Goals for tracheal intubation are to secure the airway rapidly, on the first attempt, and to reduce or eliminate aerosolization of respiratory secretions. Key considerations during intubation are described above. (See 'Endotracheal intubation' above.)

-The basic principles for management of the difficult airway apply to patients with COVID-19. (See 'Management of the difficult airway' above.)

-Considerations for endotracheal intubation in locations outside the operating room are summarized in a table (table 3). (See 'Off-site endotracheal intubation' above.)

Extubation – Goals should be to achieve a smooth extubation without coughing. The patient's mouth should be covered with a surgical mask after the endotracheal tube is removed and mask ventilation is no longer necessary. (See 'Extubation' above.)

Infection control

Personal protective equipment (PPE) – For patients with confirmed or suspected COVID-19 who undergo airway management or aerosol-generating procedures, clinicians involved in their care should use PPE appropriate for contact, aerosol, and airborne precautions, including the following (figure 2) (see 'PPE during airway management or aerosol generating procedures' above):

-N95 (picture 1) or other respirator (eg, a powered air-purifying respirator [PAPR]) that offers a higher level of protection

-Eye protection (goggles, face shield that covers the front and sides of the face, or full face PAPR)

-Gloves (double gloves for intubation)

-Water resistant gown

-Disposable hair cover cap and beard cover

For patients who undergo non-aerosol-generating procedures, the same level of protection should be used as for aerosol-generating procedures. (See 'PPE during low risk procedures' above and "COVID-19: Infection prevention for persons with SARS-CoV-2 infection", section on 'Type of PPE'.)

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